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Simultaneous preparation of multiple potential movements: opposing effects of spatial proximity mediated by premotor and parietal cortex

Lookup NU author(s): Professor Kianoush Nazarpour

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Abstract

Neurophysiological studies in monkey have suggested that premotor and motor cortex may prepare for multiple movements simultaneously, sustained by cooperative and competitive interactions within and between the neural populations encoding different actions. Here, we investigate whether competition between alternative movement directions, manipulated in terms of number and spatial angle, is reflected in electroencephalographic (EEG) measures of (pre)motor cortical activity in humans. EEG was recorded during performance of a center-out pointing task in which response signals were preceded by cues providing prior information in the form of arrows pointing to one or more possible movement targets. Delay-period activity in (pre)motor cortex was modulated in the predicted manner by the number of possible movement directions and by the angle separating them. Response latencies, however, were determined not only by the amplitude of movement-preparatory activity, but also by differences in the duration of stimulus evaluation against the visuospatial memory of the cue, reflected in EEG potentials originating from posterior parietal cortex (PPC). Specifically, the spatial proximity of possible movement targets was processed differently by (pre)motor and posterior parietal cortex. Spatial proximity enhanced the amplitude of (pre)motor cortex preparatory activity during the delay period but delayed evaluation of the response signal in the PPC, thus producing opposite effects on response latency. The latter finding supports distributed control of movement decisions in the frontoparietal network, revealing a feature of distributed control that is of potential significance for the understanding of distracter effects in reaching and pointing.

Publication metadata

Author(s): Praamstra P, Kourtis D, Nazarpour K

Publication type: Article

Publication status: Published

Journal: Journal of Neurophysiology

Year: 2009

Volume: 102

Issue: 4

Pages: 2084-2095

Date deposited: 14/07/2014

ISSN (print): 0022-3077

ISSN (electronic): 1522-1598

Publisher: American Physiological Society

URL: http://dx.doi.org/10.1152/jn.00413.2009

DOI: 10.1152/jn.00413.2009

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