Seeing Consciousness Through the Lens of Memory
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ll Magazine infected rhesus macaques. bioRxiv https://doi. what the experience is about, for org/10.1101/2020.03.13.990226. My Word 17. McCray Jr., P.B., Pewe, L., Wohlford-Lenane, C., example, an apple or a snake. Hickey, M., Manzel, L., Shi, L., Netland, J., Seeing First-order theories, such as Jia, H.P., Halabi, C., Sigmund, C.D., et al. recurrent processing theory [2,3], posit (2007). Lethal infection of K18-hACE2 mice infected with severe acute respiratory syndrome consciousness that consciousness originates in brain coronavirus. J. Virol. 81, 813–821. regions specialized in the processing 18. Docherty, A.B., Harrison, E.M., Green, C.A., through the lens of Hardwick, H.E., Pius, R., Norman, L., of a given kind of information. For Holden, K.A., Read, J.M., Dondelinger, F., memory perceptual states of consciousness, Carson, G., et al. (2020). Features of 20,133 these include, for instance, visual UK patients in hospital with covid-19 using the ISARIC WHO Clinical Characterisation Protocol: or auditory cortices. For emotions prospective observational cohort study. BMJ Joseph E. LeDoux1,2,3,* like fear, subcortical areas such as 369, m1985. and Hakwan Lau4,5 19. Mao, L., Jin, H., Wang, M., Hu, Y., Chen, S., the amygdala have been proposed He, Q., Chang, J., Hong, C., Zhou, Y., Wang, D., to be a fi rst-order locus [4]. In fi rst- et al. (2020). Neurologic manifestations of We humans have long thought of order theories, the phenomenal feel hospitalized patients with coronavirus disease 2019 in Wuhan, China. JAMA Neurol. 77, 1–9. ourselves in terms of bodily and mental and content of the experience are 20. Poyiadji, N., Shahin, G., Noujaim, D., Stone, M., spheres of existence. These days fully accounted for by some specifi c Patel, S., and Griffi th, B. (2020). COVID-19- associated acute hemorrhagic necrotizing many of us understand that the mental pattern of neural activity within these encephalopathy: CT and MRI features. 296, aspect of who we are is embedded fi rst-order areas. E119–E120. in the part of the body known as the Higher-order theories, on the 21. Klok, F.A., Kruip, M., van der Meer, N.J.M., Arbous, M.S., Gommers, D., Kant, K.M., Kaptein, brain, and is therefore also part of our other hand, suggest that fi rst- F.H.J., van Paassen, J., Stals, M.A.M., Huisman, physical, bodily self. Although most order representations may not be M.V., et al. (2020). Incidence of thrombotic complications in critically ill ICU patients with of us accept this scientifi c conclusion suffi cient to account for either the COVID-19. Thromb. Res. 191, 145–147. about the physicality of the mind, phenomenal feel or the content of many nevertheless feel as though the conscious experience [5–7]. They 1Radboud University, 6525 XZ Nijmegen, their mind possesses some quality posit that some higher-order cognitive The Netherlands. 2University Medical Center, lacking in other physical systems mechanism, possibly involving circuits Utrecht Brain Center, Utrecht University, 3584 within their body, and even within their in prefrontal cortex, is needed in order 3 CG Utrecht, The Netherlands. Netherlands brain — we have fi rst-hand knowledge to monitor or meta-represent the Cancer Institute, 1066 CX Amsterdam, The Netherlands. 4Radboud University Medical of our thoughts and feelings, but not fi rst-order information. As such, the Center, 6525 GA Nijmegen, The Netherlands. of the neural processes that control information represented in fi rst-order 5Maastricht University, 6211 LK Maastricht, body processes related to digestion, structures remains non-conscious The Netherlands. 6University of Groningen, respiration, heart rhythm, and so on, (or pre-conscious) if no higher-order 9712 CP Groningen, The Netherlands. nor of the brain’s control of much of re-representation is involved. With 7 University of Groningen, University our behavior. respect to fear, this view posits Medical Center, 9713 GZ Groningen, The Netherlands. 8Biomedical Primate Research In this My Word, we explore the that the amygdala controls non- Center, 2288 GJ Rijswijk, The Netherlands. question of what is different about conscious defensive responses, 9Metris BV, 2132 NG Hoofddorp, The a brain state about which you are such as behavioral and physiological Netherlands. 10University Medical Center, conscious from one that you are responses to threats, but that higher- 3584 CX Utrecht, The Netherlands. 11Leiden not? We will argue that all conscious order re-representation, possibly University Medical Center, 2333 ZA Leiden, experiences involve elements of involving prefrontal cortex, is required The Netherlands. 12Amsterdam University Medical Centers, 1105 AZ Amsterdam, memory and meta-representation. in order to generate the subjective The Netherlands. 