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Grujic N, Polania R, Burdakov D. Neurobehavioral meaning of pupil size. Neuron 2024:S0896-6273(24)00406-9. [PMID: 38925124 DOI: 10.1016/j.neuron.2024.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 03/22/2024] [Accepted: 05/31/2024] [Indexed: 06/28/2024]
Abstract
Pupil size is a widely used metric of brain state. It is one of the few signals originating from the brain that can be readily monitored with low-cost devices in basic science, clinical, and home settings. It is, therefore, important to investigate and generate well-defined theories related to specific interpretations of this metric. What exactly does it tell us about the brain? Pupils constrict in response to light and dilate during darkness, but the brain also controls pupil size irrespective of luminosity. Pupil size fluctuations resulting from ongoing "brain states" are used as a metric of arousal, but what is pupil-linked arousal and how should it be interpreted in neural, cognitive, and computational terms? Here, we discuss some recent findings related to these issues. We identify open questions and propose how to answer them through a combination of well-defined tasks, neurocomputational models, and neurophysiological probing of the interconnected loops of causes and consequences of pupil size.
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Affiliation(s)
- Nikola Grujic
- Neurobehavioural Dynamics Lab, ETH Zürich, Department of Health Sciences and Technology, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland.
| | - Rafael Polania
- Decision Neuroscience Lab, ETH Zürich, Department of Health Sciences and Technology, Winterthurstrasse 190, 8057 Zürich, Switzerland
| | - Denis Burdakov
- Neurobehavioural Dynamics Lab, ETH Zürich, Department of Health Sciences and Technology, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland.
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2
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Miglis MG. Autonomic Dysfunction in the Central Nervous System Hypersomnias. CURRENT SLEEP MEDICINE REPORTS 2023. [DOI: 10.1007/s40675-023-00247-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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3
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Knez R, Stevanovic D, Fernell E, Gillberg C. Orexin/Hypocretin System Dysfunction in ESSENCE (Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations). Neuropsychiatr Dis Treat 2022; 18:2683-2702. [PMID: 36411777 PMCID: PMC9675327 DOI: 10.2147/ndt.s358373] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 07/28/2022] [Indexed: 11/17/2022] Open
Abstract
Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations (ESSENCE) is an umbrella term covering a wide range of neurodevelopmental difficulties and disorders. Thus, ESSENCE includes attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and other neurodevelopmental disorders (NDDs) and difficulties, with a variety of symptoms in cognitive, motor, sensory, social, arousal, regulatory, emotional, and behavioral developmental domains, frequently co-occurring and likely having partly common neurobiological substrates. The ESSENCE concept is a clinical paradigm that promotes organizing NDDs in everyday clinical practice according to their coexistence, symptom dimensions overlapping, and treatment possibilities. Despite increased knowledge regarding NDDs, the neurobiological mechanisms that underlie them and other ESSENCE-related problems, are not well understood. With its wide range of neural circuits and interactions with numerous neurotransmitters, the orexin/hypocretin system (Orx-S) is possibly associated with a variety of neurocognitive, psychobiological, neuroendocrine, and physiological functions and behaviors. Dysfunction of Orx-S has been implicated in various psychiatric and neurological disorders. This article provides an overview of Orx-S dysfunctions' possible involvement in the development, presentation, and maintenance of ESSENCE. We provide a focused review of current research evidence linking orexin neuropeptides with specific clinical NDDs symptoms, mostly in ADHD and ASD, within the Research Domain Criteria (RDoC) framework. We propose that Orx-S dysfunction might have an important role in some of these neurodevelopmental symptom domains, such as arousal, wakefulness, sleep, motor and sensory processing, mood and emotional regulation, fear processing, reward, feeding, attention, executive functions, and sociability. Our perspective is presented from a clinical point of view. Further, more thorough systematic reviews are needed as well as planning of extensive new research into the Orx-S's role in ESSENCE, especially considering RDoC elements.
