Visual Field Map Clusters in High-Order Visual Processing: Organization of V3A/V3B and a New Cloverleaf Cluster in...

Area of Science:

• Neuroscience
• Cognitive Science
• Visual System Organization

Background:

• The human visual system exhibits a hierarchical organization based on retinal spatial coordinates, featuring visual field maps (VFMs) and larger sensory cortical field map (CFM) clusters.
• These cloverleaf clusters, observed in both visual and auditory systems, share properties like receptive field distribution and processing specialization.

Purpose of the Study:

• To investigate the extent of VFM and cluster organization in higher-level visual processing within the human temporal cortex.
• To compare the organization of VFMs in the posterior superior temporal sulcus (pSTS) with mid-level visual processing regions in the dorsal occipital cortex (V3A/B cluster).

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed to study brain activity.
• Population receptive field (pRF) modeling was used to characterize the organization and properties of VFMs.

Main Results:

• A novel cloverleaf cluster containing four VFMs (pSTS-1:4) was identified in the pSTS, a region associated with higher-order visual functions.
• These pSTS VFMs are characterized by smaller surface areas and larger pRF sizes compared to the V3A/B cluster in the dorsal occipital cortex.
• Cortical magnification analysis revealed a greater representation of the peripheral visual field in the pSTS VFMs than in the V3A/B cluster.

Conclusions:

• The findings demonstrate that VFMs in the pSTS are organized into a distinct cloverleaf cluster, adding to the understanding of sensory cortical organization.
• The remarkable consistency and functional differentiability of these clusters suggest that CFMs and cloverleaf clusters are fundamental principles of cortical sensory processing.