13Erasmus University This framework may help us better experience of fear in response to the Medical Center, 3015 GD Rotterdam, The understand the subjective qualitative threatening stimulus [7–9]. For higher- Netherlands. 14Netherlands Institute for character of conscious experiences, order theories, the phenomenal quality Neuroscience, Royal Netherlands Academy as well as why meta-representations and conscious content both require of Arts and Sciences, 1105 BA Amsterdam, may be involved in generating even the higher-order state. The Netherlands. 15Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 the simplest of such experiences. XH Amsterdam, The Netherlands. 16Charles Memory and consciousness River, 5231 DD Den Bosch, The Netherlands. Phenomenal ‘feel’ and conscious The pioneering 19th century 17Oncode Institute, 3521 AL Utrecht, The content psychologist Hermann von Helmholtz Netherlands. 18Wageningen University, William James famously referred to the proposed that conscious perception 6708 PB Wageningen, The Netherlands. special property of conscious states is an ‘unconscious inference’ based in 19Utrecht University, 3512 JE Utrecht, The Netherlands. 20Life and Medical Sciences in terms of ‘warmth and intimacy’. part on memory. Consistent with von Institute, University of Bonn, 53115 Bonn, These days it is common to describe Helmholtz’s logic, we propose that Germany. 21Netherlands Institute of Ecology, this as a phenomenal ‘feeling’ — the all states of consciousness depend Wageningen University, 6708 PB Wageningen, quality that makes red seem red, an on memory [7–9], and specifi cally The Netherlands. 22Viroclinics Xplore, 5374 apple seem like an apple, and fear on mechanisms that integrate 23 RE Schaijk, The Netherlands. Wageningen feel fearful [1]. There is considerable sensory and memory information Bioveterinary Research, 8221 RA Lelystad, The Netherlands. disagreement about what this quality unconsciously (i.e. pre-consciously). *E-mail: [email protected]; is and how it may come about in the A fundamental distinction in [email protected] brain in relation to the actual content; memory research is between R1018 Current Biology 30, R1009–R1035, September 21, 2020 © 2020 Elsevier Inc. ll Magazine Table 1. Anoetic, noetic, and autonoetic consciousness. Consciousness Knowledge Memory Meta-representation Self Example thought Anoetic Non-knowing Procedural Non-cognitive Implicit Thought not involved Noetic Fact-knowing Semantic Cognitive Assumed “There is an apple” Autonoetic Self-knowing Episodic Cognitive Explicit “I see an apple” memories that are formed and stored Noetic states of consciousness relations between dynamical neural in a way that can be consciously depend on semantic memories of profi les and sensory inputs. These retrieved, and memories that are factual and conceptual information implicit memories are used to classify stored implicitly, and hence are about what things are and are not. the wavelength of the present stimulus not consciously experienced when For example, seeing a bird and with other stimuli from the past retrieved [10]. People can have recognizing it as a robin not only with similar neural profi les. Indeed, conscious introspections and talk requires sensory processing of the empirical fi ndings show that colors about explicit memories, but they visual properties of the present and other low-level visual features can only show the effects of past robin, but also semantic, including are embedded in a local spatial and implicit procedural learning through conceptual, memories about what temporal contexts of other neurons nonverbal behavior. One consequence birds and robins are. In sharp contrast and are processed relative to these is that a person with damage to to autonoesis, noetic states do not [14]. The color of a stimulus, when the circuits underlying explicit require explicit self-awareness and do not conceptualized by semantic memories can procedurally acquire not support mental time travel. memory, can only be experienced and perform behaviors which they A third kind of state recognized relationally with respect to other have no conscious memory of having by Tulving is anoetic awareness. possible color representations, which acquired; conversely, damage to Although the most basic, it is the is what accumulated procedural one of the many procedural memory least intuitive, and requires some memories offer. Accordingly, what we circuits prevents behavioral learning discussion. Tulving referred to anoetic consciously see as red only looks red by that system, but spares the ability consciousness as states of ‘non- because of the way it looks similar to to remember the episode in which knowing’, by which he meant that and different from other stimuli that they tried to learn