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Affiliation(s)
- Rajna Knez
- Gillberg Neuropsychiatry Centre, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Pediatrics, Skaraborg Hospital, Skövde, Sweden
- School of Health Sciences, University of Skövde, Skövde, Sweden
| | - Dejan Stevanovic
- Gillberg Neuropsychiatry Centre, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Elisabeth Fernell
- Gillberg Neuropsychiatry Centre, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Christopher Gillberg
- Gillberg Neuropsychiatry Centre, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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4
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Otaiku AI. Awakening Ptosis: A Clinical Review. Neuroophthalmology 2019; 43:26-31. [PMID: 30723521 DOI: 10.1080/01658107.2018.1474371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 04/30/2018] [Accepted: 05/05/2018] [Indexed: 10/14/2022] Open
Abstract
A rare condition characterized by a transient inability to open one or both eyes upon awakening from sleep was first described in 1897. Although less than a handful of papers have been written about this condition since its initial description, a well-defined clinical entity emerges from the available literature. This article reviews the history and clinical features of this unusual condition.
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5
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The distinguishing motor features of cataplexy: a study from video-recorded attacks. Sleep 2018; 41:4841988. [DOI: 10.1093/sleep/zsy026] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Indexed: 11/12/2022] Open
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Tang X, Büttner-Ennever JA, Mustari MJ, Horn AKE. Internal organization of medial rectus and inferior rectus muscle neurons in the C group of the oculomotor nucleus in monkey. J Comp Neurol 2015; 523:1809-23. [PMID: 25684641 DOI: 10.1002/cne.23760] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 02/08/2015] [Accepted: 02/09/2015] [Indexed: 11/11/2022]
Abstract
Mammalian extraocular muscles contain singly innervated twitch muscle fibers (SIF) and multiply innervated nontwitch muscle fibers (MIF). In monkey, MIF motoneurons lie around the periphery of oculomotor nuclei and have premotor inputs different from those of the motoneurons inside the nuclei. The most prominent MIF motoneuron group is the C group, which innervates the medial rectus (MR) and inferior rectus (IR) muscle. To explore the organization of both cell groups within the C group, we performed small injections of choleratoxin subunit B into the myotendinous junction of MR or IR in monkeys. In three animals the IR and MR myotendinous junction of one eye was injected simultaneously with different tracers (choleratoxin subunit B and wheat germ agglutinin). This revealed that both muscles were supplied by two different, nonoverlapping populations in the C group. The IR neurons lie adjacent to the dorsomedial border of the oculomotor nucleus, whereas MR neurons are located farther medially. A striking feature was the differing pattern of dendrite distribution of both cell groups. Whereas the dendrites of IR neurons spread into the supraoculomotor area bilaterally, those of the MR neurons were restricted to the ipsilateral side and sent a focused bundle dorsally to the preganglionic neurons of the Edinger-Westphal nucleus, which are involved in the "near response." In conclusion, MR and IR are innervated by independent neuron populations from the C group. Their dendritic branching pattern within the supraoculomotor area indicates a participation in the near response providing vergence but also reflects their differing functional roles.
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Affiliation(s)
- Xiaofang Tang
- Institute of Anatomy and Cell Biology, Department I, Ludwig-Maximilians-University of Munich, D-80336, Munich, Germany
| | - Jean A Büttner-Ennever
- Institute of Anatomy and Cell Biology, Department I, Ludwig-Maximilians-University of Munich, D-80336, Munich, Germany
| | - Michael J Mustari
- Washington National Primate Research Center and Department of Ophthalmology, University of Washington, Seattle, Washington, 98195
| | - Anja K E Horn
- Institute of Anatomy and Cell Biology, Department I, Ludwig-Maximilians-University of Munich, D-80336, Munich, Germany
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7
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Sun W, May PJ. Central pupillary light reflex circuits in the cat: II. Morphology, ultrastructure, and inputs of preganglionic motoneurons. J Comp Neurol 2014; 522:3978-4002. [PMID: 24706263 PMCID: PMC4185308 DOI: 10.1002/cne.23601] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 03/08/2014] [Accepted: 04/03/2014] [Indexed: 01/26/2023]
Abstract
Preganglionic motoneurons supplying the ciliary ganglion control lens accommodation and pupil diameter. In cats, these motoneurons make up the preganglionic Edinger-Westphal population, which lies rostral, dorsal, and ventral to the oculomotor nucleus. A recent cat study suggested that caudal motoneurons control the lens and rostral motoneurons control the pupil. This led us to examine the morphology, ultrastructure, and pretectal inputs of these populations. Preganglionic motoneurons retrogradely labeled by introducing tracer into the cat ciliary ganglion generally fell into two morphologic categories. Fusiform neurons were located rostrally, in the anteromedian nucleus and between the oculomotor nuclei. Multipolar neurons were found caudally, dorsal and ventral to the oculomotor nucleus. The dendrites of preganglionic motoneurons within the anteromedian nucleus crossed the midline, providing a possible basis for consensual responses. Ultrastructurally, several different classes of synaptic profiles contact preganglionic motoneurons, suggesting that their activity may be modified by a variety of inputs. Furthermore, there were differences in the synaptic populations contacting the rostral vs. caudal populations, supporting the contention that these populations display functional differences. Anterogradely labeled pretectal terminals were observed in close association with labeled preganglionic motoneurons, particularly in the rostral population. Ultrastructural analysis revealed that these terminals, packed with clear, spherical vesicles, made asymmetric synaptic contacts onto motoneurons in the rostral population, indicating that these cells serve the pupillary light reflex. Thus, the preganglionic motoneurons found in the cat display morphologic, ultrastructural, and connectional differences suggesting that this rostral preganglionic population is specialized for pupil control, whereas more caudal elements control the lens.
