Original Research ARTICLE
The somatotopy of mental tactile imagery
- 1Department of Education and Psychology, Free University Berlin, Germany
To what degree mental imagery bears on the same neuronal processes as perception, has been a central question in the neurophysiological study of imagery. Sensory-recruitment models suggest that imagery of sensory material heavily relies on the involvement of sensory cortices. Empirical evidence mainly stems from the study of visual imagery and suggests that it depends on the mentally imagined material if hierarchically lower regions are recruited. However, evidence from other modalities is necessary to infer generalized principles. In this fMRI study we used the somatotopic organization of the primary somatosensory cortex (SI) to test in how far mental imagery of tactile sensations activates topographically sensory brain areas. Participants (N=19) either perceived or imagined vibrotactile stimuli on their left or right thumbs or big toes. The direct comparison to a corresponding perception condition revealed that SI was somatotopically recruited during imagery. While stimulus driven bottom-up processing induced activity throughout all SI subareas, i.e. BA1 3a/3b and BA2 defined by probabilistic cytoarchitectonic maps, top-down recruitment during imagery was limited to the hierarchically highest subarea BA2.
Keywords: tactile, Mental Imagery, Imagery Debate, tactospatial sketchpad, somatosensory, fMRI, mental codes
Received: 17 Aug 2018;
Accepted: 10 Jan 2019.
Edited by:Burkhard Pleger, University Hospitals of the Ruhr-University of Bochum, Germany
Reviewed by:Esther Kuehn, German Center for Neurodegenerative Diseases (DZNE), Germany
Christian Klaes, Ruhr-Universität Bochum, Germany
Copyright: © 2019 Schmidt and Blankenburg. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Timo Torsten Schmidt, Department of Education and Psychology, Free University Berlin, Berlin, 14195 Berlin, Berlin, Germany, email@example.com