Distinct Laminar Processing of Local and Global Context in Primate Primary Visual Cortex.

Area of Science:

• Neuroscience
• Visual Perception
• Cortical Circuits

Background:

• Visual perception relies on spatial context, with neuronal responses modulated by stimuli within and surrounding the receptive field (RF).
• Understanding the specific cortical layers and circuits involved in processing this spatial context is crucial for deciphering visual information processing.

Purpose of the Study:

• To investigate the distinct laminar contributions within the macaque primary visual cortex to processing local versus global spatial context.
• To identify the specific cortical layers activated by near-surround versus far-surround stimuli.

Main Methods:

• Simultaneous electrophysiological recordings across all layers of the macaque primary visual cortex.
• Presentation of visual stimuli at varying distances from the recorded cells' receptive fields to probe surround modulation.

Main Results:

• Near-surround stimuli elicited the earliest subthreshold responses in superficial and upper-deep layers, and earliest spiking suppression in superficial layers.
• Far-surround stimuli preferentially activated feedback-recipient layer 1 and lower-deep layers for subthreshold responses, with widespread spiking suppression occurring later, notably last in layer 4C.
• Distinct laminar activation patterns indicate separate processing streams for local and global spatial context.

Conclusions:

• The primary visual cortex utilizes distinct circuits and laminar pathways for integrating local and global spatial context.
• These findings illuminate the specialized roles of different cortical layers in constructing a comprehensive visual scene.