The Journal of Neuroscience, August 1, 2002, 22(15):6756-6765
A Double Dissociation within Striatum between Serial Reaction
Time and Radial Maze Delayed Nonmatching Performance in Rats
Robert G.
Mair,
Jennifer K.
Koch,
Julie B.
Newman,
James R.
Howard, and
Joshua A.
Burk
Department of Psychology, University of New Hampshire, Durham, New
Hampshire 03824
Lesions involving the intralaminar thalamic nuclei have been
associated with impairments in working memory and intentional motor
function in human clinical cases and animal models of amnesia. The
intralaminar nuclei have afferent and efferent connections related to
striatum. To test whether disruption of striatal function can account
for impairments produced by intralaminar lesions, we investigated the
effects of striatal lesions on two tasks known to be impaired by
intralaminar damage in the rat: radial maze delayed nonmatching (DNM),
a measure of spatial working memory, and self-paced serial reaction
time (SRT), a measure of intentional response speed. We compared the
effects of lesions in four sites: the medial and lateral caudate
putamen, nucleus accumbens, and olfactory tubercle. We found that
lesions of the medial, accumbens, or tubercle sites impaired DNM
performance, and that lesions of the lateral caudate putamen increased
choice response time for the SRT task. There was a double dissociation
between the effects of the ventral and the lateral lesions on these two
tasks. For both tasks, the effects of striatal lesions were
qualitatively similar and at least as large as intralaminar lesions in
previous studies. These results provide evidence that striatal
dysfunction can account for the DNM and SRT impairments produced by
intralaminar lesions. The dissociation of functional impairments
suggests that lateral sensorimotor areas of caudate putamen are
important for responding based on external sensory stimuli and
limbic-related areas in ventral striatum are important for responding
based on information held in working memory.
Key words:
caudate putamen; ventral striatum; serial reaction time; spatial working memory; response speed; amnesia
Copyright © 2002 Society for Neuroscience 0270-6474/02/22156756-10$05.00/0
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