The Habenular Nuclei: a Conserved Asymmetric Relay Station in the Vertebrate Brain

Total Page:16

File Type:pdf, Size:1020Kb

The Habenular Nuclei: a Conserved Asymmetric Relay Station in the Vertebrate Brain The habenular nuclei: a conserved asymmetric relay station in the vertebrate brain The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Bianco, Isaac H. and Stephen W. Wilson. 2009. The habenular nuclei: a conserved asymmetric relay station in the vertebrate brain. Philosophical Transactions of the Royal Society B: Biological Sciences 364(1519): 1005-1020. Published Version doi://10.1098/rstb.2008.0213 Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:10886852 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA Phil. Trans. R. Soc. B (2009) 364, 1005–1020 doi:10.1098/rstb.2008.0213 Published online 4 December 2008 Review The habenular nuclei: a conserved asymmetric relay station in the vertebrate brain Isaac H. Bianco1,2,* and Stephen W. Wilson1,* 1Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK 2Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA The dorsal diencephalon, or epithalamus, contains the bilaterally paired habenular nuclei and the pineal complex. The habenulae form part of the dorsal diencephalic conduction (DDC) system, a highly conserved pathway found in all vertebrates. In this review, we shall describe the neuroanatomy of the DDC, consider its physiology and behavioural involvement, and discuss examples of neural asymmetries within both habenular circuitry and the pineal complex. We will discuss studies in zebrafish, which have examined the organization and development of this circuit, uncovered how asymmetry is represented at the level of individual neurons and determined how such left–right differences arise during development. Keywords: habenula; asymmetry; interpeduncular nucleus; zebrafish; dorsal diencephalic conduction system 1. ANATOMY AND CONNECTIVITY the posterior commissure and the habenular commis- The dorsal diencephalic conduction (DDC) system sure runs between them (Nieuwenhuys et al. 1998; is one of two major pathways that interconnect the Butler & Hodos 2005). limbic forebrain and sites in the mid- and hindbrain, In mammals, the habenular complex comprises two the other pathway being the medial forebrain bundle separate nuclei on each side: the ‘medial’ (MHb) and (MFB; Sutherland 1982). These two pathways appear ‘lateral’ (LHb) habenulae. The LHb is further to represent parallel neural circuits—they share sources subdivided into principal medial and lateral subdivi- of afferent inputs as well as efferent targets and there is sions. Despite sharing some sources of afferent inputs an overlap in their physiology and function. and efferent targets, the medial and lateral habenulae The DDC comprises three core components: the appear to represent largely distinct subcircuits within habenular nuclei; the stria medullaris (SM), which is the the DDC (Herkenham & Nauta 1977, 1979; Kim & main fibre tract through which inputs from the forebrain Chang 2005). In outlining the anatomy of this arrive at the habenulae; and the fasciculus retroflexus circuit, we shall focus primarily on the patterns of (FR), a prominent fibre tract that predominantly carries connectivity in the rat, which have been well studied efferent axons from the habenula towards the targets in (figure 1). Some species differences will also be the midbrain/hindbrain. In this review, we will focus on mentioned, where relevant, but we will not attempt a the anatomy and connectivity of the habenulae and the description of the comparative neuroanatomy of the interpeduncular nucleus (IPN). The latter is a major DDC in any detail. target of habenular efferent connectivity in all vertebrates and consequently plays a pivotal role in the modulation of (i) Medial habenula nuclei downstream of the DDC. In §3, we will review the MHb circuitry is highly conserved (Sutherland 1982). various classes of neural asymmetry that have been The MHb primarily receives inputs from the septum described in the DDC, especially of anamniotes, and in and projects to the IPN of the ventral midbrain. This §4, we will discuss work in zebrafish that has addressed efferent connection comprises the ‘core’ of the FR and the developmental mechanisms by which DDC circuit appears to be conserved in all vertebrate species that asymmetries emerge. have been examined. (a) Habenula Afferent connectivity The bilaterally paired habenular nuclei (Hb) are The major source of afferent innervation of the MHb positioned adjacent to the third ventricle, rostral to derives from the supracommissural septum, with axons coursing in the SM (Herkenham & Nauta 1977). * Authors and addresses for correspondence: Department of Septal sites themselves receive inputs from the Molecular and Cellular Biology, Harvard University, Cambridge, hippocampus and subiculum. Axons from the two MA 02138, USA ([email protected]); Department of Cell and Developmental Biology, University