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Superior colliculus

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https://www.readbyqxmd.com/read/28227182/strategies-to-improve-stimulation-efficiency-for-retinal-prostheses
#1
Navya S Davuluri, Kiran Nimmagadda, Artin Petrossians, Mark S Humayun, James D Weiland, Navya S Davuluri, Kiran Nimmagadda, Artin Petrossians, Mark S Humayun, James D Weiland, Mark S Humayun, Kiran Nimmagadda, Navya S Davuluri, James D Weiland, Artin Petrossians
Retinitis Pigmentosa (RP) is a degenerative disease of the retina that leads to vision loss. Retinal prostheses are being developed in order to restore functional vision in patients suffering from RP. We conducted in-vivo experiments in order to identify strategies to efficiently stimulate the retina. We electrically stimulated the retina and measured electrically evoked potentials (EERs) from the superior colliculus of rats. We compared the strength of EERs when voltage-controlled and current-controlled pulses of varying pulse width and charge levels were applied to the retina...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
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
#2
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/28223915/oral-delivery-of-a-synthetic-sterol-reduces-axonopathy-and-inflammation-in-a-rodent-model-of-glaucoma
#3
Wendi S Lambert, Brian J Carlson, Cathryn R Formichella, Rebecca M Sappington, Clarence Ahlem, David J Calkins
Glaucoma is a group of optic neuropathies associated with aging and sensitivity to intraocular pressure (IOP). The disease is the leading cause of irreversible blindness worldwide. Early progression in glaucoma involves dysfunction of retinal ganglion cell (RGC) axons, which comprise the optic nerve. Deficits in anterograde transport along RGC axons to central visual structures precede outright degeneration, and preventing these deficits is efficacious at abating subsequent progression. HE3286 is a synthetic sterol derivative that has shown therapeutic promise in models of inflammatory disease and neurodegenerative disease...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28192394/retinal-origin-of-direction-selectivity-in-the-superior-colliculus
#4
Xuefeng Shi, Jad Barchini, Hector Acaron Ledesma, David Koren, Yanjiao Jin, Xiaorong Liu, Wei Wei, Jianhua Cang
Detecting visual features in the environment, such as motion direction, is crucial for survival. The circuit mechanisms that give rise to direction selectivity in a major visual center, the superior colliculus (SC), are entirely unknown. We optogenetically isolate the retinal inputs that individual direction-selective SC neurons receive and find that they are already selective as a result of precisely converging inputs from similarly tuned retinal ganglion cells. The direction-selective retinal input is linearly amplified by intracollicular circuits without changing its preferred direction or level of selectivity...
February 13, 2017: Nature Neuroscience
https://www.readbyqxmd.com/read/28190674/neuronal-loss-and-%C3%AE-synuclein-pathology-in-the-superior-colliculus-and-its-relationship-to-visual-hallucinations-in-dementia-with-lewy-bodies
#5
Daniel Erskine, Alan J Thomas, John-Paul Taylor, Michael A Savage, Johannes Attems, Ian G McKeith, Christopher M Morris, Ahmad A Khundakar
OBJECTIVE: Patients with dementia with Lewy bodies (DLB) often experience visual hallucinations, which are related to decreased quality of life for patients and increased caregiver distress. The pathologic changes that contribute to visual hallucinations are not known, but several hypotheses implicate deficient attentional processing. The superior colliculus has a role in visual attention and planning eye movements and has been directly implicated in several models of visual hallucinations...
January 10, 2017: American Journal of Geriatric Psychiatry
https://www.readbyqxmd.com/read/28188622/the-optic-nerve-superior-colliculus-visual-thalamus-and-primary-visual-cortex-of-the-northern-elephant-seal-mirounga-angustirostris-and-california-sea-lion-zalophus-californianus
#6
Emily C Turner, Eva K Sawyer, Jon H Kaas
The northern elephant seal (Mirounga angustirostris) and California sea lion (Zalophus californianus) are members of a diverse clade of carnivorous mammals known as pinnipeds. Pinnipeds are notable for their large, ape-sized brains, yet little is known about their central nervous system. Both the northern elephant seal and California sea lion spend most of their lives at sea, but each also spends time on land to breed and give birth. These unique coastal niches may be reflected in specific evolutionary adaptations to their sensory systems...
February 11, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28185007/the-rostromedial-zona-incerta-is-involved-in-attentional-processes-while-adjacent-lha-responds-to-arousal-c-fos-and-anatomical-evidence
#7
S Chometton, K Charrière, L Bayer, C Houdayer, G Franchi, F Poncet, D Fellmann, P Y Risold
Neurons producing melanin-concentrating hormone (MCH) are located in the tuberal lateral hypothalamus (LHA) and in the rostromedial part of the zona incerta (ZI). This distribution suggests that rostromedial ZI shares some common features with the LHA. However, its functions with regard to arousal or feeding, which are often associated with the LHA, have not been thoroughly investigated. This study analyses the responses in the tuberal LHA and adjacent rostromedial ZI after experiments related to arousal, exploration, food teasing and ingestive behavior...
