Topographic connectivity reveals task-dependent retinotopic processing throughout the human brain

Tomas Knapen

doi:10.1073/pnas.2017032118

Abstract

The human visual system is organized as a hierarchy of maps that share the topography of the retina. Known retinotopic maps have been identified using simple visual stimuli under strict fixation, conditions different from everyday vision which is active, dynamic, and complex. This means that it remains unknown how much of the brain is truly visually organized. Here I demonstrate widespread stable visual organization beyond the traditional visual system, in default-mode network and hippocampus. Detailed topographic connectivity with primary visual cortex during movie-watching, resting-state, and retinotopic-mapping experiments revealed that visual-spatial representations throughout the brain are warped by cognitive state. Specifically, traditionally visual regions alternate with default-mode network and hippocampus in preferentially representing the center of the visual field. This visual role of default-mode network and hippocampus would allow these regions to interface between abstract memories and concrete sensory impressions. Together, these results indicate that visual-spatial organization is a fundamental coding principle that structures the communication between distant brain regions.

Highlights

The human visual system is organized as a hierarchy of maps that share the topography of the retina
A parsimonious computational model for retinotopic connectivity (RC) posits that responses arise from a localized Gaussian patch on the surface of V1 (Fig. 1B), its connective field (CF) [5]
Translating the best-fitting CF parameters into visual field locations reveals the structure of visual field maps in V2, V3, and beyond (Fig. 1 E–G)

Summary

Introduction

The human visual system is organized as a hierarchy of maps that share the topography of the retina. Known retinotopic maps have been identified using simple visual stimuli under strict fixation, conditions different from everyday vision which is active, dynamic, and complex This means that it remains unknown how much of the brain is truly visually organized. I performed RC analysis on the Human Connectome Project (HCP) 7T dataset of 174 subjects in which data were collected during retinotopic-mapping, resting-state, and moviewatching experiments This allowed the identification of previously unknown visual–spatial processing throughout the brain, and the quantification of how visual space is represented—even in brain regions not traditionally considered visual. These analyses reveal how visual representations depend on cognitive state

Methods

Results

Conclusion