College London WC1E 6BT, most significant septal nuclei also terminate in different UK ([email protected]). subdomains of the MHb—the septofimbrial nucleus One contribution of 14 to a Theme Issue ‘Mechanisms and functions innervates the rostral MHb while the nucleus triangu- of brain and behavioural asymmetries’. laris innervates the caudal MHb. In the rat, almost 1005 This journal is q 2008 The Royal Society This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 1006 I. H. Bianco & S. W. Wilson Review. The habenular nuclei HippoF P septum Dors. Teg. sf tr MHb IPN region DTN, VTN, NI DBB Acb Thal FrCx SC Circad. raphe SCN retina nuclei LH LC LPO LHb VTA EP SNc CPu Figure 1. Connectivity of the DDC. This schematic shows the principal connections of the medial and lateral habenulae and interpeduncular nucleus as described in mammals, in particular the rat. Thick arrows highlight the septum–MHb–IPN axis and the convergence of limbic and striatal inputs into the lateral habenula. Notably, there are very limited data regarding the relative functional importance of the various connections shown here. Acb, nucleus accumbens; Circad., potential sources of circadian information; CPu, caudate/putamen; Dors. Teg. region, dorsal tegmental region; DBB, nucleus of diagonal band; DTN, ventral tegmental nucleus of Gu¨dden; EP, entopeduncular nucleus; FrCx, frontal cortex; HippoF, hippocampal formation; IPN, interpeduncular nucleus; LC, locus coeruleus; LH, lateral hypothalamic area; LHb, lateral habenula; LPO, lateral preoptic area; MHb, medial habenula; NI, nucleus incerta; P, pineal; SC, superior colliculus; SCN, suprachiasmatic nucleus; SNc, substantia nigra pars compacta; sf, septofimbrial nucleus; Thal, thalamic nuclei; tr, nucleus triangularis; VTA, ventral tegmental area; VTN, ventral tegmental nucleus of Gu¨dden. every neuron in these two septal nuclei is likely to MHb innervate the ventral IPN and lateral MHb project to the MHb. More minor inputs derive from the neurons project to the dorsal IPN (Herkenham & nucleus of the diagonal band (DBB). Nauta 1979; Contestabile & Flumerfelt 1981). The MHb also receives ascending inputs, principally After making lesions in the MHb, Ronnekleiv & derived from monoaminergic nuclei, which are also the Moller (1979) observed degenerating terminals in the targets of both medial and lateral habenular efferent pineal organ, suggesting that it may also be an MHb axons. Dopaminergic inputs derive from the inter- efferent target. fascicular nucleus of the ventral tegmental area (VTA; Although little is known about the intrinsic habe- Phillipson & Pycock 1982) and noradrenergic inputs nular circuitry and the extent to which communication from the locus coeruleus (Gottesfeld 1983). These exists between the MHb and LHb, two observations latter axons reach the MHb by coursing anteriorly in provide evidence for a medial-to-lateral connection. the MFB and then joining the SM. A subset of MHb axons project through the LHb and in so doing display en passant boutons that might Efferent connectivity represent presynaptic terminals (Kim & Chang The main target of MHb axons is the IPN (Herkenham & 2005), and sectioning of the MHb efferent axons has Nauta 1979). The MHb contains both cholinergic been reported to reduce substance P levels in the LHb neurons (in its ventral two-thirds) and dorsally located (see Sutherland 1982). substance P-containing neurons (Contestabile et al. 1987). Both types are contacted by the major afferent (ii) Lateral habenula axons from the septofimbrial nucleus and nucleus When compared with the MHb, the LHb shows triangularis, and both project down the core of the FR broader and less evolutionarily conserved connectivity. to innervate the IPN. MHb axons terminate in a It is thought to be involved in the motor–limbic topographic manner, wherein the neurons of the dorsal interface because it receives significant pallidal inputs MHb innervate the lateral IPN, those of the medial as well as afferent connections from numerous Phil. Trans. R. Soc. B (2009) Review. The habenular nuclei I. H. Bianco & S. W. Wilson 1007 components of the limbic system. The LHb projects to 2007). For example, the LHb projects to the limbic a wide range of targets, especially
Recommended publications
  • The Connexions of the Amygdala
