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Oculomotor circuit

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https://www.readbyqxmd.com/read/28515286/responses-of-purkinje-cells-in-the-oculomotor-vermis-of-monkeys-during-smooth-pursuit-eye-movements-and-saccades-comparison-with-floccular-complex
#1
Ramanujan T Raghavan, Stephen G Lisberger
We recorded the responses of Purkinje cells in the oculomotor vermis during smooth pursuit and saccadic eye movements. Our goal was to characterize the responses in the vermis using approaches that would allow direct comparisons with responses of Purkinje cells in another cerebellar area for pursuit, the floccular complex. Simple-spike firing of vermis Purkinje cells is direction selective during both pursuit and saccades, but the preferred directions are sufficiently independent so that downstream circuits could decode signals to drive pursuit and saccades separately...
May 17, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28452866/effects-of-dopamine-and-norepinephrine-on-exercise-induced-oculomotor-fatigue
#2
Charlotte J W Connell, Benjamin Thompson, Jason Turuwhenua, Alexa Srzich, Nicholas Gant
INTRODUCTION: Fatigue-induced impairments in the control of eye movements are detectable via reduced eye movement velocity following a bout of prolonged, strenuous exercise. Slower eye movements caused by neural fatigue within the oculomotor system can be prevented by caffeine and upregulation of central catecholamines may be responsible for this effect. This study explored the individual contribution of dopamine and norepinephrine to fatigue-related impairments in oculomotor control...
April 28, 2017: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/28443002/to-wait-or-not-to-wait-separate-mechanisms-in-the-oculomotor-circuit-of-basal-ganglia
#3
Masaharu Yasuda, Okihide Hikosaka
We reach a goal immediately after detecting the target, or later by withholding the immediate action. Each time, we choose one of these actions by suppressing the other. How does the brain control these antagonistic actions? We hypothesized that the output of basal ganglia (BG), substantia nigra pars reticulata (SNr), suppresses antagonistic oculomotor signals by sending strong inhibitory output to superior colliculus (SC). To test this hypothesis, we trained monkeys to perform two kinds of saccade task: Immediate (visually guided) and delayed (visually-withheld but memory-guided) saccade tasks...
2017: Frontiers in Neuroanatomy
https://www.readbyqxmd.com/read/28258438/clinical-application-of-eye-movement-tasks-as-an-aid-to-understanding-parkinson-s-disease-pathophysiology
#4
REVIEW
Kikuro Fukushima, Junko Fukushima, Graham R Barnes
Parkinson's disease (PD) is a progressive neurodegenerative disorder of the basal ganglia. Most PD patients suffer from somatomotor and oculomotor disorders. The oculomotor system facilitates obtaining accurate information from the visual world. If a target moves slowly in the fronto-parallel plane, tracking eye movements occur that consist primarily of smooth-pursuit interspersed with corrective saccades. Efficient smooth-pursuit requires appropriate target selection and predictive compensation for inherent processing delays...
March 3, 2017: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/28226411/the-control-of-eye-movements-by-the-cerebellar-nuclei-polysynaptic-projections-from-the-fastigial-interpositus-posterior-and-dentate-nuclei-to-lateral-rectus-motoneurons-in-primates
#5
Vincent Prevosto, Werner Graf, Gabriella Ugolini
Premotor circuits driving extraocular motoneurons and downstream motor outputs of cerebellar nuclei are well known. However, there is, as yet, no unequivocal account of cerebellar output pathways controlling eye movements in primates. Using retrograde transneuronal transfer of rabies virus from the lateral rectus (LR) eye muscle, we studied polysynaptic pathways to LR motoneurons in primates. Injections were placed either into the central or distal muscle portion, to identify innervation differences of LR motoneurons supplying singly innervated (SIFs) or multiply innervated muscle fibers (MIFs)...
February 22, 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/28177526/segregated-fronto-cortical-and-midbrain-connections-in-the-mouse-and-their-relation-to-approach-and-avoidance-orienting-behaviors
#6
Michael Anthony Savage, Richard McQuade, Alexander Thiele
The orchestration of orienting behaviors requires the interaction of many cortical and subcortical areas, for example the superior colliculus (SC), as well as prefrontal areas responsible for top-down control. Orienting involves different behaviors, such as approach and avoidance. In the rat, these behaviors are at least partially mapped onto different SC subdomains, the lateral (SCl) and medial (SCm), respectively. To delineate the circuitry involved in the two types of orienting behavior in mice, we injected retrograde tracer into the intermediate and deep layers of the SCm and SCl, and thereby determined the main input structures to these subdomains...
June 1, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28053244/distinct-neural-circuits-for-control-of-movement-vs-holding-still
#7
REVIEW
Reza Shadmehr
In generating a point-to-point movement, the brain does more than produce the transient commands needed to move the body part; it also produces the sustained commands that are needed to hold the body part at its destination. In the oculomotor system, these functions are mapped onto two distinct circuits: a premotor circuit that specializes in generating the transient activity that displaces the eyes and a "neural integrator" that transforms that transient input into sustained activity that holds the eyes. Different parts of the cerebellum adaptively control the motor commands during these two phases: the oculomotor vermis participates in fine tuning the transient neural signals that move the eyes, monitoring the activity of the premotor circuit via efference copy, whereas the flocculus participates in controlling the sustained neural signals that hold the eyes, monitoring the activity of the neural integrator...
