Laura
L. Peoples, Ph.D.
Asst. Professor, Dept of Psychology
3720 Walnut Street
Phone: (215) 898-4253
Email: lpeoples@psych.upenn.edu
Normal and abnormal goal-directed behavior. Focus on the nucleus accumbens
and associated afferent and efferent circuitry. More specifically we are
interested in the following: neurophysiological mechanisms that mediate
the normal contribution of the nucleus accumbens and related structures
to reward-directed behavior; alterations in reward-related information processing
that are induced by drugs of abuse and that may underlie the development
of drug addiction.
RESEARCH TECHNIQUES
Normal and abnormal goal-directed behavior. Focus on the nucleus accumbens
and associated afferent and efferent circuitry. More specifically we are
interested in the following: neurophysiological mechanisms that mediate
the normal contribution of the nucleus accumbens and related structures
to reward-directed behavior; alterations in reward-related information processing
that are induced by drugs of abuse and that may underlie the development
of drug addiction.
RESEARCH SUMMARY
One primary area of research aims to identify acute and
lasting drug effects that may contribute to the development of drug addiction.
Incentive motivation theories of drug addiction propose that the disorder
reflects a pathological responsivity to the influences of drug-associated
conditioned stimuli on instrumental behavior. These theories further propose
that the abnormal responsivity to drug stimuli is caused by a drug-induced
amplification of mechanisms that normally facilitate either stimulus-reward
learning or the influence of that learning on instrumental behavior. Our
research is focused on investigating this latter proposal. To carry out
our investigation we use chronic extracellular recording techniques to
characterize the effects of self-administered drug on neural responses
to drug cues and drug-directed instrumental behavior of rats. Historically,
we have focused our studies on single neuron activity within the nucleus
accumbens. We are currently extending our recordings to include several
accumbal afferent and efferent structures and to assess changes at a circuitry
level in addition to a single neuron level. We are additionally employing
a variety of new behavioral procedures to better isolate drug effects
on associative processes. Planned initiatives include integration of the
chronic recording studies with neuropharmacological methods and acute
electrophysiological procedures to identify the neurochemicals and receptors
that transduce the drug-induced changes in neural encoding of incentive-related
information.
A second line of neurophysiological research is related to the proposal
that drug-induced disruption of cortical inhibitory mechanisms contributes
to compulsive drug seeking. In addition to the neurophysiological investigations,
we have developed a behavioral research program that aims to test and
refine the hypotheses that drug effects on learning-related processes
and inhibitory mechanisms contribute to the development of drug-addicted
behavior. A corollary of these studies is the development of more clinically
relevant models of relapse. We hope that our research efforts will not
only contribute to a better understanding of drug addiction, and perhaps
other types of abnormal reward-directed behaviors, but also shed light
on mechanisms that contribute to normal reward-directed behavior.
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