scholarly journals Distinctive Spatial and Laminar Organization of Single Axons from Lateral Pulvinar in the Macaque

Vision ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 1 ◽  
Author(s):  
Kathleen S. Rockland
Keyword(s):  
Cortical Layers ◽  
Laminar Organization ◽  
Macaque Monkeys ◽  
Rodent Brain ◽  
Single Axon ◽  
Visual Areas ◽  
Functional Implications ◽  
Layer 4 ◽  
Anterograde Tracers ◽  
Extrastriate Areas

Pulvino-cortical (PC) projections are a major source of extrinsic input to early visual areas in the macaque. From bulk injections of anterograde tracers, these are known to terminate in layer 1 of V1 and densely in the middle cortical layers of extrastriate areas. Finer, single axon analysis, as reviewed here for projections from the lateral pulvinar (PL) in two macaque monkeys (n = 25 axons), demonstrates that PL axons have multiple arbors in V2 and V4, and that these are spatially separate and offset in different layers. In contrast, feedforward cortical axons, another major source of extrinsic input to extrastriate areas, are less spatially divergent and more typically terminate in layer 4. Functional implications are briefly discussed, including comparisons with the better investigated rodent brain.

scholarly journals Masking Interrupts Figure-Ground Signals in V1

2002 ◽  
Vol 14 (7) ◽  
pp. 1044-1053 ◽  
Author(s):  
Victor A. F. Lamme ◽  
Karl Zipser ◽  
Henk Spekreijse
Keyword(s):  
Neural Activity ◽  
Target Stimulus ◽  
Initial Response ◽  
Backward Masking ◽  
Dramatic Decrease ◽  
Macaque Monkeys ◽  
The Past ◽  
Visual Areas ◽  
Higher Visual Areas ◽  
Extrastriate Areas

In a backward masking paradigm, a target stimulus is rapidly (<100 msec) followed by a second stimulus. This typically results in a dramatic decrease in the visibility of the target stimulus. It has been shown that masking reduces responses in V1. It is not known, however, which process in V1 is affected by the mask. In the past, we have shown that in V1, modulations of neural activity that are specifically related to figure-ground segregation can be recorded. Here, we recorded from awake macaque monkeys, engaged in a task where they had to detect figures from background in a pattern backward masking paradigm. We show that the V1 figure-ground signals are selectively and fully suppressed at target-mask intervals that psychophysically result in the target being invisible. Initial response transients, signalling the features that make up the scene, are not affected. As figure-ground modulations depend on feedback from extrastriate areas, these results suggest that masking selectively interrupts the recurrent interactions between V1 and higher visual areas.

Divergent feedback connections from areas V4 and TEO in the macaque

1994 ◽  
Vol 11 (3) ◽  
pp. 579-600 ◽  
Author(s):  
Kathleen S. Rockland ◽  
Kadharbatcha S. Saleem ◽  
Keiji Tanaka
Keyword(s):  
High Resolution ◽  
Perceptual Discrimination ◽  
Serial Sections ◽  
Area V4 ◽  
Stimulus Salience ◽  
Layer 4 ◽  
Anterograde Tracers ◽  
Dense Projections ◽  
Feedback Connections ◽  
Extrastriate Areas

AbstractExtrastriate areas TEO and V4 have been associated with form and color vision. Area V4 has also been suggested to participate in processes concerned with attention, stimulus salience, and perceptual learning. In a continuing effort to elucidate the connectional interactions and microcircuitry of these areas, we describe in this report the pattern of feedback connections from TEO and V4. Connections were demonstrated by injections of the high-resolution anterograde tracers PHA-L or biocytin and further analyzed by reconstruction of 25 individual axons through serial sections. This analysis yielded several new results: (1) Both areas TEO and V4 have widespread feedback connections (defined by their preferential termination in layer 1 and avoidance of layer 4). From TEO, there are dense projections to area V4 and moderate ones to V2 and V1. From V4, there are dense projections to V2 and moderate ones to V3 and V1. (2) Terminal fields span large territories in area V1, up to 6.0 mm in the case of axons originating from TEO; up to 5.0 mm in the case of axons originating from V4. In V2, fields tend to be smaller, between 3.0–5.0 mm. (3) Many axons from TEO and some from V4 have terminations in both areas V1 and V2. (4) Because individual terminal clusters and segments are often larger than cytochrome oxidase compartments, especially in V1, we suggest they may not be correlated with this compartmental organization. These results are consistent with the hypothesis that feedback connections may contribute to processes other than perceptual discrimination.