April 1, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28028221/stable-population-coding-for-working-memory-coexists-with-heterogeneous-neural-dynamics-in-prefrontal-cortex
#8
John D Murray, Alberto Bernacchia, Nicholas A Roy, Christos Constantinidis, Ranulfo Romo, Xiao-Jing Wang
Working memory (WM) is a cognitive function for temporary maintenance and manipulation of information, which requires conversion of stimulus-driven signals into internal representations that are maintained across seconds-long mnemonic delays. Within primate prefrontal cortex (PFC), a critical node of the brain's WM network, neurons show stimulus-selective persistent activity during WM, but many of them exhibit strong temporal dynamics and heterogeneity, raising the questions of whether, and how, neuronal populations in PFC maintain stable mnemonic representations of stimuli during WM...
January 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27989457/bk-channels-are-required-for-multisensory-plasticity-in-the-oculomotor-system
#9
Alexandra B Nelson, Michael Faulstich, Setareh Moghadam, Kimberly Onori, Andrea Meredith, Sascha du Lac
Neural circuits are endowed with several forms of intrinsic and synaptic plasticity that could contribute to adaptive changes in behavior, but circuit complexities have hindered linking specific cellular mechanisms with their behavioral consequences. Eye movements generated by simple brainstem circuits provide a means for relating cellular plasticity to behavioral gain control. Here we show that firing rate potentiation, a form of intrinsic plasticity mediated by reductions in BK-type calcium-activated potassium currents in spontaneously firing neurons, is engaged during optokinetic reflex compensation for inner ear dysfunction...
January 4, 2017: Neuron
https://www.readbyqxmd.com/read/27916956/functional-diversity-of-neurotrophin-actions-on-the-oculomotor-system
#10
REVIEW
Beatriz Benítez-Temiño, María A Davis-López de Carrizosa, Sara Morcuende, Esperanza R Matarredona, Rosa R de la Cruz, Angel M Pastor
Neurotrophins play a principal role in neuronal survival and differentiation during development, but also in the maintenance of appropriate adult neuronal circuits and phenotypes. In the oculomotor system, we have demonstrated that neurotrophins are key regulators of developing and adult neuronal properties, but with peculiarities depending on each neurotrophin. For instance, the administration of NGF (nerve growth factor), BDNF (brain-derived neurotrophic factor) or NT-3 (neurotrophin-3) protects neonatal extraocular motoneurons from cell death after axotomy, but only NGF and BDNF prevent the downregulation in ChAT (choline acetyltransferase)...
December 1, 2016: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/27844097/the-effects-of-unilateral-versus-bilateral-subthalamic-nucleus-deep-brain-stimulation-on-prosaccades-and-antisaccades-in-parkinson-s-disease
#11
Lisa C Goelz, Fabian J David, John A Sweeney, David E Vaillancourt, Howard Poizner, Leonard Verhagen Metman, Daniel M Corcos
Unilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) in patients with Parkinson's disease improves skeletomotor function assessed clinically, and bilateral STN DBS improves motor function to a significantly greater extent. It is unknown whether unilateral STN DBS improves oculomotor function and whether bilateral STN DBS improves it to a greater extent. Further, it has also been shown that bilateral, but not unilateral, STN DBS is associated with some impaired cognitive-motor functions. The current study compared the effect of unilateral and bilateral STN DBS on sensorimotor and cognitive aspects of oculomotor control...
February 2017: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/27833536/patterns-of-activity-in-the-human-frontal-and-parietal-cortex-differentiate-large-and-small-saccades
#12
Marie-Hélène Grosbras
A vast literature indicates that small and large saccades, respectively, subserve different perceptual and cognitive strategies and may rely on different programming modes. While it is well-established that in monkeys' main oculomotor brain regions small and large eye movements are controlled by segregated neuronal populations, the representation of saccade amplitude in the human brain remains unclear. To address this question we used functional magnetic resonance imaging to scan participants while they performed saccades toward targets at either short (4°) or large (30°) eccentricity...
2016: Frontiers in Integrative Neuroscience
https://www.readbyqxmd.com/read/27793591/association-between-comt-genotype-and-the-control-of-memory-guided-saccades-individual-differences-in-healthy-adults-reveal-a-detrimental-role-of-dopamine
#13
Jutta Billino, Jürgen Hennig, Karl R Gegenfurtner
The neural circuits involved in oculomotor control are well described; however, neuromodulation of eye movements is still hardly understood. Memory guided saccades have been extensively studied and in particular neurophysiological evidence from monkey studies points to a crucial functional role of prefrontal dopamine activity. We exploited individual differences in dopamine regulation due to the well established COMT (catechol-O-methyltransferase) Val(158)Met polymorphism to explore the link between prefrontal dopamine activity and memory guided saccades in healthy subjects...
