Topographic maps representing haptic numerosity reveals distinct sensory representations in supramodal networks

Shir Hofstetter,Ben M Harvey,Serge O Dumoulin,Yuxuan Cai

doi:10.1038/s41467-020-20567-5

Shir Hofstetter, Ben M Harvey + Show 2 more

Open Access

https://doi.org/10.1038/s41467-020-20567-5

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Abstract

Dedicated maps for cognitive quantities such as timing, size and numerosity support the view that topography is a general principle of brain organization. To date, however, all of these maps were driven by the visual system. Here, we ask whether there are supramodal topographic maps representing cognitive dimensions irrespective of the stimulated sensory modality. We measured haptically and visually driven numerosity-selective neural responses using model-based analyses and ultra-high field (7T) fMRI. We found topographically organized neural populations tuned to haptic numerosity. The responses to visual or haptic numerosity shared a similar cortical network. However, the maps of the two modalities only partially overlap. Thus, although both visual and haptic numerosities are processed in a similar supramodal functional network, the underlying neural populations may be related, but distinct. Therefore, we hypothesize that overlap between modality-specific maps facilitates cross-modal interactions and supramodal representation of cognitive quantities.

Highlights

Dedicated maps for cognitive quantities such as timing, size and numerosity support the view that topography is a general principle of brain organization
These maps showed ordered responses to physical quantities of visual event duration[3,4], visual object size[5], and visual numerosity[6,7], i.e., the set size of items in a group. These findings demonstrate that topography is a common principle of brain organization that goes beyond sensory and motor organ structures
We hypothesize that the principle of minimizing neural wiring length between neurons with similar tuning properties will result in topographic maps for neurons tuned to haptic numerosity[31,32]

Summary

Introduction

Dedicated maps for cognitive quantities such as timing, size and numerosity support the view that topography is a general principle of brain organization. The maps of the two modalities only partially overlap Both visual and haptic numerosities are processed in a similar supramodal functional network, the underlying neural populations may be related, but distinct. Studies revealed dedicated topographic maps for more abstract cognitive dimensions, which do not depend on the organization of the sensory organs These maps showed ordered responses to physical quantities of visual event duration[3,4], visual object size[5], and visual numerosity[6,7], i.e., the set size of items in a group. We compared within-participant their haptic and visual topographic maps

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