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Affiliation(s)
- Wensi Sun
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi, 39216
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Hu B, Yang N, Qiao QC, Hu ZA, Zhang J. Roles of the orexin system in central motor control. Neurosci Biobehav Rev 2014; 49:43-54. [PMID: 25511388 DOI: 10.1016/j.neubiorev.2014.12.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 11/10/2014] [Accepted: 12/03/2014] [Indexed: 12/15/2022]
Abstract
The neuropeptides orexin-A and orexin-B are produced by one group of neurons located in the lateral hypothalamic/perifornical area. However, the orexins are widely released in entire brain including various central motor control structures. Especially, the loss of orexins has been demonstrated to associate with several motor deficits. Here, we first summarize the present knowledge that describes the anatomical and morphological connections between the orexin system and various central motor control structures. In the next section, the direct influence of orexins on related central motor control structures is reviewed at molecular, cellular, circuitry, and motor activity levels. After the summarization, the characteristic and functional relevance of the orexin system's direct influence on central motor control function are demonstrated and discussed. We also propose a hypothesis as to how the orexin system orchestrates central motor control in a homeostatic regulation manner. Besides, the importance of the orexin system's phasic modulation on related central motor control structures is highlighted in this regulation manner. Finally, a scheme combining the homeostatic regulation of orexin system on central motor control and its effects on other brain functions is presented to discuss the role of orexin system beyond the pure motor activity level, but at the complex behavioral level.
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Affiliation(s)
- Bo Hu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China
| | - Nian Yang
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China
| | - Qi-Cheng Qiao
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China
| | - Zhi-An Hu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China.
| | - Jun Zhang
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China.
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Klein G, Burghaus L, Vaillant M, Pieri V, Fink GR, Diederich N. Dysautonomia in narcolepsy: evidence by questionnaire assessment. J Clin Neurol 2014; 10:314-9. [PMID: 25324880 PMCID: PMC4198712 DOI: 10.3988/jcn.2014.10.4.314] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/14/2014] [Accepted: 07/16/2014] [Indexed: 12/24/2022] Open
Abstract
Background and Purpose Excessive daytime sleepiness and sudden sleep attacks are the main features of narcolepsy, but rapid-eye-movement sleep behavior disorder (RBD), hyposmia, and depression can also occur. The latter symptoms are nonmotor features in idiopathic Parkinson's disease (IPD). In the present study, IPD-proven diagnostic tools were tested to determine whether they are also applicable in the assessment of narcolepsy. Methods This was a case-control study comparing 15 patients with narcolepsy (PN) and 15 control subjects (CS) using the Scales for Outcomes in Parkinson's Autonomic Test (SCOPA-AUT), Parkinson's Disease Nonmotor Symptoms (PDNMS), University of Pennsylvania Smell Test, Farnsworth-Munsell 100 Hue test, Beck Depression Inventory, and the RBD screening questionnaire. Results Both the PN and CS exhibited mild hyposmia and no deficits in visual tests. Frequent dysautonomia in all domains except sexuality was found for the PN. The total SCOPA-AUT score was higher for the PN (18.47±10.08, mean±SD) than for the CS (4.40±3.09), as was the PDNMS score (10.53±4.78 and 1.80±2.31, respectively). RBD was present in 87% of the PN and 0% of the CS. The PN were more depressed than the CS. The differences between the PN and CS for all of these variables were statistically significant (all p<0.05). Conclusions The results of this study provide evidence for the presence of dysautonomia and confirm the comorbidities of depression and RBD in narcolepsy patients. The spectrum, which is comparable to the nonmotor complex in IPD, suggests wide-ranging, clinically detectable dysfunction beyond the narcoleptic core syndrome.
