Response modality-dependent categorical choice representations for vibrotactile comparisons

Description: Previous electrophysiological studies in monkeys and humans suggest that premotor regions are the primary loci for the encoding of perceptual choices during vibrotactile comparisons. However, in these studies choices were inextricably linked with the physical properties of the stimuli and action selection. It raises the question of what brain regions would represent choices at a more abstract level. That is, independent of the sensorimotor components of the task. To address this question, we used fMRI-MVPA and a variant of vibrotactile frequency discrimination task which enabled the isolation of choice-related signals from those related to stimulus properties and selection of the manual decision reports. We identified the left, contralateral dorsal premotor cortex (PMd) and intraparietal sulcus (IPS) as carrying information about abstract choices. Notably, our previous work using an oculomotor variant of the task also reported abstract choice representation in intraparietal and premotor regions. However, the informative premotor cluster was centered in the FEF rather than in the PMd, providing empirical support for a response effector-dependent organization of abstract choice representation in the context of vibrotactile comparisons. Together with the results from recent related studies in animals, we speculate that the premotor region might serve as a temporary storage for information necessary for the specification of concrete manual movements, while the IPS might be more directly involved in the computation of choice.

Related article: http://doi.org/10.1016/j.neuroimage.2020.117592

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