Attentional effects on local V1 microcircuits explain selective V1-V4 communication.

Area of Science:

• Neuroscience
• Computational Neuroscience
• Visual Perception

Background:

• Selective attention prioritizes specific stimuli, likely by enhancing their neural representation.
• Top-down attentional control may target presynaptic circuits to achieve stimulus routing.
• Gamma rhythms in V1 and V4 are implicated in visual processing and attentional modulation.

Purpose of the Study:

• To investigate the neural mechanisms underlying selective attention and stimulus routing.
• To model how attentional top-down influences modulate presynaptic circuits.
• To determine if presynaptic entrainment explains selective routing of visual information.

Main Methods:

• Dynamic Causal Model for Cross-Spectral Densities (DCM-CSD) was used to model induced neural responses.
• Simulated two visual stimuli inducing gamma rhythms in V1.
• Analyzed attentional modulation of intrinsic connections within the V1 circuit.

Main Results:

• Selective entrainment of V4 gamma rhythm by V1 gamma rhythm was observed for the attended stimulus.
• Attentional modulation involved decreased local inhibition in V1's granular layer and increased inhibition in the supragranular layer.
• Presynaptic attentional influences and subsequent entrainment were sufficient to explain selective routing.

Conclusions:

• Attentional top-down influences on presynaptic V1 circuits mediate selective routing of visual information.
• Modulation of local inhibition within V1 is a key mechanism for selective attention.
• Presynaptic entrainment provides a viable explanation for how attention routes stimuli to higher visual areas.