Journal of Neuroscience, Vol 7, 3505-3511, Copyright © 1987 by Society for Neuroscience
Nucleus basalis magnocellularis and medial septal area lesions differentially impair temporal memory
WH Meck, RM Church, GL Wenk and DS Olton
Department of Psychology, Columbia University, New York, New York 10027.
Functional dissociations between the medial septal area (MSA) and the
nucleus basalis magnocellularis (NBM) were examined using the concepts and
experimental procedures developed by scalar timing theory. Rats were tested
in variations of a signalled discrete-trial peak-interval schedule of
reinforcement in which the response rate functions identified the time when
the rats expected reinforcement. The variations assessed aspects of both
reference and working memory for information obtained from prior trials and
from the current trial. A double dissociation was found in reference
memory. Rats with NBM lesions, like those with frontal cortex (FC) lesions,
remembered the time of reinforcement as having occurred later than it
actually did; rats with MSA lesions, like those with fimbria-fornix (FF)
lesions, remembered the time of reinforcement as having occurred earlier
than it did. A single dissociation was found in working memory. MSA lesions
and FF lesions impaired working memory, while NBM and FC lesions had no
effect on it. These data begin to identify the brain mechanisms underlying
temporal memory; they indicate that the frontal and hippocampal systems are
both involved, but in complementary ways; and they provide information that
helps specify more clearly the functions of the frontal and hippocampal
systems.
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