    J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.2.137 on 1 April 1965. Downloaded from J. Neurol. Neurosurg. Psychiat., 1965, 28, 137 The connexions of the amygdala W. M. COWAN, G. RAISMAN, AND T. P. S. POWELL From the Department of Human Anatomy, University of Oxford The amygdaloid nuclei have been the subject of con- to what is known of the efferent connexions of the siderable interest in recent years and have been amygdala. studied with a variety of experimental techniques (cf. Gloor, 1960). From the anatomical point of view MATERIAL AND METHODS attention has been paid mainly to the efferent connexions of these nuclei (Adey and Meyer, 1952; The brains of 26 rats in which a variety of stereotactic or Lammers and Lohman, 1957; Hall, 1960; Nauta, surgical lesions had been placed in the diencephalon and and it is now that there basal forebrain areas were used in this study. Following 1961), generally accepted survival periods of five to seven days the animals were are two main efferent pathways from the amygdala, perfused with 10 % formol-saline and after further the well-known stria terminalis and a more diffuse fixation the brains were either embedded in paraffin wax ventral pathway, a component of the longitudinal or sectioned on a freezing microtome. All the brains were association bundle of the amygdala. It has not cut in the coronal plane, and from each a regularly spaced generally been recognized, however, that in studying series was stained, the paraffin sections according to the Protected by copyright. the efferent connexions of the amygdala it is essential original Nauta and Gygax (1951) technique and the frozen first to exclude a contribution to these pathways sections with the conventional Nauta (1957) method.
    [Show full text]
  • L4-Physiology of Motor Tracts.Pdf
    : chapter 55 page 667 Objectives (1) Describe the upper and lower motor neurons. (2) Understand the pathway of Pyramidal tracts (Corticospinal & corticobulbar tracts). (3) Understand the lateral and ventral corticospinal tracts. (4) Explain functional role of corticospinal & corticobulbar tracts. (5) Describe the Extrapyramidal tracts as Rubrospinal, Vestibulospinal, Reticulospinal and Tectspinal Tracts. The name of the tract indicate its pathway, for example Corticobulbar : Terms: - cortico: cerebral cortex. Decustation: crossing. - Bulbar: brainstem. Ipsilateral : same side. *So it starts at cerebral cortex and Contralateral: opposite side. terminate at the brainstem. CNS influence the activity of skeletal muscle through two set of neurons : 1- Upper motor neurons (UMN) 2- lower motor neuron (LMN) They are neurons of motor cortex & their axons that pass to brain stem and They are Spinal motor neurons in the spinal spinal cord to activate: cord & cranial motor neurons in the brain • cranial motor neurons (in brainstem) stem which innervate muscles directly. • spinal motor neurons (in spinal cord) - These are the only neurons that innervate - Upper motor neurons (UMN) are the skeletal muscle fibers, they function as responsible for conveying impulses for the final common pathway, the final link voluntary motor activity through between the CNS and skeletal muscles. descending motor pathways that make up by the upper motor neurons. Lower motor neurons are classified based on the type of muscle fiber the innervate: There are two UMN Systems through which 1- alpha motor neurons (UMN) control (LMN): 2- gamma motor neurons 1- Pyramidal system (corticospinal tracts ). 2- Extrapyramidal system The activity of the lower motor neuron (LMN, spinal or cranial) is influenced by: 1.
    [Show full text]
  • Clones in the Chick Diencephalon Contain Multiple Cell Types and Siblings Are Widely Dispersed
    Development 122, 65-78 (1996) 65 Printed in Great Britain © The Company of Biologists Limited 1996 DEV8292 Clones in the chick diencephalon contain multiple cell types and siblings are widely dispersed Jeffrey A. Golden1,2 and Constance L. Cepko1,3 1Department of Genetics, Harvard Medical School, 2Department of Pathology, Brigham and Women’s Hospital, and 3Howard Hughes Medical Institute, 200 Longwood Avenue, Boston, MA 02115, USA SUMMARY The thalamus, hypothalamus and epithalamus of the ver- clones dispersed in all directions, resulting in sibling cells tebrate central nervous system are derived from the populating multiple nuclei within the diencephalon. In embryonic diencephalon. These regions of the nervous addition, several distinctive patterns of dispersion were system function as major relays between the telencephalon observed. These included clones with siblings distributed and more caudal regions of the brain. Early in develop- bilaterally across the third ventricle, clones that originated ment, the diencephalon morphologically comprises distinct in the lateral ventricle, clones that crossed neuromeric units known as neuromeres or prosomeres. As development boundaries, and clones that crossed major boundaries of proceeds, multiple nuclei, the functional and anatomical the developing nervous system, such as the diencephalon units of the diencephalon, derive from the neuromeres. It and mesencephalon. These findings demonstrate that prog- was of interest to determine whether progenitors in the enitor cells in the diencephalon are multipotent and that diencephalon give rise to daughters that cross nuclear or their daughters can become widely dispersed. neuromeric boundaries. To this end, a highly complex retroviral library was used to infect diencephalic progeni- tors. Retrovirally marked clones were found to contain Key words: cell lineage, central nervous system, diencephalon, neurons, glia and occasionally radial glia.
