Spatial frequency processing preferentially recruits distributed cortical interactions in V1

The primary visual cortex (V1) is tuned to several visual features, including orientation and spatial frequency, that are organized into overlapping functional maps. Local neurons sharing tuning properties tend to connect more strongly, but how these features lead to distal functional connectivity in V1 remains unclear.

We recorded multiunit activity from layers II/III of cat V1 using electrode pairs separated by 410 µm and assessed functional connectivity using shift-corrected cross-correlograms. Visual stimuli were positioned to largely overlap the receptive fields of neurons at both recording sites. Functional connectivity was compared during orientation-constant and spatial frequency-constant stimulus conditions.

Neurons in the same ensemble exhibited significantly more and stronger distal functional connections during the spatial frequency-constant condition than during the orientation-constant condition. This effect persisted at the population level, indicating that distal connectivity is selectively recruited depending on the stimulus feature rather than anatomical proximity or differential stimulus drive.

These findings demonstrate that functional connectivity in V1 is stimulus-dependent, with spatial frequency processing preferentially engaging distributed cortical interactions. Such feature-dependent distal connectivity may support integration across spatial scales and reflect the flexible organization of early visual cortical networks.