Sociology Study ISSN 2159‐5526, April 2014, Volume 4, Number 4, 360‐383 D doi: 10.17265/2159‐5526/2014.04. 007 DAVID PUBLISHING

Proposal for a Reasonable Model of the : Principles of Clinical Neurosociology

Carlos De La Puentea

Abstract This paper maintains that when photons enter the and reach the (ILM), they are reflected onto a point or centroid of the , which could be the , to be transmitted by the Müller cells to the Retinal Pigment Epithelium (RPE) hexagonal cells, where an almost complete image is formed in each of them, overlapping with the adjacent images, to be carried subsequently by each of the ganglion cell axons to a place where the single image we are aware of is formed. This process calls for a high degree of control and coordination, which must be effected by the horizontal, amacrine, and interplexiform cells, gap junctions and the feedback provided from the V1 area to the Lateral Geniculate Nucleus (LGN). But, as the ILM covers the but not the fovea, the latter must produce the blind spot and the rays reflected radially from the centroid must have the same centre as the Müller cells in order to be able to channel them to the RPE cells.

Keywords Visual system, principles of clinical neurosociology, image, photon

Sight is probably one of the most remarkable facts material as well as the immaterial and subjective facts, known. In Darwin’s words: “Can we believe that natural are perceived mainly through vision, study of this selection could produce, (...) an organ so wonderful as system and knowledge of it must be a key subject to the ?” (Darwin 1859). It may only be surpassed by help us understand how and where the phenomena awareness, both visual and cognitive, life itself and observed are reproduced. Although it seems that we consequently the independent action of living beings, have a good knowledge of how vision works at the based on the information stored in neurons. Studying molecular and cellular level, now we need to know the visual system has the advantage that: what it does and this is the most interesting question for these disciplines: “Now that we have all the The visual system is the most widely studied and perhaps players, the task is to find out what they do (…). It is the best understood mammalian sensory system. Not only clear that a that possesses 29 types of amacrine have the details of its anatomical features been well described, but the behavior of it neurons have also been cells has still more tricks up its sleeve” (Masland characterized at many stages of the neural pathway. For this reason, the visual system has also become the system of choice for the study of both sensory coding as well as for aUniversity Complutense Madrid, Spain such higher cognitive processes as memory and attention. (Pasternak, Bisley, and Calkins 2003: 139) Correspondent Author: Carlos De La Puente, Campus de Somosaguas, s/n. 28223, Pozuelo de Alarcón, Madrid, Spain As the facts of sociology and neurosociology, the E‐mail: [email protected]

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2001a: 434). structures, such as the cerebellum, play a supporting The definition of the visual system will be dealt role. with in the relevant section as it is an extensive topic The senses provide paths for signals to enter and and here it will be defined the part that can be reach the neurons and (the sense of) sight has been considered as the most important, the eye, the external chosen because it may be considered that generally part through which signals enter. The minimum speaking, and in the social sciences in particular, it is definition one can give for an eye is: “The minimum the path through which most information is perceived. setting for an eye involves a photoreceptor in the As this paper uses the approach of “what it does” but vicinity of shading pigment, which allows the not “how it does it”, the text adopts a functional and detection of the direction of light. A simple eye structural perspective. consists of one photoreceptor and one pigment cell” The sense of sight will be treated as a Vision (Arendt and Wittbrodt 2001: 1545). However, the System (VS) to consider all the elements involved in definition also includes what the eye is for. Below, the forming external images and determining their author will show that the type and number of cells meaning. The VS is a combination of interconnected forming the most complex existing today is tissues and neurons of different types. The elements increasing and the relationship between them is and organs involved in vision are: the eye, the optic becoming more sophisticated. nerve, the optic chiasma, the optic tracts, the lateral In “Fundamentos de Neurosociología” (De La and lower pulvinar, the lateral geniculate nucleus, the Puente 2011), in the thesis “Jerárquica Anidada superior colliculus (SC), the medial geniculate nucleus, Duplicante” and through the “Replicante” hypothesis, visual radiation, and the areas of vision of the cortex, a reasonable model is presented of the working of the in the occipital area (Gray’s Anatomy Plate 2012). nervous system and the defense of both leads to the Reference will also be made to the claustrum. conclusion that information exists and is generated, Each of these in turn has its own tissues and stored, and processed in the genome of the nucleus of neurons and all the parts may be the subject of general each and every neuron, the base pair being the or specialized studies [Examples of general studies: minimum physical unit of storage. This information is (Ramón y Cajal 1904a; Ramón y Cajal 1904b; Guyton generated by the signals that arrive and, at the same 1997; Bear, Connors, and Paradiso 1998; Kandel, location, the information generates the signals that Schwartz, and Jessel 2001; Purves et al. 2004: 261)] produce behavior. Consequently, the information and [Examples of specialized studies: (Ryan and resides only in the genome, and what circulates are the Hinton 2006; Sarthy and Ripps 2001; Reichenbach signals. and Bringmann 2010; Land and Nilsson 2002; White This is how the need for this paper arose. It was and Munoz 2011)]. necessary to examine the paths through which signals From the functional point of view, the VS reach the genome of the neurons to generate represents external reality in a form described by Land information and where they concentrate to reach each and Nilsson (2002: 4) as “spatial vision”. In this of the target neurons, which in this case are those in scheme, reality is represented by the conversion of the cortex and some other structures where photons into electrical stimuli by phototransduction; information can be generated. It should be noted that we appreciate that this external reality is “outside” the in the diencephalon, associated with the emotions, and place where it is perceived and we become aware of it. the mesencephalon, associated with the instincts, no According to generally accepted principles, the more information could be generated, while other images from the exterior we perceive are projected

362 Sociology Study 4(4) onto the retina as if this was a screen and they are gap junctions, would be the level at which signals are inverted (Purves et al. 2004: 264; Ratznium at controlled or coordinated. The “megaconcentration” en.wikipedia 2007). One thus assumes that the would be effected by the cones, the cone bipolars, and external image is represented on the retina as a jigsaw the ganglion cells. puzzle. The position specified in Axiom 2 (De La Puente But, in line with the foregoing explanation (De La 2011: 77) would then be that in the VS the Puente 2011), for the theory to be confirmed, there megaconcentrators or megahubs are the cone, bipolar must be a point at which all the signals are cone, and ganglion cells of the retina. concentrated, so that they can be received by each and The thesis puts forward in this paper is thus every neuron in the cortex. This calls for a supported by a general universal principle of cell “mega-concentrator” that can subsequently transmit uniqueness, which would in turn be founded on cell the signals to all the neurons, a process that would theory and the neuron doctrine, according to which also require different mechanisms to synchronize the cells cooperate but do not share, although they can transmissions and to order them. exchange information by “Horizontal Gene Transfer” The proposal of this paper is that external signals (HGT). perceived are reproduced in each and every one of the The terms cooperate, share, and exchange need to hexagonal cells in the Retinal Pigment Epithelium be differentiated. “Cooperate” is used in the sense that (RPE), although not in a regular or perfect way, cells work with other cells to carry out a task. “Share” reaching them via the Müller cells (Franze et al. 2007). means to divide or distribute something among cells. The photoreceptor cells collect the signals from the “Exchange” is used in the sense of transferring RPE and via the intermediate bipolar cells carry them something between cells. to the retina’s ganglion cells and each of the axons of The position of the thesis is that, each of these ganglion cells, which make up the , carries the signals of the complete image to RPE cells form a representational network by means of overlapping repetition of external reality, as each cell each of the neurons in the corresponding part of the represents this reality, which is then carried through the cone cortex, and from there they are distributed to the rest circuit centre and transmitted to its destination by the of the cortex (Gray’s Anatomy Plate 2012). The ganglion axons. Representation of what is external is linked horizontal cells act as inhibitors between the to learning and maturity during the first years of life following the individual’s birth, as the fovea can become photoreceptor and the bipolar cells. The amacrines are mature 45 months after birth in the case of humans. inhibitors between the bipolars and the ganglion cells (Hendrickson and Yuodelis 1984; Yuodelis and Hendrickson and the interplexiforms act between the horizontal and 1986) the amacrine cells. In this scheme, the photoreceptor cells receive and The problem with this thesis is that, if each of the transform the signals-photons; the bipolar cells, some RPE cells receives signals about external reality, of which are the first level of concentration, transmit signals that are repeated and overlapped, the blind them to the ganglion cells; the horizontal cells would spot on the optic disc could not exist, because the be the first level of coordination between the signals; image would be completed by neighboring cells. the amacrines would be the second level of For a blind spot to appear in the complete image, coordination, and the interplexiforms would be all the RPE cells would need to register the presence another level of coordination between the horizontals of the blind spot. This could only happen if the image and the amacrines. These three types of cell, plus the received is reflected from another point that transmits