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Affiliation(s)
- Gilles Klein
- Department of Neurosciences, Centre Hospitalier de Luxembourg, Luxembourg-City, Luxembourg. ; Department of Internal Medicine, Brothers of Charity Hospital, Trier, Germany
| | - Lothar Burghaus
- Department of Neurology, University Hospital of Cologne, Cologne, Germany
| | - Michel Vaillant
- Competences Center for Methodology and Statistics, CRP Santé, Strassen, Luxembourg
| | - Vannina Pieri
- Department of Neurosciences, Centre Hospitalier de Luxembourg, Luxembourg-City, Luxembourg
| | - Gereon R Fink
- Department of Neurology, University Hospital of Cologne, Cologne, Germany. ; Institute of Neuroscience and Medicine (INM-3), Cognitive Neuroscience, Research Centre Juelich, Juelich, Germany
| | - Nico Diederich
- Department of Neurosciences, Centre Hospitalier de Luxembourg, Luxembourg-City, Luxembourg. ; Department of Neurology, University Hospital of Cologne, Cologne, Germany
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Zeeh C, Hess BJ, Horn AKE. Calretinin inputs are confined to motoneurons for upward eye movements in monkey. J Comp Neurol 2014; 521:3154-66. [PMID: 23696443 DOI: 10.1002/cne.23337] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 03/13/2013] [Accepted: 03/29/2013] [Indexed: 11/11/2022]
Abstract
Motoneurons of extraocular muscles are controlled by different premotor pathways, whose selective damage may cause directionally selective eye movement disorders. The fact that clinical disorders can affect only one direction, e.g., isolated up-/downgaze palsy or up-/downbeat nystagmus, indicates that up- and downgaze pathways are organized separately. Recent work in monkey revealed that a subpopulation of premotor neurons of the vertical eye movement system contains the calcium-binding protein calretinin (CR). With combined tract-tracing and immunofluorescence, the motoneurons of vertically pulling eye muscles in monkey were investigated for the presence of CR-positive afferent terminals. In the oculomotor nucleus, CR was specifically found in punctate profiles contacting superior rectus and inferior oblique motoneurons, as well as levator palpebrae motoneurons, all of which participate in upward eye movements. Double-immunofluorescence labeling revealed that CR-positive terminals lacked the γ-aminobutyric acid (GABA)-synthesizing enzyme glutamate decarboxylase, which is present in inhibitory afferents to all motoneurons mediating vertical eye movements. Therefore, CR-containing afferents are considered to be excitatory. In conclusion, a strong CR input is confined to motoneurons mediating upgaze, which derive from premotor pathways mediating saccades and smooth pursuit, but not from secondary vestibulo-ocular neurons in the magnocellular part of the medial vestibular nucleus. The functional significance of CR in these connections is unclear, but it may serve as a useful marker to locate upgaze pathways in the human brain.
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Affiliation(s)
- Christina Zeeh
- German Center for Vertigo and Balance Disorders, University of Munich, 81377 Munich, Germany
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11
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Pizza F, Franceschini C, Peltola H, Vandi S, Finotti E, Ingravallo F, Nobili L, Bruni O, Lin L, Edwards MJ, Partinen M, Dauvilliers Y, Mignot E, Bhatia KP, Plazzi G. Clinical and polysomnographic course of childhood narcolepsy with cataplexy. ACTA ACUST UNITED AC 2013; 136:3787-95. [PMID: 24142146 PMCID: PMC3859221 DOI: 10.1093/brain/awt277] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Our aim was to investigate the natural evolution of cataplexy and polysomnographic features in untreated children with narcolepsy with cataplexy. To this end, clinical, polysomnographic, and cataplexy-video assessments were performed at diagnosis (mean age of 10 ± 3 and disease duration of 1 ± 1 years) and after a median follow-up of 3 years from symptom onset (mean age of 12 ± 4 years) in 21 children with narcolepsy with cataplexy and hypocretin 1 deficiency (tested in 19 subjects). Video assessment was also performed in two control groups matched for age and sex at first evaluation and follow-up and was blindly scored for presence of hypotonic (negative) and active movements. Patients’ data at diagnosis and at follow-up were contrasted, compared with controls, and related with age and disease duration. At diagnosis children with narcolepsy with cataplexy showed an increase of sleep time during the 24 h; at follow-up sleep time and nocturnal sleep latency shortened, in the absence of other polysomnographic or clinical (including body mass index) changes. Hypotonic phenomena and selected facial movements decreased over time and, tested against disease duration and age, appeared as age-dependent. At onset, childhood narcolepsy with cataplexy is characterized by an abrupt increase of total sleep over the 24 h, generalized hypotonia and motor overactivity. With time, the picture of cataplexy evolves into classic presentation (i.e. brief muscle weakness episodes triggered by emotions), whereas total sleep time across the 24 h decreases, returning to more age-appropriate levels.
