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: firstname.lastname@example.org, Columbia-Presbyterian Medical Center,
Department of Psychiatry, 710 West 168th Street, New York, New York 10032-
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