Mental representations of movements. Brain potentials associated with imagination of eye movements

Objective: Current research in motor imagery is focused on similarities bet ween actual and imagined movements on a central and a peripheral level of t he nervous system. The present study measured slow cortical potentials (DC- potentials) during execution and internal simulation of memorized saccadic eye movements. Methods: In 19 healthy righthanded subjects DC-potentials were recorded fro m 28 electrodes during execution and during imagination of a sequence of me morized eye movements during a visual imagery condition. Results: Both oculomotor conditions showed a similar global level and simil ar topography of performance related DC-potentials, both strongly differed from the visual imagery condition and were lateralized to the left hemisphe re. Conclusion: This study therefore supports the hypothesis that cortical brai n structures responsible for execution and imagination of memorized saccadi c eye movements are similar. The observed left hemispheric lateralization i s iri contrast to a previous study using bimanual movements. This discrepan cy is discussed in relation to recent observations in apractic patients wit h parietal lesions. (C) 1999 Elsevier Science Ireland Ltd. All rights reser ved.