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collicular maps

Geoffrey Megardon, Casimir Ludwig, Petroc Sumner
When decisions drive saccadic eye movements, traces of the decision process can be inferred from the movement trajectories. For example, saccades can curve away from distractor stimuli, which was thought to reflect cortical inhibition biasing activity in the superior colliculus. Recent neurophysiological work does not support this theory, and two recent models have replaced top-down inhibition with lateral interactions in the superior colliculus or neural fatigue in the brainstem saccadic burst generator. All current models operate in retinotopic coordinates and are based on single saccade paradigms...
August 1, 2017: Journal of Neurophysiology
Bahadir Kasap, A John van Opstal
Single-unit recordings suggest that the midbrain superior colliculus (SC) acts as an optimal controller for saccadic gaze shifts. The SC is proposed to be the site within the visuomotor system where the nonlinear spatial-to-temporal transformation is carried out: the population encodes the intended saccade vector by its location in the motor map (spatial), and its trajectory and velocity by the distribution of firing rates (temporal). The neurons' burst profiles vary systematically with their anatomical positions and intended saccade vectors, to account for the nonlinear main-sequence kinematics of saccades...
August 2017: Biological Cybernetics
Elise Savier, Stephen J Eglen, Amélie Bathélémy, Martine Perraut, Frank W Pfrieger, Greg Lemke, Michael Reber
Sensory processing requires proper alignment of neural maps throughout the brain. In the superficial layers of the superior colliculus of the midbrain, converging projections from retinal ganglion cells and neurons in visual cortex must be aligned to form a visuotopic map, but the basic mechanisms mediating this alignment remain elusive. In a new mouse model, ectopic expression of ephrin-A3 ( Efna3 ) in a subset of retinal ganglion cells, quantitatively altering the retinal EFNAs gradient, disrupts cortico-collicular map alignment onto the retino-collicular map, creating a visuotopic mismatch...
March 14, 2017: ELife
Susanne Hoffmann, Tomas Vega-Zuniga, Wolfgang Greiter, Quirin Krabichler, Alexandra Bley, Mariana Matthes, Christiane Zimmer, Uwe Firzlaff, Harald Luksch
The midbrain superior colliculus (SC) commonly features a retinotopic representation of visual space in its superficial layers, which is congruent with maps formed by multisensory neurons and motor neurons in its deep layers. Information flow between layers is suggested to enable the SC to mediate goal-directed orienting movements. While most mammals strongly rely on vision for orienting, some species such as echolocating bats have developed alternative strategies, which raises the question how sensory maps are organized in these animals...
November 2016: European Journal of Neuroscience
Thilo Womelsdorf, Stefan Everling
Attention networks comprise brain areas whose coordinated activity implements stimulus selection. This selection is reflected in spatially referenced priority maps across frontal-parietal-collicular areas and is controlled through interactions with circuits representing behavioral goals, including prefrontal, cingulate, and striatal circuits, among others. We review how these goal-providing structures control stimulus selection through long-range dynamic projection motifs. These motifs (i) combine feature-tuned subnetworks to a distributed priority map, (ii) establish endogenously controlled, long-range coherent activity at 4-10 Hz theta and 12-30 Hz beta-band frequencies, and (iii) are composed of unique cell types implementing long-range networks through disynaptic disinhibition, dendritic gating, and feedforward inhibitory gain control...
November 2015: Trends in Neurosciences
Lotje Linden, Gregory Zelinsky, Françoise Vitu
In visual displays containing two stimuli, saccades reveal a global effect (GE): Even though participants aim for one of the stimuli, their eyes land in between the two. The GE presumably results from population averaging in the superior colliculus (SC): As neurons in the retinotopic sensory and motor maps have large and overlapping receptive/movement fields, overlap in the recruited populations causes activity to peak at the intermediate location. Consequently, the GE should diminish when the distance between the two recruited populations exceeds a threshold separation...
2015: Journal of Vision
Hossein Adeli, Françoise Vitu, Gregory Zelinsky
Models of eye movements during scene viewing attempt to explain distributions of fixations and do not typically address the neural basis of saccade programming. Models of saccade programming are tied more closely to neural mechanisms, but have not been applied to scenes due to limitations on the inputs that they can accept-typically just dots. This work bridges the gap between these literatures by adding an image-based "front end" to a model of saccade programming in the superior colliculus (SC). An image of a scene is first blurred to reflect acuity limitations existing at the current fixation, and a saliency map is computed from this fixation-blurred image...