    [Show full text]
  • Anatomical Specificity of Septal Projections in Active and Passive Avoidance Behavior in Rats
    MATOMICAL SPECIFICITY OF SEPTAL PROJECTIONS IN ACTIVE AND PASSIVE AVOIDANCE BEHAVIOR IN RATS by GARY W. VAN HOESEN B. A., Humboldt State College 1965 A MASTER'S THESIS submitted in partial fulfillment of the requirements for the degree MASTER OF SCIENCE Department of Psychology KANSAS STATE UNIVERSITY Manhattan, Kansas 1968 Approved by: Ma/or Professor 7'/ 'VS^^^ 1'^^^ 0^ CONTENTS ACKNOWLEDGEMENTS iii INTRODUCTION 1 METHOD 2 Subjects 2 Apparatus 2 Surgery and Histology 3 Procedure Passive Avoidance I4 Active Avoidance 5 Retention 5 Massed Extinction 5 RESULTS 5 Histology 5 Passive Avoidance 20 Active Avoidance Retention Massed Extinction 28 DISCUSSION 21 BIBLIOGRAPHY 28 Ill ACraOVJLEDGEMNTS This research was conducted while the author was a National Aeronautics and Space Administration Pre-Doctorate Trainee. Additional support was pro- vided by an NIGMS Training Grant, GM I362 awarded to the Kansas State Univer- sity Departments of Psychology, Zoology, and Physiology. I thank Dr. James C. Mitchell for his generous contributions of his time and guidance in the preparation of this work, and Dr. Charles P. Thompson and Dr. Robert C. Haygood for their interest and helpful criticisms. Additionally I would like to thank Mr. Jim MacDougall for his aid in the execution and prepara- tion of this research. The beha.vicral effects of septal lesions have been intensely investigated in recent years. Experiments encompassing wide ranges of test conditions and laboratory species have implicated the septum in a broad spectrum of psycho- logical and physiological phenomena. The lesion induced effects, as reviewed by KcCleary (1966), incl.ude hyperirritabllity or hypersensitivity, enhanced performance on active avoidance, and decrements on passive avoidance, timdng, alternation, and position reversal.
    [Show full text]
  • Thalamus and Hypothalamus
    DIENCEPHALON: THALAMUS AND HYPOTHALAMUS M. O. BUKHARI 1 DIENCEPHALON: General Introduction • Relay & integrative centers between the brainstem & cerebral cortex • Dorsal-posterior structures • Epithalamus • Anterior & posterior paraventricular nuclei • Habenular nuclei – integrate smell & emotions • Pineal gland – monitors diurnal / nocturnal rhythm • Habenular Commissure • Post. Commissure • Stria Medullaris Thalami • Thalamus(Dorsal thalamus) • Metathalamus • Medial geniculate body – auditory relay • Lateral geniculate body – visual relay Hypothalamic sulcus • Ventral-anterior structure • Sub-thalums (Ventral Thalamus) • Sub-thalamic Nucleus • Zona Inserta • Fields of Forel • Hypothalamus M. O. BUKHARI 2 Introduction THE THALAMUS Location Function External features Size Interthalamic 3 cms length x 1.5 cms breadth adhesion Two ends Anterior end– Tubercle of Thalamus Posterior end– Pulvinar – Overhangs Med & Lat.Gen.Bodies, Sup.Colliculi & their brachia Surfaces Sup. Surface – Lat. Part forms central part of lat. Vent. Med. Part is covered by tela choroidea of 3rd vent. Inf. Surface - Ant. part fused with subthalamus - Post. part free – inf. part of Pulvinar Med. Surface – Greater part of Lat. wall of 3rd ventricle Lat. Surface - Med.boundary of Post. Limb of internal capsule M. O. BUKHARI 3 Function of the Thalamus • Sensory relay • ALL sensory information (except smell) • Motor integration • Input from cortex, cerebellum and basal ganglia • Arousal • Part of reticular activating system • Pain modulation • All nociceptive information • Memory & behavior • Lesions are disruptive M. O. BUKHARI 4 SUBDIVISION OF THALAMUS M. O. BUKHARI 5 SUBDIVISION OF THALAMUS: WHITE MATTER OF THE THALAMUS Internal Medullary Stratum Zonale Lamina External Medullary Lamina M. O. BUKHARI 6 LATERAL MEDIAL Nuclei of Thalamus Stratum Zonale Anterior Nucleus Medial Dorsal Lateral Dorsal (Large) EXT.Med.Lam ILN Ret.N CMN VPL MGB VPM PVN Lateral Ventral Medial Ventral LGB (Small) LD, LP, Pulvinar – Dorsal Tier nuclei Hypothalamus VA, VL, VPL, VPM – Ventral Tier nuclei M.