De La Puente 363 the lack of information to all the RPE cells. This is blind spots. As a result of this process, the vitreous only possible if the photons received from the exterior humor is required to perform another function: the via the pupil are reflected at a point inside the eyeball. holographic representation of external reality. However, the proposed model can be extended as The thesis can be illustrated by a -shaped follows: The Inner Limiting Membrane (ILM) room lined with mirrors set at slightly different angles. receives signals from the exterior and reflects them in If one stands in the middle of a room of this type with a centroid in the vitreous humor of the eyeball in a a million mirrors, they do not reflect the reality of the way that is similar to a hologram. This membrane room split among all the mirrors like a jigsaw puzzle. covers the optic disc so the latter cannot be the blind Each one reflects the full reality of the room, and there spot; the reflection would fail in the fold of the fovea will be as many realities as there are mirrors. This and this would become the blind spot and the final example should apply to the VS of beings with image projected would not be inverted (Pedler 1961). single-chamber inversion eyes, as is the case of As proposed, the channeling of signals received primates and higher vertebrates or large mammals, via the Müller cells, as these are radial, is also a and to those with non-inversion compound eyes, such problem, because the photons entering through the as the arthropods (insects, arachnids, myriapods, pupil do not reach the retina with the same radius. crustaceans, etc.). The , the “inverted They could be captured from a centroid in the eyeball, globe” model, would not then be a simple eye but a from the vitreous humor, at the point to which the compound eye, like that of insects, and all eyes should radial Müller cells run. work in the same way. This process could also explain how the specks The thesis could be applied to all types of eye suspended in the vitreous humor are sometimes seen known at present and an empirical example from the as flies moving outside between the images and the world of insects can be seen in the words of Michel F. eye and how the RPE cells’ multiple overlapping Land and Dan-Eric Nilson (2002), “The following reproductions tend to automatically correct these quotation comes from Wehner and is from a letter anomalies. from Leeuwenhoek to the Royal Society of London, Another possible explanation involves the which was published in 1695. Evidently, each facet of functioning of the photoreceptor cells. In the fovea, the eye (at least in apposition eyes) does produce an there are only cones. Because of their thresholds for inverted image” (Land and Nilson 2002: 128). perceiving and processing photons they are photopic: They can process images in bright daylight but they Last summer I looked at an insect’s through my microscope. The cornea was mounted at some larger cannot deal with night lighting conditions. The rods distance from the objective as it was usually done when are scotopic: They are adapted to low levels of observing small objects. Then I moved the burning flame of lighting and are saturated if they are exposed to high a candle up and down at such a distance from the cornea that levels. the candle shed its light through it. What I observed by looking into the microscope were the inverted images of the So, if the cones see in daylight and the rods at burning flame: not one image, but some hundred images. As night, how is it that in the fovea area there is not a small as, I could see them all moving. blind spot in the image we see when we are in dark areas or it is night time? It must be because the image It should be noted that the inverted image may be is reflected in the vitreous humor by the ILM and, because of the optics of the microscope, not because according to the thesis, the RPE cells represent of the cornea of the eye. If the eye inverted the image, repeated overlapping images, thus eliminating the inversion by the microscope would show it upright.

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Consequently, as explained previously, the layers; neurons; dendrites and the axons of the retina. defense of the thesis will be based on a consideration However, it is difficult to accept that this is the of what can be considered as the most fundamental solution developed by nature for the nervous system; and complex element of the VS, the eye. (2) The photoreceptor neurons receive the light This study aims to make readers aware that what signals (photons) from the RPE neurons (inverted enters through the and is processed by the eyes), i.e., from the side opposite to their point of vision system are photons, i.e., energy. These are entry, and convert them into electro-chemical stimuli signals and, as such, do not carry information. If this (photo-transduction). The puzzle image described is the case, the information is only generated and is in above would be distributed in pieces among all the the genome of the nucleus of the neurons, as has been photo-receptors. This will be seen in greater detail in proposed and defended in another paper (De La the description of the retina; Puente 2011). Pasternak distinguishes between (3) The signals are channeled through the axons of perceptual attribute and the physical stimulus that the ganglion neurons, the last in the retina process, elicits it (2003: 147). until they reach the optic disc and are all combined, like the strands making up a cable (the optic nerve), which goes to the optic chiasma. Each ganglion axon VS would carry a part of the puzzle; The VS can be considered to consist of various (4) The optic chiasma apparently only acts as a structures (Gray’s Anatomy Plate 2012) responsible relay station, as the number of axons entering is the for receiving and transmitting signals to what is same as the number leaving, although they are thought to be their destination, the primary visual regrouped. The axons on the right (temporal) side of cortex, striate cortex, or V1 in the occipital cortex. the right eye and the left (temporal) side of the left eye Each of these elements would justify a study in itself are ipsilateral and pass through the on the but for the purposes of this paper, we will examine the same side. The axons on the left (nasal) side of the eye, as it is the point of entry and the origin of the right eye and the right (nasal) side of the left eye are whole process via which external images are formed; contralateral and pass through the optic tract on the it is the most external and there is abundant detailed opposite side to the one on which they enter; field information. (5) The optic tract goes to the lateral geniculate However, for an overall view it would be nucleus, the pulvinar area, and the SC on the advisable to review the VS scheme of mammals corresponding side; (Gray’s Anatomy Plate 2012). (6) Optical radiation goes from the lateral The formation of internal reality through the geniculate nucleus mainly and the pulvinar area to the reception of external signals (photons) to the formation striate (V1) in the occipital area, from of the image and awareness according to the current which it is distributed to the extrastriate cortex. paradigm is Process 1 (Gray’s Anatomy Plate 2012): Ratznium (2007) shows the organization of the (1) The photons enter via the pupil and reach the representation of the visual field and how the back of the retina, the RPE layer’s hexagonal neuron quadrants are distributed via the inversion of images. cells, where an inverted image is formed in the form The external image is represented in the retina with a of a jigsaw puzzle, distributed over all the RPE cells. rotation of 180º around the horizontal axis and another This view supposes that photons have to pass through rotation around the vertical axis. Process 1 continues all the limiting membranes; plexiform and nuclear from the retina.