2015: Journal of Vision
Jean-Hubert Courjon, Alexandre Zénon, Gilles Clément, Christian Urquizar, Etienne Olivier, Denis Pélisson
Besides its well-known contribution to orienting behaviors, the superior colliculus (SC) might also play a role in controlling visually guided reaching movements. This view has been inferred from studies in monkeys showing that some tectal cells located in the deep layers are active prior to reaching movements; it was corroborated by functional imaging studies performed in humans. Likewise, our group has already demonstrated that, in cats, SC electrical stimulation can modify the trajectory of goal-directed forelimb movements without necessarily affecting the gaze position...
2015: Frontiers in Systems Neuroscience
Timothy J Shakespeare, Diego Kaski, Keir X X Yong, Ross W Paterson, Catherine F Slattery, Natalie S Ryan, Jonathan M Schott, Sebastian J Crutch
The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal 'visual dementia' and most common atypical Alzheimer's disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients' (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer's disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system...
July 2015: Brain: a Journal of Neurology
Charles Thurat, Steve N'Guyen, Benoît Girard
The superior colliculus, a laminar structure involved in the retinotopic mapping of the visual field, plays a cardinal role in several cortical and subcortical pathways of the saccadic system. Although the selection of saccade targets has long been thought to be mainly the product of cortical processes, a growing body of evidence hints at the implication of the superior colliculus in selection processes independent from cortical inputs, capable of producing saccades at latencies incompatible with the cortical pathways...
July 2015: Neural Networks: the Official Journal of the International Neural Network Society
Pengfei Wei, Nan Liu, Zhijian Zhang, Xuemei Liu, Yongqiang Tang, Xiaobin He, Bifeng Wu, Zheng Zhou, Yaohan Liu, Juan Li, Yi Zhang, Xuanyi Zhou, Lin Xu, Lin Chen, Guoqiang Bi, Xintian Hu, Fuqiang Xu, Liping Wang
The ability of animals to respond to life-threatening stimuli is essential for survival. Although vision provides one of the major sensory inputs for detecting threats across animal species, the circuitry underlying defensive responses to visual stimuli remains poorly defined. Here, we investigate the circuitry underlying innate defensive behaviours elicited by predator-like visual stimuli in mice. Our results demonstrate that neurons in the superior colliculus (SC) are essential for a variety of acute and persistent defensive responses to overhead looming stimuli...
2015: Nature Communications
Nobuo Suga
The central auditory system produces combination-sensitive neurons tuned to a specific combination of multiple signal elements. Some of these neurons act as coincidence detectors with delay lines for the extraction of spectro-temporal information from sounds. "Delay-tuned" neurons of mustached bats are tuned to a combination of up to four signal elements with a specific delay between them and form a delay map. They are produced in the inferior colliculus by the coincidence of the rebound response following glycinergic inhibition to the first harmonic of a biosonar pulse with the short-latency response to the 2nd-4th harmonics of its echo...
June 2015: Hearing Research
Silvio Macías, Annette Hernández-Abad, Julio C Hechavarría, Manfred Kössl, Emanuel C Mora
It has been reported previously that in the inferior colliculus of the bat Molossus molossus, neuronal duration tuning is ambiguous because the tuning type of the neurons dramatically changes with the sound level. In the present study, duration tuning was examined in the auditory cortex of M. molossus to describe if it is as ambiguous as the collicular tuning. From a population of 174 cortical 104 (60 %) neurons did not show duration selectivity (all-pass). Around 5 % (9 units) responded preferentially to stimuli having longer durations showing long-pass duration response functions, 35 (20 %) responded to a narrow range of stimulus durations showing band-pass duration response functions, 24 (14 %) responded most strongly to short stimulus durations showing short-pass duration response functions and two neurons (1 %) responded best to two different stimulus durations showing a two-peaked duration-response function...
May 2015: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
Isadora Olivé, Claus Tempelmann, Alain Berthoz, Hans-Joachim Heinze
Bodily self-consciousness refers to bodily processes operating at personal, peripersonal, and extrapersonal spatial dimensions. Although the neural underpinnings of representations of personal and peripersonal space associated with bodily self-consciousness were thoroughly investigated, relatively few is known about the neural underpinnings of representations of extrapersonal space relevant for bodily self-consciousness. In the search to unravel brain structures generating a representation of the extrapersonal space relevant for bodily self-consciousness, we developed a functional magnetic resonance imaging (fMRI) study to investigate the implication of the superior colliculus (SC) in bodily illusions, and more specifically in the rubber hand illusion (RHi), which constitutes an established paradigm to study the neural underpinnings of bodily self-consciousness...