scholarly journals Targeted disruption of layer 4 during development increases GABAA receptor neurotransmission in the neocortex

2014 ◽  
Vol 111 (2) ◽  
pp. 323-335 ◽  
Author(s):  
J. Abbah ◽  
Maria F. M. Braga ◽  
S. L. Juliano
Keyword(s):  
Pyramidal Cells ◽  
Neural Cells ◽  
Cortical Layers ◽  
Targeted Disruption ◽  
Layer 2 ◽  
Layer 4 ◽  
Synaptic Neurotransmission ◽  
The Impact ◽  
Kinetics Of ◽  
Intrinsic Neuronal Properties

Cortical dysplasia (CD) associates with clinical pathologies, including epilepsy and mental retardation. CD results from impaired migration of immature neurons to their cortical targets, leading to clustering of neural cells and changes in cortical properties. We developed a CD model by administering methylazoxymethanol (MAM), an anti-mitotic, to pregnant ferrets on embryonic day 33; this leads to reduction in cortical thickness in addition to redistribution and increased expression of GABAA receptors (GABAAR). We evaluated the impact of MAM treatment on GABAAR-mediated synaptic transmission in postnatal day 0–1 neurons, leaving the ganglionic eminence (GE) and in layer 2/3 pyramidal cells of postnatal day 28–38 ferrets. Embryonic day 33 MAM treatment significantly increases the amplitude and frequency of spontaneous GABAAR-mediated inhibitory postsynaptic currents (IPSCs) in the cells leaving the GE. In older MAM-treated animals, the amplitude and frequency of GABAAR-mediated spontaneous IPSCs in layer 2/3 pyramidal cells is increased, as are the amplitude and frequency of miniature IPSCs. The kinetics of GABAAR opening also altered following treatment with MAM. Western blot analysis shows that the expression of the GABAAα3R and GABAAγ2R subunits amplified in our model animals. We did not observe any significant change in the passive properties of either the layer 2/3 pyramidal cells or cells leaving the GE after MAM treatment. These observations reinforce the idea that synaptic neurotransmission through GABAAR enhances following treatment with MAM and coincides with our finding of increased GABAAαR expression within the upper cortical layers. Overall, we demonstrate that small amounts of toxins delivered during corticogenesis can result in long-lasting changes in ambient expression of GABAAR that influence intrinsic neuronal properties.

scholarly journals Running reduces firing but improves coding in rodent higher-order visual cortex

2017 ◽  
Author(s):  
Amelia J. Christensen ◽  
Jonathan W. Pillow
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Single Neuron ◽  
Higher Order ◽  
Visual Responses ◽  
Cortical Layers ◽  
Response Properties ◽  
Stimulus Response ◽  
Allen Brain ◽  
Visual Areas

Running profoundly alters stimulus-response properties in mouse primary visual cortex (V1), but its effects in higher-order visual cortex remain unknown. Here we systematically investigated how locomotion modulates visual responses across six visual areas and three cortical layers using a massive dataset from the Allen Brain Institute. Although running has been shown to increase firing in V1, we found that it suppressed firing in higher-order visual areas. Despite this reduction in gain, visual responses during running could be decoded more accurately than visual responses during stationary periods. We show that this effect was not attributable to changes in noise correlations, and propose that it instead arises from increased reliability of single neuron responses during running.

The Influence of Single VB Thalamocortical Impulses on Barrel Columns of Rabbit Somatosensory Cortex

2000 ◽  
Vol 83 (5) ◽  
pp. 2802-2813 ◽  
Author(s):  
Harvey A. Swadlow ◽  
Alexander G. Gusev
Keyword(s):  
Somatosensory Cortex ◽  
Rise Time ◽  
Action Potentials ◽  
Field Potentials ◽  
Cortical Layers ◽  
Axon Terminals ◽  
Inhibitory Mechanisms ◽  
Layer 4 ◽  
Slow Rise ◽  
A Minor