February 9, 2017: Brain Structure & Function
https://www.readbyqxmd.com/read/28177526/segregated-fronto-cortical-and-midbrain-connections-in-the-mouse-and-their-relation-to-approach-and-avoidance-orienting-behaviors
#8
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 medial and lateral SC (SCm and SCl), and thereby determined the main input structures to these subdomains...
February 8, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28167348/3d-functional-ultrasound-imaging-of-the-cerebral-visual-system-in-rodents
#9
Marc Gesnik, Kevin Blaize, Thomas Deffieux, Jean-Luc Gennisson, José-Alain Sahel, Mathias Fink, Serge Picaud, Mickaël Tanter
3D functional imaging of the whole brain activity during visual task is a challenging task in rodents due to the complex tri-dimensional shape of involved brain regions and the fine spatial and temporal resolutions required to reveal the visual tract. By coupling functional ultrasound (fUS) imaging with a translational motorized stage and an episodic visual stimulation device, we managed to accurately map and to recover the activity of the visual cortices, the Superior Colliculus (SC) and the Lateral Geniculate Nuclei (LGN) in 3D...
February 3, 2017: NeuroImage
https://www.readbyqxmd.com/read/28163059/revising-the-link-between-microsaccades-and-the-spatial-cueing-of-voluntary-attention
#10
Susann Meyberg, Petra Sinn, Ralf Engbert, Werner Sommer
Microsaccades - i.e., small fixational saccades generated in the superior colliculus (SC) - have been linked to spatial attention. While maintaining fixation, voluntary shifts of covert attention toward peripheral targets result in a sequence of attention-aligned and attention-opposing microsaccades. In most previous studies the direction of the voluntary shift is signaled by a spatial cue (e.g., a leftwards pointing arrow) that presents the most informative part of the cue (e.g., the arrowhead) in the to-be attended visual field...
February 17, 2017: Vision Research
https://www.readbyqxmd.com/read/28137699/frequency-dependent-fine-structure-in-the-frequency-following-response-the-byproduct-of-multiple-generators
#11
Parker Tichko, Erika Skoe
The frequency-following response (FFR) is an auditory-evoked response recorded at the scalp that captures the spectrotemporal properties of tonal stimuli. Previous investigations report that the amplitude of the FFR fluctuates as a function of stimulus frequency, a phenomenon thought to reflect multiple neural generators phase-locking to the stimulus with different response latencies. When phase-locked responses are offset by different latencies, constructive and destructive phase interferences emerge in the volume-conducted signals, culminating in an attenuation or amplification of the scalp-recorded response in a frequency-specific manner...
January 27, 2017: Hearing Research
https://www.readbyqxmd.com/read/28129425/vision-recovery-and-connectivity-by-fetal-retinal-sheet-transplantation-in-an-immunodeficient-retinal-degenerate-rat-model
#12
Magdalene J Seiler, Robert E Lin, Bryce T McLelland, Anuradha Mathur, Bin Lin, Jaclyn Sigman, Alexander T De Guzman, Leonard M Kitzes, Robert B Aramant, Biju B Thomas
Purpose: To characterize a recently developed model, the retinal degenerate immunodeficient S334ter line-3 rat (SD-Foxn1 Tg(S334ter)3Lav) (RD nude rat), and to test whether transplanted rat fetal retinal sheets can elicit lost responses to light. Methods: National Institutes of Health nude rats (SD-Foxn1 Tg) with normal retina were compared to RD nude rats with and without transplant for morphology and visual function. Retinal sheets from transgenic rats expressing human placental alkaline phosphatase (hPAP) were transplanted into the subretinal space of RD nude rats between postnatal day (P) 26 and P38...
January 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28123079/zika-virus-targeting-in-the-developing-brain
#13
Anthony N van den Pol, Guochao Mao, Yang Yang, Sara Ornaghi, John N Davis
: Zika virus (ZIKV), a positive-sense RNA flavivirus, has attracted considerable attention recently for its potential to cause serious neurological problems including microcephaly, cortical thinning and blindness during early development. Recent findings suggest that ZIKV infection of the brain can occur not only during very early stages of development, but also in later fetal/early neonatal stages of maturation. Surprisingly, after peripheral inoculation of immunocompetent mice on the day of birth, the first cells targeted throughout the brain were isolated astrocytes...
January 25, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28117340/superior-colliculus-neurons-encode-a-visual-saliency-map-during-free-viewing-of-natural-dynamic-video
#14
Brian J White, David J Berg, Janis Y Kan, Robert A Marino, Laurent Itti, Douglas P Munoz
Models of visual attention postulate the existence of a saliency map whose function is to guide attention and gaze to the most conspicuous regions in a visual scene. Although cortical representations of saliency have been reported, there is mounting evidence for a subcortical saliency mechanism, which pre-dates the evolution of neocortex. Here, we conduct a strong test of the saliency hypothesis by comparing the output of a well-established computational saliency model with the activation of neurons in the primate superior colliculus (SC), a midbrain structure associated with attention and gaze, while monkeys watched video of natural scenes...
