Topographic maps representing haptic numerosity in the human brain1 April 2021
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.
In a recent paper published in Nature Communications, Shir Hofstetter and colleagues ask the question whether topographic maps representing cognitive dimensions exist irrespective of the stimulated sensory modality. Is there a difference, between seeing two cookies in front of you, or feeling them in your hand? To answer this question, they measured haptically and visually driven numerosity-selective neural responses using model-based analyses and ultra-high field (7T) fMRI. They found topographically organized neural populations tuned to haptic numerosity. These haptic response partially overlap with the visual numerosity maps. Therefore, they hypothesize that overlap between modality-specific maps facilitates cross-modal interactions and supramodal representation of cognitive quantities.