February 2015: Human Brain Mapping
Todd McLaughlin, Yoo-Shick Lim, Alicia Santiago, Dennis D M O'Leary
The projection from the retina to the superior colliculus in mice is organized in a retinotopic map that develops through the formation and guidance of interstitial branches extended by retinal ganglion cell axons. Bidirectional branch guidance along the lateral-medial collicular axis is critical to mapping the dorsal-ventral retinal axis. EphB receptor tyrosine kinases expressed in an overall low to high dorsal-ventral retinal gradient have been implicated in this mapping in response to the graded low to high lateral-medial expression of a ligand, ephrin-B1, in the superior colliculus...
November 2014: Molecular and Cellular Neurosciences
Chantal Mathis, Elise Savier, Jean-Bastien Bott, Daniel Clesse, Nicholas Bevins, Dominique Sage-Ciocca, Karin Geiger, Anaïs Gillet, Alexis Laux-Biehlmann, Yannick Goumon, Adrien Lacaud, Vincent Lelièvre, Christian Kelche, Jean-Christophe Cassel, Frank W Pfrieger, Michael Reber
The superior colliculus is a hub for multisensory integration necessary for visuo-spatial orientation, control of gaze movements and attention. The multiple functions of the superior colliculus have prompted hypotheses about its involvement in neuropsychiatric conditions, but to date, this topic has not been addressed experimentally. We describe experiments on genetically modified mice, the Isl2-EphA3 knock-in line, that show a well-characterized duplication of the retino-collicular and cortico-collicular axonal projections leading to hyperstimulation of the superior colliculus...
2015: Brain Structure & Function
Jinxia Dai, Mona Buhusi, Galina P Demyanenko, Leann H Brennaman, Martin Hruska, Matthew B Dalva, Patricia F Maness
NrCAM (Neuron-glial related cell adhesion molecule), a member of the L1 family of cell adhesion molecules, reversibly binds ankyrin and regulates axon growth, but it has not been studied for a role in retinotopic mapping. During development of retino-collicular topography, NrCAM was expressed uniformly in retinal ganglion cells (RGCs) along both mediolateral and anteroposterior retinal axes, and was localized on RGC axons within the optic tract and superior colliculus (SC). Anterograde tracing of RGC axons in NrCAM null mutant mice at P10, when the map resembles its mature form, revealed laterally displaced ectopic termination zones (eTZs) of axons from the temporal retina, indicating defective mediolateral topography, which is governed by ephrinB/EphBs...
2013: PloS One
Gregory J Zelinsky, Hossein Adeli, Yifan Peng, Dimitris Samaras
We introduce a model of eye movements during categorical search, the task of finding and recognizing categorically defined targets. It extends a previous model of eye movements during search (target acquisition model, TAM) by using distances from an support vector machine classification boundary to create probability maps indicating pixel-by-pixel evidence for the target category in search images. Other additions include functionality enabling target-absent searches, and a fixation-based blurring of the search images now based on a mapping between visual and collicular space...
October 19, 2013: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Jayalakshmi Viswanathan, Jason J S Barton
In the global effect, prosaccades are deviated to a position intermediate between two targets or between a distractor and a target, which may reflect spatial averaging in a map encoded by the superior colliculus. Antisaccades differ from prosaccades in that they dissociate the locations of the stimulus and goal and generate weaker collicular activity. We used these antisaccade properties to determine whether the global effect was generated in stimulus or goal computations, and whether the global effect would be larger for antisaccades, as predicted by collicular averaging...
March 2013: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Soazig Casteau, Françoise Vitu
Two proposals have been made to account for the generation of saccadic eye movements. The first assumes that when the eyes move is under the control of a fixation gating system. The second attributes the decisions of both when and where the eyes move to the interplay between short-range excitatory and long-range inhibitory interactions within the motor map of the superior colliculus (SC). To distinguish both views, three behavioral experiments conducted on human participants tested the respective contributions of stimulus eccentricity and interstimulus distance on the effects of remote and proximal distractors on the latency and accuracy of saccades...
2012: Journal of Vision
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