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THE RETINA These characteristics of the ILM mean that it can behave as a mirror that allows light to be reflected in But, as we are going to see in the description of the the centroid of the vitreous body to form the retina, the process supports the thesis proposed. The holographic image which will then be captured by the retina is the part of the eye in which the process of Müller cells. This feature is fundamental to the thesis capturing, transforming, and concentrating signals of this study. The vitreous nature of the ILM can be from external images takes place. It is situated seen in some YouTube documentaries, such as the one between the vitreous body and the membrane, made by Buenestado and López (2012). which prevents rays of light that enter the eye from The layers are of two main types, the nuclear, leaving. It is in the form of a sphere bounded by the which contains the soma or bodies of the neurons, and which links it to the (Perkins the plexiform, which contains the dendrite 2013). connections and the axons. The neurons in the retina The retina is divided into layers delimited by have no synapse in the soma. The layers from the membranes and the neurons are distributed in these innermost (proximal) to the outermost (distal) are layers. shown in Figure 2. The layers of the retina are distributed between the Nine different types of neuron have been innermost membrane, the ILM, which supports the observed in the retina, with 55 sub-types (Masland endfoot of the Müller cells, and Bruch’s Membrane 2001b; Masland 2001a). For the purposes of this (BM) which is the outermost. The other two study, the researcher summarizes these in a list of 26, membranes are Verhoeff’s Membrane (VM) and the which is indicative but not exhaustive. A summary of Outer Limiting Membrane (OLM), which link to the the features of each neuron is shown in Table 1. microvilli of the Müller cells. Figure 1 shows each type of neuron symbolically and The ILM has been described as follows: Figure 2 shows the position occupied by each cell in

It may be concluded therefore, that the inner limiting the retina. membrane is a separate and specific extracellular structure Light enters from the opposite side of the RPE and containing both hyaluronic acid and reticulin and that it is the signals go in the opposite direction exiting toward separate from the radial fibers (The Müller cells) and not the Lateral Geniculate Nucleus (LGN) and the striate formed by lateral extension of their vitrad ends although these are firmly attached to it. (Pedler 1961: 435; Heegaard, cortex, via the ganglion cell axons. Jensen, and Prause 1986) To study the number and density of cells in the retina, it can be dissected and divided in circular areas. “Hyaluronic acid is derived from hyalos (Greek Starting from the fovea, which is taken as the centre, it for vitreous) and uronic acid because it was first is divided into rings so that 290 μm is equivalent to 1º isolated from the vitreous humor and possesses a high of visual angle. Its density can then be measured in uronic acid content” (Wikipedia 2013a). cells/mm2 or cells/deg2. Four quadrants are taken into Moreover, the ILM “(…) shows the mosaic pattern account. The “nasal” quadrant is nearest to the nose, to be evenly continuous over the entire internal surface, the “temporal” quadrant is nearest to the temporal lobe, including the inner aspect of the nerve fiber bundles the “ventral” quadrant is in the lower part, and the (ganglionar axons), the vascular tree, and the optic disc, “dorsal” quadrant is at the top (Panda-Jonas, Jonas, with the exception of the central pit (fovea) in the and Jakobczyk-Zmija 1996; Harman et al. 1997; human” (Pedler 1961: 432). Pasternak et al. 2003).

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Table 1. Retinal Neurons Neuron Sub‐types Description Hexagonal neurons. A single layer of pigmented cells which absorb light energy RPE focused on the retina by the lens, among other functions Rod Rod photoreceptor. Transduces absorbed light into electrical activity Short wavelength Cone Middle wavelength Photoreceptor cones Transduce absorbed light into electrical activity Long wavelength HI They receive stimuli from a great number of photoreceptors and proportionally Horizontal HII inhibit the photoreceptors themselves and the dendritic trees of the bipolar cells Midget ON Transmission from rods to ganglion cells via their circuit. They end in the ON layer Rod Diffuse ON of the IPL Midget ON Bipolar Diffuse ON Transmission from cones to ganglion cells via their circuit. They end in the ON or Cone Midget OFF OFF layer of the IPL Diffuse OFF Narrow OFF Wide OFF Narrow ON They receive more localized stimuli from bipolar cells and facilitate inhibition in the axons of bipolar cells and the dendritic tree of the ganglion cells Amacrine Wide ON Narrow ON‐OFF Wide ON‐OFF Neuron which channels the signal from rods to ganglion cells: rod‐bipolar rod‐All‐ AII ganglion Interplexiform Inhibitor cells between the IPL and the OPL They codify the activity of the above neurons in a potential sequence carried along Ganglion the axon fibers of the optic nerve Muller “Are radial glial cells spanning the entire retinal thickness” Notes: “Gap junctions” are an element found in cone pedicles, in the rod spheres, soma of the horizontal cells, amacrine AII and cone bipolars. They probably serve to attenuate or average out electrical activity between neurons (Pasternak et al. 2003; Bloomfield and Völgyi 2004). Sources: The Elaboration Based on Rodieck (1988), Reichenbach and Robinson (1995), Masland (2001a), Pasternak et al. (2003), Strauss (2005), Franze et al. (2007: 8287), Panda‐Jonas et al. (1996), Reichenbach and Bringmann (2010), Sarthy and Ripps (2001), Kolb et al. (2011; 2000), and Hildebrand and Fielder (2011).

The area of the retina is approximately 520 mm2 see the specific letter, but the others are blurred. One and its thickness is between .3 and .4 mm (300-400 needs to look straight at something to see it clearly. μm). The fovea, which is 150 to 300 μm thick (Kolb et The impression that we are seeing all the letters is al. 2011), is an area measuring 1.5 mm (5.2º) and is because the eye moves quickly from one point to considered to be the centre of the retina. It is a another (Strasburger, Rentschler, and Jüttner 2011: 8). specialized area with a high degree of visual acuity For distribution of the density of photoreceptor cells (Pasternak et al. 2003: 139-140). in the retina, see Kolb et al. (2011). The concept of visual acuity can be appreciated by The retina “is an extension of the central nervous staring at one letter in the middle of other text. We can system, much like the olfactory bulb” (Pasternak et al.

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Figure 1. Retinal Cells Classification (Symbolic Representation). Sources: The Elaboration Based on Masland (2001a; 2001b) and Pasternak et al. (2003).

To optic nerve Figure 2. Retinal Cross Section. Situation of the Neurons in the Retina (Symbolic Representation). Sources: The Elaboration Based on Rodieck (1988: 207, 212, 226, 231), Reichenbach and Robinson (1995: 141), Masland (2001a: 432), and Pasternak et al. (2003). Notes: CC—Choriocapillaris; BM—Bruch’s Membrane; RPE—Retinal Pigment Epithelium; VM—Verhoeff's Membrane; OS—Outer Segments; IS—Inner Segments; OLM—Outer Limiting Membrane; ONL—; OPL—; INL—; IPL— (OFF, ON); GCL—; OFL—Optic Fiber Layer; ILM—Inner Limiting Membrane.

