Columnar and Laminar Segregation of Retinal Input to the Primate Superior Colliculus Revealed by Anterograde Tracer Injection Into Each Eye

AbstractWe used an in vivo transplant approach to examine how adult Schwann cells and olfactory ensheathing glia OEG influence the specificity of axontarget cell interactions when they are introduced into the CNS. Populations of either Schwann cells or OEG were mixed with dissociated fetal tectal cells presumptive superior colliculus and, after reaggregation, pieces were grafted onto newborn rat superior colliculus. Both glial types were prelabeled with lentiviral vectors encoding green fluorescent protein. Grafts rapidly established fiber connections with the host and retinal projections into cografts were assessed 656 days posttransplantation by injecting cholera toxinB into host eyes. In control rats that received pure dissociatedreaggregated tectal grafts, retinal ganglion cell RGC axons selectively innervated defined target areas, corresponding to the retinorecipient layer in normal superior colliculus. The pattern of RGC axon ingrowth into OEG containing cografts was similar to that in control grafts. However, in Schwann cell cografts there was reduced host retinal input into presumptive target areas and many RGC axons were scattered throughout the neuropil. Given that OEG in cografts had minimal impact on axontarget cell recognition, OEG might be an appropriate cell type for direct transplantation into injured neuropil when attempting to stimulate specific pathway reconstruction.

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A reciprocal connection between the ventral lateral geniculate nucleus and the pretectal nuclear complex and the superior colliculus: Anin vitrocharacterization in the rat

Visual Neuroscience ◽

10.1017/s0952523808080048 ◽

2008 ◽

Vol 25 (1) ◽

pp. 39-51 ◽

Cited By ~ 13

Author(s):

GESCHE BORN ◽

MATTHIAS SCHMIDT

Keyword(s):

Superior Colliculus ◽

Lateral Geniculate Nucleus ◽

Brain Slices ◽

Double Labeling ◽

Nuclear Complex ◽

Lateral Geniculate ◽

Retinal Input ◽

Strongly Connected ◽

Tectal Neurons

The ventral lateral geniculate nucleus (vLGN), the pretectal nuclear complex (PNC) and the superior colliculus (SC) are structures that all receive retinal input. All three structures are important relay stations of the subcortical visual system. They are strongly connected with each other and involved in circadian and/or visuomotor processes. However, the information transferred along these pathways is unknown and their possible functions are, therefore, not well understood. Here, we characterized multiple pathways between the vLGN, the PNC, and the SC electrophysiologically and anatomically in anin vitrostudy using acute rat brain slices. Using orthodromic and antidromic electrical stimulation, we first characterized vLGN neurons that receive pretectal input and those that project to the PNC. Morphological reconstructions of cells labeled after patch clamp recordings identified these neurons as geniculo-tectal neurons and as medium-sized multipolar neurons. We identified inhibitory connections in both pathways and we could show that inhibitory postsynaptic currents (IPSCs) evoked from the PNC in vLGN neurons are mediated only by GABAAreceptors, while IPSCs evoked in PNC neurons by vLGN stimulation are either mediated by both, GABAAand GABACreceptors or by a GABA receptor with mixed GABAAand GABACreceptor-like pharmacology. Finally, retrograde double labeling experiments with two different fluorescent dextran amines indicated that pretectal neurons which project to the ipsilateral vLGN also project to the ipsilateral SC.

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150 Development of the rat superior colliculus (SC) in the absence of the retinal input. Quantitative analysis of adult tissue

International Journal of Developmental Neuroscience ◽

10.1016/0736-5748(96)80339-x ◽

1996 ◽

Vol 14 ◽

pp. 86-86

Author(s):

S.S. Warton ◽

S.E. Dyson

Keyword(s):

Quantitative Analysis ◽

Superior Colliculus ◽

Adult Tissue ◽

Retinal Input

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The foveal visual representation of the primate superior colliculus

10.1101/554121 ◽

2019 ◽

Cited By ~ 1

Author(s):

Chih-Yang Chen ◽

Klaus-Peter Hoffmann ◽

Claudia Distler ◽

Ziad M. Hafed

Keyword(s):

Superior Colliculus ◽

Visual Representation ◽

Scene Analysis ◽

Gaze Shifts ◽

Retinal Input ◽

Highly Sensitive ◽

Specific Manner ◽

Visual Tasks ◽

High Acuity ◽

Visual Cortices

AbstractProcessing of foveal retinal input is important not only for high quality visual scene analysis, but also for ensuring precise, albeit tiny, gaze shifts during high acuity visual tasks. The representations of foveal retinal input in primate lateral geniculate nucleus and early visual cortices have been characterized. However, how such representations translate into precise eye movements remains unclear. Here we document functional and structural properties of the foveal visual representation of midbrain superior colliculus. We show that superior colliculus, classically associated with extra-foveal spatial representations needed for gaze shifts, is highly sensitive to visual input impinging on the fovea. Superior colliculus also represents such input in an orderly and very specific manner, and it magnifies representation of foveal images in neural tissue as much as primary visual cortex does. Primate superior colliculus contains a high-fidelity visual representation, with large foveal magnification, perfectly suited for active visuomotor control and perception.

