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Lateral Spread of Orientation Selectivity in V1 is Controlled by Intracortical Cooperativity.

Chavane F, Sharon D, Jancke D, Marre O, Frégnac Y, Grinvald A - Front Syst Neurosci (2011)

Bottom Line: To understand the role of these lateral interactions, it is crucial to characterize their effective functional connectivity and tuning properties.In contrast, when the stimulus size was increased, we observed orientation-selective spread of activation beyond the feedforward imprint.We conclude that stimulus-induced cooperativity enhances the long-range orientation-selective spread.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology, Weizmann Institute of Science Rehovot, Israel.

ABSTRACT
Neurons in the primary visual cortex receive subliminal information originating from the periphery of their receptive fields (RF) through a variety of cortical connections. In the cat primary visual cortex, long-range horizontal axons have been reported to preferentially bind to distant columns of similar orientation preferences, whereas feedback connections from higher visual areas provide a more diverse functional input. To understand the role of these lateral interactions, it is crucial to characterize their effective functional connectivity and tuning properties. However, the overall functional impact of cortical lateral connections, whatever their anatomical origin, is unknown since it has never been directly characterized. Using direct measurements of postsynaptic integration in cat areas 17 and 18, we performed multi-scale assessments of the functional impact of visually driven lateral networks. Voltage-sensitive dye imaging showed that local oriented stimuli evoke an orientation-selective activity that remains confined to the cortical feedforward imprint of the stimulus. Beyond a distance of one hypercolumn, the lateral spread of cortical activity gradually lost its orientation preference approximated as an exponential with a space constant of about 1 mm. Intracellular recordings showed that this loss of orientation selectivity arises from the diversity of converging synaptic input patterns originating from outside the classical RF. In contrast, when the stimulus size was increased, we observed orientation-selective spread of activation beyond the feedforward imprint. We conclude that stimulus-induced cooperativity enhances the long-range orientation-selective spread.

No MeSH data available.


Related in: MedlinePlus

Group analysis of the spatial decay of modulation depth. The                            analysis was generalized over nine hemispheres [three in area 17 (o) and                            six in area 18 (+)]. (A) Decrease in condition-wise                            modulation depth with lateral propagation distance as a function of the                            total area and equivalent radius or as a function of the pinwheel                            neighborhood order (B). Exponential fits are given for the                            total population (dark) and for the area 17 (gray dashed) and area 18                            (gray dotted) sub-populations.
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Figure 8: Group analysis of the spatial decay of modulation depth. The analysis was generalized over nine hemispheres [three in area 17 (o) and six in area 18 (+)]. (A) Decrease in condition-wise modulation depth with lateral propagation distance as a function of the total area and equivalent radius or as a function of the pinwheel neighborhood order (B). Exponential fits are given for the total population (dark) and for the area 17 (gray dashed) and area 18 (gray dotted) sub-populations.

Mentions: Applying the above analysis to all of the nine imaged hemispheres revealed a similar trend, a mean decrease in modulation depth was observed with an exponential decay space constant of 9.8 mm2 (EP: 1206 μm; Figure 8A) or 1.2 pinwheels units (Figure 8B). Hence, both the absolute orientation-preference bias and the tuning selectivity decrease with identical spatial decay constants.


Lateral Spread of Orientation Selectivity in V1 is Controlled by Intracortical Cooperativity.

Chavane F, Sharon D, Jancke D, Marre O, Frégnac Y, Grinvald A - Front Syst Neurosci (2011)

Group analysis of the spatial decay of modulation depth. The                            analysis was generalized over nine hemispheres [three in area 17 (o) and                            six in area 18 (+)]. (A) Decrease in condition-wise                            modulation depth with lateral propagation distance as a function of the                            total area and equivalent radius or as a function of the pinwheel                            neighborhood order (B). Exponential fits are given for the                            total population (dark) and for the area 17 (gray dashed) and area 18                            (gray dotted) sub-populations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3100672&req=5

Figure 8: Group analysis of the spatial decay of modulation depth. The analysis was generalized over nine hemispheres [three in area 17 (o) and six in area 18 (+)]. (A) Decrease in condition-wise modulation depth with lateral propagation distance as a function of the total area and equivalent radius or as a function of the pinwheel neighborhood order (B). Exponential fits are given for the total population (dark) and for the area 17 (gray dashed) and area 18 (gray dotted) sub-populations.
Mentions: Applying the above analysis to all of the nine imaged hemispheres revealed a similar trend, a mean decrease in modulation depth was observed with an exponential decay space constant of 9.8 mm2 (EP: 1206 μm; Figure 8A) or 1.2 pinwheels units (Figure 8B). Hence, both the absolute orientation-preference bias and the tuning selectivity decrease with identical spatial decay constants.

Bottom Line: To understand the role of these lateral interactions, it is crucial to characterize their effective functional connectivity and tuning properties.In contrast, when the stimulus size was increased, we observed orientation-selective spread of activation beyond the feedforward imprint.We conclude that stimulus-induced cooperativity enhances the long-range orientation-selective spread.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology, Weizmann Institute of Science Rehovot, Israel.

ABSTRACT
Neurons in the primary visual cortex receive subliminal information originating from the periphery of their receptive fields (RF) through a variety of cortical connections. In the cat primary visual cortex, long-range horizontal axons have been reported to preferentially bind to distant columns of similar orientation preferences, whereas feedback connections from higher visual areas provide a more diverse functional input. To understand the role of these lateral interactions, it is crucial to characterize their effective functional connectivity and tuning properties. However, the overall functional impact of cortical lateral connections, whatever their anatomical origin, is unknown since it has never been directly characterized. Using direct measurements of postsynaptic integration in cat areas 17 and 18, we performed multi-scale assessments of the functional impact of visually driven lateral networks. Voltage-sensitive dye imaging showed that local oriented stimuli evoke an orientation-selective activity that remains confined to the cortical feedforward imprint of the stimulus. Beyond a distance of one hypercolumn, the lateral spread of cortical activity gradually lost its orientation preference approximated as an exponential with a space constant of about 1 mm. Intracellular recordings showed that this loss of orientation selectivity arises from the diversity of converging synaptic input patterns originating from outside the classical RF. In contrast, when the stimulus size was increased, we observed orientation-selective spread of activation beyond the feedforward imprint. We conclude that stimulus-induced cooperativity enhances the long-range orientation-selective spread.

No MeSH data available.


Related in: MedlinePlus