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Processing of visual signals for direct specification of motor targets and for conceptual representation of action targets in the dorsal and ventral premotor cortex.

Abstract：

:Previous reports have indicated that the premotor cortex (PM) uses visual information for either direct guidance of limb movements or indirect specification of action targets at a conceptual level. We explored how visual inputs signaling these two different categories of information are processed by PM neurons. Monkeys performed a delayed reaching task after receiving two different sets of visual instructions, one directly specifying the spatial location of a motor target (a direct spatial-target cue) and the other providing abstract information about the spatial location of a motor target by indicating whether to select the right or left target at a conceptual level (a symbolic action-selection cue). By comparing visual responses of PM neurons to the two sets of visual cues, we found that the conceptual action plan indicated by the symbolic action-selection cue was represented predominantly in dorsal PM (PMd) neurons with a longer latency (150 ms), whereas both PMd and ventral PM (PMv) neurons responded with a shorter latency (90 ms) when the motor target was directly specified with the direct spatial-target cue. We also found that excited, but not inhibited, responses of PM neurons to the direct spatial-target cue were biased toward contralateral preference. In contrast, responses to the symbolic action-selection cue were either excited or inhibited without laterality preference. Taken together, these results suggest that the PM constitutes a pair of distinct circuits for visually guided motor act; one circuit, linked more strongly with PMd, carries information for retrieving action instruction associated with a symbolic cue, and the other circuit, linked with PMd and PMv, carries information for directly specifying a visuospatial position of a reach target.

journal_name

J Neurophysiol

journal_title

Journal of neurophysiology

authors

Yamagata T,Nakayama Y,Tanji J,Hoshi E

doi

10.1152/jn.00452.2009

subject

Has Abstract

pub_date

2009-12-01 00:00:00

pages

3280-94

issue

eissn

0022-3077

issn

1522-1598

pii

00452.2009

journal_volume

102

pub_type

杂志文章

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Processing of visual signals for direct specification of motor targets and for conceptual representation of action targets in the dorsal and ventral premotor cortex.