Use of implicit motor imagery for visual shape discrimination as revealed by PET

Lawrence M. Parsons, Peter T. Fox, J. Hunter Downs, Thomas Glass, Traci B. Hirsch, Charles C. Martin, Paul A. Jerabek, Jack L. Lancaster

Research output: Contribution to journalArticlepeer-review

530 Scopus citations


POSITRON emission tomography (PET) can be used to map brain regions that are active when a visual object (for example, a hand) is discriminated from its mirror form. Chronometric studies1á€-3 suggest that viewers 'solve' this visual shape task by mentally modelling it as a reaching task, implicitly moving their left hand into the orientation of any left-hand stimulus (and conversely for a right-hand stimulus). Here we describe an experiment in which visual and somatic processing are dissociated by presenting right hands to the left visual field and vice versa. Frontal (motor), parie- tal (somatosensory) and cerebellar (sensorimotor) regions similar to those activated by actual4,5 and imagined6á€-8 movement are strongly activated, whereas primary somatosensory and motor cortices are not. We conclude that mental imagery is realized at intermediate-to-high order, modality-specific cortical systems, but does not require primary cortex and is not constrained to the perceptual systems of the presented stimuli.

Original languageEnglish (US)
Pages (from-to)54-58
Number of pages5
Issue number6526
StatePublished - 1995

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Use of implicit motor imagery for visual shape discrimination as revealed by PET'. Together they form a unique fingerprint.

Cite this