Dynamic coding of tactile-to-motor transformation in human and macaque posterior parietal cortex
General, Cognitive and Mathematical Psychology
Cognitive, Systems and Behavioural Neurobiology
Final Report Abstract
The project aimed to investigate the role of the posterior parietal cortex (PPC) in goal-directed tactile-motor processing of humans and macaque monkeys, with a focus on tactile processing for eye and hand movements, as compared with visual processing. The project sought to clarify the roles of PPC areas such as the ventral and lateral intraparietal areas (VIP and LIP, respectively) for tactile-spatial coding in the context of spatial transformation and motor planning. We chose a cross-species approach to allow linking the project results to the large body of visuo-motor (as compared to tactile-motor) neuroscience that has explored parietal organization and function on both humans and monkeys as well as complement neuroscientific methodologies. An exhaustive literature review led to the hypothesis that the macaque VIP has diversified into three separate regions in humans and that precursors of this specialization may already exist in macaques. Follow-up functional connectivity analysis of macaque brain activity supported these initial, literature-based findings. Moreover, the project sought to conduct closely-matched human and macaque move-to-touch experiments. The respective human studies revealed wide-spread overlap of parietal coding for tactile and visual stimuli, with fMRI multi-voxel pattern decoding generalizing between the two sensory modalities. Moreover, human fMRI work uncovered within-trial dynamics of spatial coding both for reaching and saccading. The respective monkey experiment presented unexpected behavioral results in that monkeys systematically saccaded to empty space, rather than towards tactile stimuli, in some postures. Such behavior is exciting in that it fits with very recent suggestions that touch may not be coded spatially, contrary to what has been assumed for decades. However, the finding required time-intensive modification of our experimental paradigm and animal training, and the analysis of this work is in progress at the time of reporting.
Publications
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Dynamic spatial coding in parietal cortex mediates tactile-motor transformation. Cold Spring Harbor Laboratory.
Klautke, Janina; Foster, Celia; Medendorp, W. Pieter & Heed, Tobias
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The macaque ventral intraparietal area has expanded into three homologue human parietal areas. Progress in Neurobiology, 209, 102185.
Foster, Celia; Sheng, Wei-An; Heed, Tobias & Ben, Hamed Suliann
