FENS Forum 2006

For lectures, symposia and workshops, time indicates the beginning of the session.
For posters, authors are expected to be in attendance at their posters at the time indicated.

First author: Baunez, Christelle (poster)

Poster board 410 - Tue 11/07, 16:00 - Hall Y
Session 199 - Motivation and emotion
Abstract A199.1, published in FENS Forum Abstracts, vol. 3, 2006.
Ref.: FENS Abstr., vol.3, A199.1, 2006

Author(s) Baunez C. (1), Cortright J. J. (2) & Rebec G. V. (2)

Addresse(s) (1) Lab. Neurobiol. Cogn. CNRS UMR6155, Univ. Provence, Marseille, France; (2) Program in Neural Science, Dept. Psychology, Indiana Univ., Bloomington, USA

Title Electrophysiological activity of subthalamic nucleus neurons in rats working for sucrose or cocaine reward.

Text The subthalamic nucleus (STN) belongs to the basal ganglia and has long been considered as a motor structure. Increasing evidence suggests that it is also involved in cognitive and motivational functions. Excitotoxic lesions of the STN increase motivation for food, but decrease the motivation for cocaine (Baunez et al., 2005 Nat. Neurosci., 8(4) 484-9). To assess the role of the STN at the neuronal level, we recorded STN neuronal activity in rats working for sucrose reward or for cocaine in a self-administration procedure. Male, Sprague-Dawley rats were trained to press a lever to obtain sucrose or to self-administer cocaine (i. v., 0.25 mg/infusion) contingent upon a FR-5 schedule of reinforcement in daily sessions. Cocaine infusions or sucrose delivery were delivered over a 4-sec period accompanied by compound conditioned stimuli (CS) (light and tone). In another procedure, delays were introduced between the lever press, the CS and the onset of the pump in order to clearly separate the various events.
To date, our data indicate that STN neurons show increased activity in response to lever press, to the CS and to the sucrose solution when recorded in the procedure with delays. In the FR5 condition, most of STN neurons showed a different modulation of activity at the lever press on the rewarded trial, when compared to the non-rewarded trials (the first 4 lever presses). In contrast, the changes of activity recorded at lever press were unchanged for the rewarded trials when the animals were self-administering cocaine. Collectively, our results indicate that the STN encodes information related to the expectation of reward, but seems to encode differentially sucrose and cocaine reward, supporting the dissociation between natural and cocaine reward observed after STN lesions.
Supported by DA02451, DRI CNRS and France Parkinson.

Theme Cognition and behaviour
Motivation and emotion

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Author(s)	Baunez C. (1), Cortright J. J. (2) & Rebec G. V. (2)
Addresse(s)	(1) Lab. Neurobiol. Cogn. CNRS UMR6155, Univ. Provence, Marseille, France; (2) Program in Neural Science, Dept. Psychology, Indiana Univ., Bloomington, USA
Title	Electrophysiological activity of subthalamic nucleus neurons in rats working for sucrose or cocaine reward.
Text	The subthalamic nucleus (STN) belongs to the basal ganglia and has long been considered as a motor structure. Increasing evidence suggests that it is also involved in cognitive and motivational functions. Excitotoxic lesions of the STN increase motivation for food, but decrease the motivation for cocaine (Baunez et al., 2005 Nat. Neurosci., 8(4) 484-9). To assess the role of the STN at the neuronal level, we recorded STN neuronal activity in rats working for sucrose reward or for cocaine in a self-administration procedure. Male, Sprague-Dawley rats were trained to press a lever to obtain sucrose or to self-administer cocaine (i. v., 0.25 mg/infusion) contingent upon a FR-5 schedule of reinforcement in daily sessions. Cocaine infusions or sucrose delivery were delivered over a 4-sec period accompanied by compound conditioned stimuli (CS) (light and tone). In another procedure, delays were introduced between the lever press, the CS and the onset of the pump in order to clearly separate the various events. To date, our data indicate that STN neurons show increased activity in response to lever press, to the CS and to the sucrose solution when recorded in the procedure with delays. In the FR5 condition, most of STN neurons showed a different modulation of activity at the lever press on the rewarded trial, when compared to the non-rewarded trials (the first 4 lever presses). In contrast, the changes of activity recorded at lever press were unchanged for the rewarded trials when the animals were self-administering cocaine. Collectively, our results indicate that the STN encodes information related to the expectation of reward, but seems to encode differentially sucrose and cocaine reward, supporting the dissociation between natural and cocaine reward observed after STN lesions. Supported by DA02451, DRI CNRS and France Parkinson.
Theme	Cognition and behaviour Motivation and emotion