    [Show full text]
  • Agmatine Modulates Spontaneous Activity in Neurons of the Rat Medial
    Weiss et al. Translational Psychiatry (2018) 8:201 DOI 10.1038/s41398-018-0254-z Translational Psychiatry ARTICLE Open Access Agmatine modulates spontaneous activity in neurons of the rat medial habenular complex—a relevant mechanism in the pathophysiology and treatment of depression? Torsten Weiss1,RenéBernard2, Hans-Gert Bernstein3,RüdigerW.Veh1 and Gregor Laube1 Abstract The dorsal diencephalic conduction system connects limbic forebrain structures to monaminergic mesencephalic nuclei via a distinct relay station, the habenular complexes. Both habenular nuclei, the lateral as well as the medial nucleus, are considered to play a prominent role in mental disorders like major depression. Herein, we investigate the effect of the polyamine agmatine on the electrical activity of neurons within the medial habenula in rat. We present evidence that agmatine strongly decreases spontaneous action potential firing of medial habenular neurons by activating I1-type imidazoline receptors. Additionally, we compare the expression patterns of agmatinase, an enzyme capable of inactivating agmatine, in rat and human habenula. In the medial habenula of both species, agmatinase is similarly distributed and observed in neurons and, in particular, in distinct neuropil areas. The putative relevance of 1234567890():,; 1234567890():,; 1234567890():,; 1234567890():,; these findings in the context of depression is discussed. It is concluded that increased activity of the agmatinergic system in the medial habenula may strengthen midbrain dopaminergic activity. Consequently,
    [Show full text]
  • Lecture 12 Notes
    Somatic regions Limbic regions These functionally distinct regions continue rostrally into the ‘tweenbrain. Fig 11-4 Courtesy of MIT Press. Used with permission. Schneider, G. E. Brain structure and its Origins: In the Development and in Evolution of Behavior and the Mind. MIT Press, 2014. ISBN: 9780262026734. 1 Chapter 11, questions about the somatic regions: 4) There are motor neurons located in the midbrain. What movements do those motor neurons control? (These direct outputs of the midbrain are not a subject of much discussion in the chapter.) 5) At the base of the midbrain (ventral side) one finds a fiber bundle that shows great differences in relative size in different species. Give examples. What are the fibers called and where do they originate? 8) A decussating group of axons called the brachium conjunctivum also varies greatly in size in different species. It is largest in species with the largest neocortex but does not come from the neocortex. From which structure does it come? Where does it terminate? (Try to guess before you look it up.) 2 Motor neurons of the midbrain that control somatic muscles: the oculomotor nuclei of cranial nerves III and IV. At this level, the oculomotor nucleus of nerve III is present. Fibers from retina to Superior Colliculus Brachium of Inferior Colliculus (auditory pathway to thalamus, also to SC) Oculomotor nucleus Spinothalamic tract (somatosensory; some fibers terminate in SC) Medial lemniscus Cerebral peduncle: contains Red corticospinal + corticopontine fibers, + cortex to hindbrain fibers nucleus (n. ruber) Tectospinal tract Rubrospinal tract Courtesy of MIT Press. Used with permission. Schneider, G.