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2003: 140). “The neural plate is derived from more striking than in the retina, where some classes of ectoderm and represents the embryonic precursor of neurons are positioned with almost crystalline the nervous system, including the retina (…) different regularity” (Rockhill, Euler, and Masland 2000: 2303). areas of ectoderm are committed to form specific parts “Every neuron studied was found to be nonrandomly of the CNS (Central Nervous System), including of positioned: Cells of a particular type were evenly the neural elements of the eye” (Sharma and Johnson spaced. However, all cells were positioned randomly 2007: 20). “The retinal anlage (installation) (…) first with respect to members of the other cell classes” appears as the optic vesicle, an epithelial vesicle (Rockhill et al. 2000: 2303). evaginating laterally from the diencephalon. Subsequently, its distal (the most distant) portion Cells within a particular mosaic cover the retina so that signals from each location in the photoreceptor mosaic are invaginates to form a two-walled cup-like structure, represented at least once within that mosaic. This implies that the , which develops into the outer as the density of a particular cell type decreases with increasing (pigmented) and inner (neurosensory) layers of the eccentricity, the area covered by that cell’s processes (the retina” (Eiraku et al. 2011: 51). “As the primary brain so-called “collecting aperture”) becomes larger to accommodate the greater spacing between photoreceptors. vesicles subdivide, the optic stalk becomes visible at (Pasternak et al. 2003: 141) the junction of the telencephalon and the diencephalon” (Sharma and Johnson 2007: 20). The neurons in the retina are thus evenly distributed but the different types may form random A multitude of factors have been shown to play a role in clusters. guiding optic axons to their target nuclei within the brain (…) direct axonal growth radially toward the optic nerve head (…) “The mosaic of M and L cones in the primate contributes to fiber entry into the optic stalk (…) influence retina is patchy, with cones of like type distributing the positioning of optic axons as they arrive at the base of the into small clusters” (Pasternak et al. 2003: 146). brain (…) contribute to the chronotopic reordering of optic axons as they enter the optic tract. (Reese 2011: 622-623) The general scheme for the functioning of the retina, considering the different types of cell To summarize, the eye develops from the separately and jointly, would be as follows. The ectoderm, separates from the CNS, remaining description omits genetic and molecular aspects, with attached only by the optic stalk, through which the some exceptions, as this study deals with “what it axons of the ganglion cells will pass to reach their does” and not “how it does it”. target, area V1, the striate cortex or primary visual General Description area. Afterwards, the optic stalk disappears. The end result is shown in Figure 3, retinotopical order The output of the photoreceptor mosaic is carried to the being maintained throughout the process (Reese ganglion cells via parallel and iterative circuits composed of 2011; Pasternak et al. 2003; Haar Romeny 2003: serial connections between a variety of both excitatory and inhibitory inter-neurons (…). The activity of a ganglion cell 179-195). at a particular moment in its physiological history is therefore

Morphologically, the retina follows the patterns of the confluence of all excitation and inhibition in its the nervous system “It is self-evident that the number pre-synaptic circuitry point. Excitation in and from the retina of neurons within a structure of the central nervous is conveyed primarily through the feed-forward circuit from photoreceptors to ganglion cells via a class of system is developmentally regulated and that their intermediate neurons called bipolar cells (…). Inhibition spacing must not be entirely random. This is nowhere within the retina, in contrast, is conveyed primarily through

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Figure 3. Visual Pathway From Retina to LGN (Lateral Geniculate Nucleus) to Primary Visual Cortex (Symbolic Representation). Sources: The Elaboration Based on Pasternak et al. (2003), Haar Romeny (2003: 179‐195), and Majumder (2010: 4).

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two levels of feedback circuits. In the outer retina, horizontal 430 nm (violet-blue zone). The M cones are sensitive cells collect excitation from a large number of photoreceptors to a wavelength of around 535 nm (green zone). The L (…) and provide inhibition proportionally back to the cones are sensitive to a wavelength of around 567 nm photoreceptors themselves and to the dendritic trees of bipolar cells (…). In the inner retina, amacrine cells collect more (orange zone). The M and L cones account for the localized excitation from bipolar cells and provide inhibition other 95%, probably in similar proportions (Pasternak back to the bipolar cell axon and to the dendritic trees of et al. 2003: 142). ganglion cells”. (Pasternak et al. 2003: 141) Each of the cones and rods is connected electrically to the neighboring cones and rods via gap “The interplexiform cell processes were found to junctions. be pre- and post-synaptic in the inner plexiform layer To summarize, each of the segments in the mosaic and presynaptic to horizontal and bipolar cells in the of the retina must contain at least one S cone and outer plexiform layer” (Boycott et al. 1975: 363, 365). several M and L cones, the latter probably in similar Photoreceptors numbers. All the cones and rods are connected via gap junctions. About 94% of the photoreceptors are rods, each sufficiently Details of the connections in the pedicles of the sensitive to signal the absorption of even a single photon at cones and the spheres of the rods can be found in the absolute threshold of vision. Rods dominate the photoreceptor population over most of the retina, with a Wässle (2004). peak density of 170,000 rods mm-2 at 15 deg eccentricity, which drops to 50,000-70,000 rods mm-2 at 45 deg. The Horizontal Cells fovea contains a small region, about 150 μm in diameter, The horizontal cells, that is rod-free, completely avascular and devoid of all post-photoreceptor elements of the retina, which are displaced laterally to form the foveal wall. This region Which are thought to collect excitation from the synapse contains the highest density of cone photoreceptors, which and provide inhibitory (…) feed-back to the photoreceptor comprise the remaining 6% and are each capable of axon terminal (and to the dendritic trees of bipolar cells) operating at light levels eliciting as many as 10 million (Pasternak et al. 2003: 141). There are two types of photon absorptions per cone each second. The cone horizontal cells in the primate retina (…). The HI cell has density peaks at about 210,000 cones mm-2 and drops one arbor that collects from (and feeds back to) M and L precipitously to about 5,000 cones mm-2 at 20 deg (…). For cones, but not S cones, and a second arbor that is separated both rods and cones, the light-funneling inner segment of from the main arbor by a long axon-like process that the photoreceptor increases in diameter the further it is contacts rods. The HII cell has a main arbor and a smaller from fovea, with a five fold increase for cones and a three arbor that both collect from all cone types, but not from rods. fold increase for rods. Thus, the collecting aperture of Therefore, the spectral sensitivity of both HI and HII cells is each photoreceptor increases with eccentricity, as it does for broadband. Each horizontal cell collects from multiple other retinal neurons. (Pasternak et al. 2003: 142; Kolb et al. photoreceptors. For example, the HI cell collects from some 2011) 15-25 cones in the fovea and from 10-15 further in the periphery as the spacing between cones increases (…). However, HI cells couple electrotonically to one another via The rods have their maximum sensitivity near a gap junctions, and HII cells are likewise interconnected. wavelength of 500 nm (blue-green zone). The cones This connectivity produces a large network of horizontal fall into three types: short (S) wavelength, middle (M) cells that effectively enlarges laterally the photoreceptor wavelength, and long (L) wavelength. input to any one cell. Consequently, the feedback to any single photoreceptor reflects not only its own activity, but The S cones account for approximately 5% of the the average activity pooled across two independent networks total and they are sensitive to a wavelength of around of horizontal cells. (Pasternak et al. 2003: 143)