December 15, 2016: Vision Research
https://www.readbyqxmd.com/read/27781300/functional-synergy-between-postural-and-visual-behaviors-when-performing-a-difficult-precise-visual-task-in-upright-stance
#14
Cédrick T Bonnet, Sébastien Szaffarczyk, Stéphane Baudry
Previous works usually report greater postural stability in precise visual tasks (e.g., gaze-shift tasks) than in stationary-gaze tasks. However, existing cognitive models do not fully support these results as they assume that performing an attention-demanding task while standing would alter postural stability because of the competition of attention between the tasks. Contrary to these cognitive models, attentional resources may increase to create a synergy between visual and postural brain processes to perform precise oculomotor behaviors...
October 26, 2016: Cognitive Science
https://www.readbyqxmd.com/read/27335412/adaptive-acceleration-of-visually-evoked-smooth-eye-movements-in-mice
#15
Takashi Kodama, Sascha du Lac
UNLABELLED: The optokinetic response (OKR) consists of smooth eye movements following global motion of the visual surround, which suppress image slip on the retina for visual acuity. The effective performance of the OKR is limited to rather slow and low-frequency visual stimuli, although it can be adaptably improved by cerebellum-dependent mechanisms. To better understand circuit mechanisms constraining OKR performance, we monitored how distinct kinematic features of the OKR change over the course of OKR adaptation, and found that eye acceleration at stimulus onset primarily limited OKR performance but could be dramatically potentiated by visual experience...
June 22, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27252629/compensatory-recovery-after-multisensory-stimulation-in-hemianopic-patients-behavioral-and-neurophysiological-components
#16
Paolo A Grasso, Elisabetta Làdavas, Caterina Bertini
Lateralized post-chiasmatic lesions of the primary visual pathway result in loss of visual perception in the field retinotopically corresponding to the damaged cortical area. However, patients with visual field defects have shown enhanced detection and localization of multisensory audio-visual pairs presented in the blind field. This preserved multisensory integrative ability (i.e., crossmodal blindsight) seems to be subserved by the spared retino-colliculo-dorsal pathway. According to this view, audio-visual integrative mechanisms could be used to increase the functionality of the spared circuit and, as a consequence, might represent an important tool for the rehabilitation of visual field defects...
2016: Frontiers in Systems Neuroscience
https://www.readbyqxmd.com/read/27197595/extraocular-motoneuron-pools-develop-along-a-dorsoventral-axis-in-zebrafish-danio-rerio
#17
Marie R Greaney, Ann E Privorotskiy, Kristen P D'Elia, David Schoppik
Both spatial and temporal cues determine the fate of immature neurons. A major challenge at the interface of developmental and systems neuroscience is to relate this spatiotemporal trajectory of maturation to circuit-level functional organization. This study examined the development of two extraocular motor nuclei (nIII and nIV), structures in which a motoneuron's identity, or choice of muscle partner, defines its behavioral role. We used retro-orbital dye fills, in combination with fluorescent markers for motoneuron location and birthdate, to probe spatial and temporal organization of the oculomotor (nIII) and trochlear (nIV) nuclei in the larval zebrafish...
January 1, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/27030761/transient-pupil-dilation-after-subsaccadic-microstimulation-of-primate-frontal-eye-fields
#18
Sebastian J Lehmann, Brian D Corneil
UNLABELLED: Pupillometry provides a simple and noninvasive index for a variety of cognitive processes, including perception, attention, task consolidation, learning, and memory. The neural substrates by which such cognitive processes influence pupil diameter remain somewhat unclear, although cortical inputs to the locus coeruleus mediating arousal are likely involved. Changes in pupil diameter also accompany covert orienting; hence the oculomotor system may provide an alternative substrate for cognitive influences on pupil diameter...
March 30, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/26998716/infantile-nystagmus-and-abnormalities-of-conjugate-eye-movements-in-down-syndrome
#19
Avery H Weiss, John P Kelly, James O Phillips
PURPOSE: Subjects with Down syndrome (DS) have an anatomical defect within the cerebellum that may impact downstream oculomotor areas. This study characterized gaze holding and gains for smooth pursuit, saccades, and optokinetic nystagmus (OKN) in DS children with infantile nystagmus (IN). METHODS: Clinical data of 18 DS children with IN were reviewed retrospectively. Subjects with constant strabismus were excluded to remove any contribution of latent nystagmus...
March 2016: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/26831067/decision-related-perturbations-of-decision-irrelevant-eye-movements
#20
Sung Jun Joo, Leor N Katz, Alexander C Huk
It is well established that ongoing cognitive functions affect the trajectories of limb movements mediated by corticospinal circuits, suggesting an interaction between cognition and motor action. Although there are also many demonstrations that decision formation is reflected in the ongoing neural activity in oculomotor brain circuits, it is not known whether the decision-related activity in those oculomotor structures interacts with eye movements that are decision irrelevant. Here we tested for an interaction between decisions and instructed saccades unrelated to the perceptual decision...
February 16, 2016: Proceedings of the National Academy of Sciences of the United States of America
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