Abstract Body

Pavlovian conditioning pairing a conditioned stimulus (CS) with an unconditioned stimulus (US) leads to a conditioned response. With training, a temporal pattern emerges, reflecting a timed expectancy of the US arrival. The literature suggests an anticipated expectancy (peak time) with an aversive US, but a better accuracy with an appetitive US. Different brain structures have been highlighted to be involved in temporal behavior. The difference in temporal response between appetitive and aversive conditions raises the question of whether the implication of these structures may differ between conditions. In the present study, we compared the temporal response of rats submitted to both appetitive and aversive Pavlovian conditioning, and we explored the implication of the striatum-hippocampus-amygdala network in this response through local field potentials (LFP) recording. Rats were trained to a double Pavlovian conditioning (sound1-shock and sound2-chocolate), with the US moment at 20 seconds in both conditions. After training, we recorded LFP in three structures (dorsal striatum, hippocampus, and basolateral amygdala) during unreinforced probe trials. Time-frequency analyses highlighted the engagement of the striatum and the hippocampus in both conditions around the moment of the expected reinforcement, but with opposite modulations in the power spectrum density of oscillatory activity at 8Hz. Concerning the engagement of the amygdala, the aversive, but not appetitive, CS triggered onset-evoked modulations. Whether the differential modulations reflect different behavior/motor-related correlates and/or some competition in neuronal mechanism between appetitive and aversive conditions is an open question to be addressed in future studies.

Funding: ANR TimeMemory