    [Show full text]
  • A Transmitter Candidate for the Retinohypothalamic Tract (Suprachiasmatic Nucleus/Supraoptic Nucleus/Peptide Immunohistochemistry/Circadian Rhythms) JOHN R
    Proc. Nati. Acad. Sci. USA Vol. 87, pp. 8065-8069, October 1990 Neurobiology N-Acetylaspartylglutamate: A transmitter candidate for the retinohypothalamic tract (suprachiasmatic nucleus/supraoptic nucleus/peptide immunohistochemistry/circadian rhythms) JOHN R. MOFFETT*, LuRA WILLIAMSON*, MIKLOS PALKOVITSt, AND M. A. A. NAMBOODIRI*t *Department of Biology, Georgetown University, Washington, D.C. 20057; and tLaboratory of Cell Biology, National Institute of Mental Health, Bethesda, MD 20892 Communicated by Dominick P. Purpura, July 2, 1990 ABSTRACT The retinohypothalamic tract is the neural mission in a number of sensory and motor systems in the pathway mediating the photic entrainment of circadian brain (15). Therefore, it was ofinterest to determine ifNAAG rhythms in mammals. Important targets for these retinal fibers could be identified in the terminal fields of the RHT within are the suprachiasmatic nuclei (SCN) of the hypothalamus, the hypothalamus. Here we present immunohistochemical which are thought to be primary sites for the biological clock. and radioimmunoassay data indicating extensive NAAG The neurotransmitters that operate in this projection system immunoreactivity (NAAG-IR) in the SCN and other target have not yet been determined. Immunohistochemistry and zones of the RHT in the rat. Further, the NAAG-IR in the radioimmunoassay performed with affinity-purified antibodies optic chiasm and SCN decreased substantially following to N-acetylaspartylglutamate (NAAG) demonstrate that this unilateral or bilateral optic nerve transections. This obser- neuron-specific dipeptide, which may act as an excitatory vation raises the possibility that NAAG may act as a trans- neurotransmitter, is localized extensively in the retinohypotha- mitter mediating the effects of light in the retinohypothalamic lamic tract and its target zones, including the SCN.
    [Show full text]
  • Microstimulation of the Midbrain Tegmentum Creates Learning Signals for Saccade Adaptation
    The Journal of Neuroscience, April 4, 2007 • 27(14):3759–3767 • 3759 Behavioral/Systems/Cognitive Microstimulation of the Midbrain Tegmentum Creates Learning Signals for Saccade Adaptation Yoshiko Kojima, Kaoru Yoshida, and Yoshiki Iwamoto Department of Neurophysiology, Doctoral Program in Kansei Behavioral and Brain Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8574, Japan Error signals are vital to motor learning. However, we know little about pathways that transmit error signals for learning in voluntary movements. Here we show that microstimulation of the midbrain tegmentum can induce learning in saccadic eye movements in mon- keys. Weak electrical stimuli delivered ϳ200 ms after saccades in one horizontal direction produced gradual and marked changes in saccade gain. The spatial and temporal characteristics of the produced changes were similar to those of adaptation induced by real visual error. When stimulation was applied after saccades in two different directions, endpoints of these saccades gradually shifted in the same direction in two dimensions. We conclude that microstimulation created powerful learning signals that dictate the direction of adaptive shift in movement endpoints. Our findings suggest that the error signals for saccade adaptation are conveyed in a pathway that courses through the midbrain tegmentum. Key words: motor learning; electrical stimulation; midbrain; saccade; adaptation; macaque; monkey Introduction superior colliculus, a key midbrain structure that issues saccade Motor learning ensures the accuracy of the movements we exe- signals to the premotor reticular circuitry (Scudder et al., 2002). cute daily. Vital to learning is the information about the error that The colliculus also has indirect access to the cerebellum via both results from executed movements.
