title: Prefrontal tetanic stimulation, following fear reconditioning, facilitates expression of previously acquired extinction.
abstract: We have recently shown that post-extinction retraining of rats, with a shock intensity that is too weak to induce by itself significant fear acquisition, impairs the recall of fear extinction memory. Tetanic stimulation (TS) of the medial prefrontal cortex (mPFC), applied before or following this retraining, facilitates extinction recall. Here we investigated whether mPFC TS can also facilitate expression of fear extinction when rats are retrained with the same shock intensity as during the initial fear acquisition. Rats were implanted with stimulating electrodes in the mPFC and were trained to acquire freezing to a conditioning chamber, in which they had to enter freely. In Experiment 1, extinction of this response was followed by reconditioning and then another extinction training. Acquired freezing was extinguished successfully, while reacquired freezing, which was associated with increased chamber entry latencies, was resistant to subsequent extinction. Both reacquired freezing and increased chamber entry latencies were absent in rats that received post-reconditioning mPFC TS. In Experiment 2, post-conditioning mPFC TS had no effect on initially acquired freezing. In Experiment 3, rats were submitted to reconditioning without experiencing extinction training. In this condition, both reacquired freezing and increased chamber entry latencies were still present in rats that received post-reconditioning mPFC TS. These findings provide additional evidence for the fundamental role of the mPFC in maintaining expression of fear extinction.
authors: Institut de Neurosciences de la Timone, UMR7289, Aix-Marseille Université & CNRS, 13385 Marseille, France; Laboratoire d'Anthropologie et de Psychologie Cognitives et Sociales, Institut des Sciences Humaines et Sociales de Nice, Université de Nice-Sophia Antipolis, 06357 Nice, France.
authors: Ophélie
authors: O
authors: Nachon
authors: Laboratoire Néovasc, ERI-28, Normandie Université, IRIB, 76183 Rouen, France.
authors: Carine
authors: C
authors: Cleren
authors: Département des Sciences de la Vie, Université de Nice-Sophia Antipolis, 06108 Nice, France.
authors: Sébastien
authors: S
authors: Husson
authors: Département des Sciences de la Vie, Université de Nice-Sophia Antipolis, 06108 Nice, France.
authors: Célia
authors: C
authors: Huguet
authors: Département des Sciences de la Vie, Université de Nice-Sophia Antipolis, 06108 Nice, France.
authors: Julie
authors: J
authors: Auclair
authors: Laboratoire d'Anthropologie et de Psychologie Cognitives et Sociales, Institut des Sciences Humaines et Sociales de Nice, Université de Nice-Sophia Antipolis, 06357 Nice, France.
authors: Sylvane
authors: S
authors: Faure
authors: Department of Psychology, University of Haifa, Haifa 31905, Israel.
authors: Irit
authors: I
authors: Akirav
authors: Pharma Division, CNS Department, Hoffmann-La Roche, Basel, Switzerland.
authors: Jean-Luc
authors: JL
authors: Moreau
authors: Institut de Neurosciences de la Timone, UMR7289, Aix-Marseille Université & CNRS, 13385 Marseille, France. Electronic address: rene.garcia@unice.fr.
authors: René
authors: R
authors: Garcia
mesh_terms: D000818:Animals; D003213:Conditioning, Psychological / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods*; D005108:Extinction, Psychological / Q000502:physiology*; D005239:Fear / Q000502:physiology*; D046352:Freezing Reaction, Cataleptic / Q000502:physiology; D008297:Male; D017397:Prefrontal Cortex / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
keywords: Conditioned freezing; Fear extinction; Fear re-acquisition; Prefrontal electrical stimulation; Rats