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Topological Skeletonization and Tree-Summarization of Neurons Using Discrete Morse Theory

10.1101/321489 ◽

2018 ◽

Author(s):

Suyi Wang ◽

Xu Li ◽

Partha Mitra ◽

Yusu Wang

Keyword(s):

Morse Theory ◽

Stable Manifold ◽

Image Data ◽

Density Field ◽

Discrete Morse Theory ◽

Connectivity Matrix ◽

Data Sets ◽

Consensus Tree ◽

Tracer Injection ◽

Anterograde Tracer

AbstractNeuroscientific data analysis has classically involved methods for statistical signal and image processing, drawing on linear algebra and stochastic process theory. However, digitized neuroanatomical data sets containing labelled neurons, either individually or in groups labelled by tracer injections, do not fully fit into this classical framework. The tree-like shapes of neurons cannot mathematically be adequately described as points in a vector space (eg, the subtraction of two neuronal shapes is not a meaningful operation). There is therefore a need for new approaches. Methods from computational topology and geometry are naturally suited to the analysis of neuronal shapes. Here we introduce methods from Discrete Morse Theory to extract tree-skeletons of individual neurons from volumetric brain image data, or to summarize collections of neurons labelled by localized anterograde tracer injections. Since individual neurons are topologically trees, it is sensible to summarize the collection of neurons labelled by a localized anterograde tracer injection using a consensus tree-shape. This consensus tree provides a richer information summary than the regional or voxel-based “connectivity matrix” approach that has previously been used in the literature.The algorithmic procedure includes an initial pre-processing step to extract a density field from the raw volumetric image data, followed by initial skeleton extraction from the density field using a discrete version of a 1-(un)stable manifold of the density field. Heuristically, if the density field is regarded as a mountainous landscape, then the 1-(un)stable manifold follows the “mountain ridges” connecting the maxima of the density field. We then simplify this skeletongraph into a tree using a shortest-path approach and methods derived from persistent homology. The advantage of this approach is that it uses global information about the density field and is therefore robust to local fluctuations and non-uniformly distributed input signals. To be able to handle large data sets, we use a divide-and-conquer approach. The resulting software DiMorSC is available on Github[40]. To the best of our knowledge this is currently the only publicly available code for the extraction of the 1-unstable manifold from an arbitrary simplicial complex using the Discrete Morse approach.

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Retinal Input Induces Three Firing Patterns in Neurons of the Superficial Superior Colliculus of Neonatal Rats

Journal of Neurophysiology ◽

10.1152/jn.1999.81.2.954 ◽

1999 ◽

Vol 81 (2) ◽

pp. 954-958 ◽

Cited By ~ 20

Author(s):

Fu-Sun Lo ◽

R. Ranney Mize

Keyword(s):

Calcium Channels ◽

Superior Colliculus ◽

Ganglion Cells ◽

Calcium Influx ◽

Optic Tract ◽

High Threshold ◽

Neonatal Rats ◽

Firing Patterns ◽

Retinal Input

Retinal input induces three firing patterns in neurons of the superficial superior colliculus of neonatal rats. By using an in vitro isolated brain stem preparation, we recorded extracellular responses to electrical stimulation of the optic tract (OT) from 71 neurons in the superficial superior colliculus (SC) of neonatal rats (P1–13). At postnatal day 1 (P1), all tested neurons ( n = 10) already received excitatory input from the retina. Sixty-nine (97%) superficial SC neurons of neonatal rats showed three response patterns to OT stimulation, which depended on stimulus intensity. A weak stimulus evoked only one spike that was caused by activation of non– N-methyl-d-aspartate (NMDA) glutamate receptors. A moderate stimulus elicited a short train (<250 ms) of spikes, which was induced by activation of both NMDA and non-NMDA receptors. A strong stimulus gave rise to a long train (>300 ms) of spikes, which was associated with additional activation of L-type high-threshold calcium channels. The long train firing pattern could also be induced either by temporal summation of retinal inputs or by blocking γ-aminobutyric acid-A receptors. Because retinal ganglion cells show synchronous bursting activity before eye opening at P14, the retinotectal inputs appear to be sufficient to activate L-type calcium channels in the absence of pattern vision. Therefore activation of L-type calcium channels is likely to be an important source for calcium influx into SC neurons in neonatal rats.

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The NanoZoomer Connectomics Pipeline for Tracer Injection Studies of the Marmoset Brain

10.1101/748376 ◽

2019 ◽

Author(s):

Alexander Woodward ◽

Rui Gong ◽

Hiroshi Abe ◽

Ken Nakae ◽

Junichi Hata ◽

...

Keyword(s):

Large Scale ◽

Common Marmoset ◽

Registration Accuracy ◽

Tracer Injection ◽

Common Space ◽

Atlas Registration ◽

Block Face ◽

The Individual ◽

Anterograde Tracer ◽

The Brain

AbstractWe describe our connectomics pipeline for processing tracer injection data for the brain of the common marmoset (Callithrix jacchus). Brain sections were imaged using a batch slide scanner (NanoZoomer 2.0-HT) and we used artificial intelligence to precisely segment the anterograde tracer signal from the background in the fluorescence images. The shape of each brain was reconstructed by reference to a block-face and all data was mapped into a common 3D brain space with atlas and 2D cortical flat map. To overcome the effect of using a single template atlas to specify cortical boundaries, each brain was cytoarchitectonically annotated and used for making an individual 3D atlas. Registration between the individual and common brain cortical boundaries in the flat map space was done to absorb the variation of each brain and precisely map all tracer injection data into one cortical brain space. We describe the methodology of our pipeline and analyze tracer segmentation and brain registration accuracy. Results show our pipeline can successfully process and normalize tracer injection experiments into a common space, making it suitable for large-scale connectomics studies with a focus on the cerebral cortex.

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