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In short, there are two types of horizontal cell: HI Diverge to the remaining 9-11 types of bipolar cell (the cone bipolar cells). (…) for a particular ON type there is an and HII. Each of the types forms a complete network analogous OFF type bipolar cell type. (…), their response all over the retina, linked by gap junctions. polarity (ON or OFF) is conserved in the synapse to the ganglion cell. Thus, some 85%-90% of the ganglion cells are Bipolar Cells either ON or OFF, while the rest are both (…). Most morphological types of ganglion cells therefore also Approximately, distribute into separate ON and OFF mosaics (…). Cone bipolar cells distribute into two main categories, midget and Half of the 10-12 types of bipolar cell respond with diffuse, defined by differences in the morphology of their excitation (…) to increments in local light activity (“ON dendritic trees and the number of cones contacting them. cells”), while the remainder responds to decrements in (Pasternak et al. 2003: 143-144) activity (“OFF” cells) (…). The physiological division into ON and OFF also correlates with a morphological division. Each of the cones, ON bipolar cells send long axons into the proximal half of the inner plexiform layer, closest to the ganglion cell layer, while OFF bipolar cells have shorter axons that stratify in Contacts a single ON and a single OFF midget bipolar the distal half of the inner plexiform layer. (Pasternak et al. cell and, over most of the retina, each collects 2003: 143) from only a single cone (…). Far in the periphery, beyond about 45 deg, up to 3-5 cones may contact each midget bipolar cell (…). In contrast, each of the six or so types of The rod bipolar cells, diffuse bipolar cells collect from 8-12 cones over the entire retina with types named DB1-DB3 providing OFF signals to Each rod diverges to 2-3 representatives of a single type the inner retina and the types named DB4-DB6 providing of ON bipolar cell. Each of these so-called “rod” bipolar ON signals. (Pasternak et al. 2003: 144) cells (midget) collects signals from 12-15 rods in the central retina, increasing gradually to 50-60 rods in the periphery (diffuse) (…). At night, both the absolute level of light and Amacrine Cells the contrast from a reflective surface are far less. Thus, the retinal circuit for rod or scotopic vision, like the rod itself, is The amacrine cells, designed to transmit with the highest possible sensitivity. The convergence of so many rods to the rod bipolar cell Of the vertebrate retina are interneurons that interact at increases this sensitivity, so that the signal from the the second synaptic level of the vertically direct pathways absorption of even a single photon of light is preserved and consisting of the photoreceptor-bipolar-ganglion cell chain. transmitted with great fidelity (…). Interestingly, the They are synaptically active in the Inner Plexiform Layer collected excitatory signal from this pool of rods is conveyed (IPL) and serve to integrate, modulate, and interpose a indirectly to different types of ganglion cells via a temporal domain to the visual message presented to the specialized (the AII amacrine) that contacts ganglion cell. Amacrine cells were so named because they both ON and OFF bipolar cells (but the cells in contact with are nerve cells thought to lack an axon. Today we know that the OFF level are cone bipolar cells). (Pasternak et al. 2003: certain large-field amacrine cells of the vertebrate retina can 143) have long “axon-like” processes that probably function as true axons in the sense that they are output fibers of the cell (…). However, these amacrine axons remain within the Bloomfield and Völgyi (2004) also observe that retina and do not leave the retina in the optic nerve as do the the rod bipolar cells are only ON and “Interestingly, ganglion cell axons. (Kolb 1997: 904) the axons of rod bipolar cells do not directly contact ganglion cells, but, instead, contact mainly the The AII amacrine cells, small-field, bistratified AII amacrine cell” Are critical elements in the primary rod pathway of the (Bloomfield and Völgyi 2004: 3297). mammalian retina, acting as an obligatory conduit of rod The cone cells (photopic vision), signals to both on- and off-center ganglion cells. In addition

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to the chemical synaptic circuitry they subserve, AII cells these types depends critically upon species. For the primate form two types of electrical synapses corresponding to gap retina, the number is likely 15-20, each with a distinct junctions formed between neighboring AII cells as well as pattern of pre-synaptic input, physiology, and central junctions formed between AII cells and on-center cone projection into the (…). These divide broadly first bipolar cells. (Bloomfield and Völgyi 2004: 3297) into ON and OFF, following the pairing of ON and OFF bipolar cell types, and this is reflected by the level of stratification of the ganglion cell dendritic tree in the inner The amacrine cells, retina (…). These circuits also divide broadly according to whether the bipolar cell input is midget or diffuse. In the cat (…) signal is transmitted in the retina by the (Pasternak et al. 2003: 145) rod bipolar pathway: rod → rod bipolar → AII → cone bipolar → ganglion cell. The two-dimensional circuit underlying this pathway includes extensive convergence Midget or “P” Ganglion Cells from rods to an AII amacrine cell, divergence from a rod to several AII and ganglion cells, and coupling between the AII It can be identified three types of ganglion cell: amacrine cells. (Vardi and Smith 1996: 3743) midget or “P” cells, parasol or “M” cells, and koniocellular or “K” cells. Amacrine cells thus form a network using gap junctions, together with the cone bipolar cells. Midget bipolar cells collect from a single cone over most of the retina and each cone diverges to a single ON and Interplexiform Cells single OFF midget bipolar cell (…). In and around the fovea, each ON and OFF midget bipolar cell contacts a single ON According to Boycott et al. (1975), the interplexiform or OFF midget ganglion cell, and no midget ganglion cell collects from more than one midget bipolar cell (…). Midget cells, ganglion cells comprise about 80% of the ganglion cells in the foveal region, (…). Outside of the fovea, as the optics of (…) that there is a previously inadequately recognized the eye worsens and the spacing between cones increases class of nerve cell in the mammalian retina with perikarya at (…), the dendritic tree of the midget ganglion cell expands the inner edge of the inner nuclear layer and processes considerably, and each cell collects from increasing numbers within both the outer and inner plexiform layers (...). The of midget bipolar cells and cones (…). Even so, these interplexiform cell processes were found to be pre- and ganglion cells remain the smallest and most numerous, with post-synaptic in the inner plexiform layer and presynaptic to the least convergence of cones. (Pasternak et al. 2003: 145) horizontal and bipolar cells in the outer plexiform layer. (Boycott et al. 1975: 363, 365) “Midget ganglion cells provide the dominant retinal input to the parvocellular region of the lateral The interplexiform cells should thus act as geniculate nucleus (LGN). For this reason, midget regulators-coordinators-inhibitors between the cells are often referred to as ‘P’ cells, as are the horizontal cells and the amacrines. parvocellular relay neurons to which they connect” Ganglion Cells (Pasternak et al. 2003: 145).

Even though the fovea only comprises 1%-2% of the retinal Parasol or “M” Ganglion Cells surface area, it contains more than 35% of all retinal ganglion cells (…). Though the peak density of ganglion The Parasol or “M” ganglion cells, cells (about 60,000 cells mm-2) is less than the peak cone density by more than a factor of three, the tight packing of Like the midget ganglion cell, the parasol ganglion cell cells within the fovea renders the effective sampling of the comes in both ON and OFF types, both of which have a ganglion cell mosaic much higher, with 3-4 ganglion cells broad, circularly symmetric dendritic tree that resembles a per cone (…). This is sufficient to provide each cone access parasol one might carry to keep the rain off. At a given to several parallel ganglion cell circuits (…). The number of retinal eccentricity, the area covered by the dendritic tree of

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the is some 20 times the area covered by a low-scattering passage for light from the retinal surface to midget cell (…), and the parasol mosaic is accordingly the photoreceptor cells. Using a modified dual-beam laser sparser, comprising some 5%-8% of all ganglion cells (…). trap we could also demonstrate that individual Müller cells As a consequence of its size, the convergence of cones to the act as optical fibers. Furthermore, their parallel array in the parasol cell is also a factor of 20 greater. For example, in the retina is reminiscent of fiberoptic plates used for fovea, the parasol cell collects from 20-25 cones via 4-5 low-distortion image transfer. Thus, Müller cells seem to diffuse bipolar cells (…). Physiologically, this contributes to mediate the image transfer through the vertebrate retina with a broader center with higher contrast minimal distortion and low loss. This finding elucidates a sensitivity, about six times greater on average than that of fundamental feature of the inverted retina as an optical the midget ganglion cell (…). In terms of their projections to system and ascribes a new function to glial cells. (Franze et the brain, parasol ganglion cells provide the dominant retinal al. 2007: 8287) input to the magnocellular region of the LGN (…). Thus, they are generally called “M” cells. Like their retinal Representation of the Functioning of the Cells counterparts, M cells in the LGN have a receptive field center that is much broader than that of P cells, in the Retina corresponding to the larger dendritic tree of the parasol ganglion cell. There is also some evidence that some parasol The response of a particular retinal neuron to a given pattern cells may send axon collaterals to the SC. (Pasternak et al. of light impinging on the photoreceptor array depends on the 2003: 146) distribution of spectral, spatial and temporal energy within that pattern. The quality and degree of tuning to this energy depends upon the structure of the receptive field of the Koniocellular or “K” Ganglion Cells neuron consisting of an excitatory center arising from the photoreceptor → bipolar cell → ganglion cell circuitry and Other cells have been detected in the LGN, which, an inhibitory surround arising from the lateral circuitry of horizontal and amacrine cells (Pasternak et al. 2003: 144). Reveal a diverse array of more sparsely populating ganglion The precise physiology of the center and surround for a cells, each with a unique morphology and, presumably, particular retinal neuron depends on the circuitry providing retinal circuitry (…), we now appreciate that some of them its pre-synaptic input and where that neuron is in the retinal are likely to project not to the primary P and M layers of the hierarchy. For example, the center of the receptive field of a LGN, but to the intercalated or koniocellular layers in photoreceptor is formed primarily by that photoreceptor, between (…). One of these is the small bistratified ganglion plus the excitation pooled from its neighbors via gap cell. junctions (…). On the other hand, the center for a bipolar cell is comprised of the contributions from overlying So “The small number of K cells, (…) receives photoreceptors (…). Similarly, the excitatory center of a ganglion cell arises from the convergence within the input from the small bistratified ganglion cell (…). photoreceptor to the bipolar cell circuitry that contacts its Other types of ganglion cell project to each of the M, dendritic tree, while much (but likely not all) of the P and K populations, each with a unique morphology inhibitory surround arises in the lateral connections from and presynaptic circuitry” (Pasternak et al. 2003: 147, horizontal cells to photoreceptors (and bipolar cell dendrites) (…). Thus, spatially the center and surround are quantified 148). in reference to the area of the photoreceptor mosaic contributing to each (see Figure 4). (Pasternak et al. 2003: Müller Cells 144) The Müller cells, The Müller cells would be the structural Are radial glial cells spanning the entire retinal thickness? equivalent of the ommatidia in the eye of drosophila Müller cells have an extended funnel shape, a higher melanogaster. refractive index than their surrounding tissue, and are Briefly, the photons entering through the pupil are oriented along the direction of light propagation. Transmission and reflection confocal microscopy of retinal projected onto the ILM and reflected in a centroid in tissue in vitro and in vivo showed that these cells provide a the vitreous body. Subsequently they are captured by