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Affiliation(s)
- Fabio Pizza
- 1 Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
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Chase MH. A unified survival theory of the functioning of the hypocretinergic system. J Appl Physiol (1985) 2013; 115:954-71. [PMID: 23640599 DOI: 10.1152/japplphysiol.00700.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
This article advances the theory that the hypocretinergic (orexinergic) system initiates, coordinates, and maintains survival behaviors and survival-related processes (i.e., the Unified Survival Theory of the Functioning of the Hypocretinergic System or "Unified Hypocretinergic Survival Theory"). A priori presumptive support for the Unified Hypocretinergic Survival Theory emanates from the fact that neurons that contain hypocretin are located in the key executive central nervous system (CNS) site, the lateral hypothalamus, that for decades has been well-documented to govern core survival behaviors such as fight, flight, and food consumption. In addition, the hypocretinergic system exhibits the requisite morphological and electrophysiological capabilities to control survival behaviors and related processes. Complementary behavioral data demonstrate that all facets of "survival" are coordinated by the hypocretinergic system and that hypocretinergic directives are not promulgated except during survival behaviors. Importantly, it has been shown that survival behaviors are selectively impacted when the hypocretinergic system is impaired or rendered nonfunctional, whereas other behaviors are relatively unaffected. The Unified Hypocretinergic Survival Theory resolves the disparate, perplexing, and often paradoxical-appearing results of previous studies; it also provides a foundation for future hypothesis-driven basic science and clinical explorations of the hypocretinergic system.
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Affiliation(s)
- Michael H Chase
- WebSciences International, Veterans Affairs-Greater Los Angeles Healthcare System, University of California, Los Angeles School of Medicine, Los Angeles, California
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King WM. Binocular coordination of eye movements--Hering's Law of equal innervation or uniocular control? Eur J Neurosci 2011; 33:2139-46. [PMID: 21645107 DOI: 10.1111/j.1460-9568.2011.07695.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The neurophysiological basis for binocular control of eye movements in primates has been characterized by a scientific controversy that has its origin in the historical conflict of Hering and Helmholtz in the 19th century. This review focuses on two hypotheses, linked to that conflict, that seek to account for binocular coordination - Hering's Law vs. uniocular control of each eye. In an effort to manage the length of the review, the focus is on extracellular single-unit studies of premotor eye movement cells and extraocular motoneurons. In the latter half of the 20th century, these studies provided a wealth of neurophysiological data pertaining to the control of vergence and conjugate eye movements. The data were initially supportive of Hering's Law. More recent data, however, have provided support for uniocular control of each eye consistent with Helmholtz's original idea. The controversy is far from resolved. New anatomical descriptions of the disparate inputs to multiply and singly innervated extraocular muscle fibers challenge the concept of a 'final common pathway' as they suggest there may be separate groups of motoneurons involved in vergence and conjugate control of eye position. These data provide a new challenge for interpretation of uniocular premotor control networks and how they cooperate to produce coordinated eye movements.
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Affiliation(s)
- W M King
- University of Michigan, 1500 East Medical Center Drive, Ann Arbor, MI 48109-5816, USA.
