Micro-probing enables high-resolution mapping of neuronal subpopulations using fMRI

Abstract

The characterization of receptive field (RF) properties is fundamental to understanding the neural basis of sensory and cognitive behaviour. The combination of non-invasive imaging, such as fMRI, with biologically inspired neural modeling has enabled the estimation of population RFs directly in humans. However, current approaches require making numerous a priori assumptions, so these cannot reveal unpredicted properties, such as fragmented RFs or subpopulations. This is a critical limitation in studies on adaptation, pathology or reorganization. Here, we introduce micro-probing (MP), a technique for fine-grained and assumption free characterisation of subpopulation RFs. Without specific stimuli or adapted models, MP mapped the bilateral RFs characteristic of observers with a congenital pathway disorder. Moreover, in healthy observers, MP revealed voxels that capture the activity of multiple neuronal subpopulations. Thus, MP provides a versatile framework to visualize, analyze and model, without restrictions, the diverse RFs of cortical subpopulations in health and disease.