    [Show full text]
  • The Effects of Habenular and Medial Forebrain Bundle Lesions on Sexual Behavior in Female Rats'
    The effects of habenular and medial forebrain bundle lesions on sexual behavior in female rats' CHARLES H. RODGERS:?, DEPARTMENT OF PHYSIOLOGY, STANFORD UNIVERSITY O. THOMAS LAW, DEPARTMENT OF PSYCHOLOGY, CLAREMONT GRADUATE SCHOOL A comparison was made of the effects of habenular and subsequent to the experiencing trials, the preoperative medial forebrain bundle lesions on female rat sexual behavior tests were initiated. Each S received one 15 min. trial as measured by the lordosis-to-mount ratio, and by the fe­ while nonreceptive and one 15 min. trial while receptive. male's avoidance of sexual contact. Results show that Receptivity was induced as described above. destruction of the habenulae causes a decreased lordosis Lesions were produced by monopolar stainless steel response, and a greater avoidance of male sexual contacts. electrodes, insulated except for .008 in. at the tip, under Medial forebrain bundle lesions had a less pronounced effect the following conditions: (1) Habenula (Hab)-2 rnA on the female's behavior. anodal current for 10 sec.; (2) Medial forebrain bundle (MFB)-2 rnA anodal current for 15 sec. Coordinates Few studies have reported the effects of subcortical for the target areas were obtained fromdeGroot(1959). destruction on copulatory behavior in the female rat. Copulatory tests were conducted in a cylindrical It is accepted that circumscribed destruction of the mating arena made of clear Plexiglas 18 in. high x anterior hypothalamus causes female rats to become 20 in. in diameter, supported on a table surfaced with anovulatory and behaviorally nonreceptive (Flerko, 1/2-in. hardware cloth. A mirror, fixed at an angle 1963).
    [Show full text]
  • Brain Structure and Function Related to Headache
    Review Cephalalgia 0(0) 1–26 ! International Headache Society 2018 Brain structure and function related Reprints and permissions: sagepub.co.uk/journalsPermissions.nav to headache: Brainstem structure and DOI: 10.1177/0333102418784698 function in headache journals.sagepub.com/home/cep Marta Vila-Pueyo1 , Jan Hoffmann2 , Marcela Romero-Reyes3 and Simon Akerman3 Abstract Objective: To review and discuss the literature relevant to the role of brainstem structure and function in headache. Background: Primary headache disorders, such as migraine and cluster headache, are considered disorders of the brain. As well as head-related pain, these headache disorders are also associated with other neurological symptoms, such as those related to sensory, homeostatic, autonomic, cognitive and affective processing that can all occur before, during or even after headache has ceased. Many imaging studies demonstrate activation in brainstem areas that appear specifically associated with headache disorders, especially migraine, which may be related to the mechanisms of many of these symptoms. This is further supported by preclinical studies, which demonstrate that modulation of specific brainstem nuclei alters sensory processing relevant to these symptoms, including headache, cranial autonomic responses and homeostatic mechanisms. Review focus: This review will specifically focus on the role of brainstem structures relevant to primary headaches, including medullary, pontine, and midbrain, and describe their functional role and how they relate to mechanisms
    [Show full text]
  • PACAP in Hypothalamic Regulation of Sleep and Circadian Rhythm: Importance for Headache Philip R
    Holland et al. The Journal of Headache and Pain (2018) 19:20 The Journal of Headache https://doi.org/10.1186/s10194-018-0844-4 and Pain REVIEWARTICLE Open Access PACAP in hypothalamic regulation of sleep and circadian rhythm: importance for headache Philip R. Holland1*, Mads Barloese2* and Jan Fahrenkrug3 Abstract The interaction between sleep and primary headaches has gained considerable interest due to their strong, bidirectional, clinical relationship. Several primary headaches demonstrate either a circadian/circannual rhythmicity in attack onset or are directly associated with sleep itself. Migraine and cluster headache both show distinct attack patterns and while the underlying mechanisms of this circadian variation in attack onset remain to be fully explored, recent evidence points to clear physiological, anatomical and genetic points of convergence. The hypothalamus has emerged as a key brain area in several headache disorders including migraine and cluster headache. It is involved in homeostatic regulation, including pain processing and sleep regulation, enabling appropriate physiological responses to diverse stimuli. It is also a key integrator of circadian entrainment to light, in part regulated by pituitary adenylate cyclase-activating peptide (PACAP). With its established role in experimental headache research the peptide has been extensively studied in relation to headache in both humans and animals, however, there are only few studies investigating its effect on sleep in humans. Given its prominent role in circadian entrainment, established in preclinical research, and the ability of exogenous PACAP to trigger attacks experimentally, further research is very much warranted. The current review will focus on the role of the hypothalamus in the regulation of sleep-wake and circadian rhythms and provide suggestions for the future direction of such research, with a particular focus on PACAP.
    [Show full text]