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Figure 4. Column Centre‐Surround of the Retina Cells (Symbolic Representation). Main Circuit: Cone (SC), Conebipolar (CB1), and Ganglion Cell (G2). Sources: The Elaboration Based on Rodieck (1988: 207, 212, 226, 231), Reichenbach and Robinson (1995: 141), Masland (2001a: 432), and Pasternak et al. (2003).

the Müller cells and projected onto the RPE, from photoreceptor mosaic more sparsely than the major types involved in acquiring sensory information”. (Pasternak et al. which they are transduced as electrical stimuli by the 2003: 147) photoreceptors and transmitted to the ganglion cells via the main circuits formed by the cone bipolar cells It will be referred below to those that lead to the constituting the vertical process. There is also a SC. horizontal process implemented by the horizontal cells, The LGN has the shape and size of a large peanut. the amacrines and interplexiforms, which serve to It is located in the posterior quarter of the thalamus. coordinate the vertical process which leads to each The LGN receives input from the visual hemifields of and every ganglion cell. the retina in both eyes, ipsilaterally from the temporal retina and contralaterally from the nasal retina. Input LATERAL GENICULATE NUCLEUS is anatomically segregated in six layers, layers one, four, and six (numbered from ventral to dorsal) Visual pathways comprise a massive sensory component that receive contralateral input and layers two, three, and involves about 90% of the retinal ganglion cells, those that five receive ipsilateral input. The number of LGN project into the lateral geniculate nucleus (LGN) of the neurons receiving input from the retina, which is then thalamus and from there to the primary visual cortex (...) (see Figure 3). Another component involves the remaining projected onto the striate cortex (primary visual cortex 10% or so, mostly large ganglion cells that sample the or area 17 according to Brodman), is approximately

De La Puente 375 the same as the ganglion cells that project onto the structures with functionally distinct roles. One compartment is consistent with the role of a salience map (Fecteau and LGN. The relationship between ganglion cells and Munoz 2006), where salience is defined as the sensory LGN relay neurons is assumed to be 1:1, and 75% of qualities that make a stimulus distinctive from its this bunch are corticofugal, running from area 17 to surroundings. The other compartment is consistent with the the LGN. Layers one and two account for a third of role of a priority map (…), where priority is defined as the integration of visual salience and behavioral relevance, the the ventral cells of the LGN and 10% of the neurons relative importance of a stimulus for the goal of the observer. that project onto the striate cortex. As they are large, (White and Munoz 2011: 195) these neurons are called magnocellular (M). Layers three and six account for two thirds of the dorsal cells The laminated structure of the SC of mammals, of the LGN and 80% of the LGN relay neurons. These neurons are small and are known as parvocellular (P). Consisting of seven anatomically distinct layers that The remaining 10% of the LGN relay neurons are have been traditionally grouped into two functional regions (…), a superficial region concerned exclusively with visual distributed unevenly, mainly in the intermediate layers, processing (…), and a deeper region concerned with in the ventral position of each of the six primary M multisensory (…), motor (…), and higher-level cognitive and P layers, and are known as koniocellular (K) processes (…). In this review we will highlight important functional differences between the superficial (…) and because of their small size (Pasternak et al. 2003: 148; intermediate (…) layers of the SC, which we henceforth Haar Romeny 2003: 183). refer to as the SCs and SCi, respectively. (White and Munoz 2011: 196) The relative number of M, P, and K cells in the LGN reflects the nature of their retinal inputs. The population of P The SCs receive visual inputs from two primary cells is the most numerous because most of these receive input from a midget ganglion cell, while the population of M sources: (1) a direct projection from the retina (the cells is more sparse because many (but probably not all) retinotectal pathway) (…); and (2) direct projections receive input from a parasol ganglion cell (…). The small from visual cortex, specifically primary visual cortex number of K cells, probably 3%-5% (...), receives input from (V1), V2, V3, V4, and Middle Temporal Area (MT) the small bistratified ganglion cell (…). Other types of ganglion cell project to each of the M, P, and K populations, (White and Munoz 2011: 196-197). each with a unique morphology and presynaptic circuitry The primate SCs have three dominant outputs, (Figure 3). (Pasternak et al. 2003: 148) The pulvinar complex (…), the LGN (…), and intrinsic vertical connections with the SCi (...). The SCs projects to all THE SC layers of the pulvinar, and the magnocellular and interlaminar layers of the LGN, (…). The intrinsic vertical connection The SC is, between the SCs and the premotor layers of the SCi (…) has been proposed to mediate visually-guided orienting, and Located on the dorsal surface of the midbrain, the might act as an important locus for the interaction between mammalian SC is ideally situated to guide and coordinated sensory (bottom-up) and goal-related (top-down) processes. orienting behavior. By integrating multiple sources of (White and Munoz 2011: 197-198) sensory, motor, and cognitive signals, and in turn sending motor commands directly to the brainstem circuitry, the SC initiates a rapid orienting response that can invoke the eyes, Compared to the SCs, neck, and shoulder muscles. (White and Munoz 2011: 195) The primate SCi receives a broader set of corticotectal projections (…) from occipital, temporal, parietal, and White and Munoz present the idea that, frontal cortices (…). These include Lateral Intraparietal Area (LIP) (…), the Frontal Eye Fields (FEFs) (...), The mammalian SC represents two largely independent Supplementary Eye Fields (SEFs) (...), Dorsolateral

