The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Markus Meister - One of the best experts on this subject based on the ideXlab platform.
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orientation columns in the mouse Superior Colliculus
Nature, 2015Co-Authors: Evan H Feinberg, Markus MeisterAbstract:More than twenty types of retinal ganglion cells conduct visual information from the eye to the rest of the brain. Each retinal ganglion cell type tessellates the retina in a regular mosaic, so that every point in visual space is processed for visual primitives such as contrast and motion. This information flows to two principal brain centres: the visual cortex and the Superior Colliculus. The Superior Colliculus plays an evolutionarily conserved role in visual behaviours, but its functional architecture is poorly understood. Here we report on population recordings of visual responses from neurons in the mouse Superior Colliculus. Many neurons respond preferentially to lines of a certain orientation or movement axis. We show that cells with similar orientation preferences form large patches that span the vertical thickness of the retinorecipient layers. This organization is strikingly different from the randomly interspersed orientation preferences in the mouse’s visual cortex; instead, it resembles the orientation columns observed in the visual cortices of large mammals. Notably, adjacent Superior Colliculus orientation columns have only limited receptive field overlap. This is in contrast to the organization of visual cortex, where each point in the visual field activates neurons with all preferred orientations. Instead, the Superior Colliculus favours specific contour orientations within ~30° regions of the visual field, a finding with implications for behavioural responses mediated by this brain centre.
William C. Hall - One of the best experts on this subject based on the ideXlab platform.
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exploring the Superior Colliculus in vitro
Journal of Neurophysiology, 2009Co-Authors: William C. HallAbstract:The Superior Colliculus plays an important role in the translation of sensory signals that encode the location of objects in space into motor signals that encode vectors of the shifts in gaze direction called saccades. Since the late 1990s, our two laboratories have been applying whole cell patch-clamp techniques to in vitro slice preparations of rodent Superior Colliculus to analyze the structure and function of its circuitry at the cellular level. This review describes the results of these experiments and discusses their contributions to our understanding of the mechanisms responsible for sensorimotor integration in the Superior Colliculus. The experiments analyze vertical interactions between its superficial visuosensory and intermediate premotor layers and propose how they might contribute to express saccades and to saccadic suppression. They also compare and contrast the circuitry within each of these layers and propose how this circuitry might contribute to the selection of the targets for saccades and to the build-up of the premotor commands that precede saccades. Experiments also explore in vitro the roles of extrinsic inputs to the Superior Colliculus, including cholinergic inputs from the parabigeminal and parabrachial nuclei and GABAergic inputs from the substantia nigra pars reticulata, in modulating the activity of the collicular circuitry. The results extend and clarify our understanding of the multiple roles the Superior Colliculus plays in sensorimotor integration.
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The Superior Colliculus: New Approaches for Studying Sensorimotor Integration - The Superior Colliculus : New Approaches for Studying Sensorimotor Integration
2003Co-Authors: William C. Hall, Adonis MoschovakisAbstract:Presenting information amassed from more than 30 years of research, this book gathers together the most important pieces of evidence regarding the structure and function of the Superior Colliculus. It explores the involvement of the Superior Colliculus in the control of gaze shift and rapid eye movements and provides a detailed discussion of structural features as they relate to functional properties. Placing empirical data in the context of theory, the editors use computational models of the Superior Colliculus as scaffolds around which to organize psychophysical, neurological, anatomical, and physiological findings concerning its involvement in orienting movements.
Alexander J Heimel - One of the best experts on this subject based on the ideXlab platform.
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functional modulation of primary visual cortex by the Superior Colliculus in the mouse
Nature Communications, 2018Co-Authors: Mehran Ahmadlou, Larry S Zweifel, Alexander J HeimelAbstract:The largest targets of retinal input in mammals are the dorsal lateral geniculate nucleus (dLGN), a relay to the primary visual cortex (V1), and the Superior Colliculus. V1 innervates and influences the Superior Colliculus. Here, we find that, in turn, Superior Colliculus modulates responses in mouse V1. Optogenetically inhibiting the Superior Colliculus reduces responses in V1 to optimally sized stimuli. Superior Colliculus could influence V1 via its strong projection to the lateral posterior nucleus (LP/Pulvinar) or its weaker projection to the dLGN. Inhibiting Superior Colliculus strongly reduces activity in LP. Pharmacologically silencing LP itself, however, does not remove collicular modulation of V1. The modulation is instead due to a collicular gain modulation of the dLGN. Surround suppression operating in V1 explains the different effects for differently sized stimuli. Computations of visual saliency in the Superior Colliculus can thus influence tuning in the visual cortex via a tectogeniculate pathway.
