A local circuit approach to understanding integration of long-range inputs in primary visual cortex

1998 ◽  
Vol 8 (3) ◽  
pp. 204-217 ◽  
Author(s):  
D. Somers
1989 ◽  
Vol 2 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Rodrigo O. Kuljis ◽  
Pasko Rakic

AbstractLayers II/III of the primary visual cortex contain a regular pattern of histochemically detectable cytochrome oxidase (CO)-rich “puffs,” which differ from the interpuff regions in their thalamo-cortical and cortico-cortical connectivity, receptive-field properties, and the density of inhibitory GABA-containing synaptic terminals. We used an immunocytochemical method, in combination with cytochrome oxidase histochemistry, to analyze the spatial relationship between neurons that contain neuropeptide Y (NPY) and the CO puffs. Of a total of 606 neurons, only 2.6% of the NPY-containing cells are located in the puffs, whereas the rest are situated in the interpuffs, or at the interface between puffs and interpuffs. The number of NPY-containing neurons in the puffs is substantially less than that expected in an equal volume of the interpuffs (X2 = 13.86; df = 1; P < 0.001).These observations indicate that columns containing the puffs may differ also from those in the interpuff regions in that they contain a unique array of chemically and morphologically distinct local circuit neurons.


Author(s):  
Jinwoo Kim ◽  
Min Song ◽  
Se-Bum Paik

AbstractIn the primary visual cortex (V1) of higher mammals, long-range horizontal connections (LHCs) are observed to develop, linking iso-orientation domains of cortical tuning. It is unknown how this feature-specific wiring of circuitry develops before eye opening. Here, we show that LHCs in V1 may originate from spatio-temporally structured feedforward activities generated from spontaneous retinal waves. Using model simulations based on the anatomy and observed activity patterns of the retina, we show that waves propagating in retinal mosaics can initialize the wiring of LHCs by co-activating neurons of similar tuning, whereas equivalent random activities cannot induce such organizations. Simulations showed that emerged LHCs can produce the patterned activities observed in V1, matching topography of the underlying orientation map. We also confirmed that the model can also reproduce orientation-specific microcircuits in salt-and-pepper organizations in rodents. Our results imply that early peripheral activities contribute significantly to cortical development of functional circuits.HighlightsDevelopmental model of long-range horizontal connections (LHCs) in V1 is simulatedSpontaneous retinal waves generate feature-specific wiring of LHCs in visual cortexEmerged LHCs induce orientation-matching patterns of spontaneous cortical activityRetinal waves induce orientation-specific microcircuits of visual cortex in rodentsSignificance statementLong-range horizontal connections (LHCs) in the primary visual cortex (V1) are observed to emerge before the onset of visual experience, selectively connecting iso-domains of orientation maps. However, it is unknown how such tuning-specific wirings develop before eye-opening. Here, we show that LHCs in V1 originate from the tuning-specific activation of cortical neurons by spontaneous retinal waves during early developmental stages. Our simulations of a visual cortex model show that feedforward activities from the retina initialize the spatial organization of activity patterns in V1, which induces visual feature-specific wirings of V1 neurons. Our model also explains the origin of cortical microcircuits observed in rodents, suggesting that the proposed developmental mechanism is applicable universally to circuits of various mammalian species.


2010 ◽  
Vol 2 (7) ◽  
pp. 108-108
Author(s):  
J. D. Dorn ◽  
D. L. Ringach

1999 ◽  
Vol 16 (4) ◽  
pp. 755-770 ◽  
Author(s):  
JEAN LORENCEAU ◽  
LAURE ZAGO

Recovering the velocity of objects moving in the visual field requires both the integration and segmentation of local neuronal responses elicited by moving stimuli in primary visual cortex. Herein, we investigate the effects of the contrast, density, spatial proximity, spatial frequency, and spatial configuration of component motions on these complementary processes. Measuring the ability of human observers to discriminate the global direction of motion displays composed of spatially distributed patches of drifting gratings whose motion is locally ambiguous, we provide psychophysical evidence that linking component motion across space is facilitated at low contrast and high patch density. Furthermore, direction discrimination depends on the spatial frequency of component gratings and is more accurate for spatial configurations that contain “virtual” L junctions as compared to configurations composed of “virtual” T junctions. We suggest that the conditions yielding global motion coherence can be accounted for by the existence of anisotropic cooperative/competitive, contrast-dependent, long-range interactions among oriented direction-selective units. In addition, we bring evidence that motion segmentation processes rely upon the processing of moving local spatial discontinuities. The results are discussed in the light of recent psychophysical and physiological evidence that long-range excitatory and inhibitory interactions within primary visual cortex modulate perceptual linking.


2019 ◽  
Author(s):  
Pawan Bista ◽  
Rinaldo D. D’Souza ◽  
Andrew M. Meier ◽  
Weiqing Ji ◽  
Andreas Burkhalter

SUMMARYWhether mouse visual cortex contains orderly feature maps is debated. The overlapping pattern of geniculocortical (dLGN) inputs with M2 muscarinic acetylcholine receptor-rich patches in layer 1 (L1) suggests a non-random architecture. Here, we found that L1 inputs from the lateral posterior thalamus (LP) avoid patches and target interpatches. Channelrhodopsin-assisted mapping of EPSCs in L2/3 shows that the relative excitation of parvalbumin-expressing interneurons (PVs) and pyramidal neurons (PNs) by dLGN, LP and cortical feedback are distinct and depend on whether the neurons reside in clusters aligned with patches or interpatches. Paired recordings from PVs and PNs shows that unitary IPSCs are larger in interpatches than patches. The spatial clustering of inhibition is matched by dense clustering of PV-terminals in interpatches. The results show that the excitation/inhibition balance across V1 is organized into patch and interpatch subnetworks which receive distinct long-range inputs and are specialized for the processing of distinct spatiotemporal features.


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