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Prefrontal Cortex (DLPFC) (...), and Anterior Cingulate THE CLAUSTRUM Cortex (ACC) (...). The SCi also receives important subcortical projections from the basal ganglia (...), The Claustrum (Cl) “is a thin layer of the gray matter, cerebellum and brainstem. (White and Munoz 2011: 198) placed in the deep part of both the cerebral lobes, found in mammalian brains. Laterally, it is separated In terms of outputs, from the insular cortex by the extreme capsule and, medially, from the lenticular nucleus by the external The SCi projects to the Paramedian Pontine Reticular capsule” (Milardi et al. 2013: 1). And “it first appears Formation (PPRF) and Rostral Interstitial Nucleus of the Medial Longitudinal Fasciculus (riMLF) where the as a readily discernible nucleus in the Insectiovores, horizontal and vertical saccade premotor circuitry is Prosimians, and Marsupials” (Edelstein and Denaro located (...). The SCi also projects to the substantia 2004: 676). nigra pars compacta (SNc) (...). The SCi also projects to The Cl has reciprocal connections with nearly all the FEF via the mediodorsal thalamus, MDN (Mediodorsal Nucleus or Mediodorsal Nucleus of Thalamus) (...). Finally, the regions of the cortex and with many sub-cortical there is anatomical evidence of long-range connections structures which do not pass through the thalamus. In within the Sci. (White and Munoz 2011: 198-199; Isa all cases, the connections are ipsilateral and 2002) contralateral and they are linked to each other (Edelstein and Denaro 2004; Crick and Koch 2005; The SC would thus be responsible for an Park, Tyszka, and Allman 2012; Milardi et al. 2013; immediate systemic response to the appearance of Smythies 2014). something moving round our nearby visual field, such “If the thalamus were radically and irreversibly as a wasp, or making us blink when something is damaged, the physiological repercussions would no about to go into our eyes. It could be said that this is doubt be devastating. If the Cl was similarly damaged the Formula 1 driver in the nervous system, but one or altogether obviated, the consequences would likely with little or no awareness. This would only be be much more subtle and perhaps difficult to produced later, when it was realized what had characterize” (Edelstein and Denaro 2004: 688). happened. These characteristics of the Cl would incline us to The retinotectal projection to the SC is not greater accept the suggestion by Crick and Koch (2005) and than 10% of the ganglion cells, mainly Pγ, and they Smythies, Edelstein, and Ramachandra (2012) that must be distributed evenly throughout the retina, 6% awareness is produced by the Cl. As the researcher has of the ganglion cells being near the fovea, the number argued elsewhere (De La Puente 2011), the data or increasing gradually as one moves away from the information would be replicated in the genome of the centre (Pasternak et al. 2003: 147-148; Perry and neuron nucleus but, assuming that awareness is a fact Cowey 1984; Williams, Azzopardi, and Cowey 1995). and must be somewhere and must be produced by Then, according to the accepted view, if the image something, one would be led to think that it is was formed on the retina like a jigsaw puzzle and one produced holistically by the system formed by the Cl piece was transported by each axon of the ganglion with the other encephalic structures to which it is cells, it would not be possible to form a salience map interconnected. Elsewhere (De La Puente 2011), the with such a small percentage. However, according to researcher has pointed out that if life and awareness the thesis presented in this paper, it would be possible are not matter, they must be energy. to form a salience map with such a small number of The cortex is a dome formed by a mosaic of axons. neurons which are massively interconnected with each

De La Puente 377 other and with the Cl, the latter being linked in turn to fifty years of conscious brooding have brought me no closer to the answer to the question: What are light quanta? Of subcortical structures. The connections involve course today every rascal thinks he knows the answer, but he chemical elements such as neurotransmitters, metals is deluding himself”. We are today in the same state of such as Na, K, and Ca, and electrical stimuli, as “learned ignorance” with respect to light as was Einstein. drivers of action. This system must do something and (Zajonc 2008: 3) it may well be to produce awareness. The researcher is inclined to think that visual and cognitive awareness While Galileo and Newton upheld a corpuscular are the same but one would need to determine whether theory of light (light as particles), Huygens, Young, this awareness is associated with a unitary way of and Euler defended a theory based on waves. In representing the external world. It should also be born December 1900, Max Planck developed a new theory in mind that damage to the thalamus is devastating according to which black bodies emit light only as and damage to the Cl does not prevent behavior, but packets of energy, which he called “quanta”. In 1905, makes it disorganized, which must be from a lack of Albert Einstein proposed that these light quanta could awareness (Edelstein and Denaro 2004). The question be considered as true particles and in 1926 Gilbert N. is whether we have already discovered everything or Lewis suggested the name “photon” for these particles. everything we need to know to determine what Modern theory suggests that light has a dual nature, awareness is and how and where it is produced, or if behaving as a wave and a particle, although in 1927, something is missing. Dirac, one of the inventors of Quantum If the colliculus superior can be seen as a Formula Electro-Dynamics went a little further than this duality 1 driver who lacks awareness, this system would be and considered the photon as a unit of perturbation more like a moving van which has awareness. associated with a quantum mode of the radiation field. As such, it is associated with a plane-wave with moment, energy, and polarization (Zajonc 2008). WHAT IS LIGHT OR WHAT ENTERS VIA For the purposes of this paper and what will be THE PUPIL explained below, it will be considered that the photon The researcher has proposed that information is is a particle which is displaced with a wave-like generated, stored, and processed in the genome of the movement which the researcher will call photon neuron nucleus and that consequently only signals vibration, disregarding the wave-particle duality. (photons, sound waves, molecules, etc.) enter from the Depending on the measuring equipment, observation exterior and that these signals enter via the senses (De may give results in the form of waves (particles that La Puente 2009; De La Puente 2011). In this paper, vibrate) or particles. Observations over time would dealing with vision, it was necessary to examine what give us a vibrating behavior, but looked at it is that enters via the pupil and, consequently, what transversally the photon would seem to be a particle is processed by the sense of sight, but applying (Kim et al. 2000; Walborn et al. 2002; Kaiser et al. Einstein’s (1919) criterion and considering only 2012; Peruzzo et al. 2012). concepts with some mathematical component and As a result, when light enters the pupil, it is in the limiting the study to light emitted by the sun. form of particles (photons) of energy which vibrate Light is a strange phenomenon that we still do not and have density (photons/unit of area). The completely understand. researcher will then consider a ray of light to be a continuous stream of stimulation units (photons), one Near the end of his life Albert Einstein wrote, “All the after the other, discrete but apparently continuous, and

378 Sociology Study 4(4) light as a fluid composed of these units of perturbation, or any other two points. which are energy particles with no mass and little or The frequency is the number of cycles or no cohesion with each other. The speed of this fluid wavelengths in a specified time, normally a second, can be reduced and it can be stored and then released and it is measured in cycles/s or Hz. in a medium where certain conditions apply (Hau et al. According to Formula 3, the relationship between 1999; Novikova et al. 2007; Hau 2011). Light as a frequency and wavelength is inverse, i.e., if one fluid can be deviated from its trajectory by the increases, the other decreases and vice versa. curvature of space produced by massive bodies like Similarly, as it can be seen in Formula 4, the the sun when it passes near them. This effect of the relationship between energy and wavelength is also General Theory of Relativity was demonstrated by inverse and the relationship between energy and Eddington in 1919 (1920). frequency is direct, as shown in Formula 1. It can be At rest the photon has no mass, although this is a thus seen that the shorter the wavelength, the greater theoretical concept, as by its definition and nature, it is the energy, and vice versa, and the greater the never at rest. It has energy, frequency, and wavelength. frequency, the greater the energy, and vice versa. Consequently, when referring to light and what enters Consequently, the greater the frequency of the via the pupil we shall speak of the photon, considering photon, the shorter the wavelength and the greater the it as the Minimum Unit of Resolution (MUR) capable energy, so variations in energy are produced by of stimulating the photoreceptor cells, from which, by variations in the vibrations of the photon’s wave means of vibration and density, the visual system is pattern. If we apply Formula 1, with υ = 1, the energy able to reconstruct a representation of external reality of the photon is equal to Planck’s constant h (6.63 × that allows us to adapt to our environment and survive. 10-34 J × s), and is the same for all photons, so we We will not be concerned with the photon in its shall consider it as the basic or base energy of the environment, its possible collisions, its trajectory, and photon, which is constant and always the same. Total the interactions between photon and matter (electrons) energy E is thus equal to the base energy (Planck’s (Mozumder and Hatano 2004: 1-5, 20; Roychoudhuri constant h) by the number of vibrations, and thus et al. 2008; Hill and Lee 2007). We conclude, in the varies according to the latter. Different frequencies are final instance, that, independently of its behavior in assigned names and in the visible light spectrum these the medium, the photon enters via the pupil. The go from infra-red to ultra-violet. relationship among energy, wavelength, and Then, if the photon is the MUR and it is only frequency is as follows: energy and does not provide anything else, we can conclude that we recreate external reality as E: Energy in J (joules). h: Planck constant = (6.63 × 10 - information and that the recreation is based on the E = h×υ 34 J × s) Formula 1 vibration and density of the photons that enter the υ: Frequency (Ipsilon) (Hz or cycles/s). pupil and produce a salience map (Fecteau and Munoz c: Light speed ≅ 3.0 ×108 m/s 2006). When a surface has color or texture, it reflects c = λ × υ Formula 2 λ: Wavelength (in m) the packet of photons it receives and modifies their υ = c/λ Formula 3 frequency, producing the sensation of color or texture, E = (h × c)/λ Formula 4 and the density of the packet (higher or lower The length of the wave or cycle (λ) is the distance brightness level) determines the resolution of the between two consecutive points in the same position, salience map. for example, two peaks, two troughs, two zero points The photons considered, which are those emitted