Greg J Stuart - One of the best experts on this subject based on the ideXlab platform.
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Superior Colliculus modulates cortical coding of somatosensory information.
Nature Communications, 2020Co-Authors: Saba Gharaei, Ehsan Arabzadeh, Suraj Honnuraiah, Greg J StuartAbstract:The cortex modulates activity in Superior Colliculus via a direct projection. What is largely unknown is whether (and if so how) the Superior Colliculus modulates activity in the cortex. Here, we investigate this issue and show that optogenetic activation of Superior Colliculus changes the input-output relationship of neurons in somatosensory cortex, enhancing responses to low amplitude whisker deflections. While there is no direct pathway from Superior Colliculus to somatosensory cortex, we found that activation of Superior Colliculus drives spiking in the posterior medial (POm) nucleus of the thalamus via a powerful monosynaptic pathway. Furthermore, POm neurons receiving input from Superior Colliculus provide monosynaptic excitatory input to somatosensory cortex. Silencing POm abolished the capacity of Superior Colliculus to modulate cortical whisker responses. Our findings indicate that the Superior Colliculus, which plays a key role in attention, modulates sensory processing in somatosensory cortex via a powerful di-synaptic pathway through the thalamus.
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Superior Colliculus modulates cortical coding of somatosensory information
bioRxiv, 2019Co-Authors: Saba Gharaei, Ehsan Arabzadeh, Suraj Honnuraiah, Greg J StuartAbstract:The cortex sends a direct projection to the Superior Colliculus. What is largely unknown is whether (and if so how) the Superior Colliculus modulates activity in the cortex. Here, we directly investigate this issue, showing that optogenetic activation of Superior Colliculus changes the input-output relationship of neurons in somatosensory cortex during whisker movement, enhancing responses to low amplitude whisker deflections. While there is no direct pathway from Superior Colliculus to somatosensory cortex, we found that activation of Superior Colliculus drives spiking in the posterior medial (POm) nucleus of the thalamus via a powerful monosynaptic pathway. Furthermore, POm neurons receiving input from Superior Colliculus provide excitatory input to somatosensory cortex. Silencing POm abolished the capacity of Superior Colliculus to modulate cortical whisker responses. Our findings indicate that the Superior Colliculus, which plays a key role in attention, modulates sensory processing in somatosensory cortex via a powerful disynaptic pathway through the thalamus.
Mehran Ahmadlou - One of the best experts on this subject based on the ideXlab platform.
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functional modulation of primary visual cortex by the Superior Colliculus in the mouse
Nature Communications, 2018Co-Authors: Mehran Ahmadlou, Larry S Zweifel, Alexander J HeimelAbstract:The largest targets of retinal input in mammals are the dorsal lateral geniculate nucleus (dLGN), a relay to the primary visual cortex (V1), and the Superior Colliculus. V1 innervates and influences the Superior Colliculus. Here, we find that, in turn, Superior Colliculus modulates responses in mouse V1. Optogenetically inhibiting the Superior Colliculus reduces responses in V1 to optimally sized stimuli. Superior Colliculus could influence V1 via its strong projection to the lateral posterior nucleus (LP/Pulvinar) or its weaker projection to the dLGN. Inhibiting Superior Colliculus strongly reduces activity in LP. Pharmacologically silencing LP itself, however, does not remove collicular modulation of V1. The modulation is instead due to a collicular gain modulation of the dLGN. Surround suppression operating in V1 explains the different effects for differently sized stimuli. Computations of visual saliency in the Superior Colliculus can thus influence tuning in the visual cortex via a tectogeniculate pathway.
