Eye-centered, head-centered and intermediate coding of remembered sound locations in area LIP. Brigitte Stricanne, Richard Andersen, and Pietro Mazzoni. Centre de Recherche Cerveau et Cogniscience, Universite Paul Sabatier, Faculte de Medecine de Rangueil, 133, route de Narbonne, 31 000 Toulouse, France, Division of Biology, California Institute of Technology, Mail Code 216-76, Pasadena, California 91125, (818) 395-8336, fax (818) 795-2397, e- mail: andersen@vis.caltech.edu, Columbia-Presbyterian Medical Center, Department of Psychiatry, 710 West 168th Street, New York, New York 10032- 2603.
APStracts 3:0101N, 1996.
SUMMARY AND CONCLUSIONS
1) The lateral intraparietal area (LIP) of the posterior parietal cortex lies within the dorsal cortical stream for spatial vision and processes visual information in order to plan saccadic eye movements. We investigated how LIP neurons respond when a monkey makes saccades to the remembered location of sound sources in the absence of visual stimulation. 2) Forty three (36%) of the 118 neurons sampled showed significant auditory triggered activity during the memory period. This figure is similar to the proportion of cells showing visually triggered memory activity (Gnadt and Andersen 1988, Barash et al. 1991a). 3) Of the cells showing auditory memory activity, 44% discharged in an eye-centered manner, similar to the way in which LIP cells discharge for visually initiated saccades. Another 33% responded in head-centered coordinates, and the remaining 23% had responses intermediate between the two reference frames. 4) For a substantial number of cells in all three categories, the magnitude of the response was modulated by eye position. Similar orbital "gain fields" had been shown previously for visual saccades (Andersen et al. 1990). 5) We propose that area LIP is either at the origin of, or participates in, the transformation of auditory signals for oculomotor purposes, and that orbital gains on the discharge are part of this process. 6) Finally, we suggest that, by the level of area LIP, cells are concerned with the abstract quality of where a stimulus is in space, independent of the exact nature of the stimulus.

Received  1995; accepted in final form  1996.
APS Manuscript Number J.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 June 96