De La Puente 379 by the sun, are within the electromagnetic wave the width of the band of visible light, because what spectrum and are referred to as visible and non-visible interests us is the range of colors (Cavani 2008). light. World Health Organization (WHO) (1994) As proposed in the second point, when the sun’s shows the electromagnetic spectrum and, within it, rays pass through the prism, their wavelength must be details of the part considered to be visible photons, reduced and their frequency and energy accordingly with wavelengths in the range 400 nm (4.0 × 10-7 m) increased (see Formula 1 and Formula 4), so the to 760 nm (7.6 × 10-7 m) (World Health Organization highest frequency (violet) is produced by the widest [WHO] 1994; Frank 2012). The photoreceptor cells part of the prism and the lowest frequency (red) by the are sensitive to these photons and able to recreate narrowest part. external reality by processing them. In the final instance, the characteristics of the The photoreceptor cells are also sensitive to part of photons are influenced by the last body with which the electromagnetic spectrum considered non-visible they have interacted and these final photons are the in the ultra-violet range from 100 nm (1.0 × 10-7 m) to ones that enter the eyes and the ones under 400 nm (4.0 × 10-7 m) and the infra-red range from consideration here. Interaction or clashes between 760 nm (7.6 × 10-7 m) to 106 nm (1.0 × 10-3 m = 1mm) photons are not considered. (WHO 1994). Consequently, according to the electromagnetic If, then, the photons emitted by the sun are carriers spectrum of the photons in visible light, those entering “of all the forms of electromagnetic radiation, the eyes to recreate external reality have an energy of -7 including gamma rays, X-rays, ultra-violet light, between 4.9725 x 10 J and 2.6171 x 10-19 J and a 14 14 visible light (electromagnetic spectrum), infra-red frequency of between 7.50 x 10 Hz and 3.95 x 10 light, microwaves and radio waves” (Wikipedia 2013b) Hz (WHO 1994). (translation from Spanish), it means that: If we consider that the photoreceptor cells of the human eye can discriminate between a difference of 1 (1) The sun emits different photons with different nm, the scale from 400 nm to 760 nm allows for 361 wavelengths and these are sep arated when they are reflected, different positions, colors or tones. But the construction diffracted, or undergo any type of interference; of external reality by the neurons consists not only of (2) When photons are emitted by the sun as visible and colors but also differences in texture and type of non-visible light, they have the same speed, frequency, wavelength, and energy; when they interact with a medium, material. The construction of reality is therefore based the speed, frequency, wavelength, and therefore the energy on colors, or rather different wavelengths and of each photon are modified. frequencies providing different levels of energy, which are the signals, the information associated with the This can be seen in the following experiment. If external world being generated, stored, and processed we use a transparent triangular polyhedron and in the genome of the neuronal nucleus, specifically in position it so that the sun strikes one of the sides. At a the base pairs (De La Puente 2009; De La Puente certain angle of diffraction the light displays a range 2011). of colors, with violet in the part corresponding to the Therefore, when we perceive external reality, what side that is almost parallel to the sun’s rays and red at enters via the pupil is a number of photons grouped in the opposite vertex. The difference in thickness packets with the same energy, corresponding to colors, modifies the wavelength, the frequency, and the textures and materials to create an internal energy. We can ignore factors such as the angle of representation. For example, when one observes two incidence, the angle of diffraction, the exit angle and rectangles of different colors, there are two flows of

380 Sociology Study 4(4) photon packets entering the pupil with different nuclei and the claustrum creates cognitive and visual energy levels. If one surface reflects photons where λ awareness. = 550 nm, the visual system perceives a package of The other purpose of this paper is to make readers photons where each one has an energy of 3.6164 x aware that what enters the eyes and is processed by the 10-19 J, and the visual system interprets the green color. visual system is photons, i.e., energy. These are signals If another surface reflects photons where λ = 750 nm, and do not, therefore, carry information, the latter being the visual system perceives a package of photons generated, processed and stored exclusively in the where each one has an energy of 2.6520 x 10-19 J, and genome of the neuronal nucleus (De La Puente 2011). the visual system interprets the red color. This conclusion leads the researcher to put forward the following ideas: (1) “Life” and “awareness” may not be separate CONCLUSIONS phenomena. Life cannot be merely movement, as any In the light of two previous texts (De La Puente 2009; automaton would then be alive. Nor can it be a matter De La Puente 2011), the researcher detected a need to of feeding and reproduction because these functions see how the signals that generate information reached are performed by microorganisms and the cells of the genome of the neuronal nucleus. multicellular organisms. The definitions of “life” and This was the reason for this paper dealing with the “awareness” cannot be separated and a living being sense of sight, the sense through which we perceive would thus be one which, apart from its own the greatest number of signals, the most sophisticated, physiological functions, exhibits awareness; and the one about which we have the most (2) Life defined in itself would then have no information. meaning and would be of no interest to the researcher. The conclusion is that the photons entering via the Ultimately, it is the subject of other areas of study and pupil reach the ILM, where the image perceived from may be no more than the result of the chemical action outside is formed. From there, it is reflected at a point of a series of moving molecules. The researcher’s or in an area of the vitreous body, possibly in the lens. main concern is a social phenomena and he considers This image, which is almost complete, is captured or these to be information forming part of the awareness, processed by each and every one of the Müller cells, which he sees as the most interesting aspect: life and which carry it to the hexagonal cells of the RPE. The awareness as a combined concept; image is received there and phototransduction is (3) The question then becomes what produces effected by the photoreceptor cells. The cells of the awareness and where it is produced. As put forward retina transmit the image in centre-surround format, previously, the cortex is a vault consisting of a mosaic organized round the S photoreceptor cone, to the of neurons massively interconnected with each other ganglion cells, the process being regulated by the and with the Cl, the latter being connected in turn to horizontal, amacrine and interplexiform cells and the the subcortical structures. The connections involve gap junctions. The optic nerve is formed by the axons chemical elements such as neurotransmitters, metals of the ganglion cells, each of which carries an almost such as Na, K, and Ca, and electrical stimuli, as complete image. They are reorganized in the optic drivers of action. This system must do something and chiasma, and go on to the LGN and from there to the it may well be that it produces awareness. This leads cortex areas, to generate information in the genome of him to think that visual and cognitive awareness are each neuronal nucleus, these being read-write. The the same; system consisting of the cortical and sub-cortical (4) The researcher considers that the division of

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