January 24, 2017: Nature Communications
https://www.readbyqxmd.com/read/28100734/does-the-superior-colliculus-control-perceptual-sensitivity-or-choice-bias-during-attention-evidence-from-a-multialternative-decision-framework
#15
Devarajan Sridharan, Nicholas A Steinmetz, Tirin Moore, Eric I Knudsen
: Distinct networks in the forebrain and the midbrain coordinate to control spatial attention. The critical involvement of the superior colliculus (SC)-the central structure in the midbrain network-in visuospatial attention has been shown by four seminal, published studies in monkeys (Macaca mulatta) performing multialternative tasks. However, due to the lack of a mechanistic framework for interpreting behavioral data in such tasks, the nature of the SC's contribution to attention remains unclear...
January 18, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28100659/a-neural-locus-for-spatial-frequency-specific-saccadic-suppression-in-visual-motor-neurons-of-the-primate-superior-colliculus
#16
Chih-Yang Chen, Ziad M Hafed
Saccades cause rapid retinal-image shifts that go perceptually unnoticed several times per second. The mechanisms for saccadic suppression have been controversial, in part due to sparse understanding of neural substrates. Here we uncovered an unexpectedly specific neural locus for spatial-frequency specific saccadic suppression in the superior colliculus (SC). We first developed a sensitive behavioral measure of suppression in two macaque monkeys, demonstrating selectivity to low spatial frequencies similar to that observed in earlier behavioral studies...
January 18, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28097439/modeling-responses-in-the-superior-paraolivary-nucleus-implications-for-forward-masking-in-the-inferior-colliculus
#17
Nima Salimi, Muhammad S A Zilany, Laurel H Carney
A phenomenological model of the responses of neurons in the superior paraolivary nucleus (SPON) of the rodent is presented in this study. Pure tones at the characteristic frequency (CF) and broadband noise stimuli evoke offset-type responses in these neurons. SPON neurons also phase-lock to the envelope of sinusoidally amplitude-modulated (SAM) stimuli for a range of modulation frequencies. Model SPON neuron received inhibitory input that was relayed by the ipsilateral medial nucleus of the trapezoid body from the contralateral model ventral cochlear nucleus neuron...
January 17, 2017: Journal of the Association for Research in Otolaryngology: JARO
https://www.readbyqxmd.com/read/28088609/leukemia-inhibitory-factor-impairs-structural-and-neurochemical-development-of-rat-visual-cortex-in-vivo
#18
Maren Engelhardt, Graziella di Cristo, Jochen Grabert, Silke Patz, Lamberto Maffei, Nicoletta Berardi, Petra Wahle
Minipump infusions into visual cortex in vivo at the onset of the critical period have revealed that the proinflammatory cytokine leukemia inhibitory factor (LIF) delays the maturation of thalamocortical projection neurons of the lateral geniculate nucleus, and tecto-thalamic projection neurons of the superior colliculus, and cortical layer IV spiny stellates and layer VI pyramidal neurons. Here, we report that P12-20 LIF infusion inhibits somatic maturation of pyramidal neurons and of all interneuron types in vivo...
January 11, 2017: Molecular and Cellular Neurosciences
https://www.readbyqxmd.com/read/28054126/longitudinal-multi-modal-neuroimaging-in-opsoclonus-myoclonus-syndrome
#19
Sun-Young Oh, Rainer Boegle, Peter Zu Eulenburg, Matthias Ertl, Ji-Soo Kim, Marianne Dieterich
To investigate structural, metabolic, and functional connectivity changes in visual and oculomotor structures in a patient with paraneoplastic opsoclonus-myoclonus syndrome, serial resting-state functional and structural MRI, and FDG-PET data were collected during the acute stage and later on when the opsoclonus had resolved. In the acute stage, an FDG-PET scan demonstrated a substantially increased metabolism in structures around the deep cerebellar nuclei [e.g., fastigial nucleus (FN)] and a relatively reduced metabolism in the bilateral occipital lobes which normalized over 12 months...
January 4, 2017: Journal of Neurology
https://www.readbyqxmd.com/read/28044023/how-is-visual-salience-computed-in-the-brain-insights-from-behaviour-neurobiology-and-modelling
#20
REVIEW
Richard Veale, Ziad M Hafed, Masatoshi Yoshida
Inherent in visual scene analysis is a bottleneck associated with the need to sequentially sample locations with foveating eye movements. The concept of a 'saliency map' topographically encoding stimulus conspicuity over the visual scene has proven to be an efficient predictor of eye movements. Our work reviews insights into the neurobiological implementation of visual salience computation. We start by summarizing the role that different visual brain areas play in salience computation, whether at the level of feature analysis for bottom-up salience or at the level of goal-directed priority maps for output behaviour...
February 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
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