INTERACTIONS BETWEEN SPATIAL AND EFFECTOR - SPECIFIC INFORMATION IN TWO DISTINCT AREAS OF MONKEY POSTERIOR PARIETAL CORTEX ( PPC ) .

T.R.Dickinson^*; J.L.Calton; L.H.Snyder

Interactions between spatial and effector-specific information in two distinct areas of monkey posterior parietal cortex (PPC). Neurons of the lateral interparietal area (LIP) and the parietal reach region (PRR) of PPC are differentially driven by arm and eye-movement instructions in the absence of spatial target information. We now ask how such effector-specificity interacts with the coding of the spatial goal of the movement. We address this question by using visually-guided movement tasks in which the effector and spatial target were presented sequentially, in either order, and separated in time by a short delay. Effector information might be potentiated, displaced, or be uneffected by spatial information. Across 135 PRR cells in two monkeys, cueing an arm movement produced 4.21 sp/s higher firing than cueing an eye movement (35 to 160 ms after cue onset). Across 67 LIP cells in the same two animals, a difference of 2.00 sp/s was found, with a reversal of motor-specifity (eye over arm). When spatial information followed effector information, activity was 7.90 (PRR) and 0.69 (LIP) sp/s higher with the preferred effector. These results indicate that effector and spatial information combine differently in PRR and LIP. In PRR, spatial information potentiates differences in activity due to effector information. In LIP, spatial information diminishes differences in activity due to effector information.
Supported by: NIH, McDonnell-Pew, EJLB

Citation: T.R.Dickinson, J.L.Calton, L.H.Snyder. INTERACTIONS BETWEEN SPATIAL AND EFFECTOR - SPECIFIC INFORMATION IN TWO DISTINCT AREAS OF MONKEY POSTERIOR PARIETAL CORTEX ( PPC ) . Program No. 622.9. 2002 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2002. CD-ROM.