Extracellular recordings were obtained from single neurons in ventrobasal (VB) thalamus of awake rabbits while field potentials were recorded at various depths within topographically aligned and nonaligned barrel columns of somatosensory cortex (S1). Spike-triggered averages of cortical field potentials were obtained following action potentials in thalamic neurons. Action potentials in a VB neuron elicited a cortical response within layer 4 with three distinct components. 1) A biphasic, initially positive response (latency <1 ms) was interpreted to reflect activation of the VB axon terminals (the AxTP). This response was not affected by infusion of an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor antagonist within the barrel. In contrast, later components of the response were completely eliminated and were interpreted to reflect focal synaptic potentials. 2) A negative potential [focal synaptic negativity (FSN)] occurred at a mean latency of 1.65 ms and lasted ∼4 ms. This response had a rapid rise time (∼0.7 ms) and was interpreted to reflect monosynaptic excitation. 3) The third component was a positive potential (the FSP), with a slow rise time and a half-amplitude duration of ∼30 ms. The FSP showed a weak reversal in superficial cortical layers and was interpreted to reflect di/polysynaptic inhibition. The amplitudes of the AxTP, the FSN, and the FSP reached a peak near layer 4 and were highly attenuated in both superficial and deep cortical layers. All components were attenuated or absent when the cortical electrode was missaligned from the thalamic electrode by a single cortical barrel. Deconvolution procedures revealed that the autocorrelogram of the presynaptic VB neuron had very little influence on either the amplitude or duration of the AxTP or the FSN, and only a minor influence (mean, 11%) on the amplitude of the FSP. We conclude that individual VB thalamic impulses entering a cortical barrel engage both monosynaptic excitatory and di/polysynaptic inhibitory mechanisms. Putative inhibitory interneurons of an S1 barrel receive a highly divergent/convergent monosynaptic input from the topographically aligned VB barreloid, and this results in sharp synchrony among these interneurons. We suggest that single-fiber access to disynaptic inhibition is facilitated by this sharp synchrony, and that the FSP reflects a consequent synchronous wave of feed-forward inhibition within the S1 barrel.

scholarly journals Visual Interhemispheric and Striate-Extrastriate Cortical Connections in the Rabbit: A Multiple Tracer Study

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Adrian K. Andelin ◽  
David J. Bruning ◽  
Daniel J. Felleman ◽  
Jaime F. Olavarria
Keyword(s):  
Visual Processing ◽  
Alternative Model ◽  
Tracer Study ◽  
Cortical Areas ◽  
Callosal Connections ◽  
Cortical Connections ◽  
Visual Areas ◽  
Cortical Visual Processing ◽  
Rats And Mice ◽  
Extrastriate Areas

Previous studies in rabbits identified an array of extrastriate cortical areas anatomically connected with V1 but did not describe their internal topography. To address this issue, we injected multiple anatomical tracers into different regions in V1 of the same animal and analyzed the topography of resulting extrastriate labeled fields with reference to the patterns of callosal connections and myeloarchitecture revealed in tangential sections of the flattened cortex. Our results extend previous studies and provide further evidence that rabbit extrastriate areas resemble the visual areas in rats and mice not only in their general location with respect to V1 but also in their internal topography. Moreover, extrastriate areas in the rabbit maintain a constant relationship with myeloarchitectonic borders and features of the callosal pattern. These findings highlight the rabbit as an alternative model to rats and mice for advancing our understanding of cortical visual processing in mammals, especially for projects benefiting from a larger brain.

Single axon analysis of pulvinocortical connections to several visual areas in the Macaque

1999 ◽  
Vol 406 (2) ◽  
pp. 221-250 ◽  
Author(s):  
Kathleen S. Rockland ◽  
Jon Andresen ◽  
Robert J. Cowie ◽  
David Lee Robinson
Keyword(s):  
Single Axon ◽  
Visual Areas

Single Units and Visual Cortical Organization

Perception ◽  
1998 ◽  
Vol 27 (8) ◽  
pp. 889-935 ◽  
Author(s):  
Peter Lennie
Keyword(s):  
Visual System ◽  
Striate Cortex ◽  
Occipital Cortex ◽  
Relevant Information ◽  
Hierarchical Organization ◽  
Cortical Organization ◽  
Visual Areas ◽  
The World ◽  
Visual Cortical ◽  
Extrastriate Areas

The visual system has a parallel and hierarchical organization, evident at every stage from the retina onwards. Although the general benefits of parallel and hierarchical organization in the visual system are easily understood, it has not been easy to discern the function of the visual cortical modules. I explore the view that striate cortex segregates information about different attributes of the image, and dispatches it for analysis to different extrastriate areas. I argue that visual cortex does not undertake multiple relatively independent analyses of the image from which it assembles a unified representation that can be interrogated about the what and where of the world. Instead, occipital cortex is organized so that perceptually relevant information can be recovered at every level in the hierarchy, that information used in making decisions at one level is not passed on to the next level, and, with one rather special exception (area MT), through all stages of analysis all dimensions of the image remain intimately coupled in a retinotopic map. I then offer some explicit suggestions about the analyses undertaken by visual areas in occipital cortex, and conclude by examining some objections to the proposals.

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