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Plazzi G, Pizza F, Palaia V, Franceschini C, Poli F, Moghadam KK, Cortelli P, Nobili L, Bruni O, Dauvilliers Y, Lin L, Edwards MJ, Mignot E, Bhatia KP. Complex movement disorders at disease onset in childhood narcolepsy with cataplexy. ACTA ACUST UNITED AC 2011; 134:3477-89. [PMID: 21930661 PMCID: PMC3235554 DOI: 10.1093/brain/awr244] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Narcolepsy with cataplexy is characterized by daytime sleepiness, cataplexy (sudden loss of bilateral muscle tone triggered by emotions), sleep paralysis, hypnagogic hallucinations and disturbed nocturnal sleep. Narcolepsy with cataplexy is most often associated with human leucocyte antigen-DQB1*0602 and is caused by the loss of hypocretin-producing neurons in the hypothalamus of likely autoimmune aetiology. Noting that children with narcolepsy often display complex abnormal motor behaviours close to disease onset that do not meet the classical definition of cataplexy, we systematically analysed motor features in 39 children with narcolepsy with cataplexy in comparison with 25 age- and sex-matched healthy controls. We found that patients with narcolepsy with cataplexy displayed a complex array of ‘negative’ (hypotonia) and ‘active’ (ranging from perioral movements to dyskinetic–dystonic movements or stereotypies) motor disturbances. ‘Active’ and ‘negative’ motor scores correlated positively with the presence of hypotonic features at neurological examination and negatively with disease duration, whereas ‘negative’ motor scores also correlated negatively with age at disease onset. These observations suggest that paediatric narcolepsy with cataplexy often co-occurs with a complex movement disorder at disease onset, a phenomenon that may vanish later in the course of the disease. Further studies are warranted to assess clinical course and whether the associated movement disorder is also caused by hypocretin deficiency or by additional neurochemical abnormalities.
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Affiliation(s)
- Giuseppe Plazzi
- Department of Neurological Sciences, University of Bologna, 40123 Bologna, Italy.
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Plazzi G, Moghadam KK, Maggi LS, Donadio V, Vetrugno R, Liguori R, Zoccoli G, Poli F, Pizza F, Pagotto U, Ferri R. Autonomic disturbances in narcolepsy. Sleep Med Rev 2011; 15:187-96. [PMID: 20634114 DOI: 10.1016/j.smrv.2010.05.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 05/14/2010] [Accepted: 05/21/2010] [Indexed: 11/24/2022]
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16
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Prasad B, Choi YK, Weaver TE, Carley DW. Pupillometric assessment of sleepiness in narcolepsy. Front Psychiatry 2011; 2:35. [PMID: 21713070 PMCID: PMC3113169 DOI: 10.3389/fpsyt.2011.00035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 05/26/2011] [Indexed: 11/13/2022] Open
Abstract
PURPOSE Excessive daytime sleepiness is highly prevalent in the general population, is the hallmark of narcolepsy, and is linked to significant morbidity. Clinical assessment of sleepiness remains challenging and the common objective multiple sleep latency test (MSLT) and subjective Epworth sleepiness scale (ESS) methods correlate poorly. We examined the relative utility of pupillary unrest index (PUI) as an objective measure of sleepiness in a group of unmedicated narcoleptics and healthy controls in a prospective, observational pilot study. METHODS Narcolepsy (n = 20; untreated for >2 weeks) and control (n = 56) participants were tested under the same experimental conditions; overnight polysomnography was performed on all participants, followed by a daytime testing protocol including: MSLT, PUI, sleepiness visual analog scale (VAS), ESS, and the psychomotor vigilance test (PVT). RESULTS The narcolepsy and control groups differed significantly on psychomotor performance and each measure of objective and subjective sleepiness, including PUI. Across the entire sample, PUI correlated significantly with objective (mean sleep latency, SL) and subjective (ESS and VAS) sleepiness, but none of the sleepiness measures correlated with performance (PVT). Among narcoleptics, VAS correlated with PVT measures. Within the control group, mean PUI was the only objective sleepiness measure that correlated with subjective sleepiness. Finally, in an ANCOVA model, SL and ESS were significantly predictive of PUI as measure of sleepiness. CONCLUSION The role of PUI in quantifying and distinguishing sleepiness of narcolepsy from sleep-satiated healthy controls merits further investigation as it is a portable, brief, and objective test.
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Affiliation(s)
- Bharati Prasad
- Center for Narcolepsy, Sleep and Health Research, University of Illinois at Chicago Chicago, IL, USA
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