title: Maintenance of aversive memories shown by fear extinction-impaired phenotypes is associated with increased activity in the amygdaloid-prefrontal circuit.
abstract: Although aversive memory has been mainly addressed by analysing the changes occurring in average populations, the study of neuronal mechanisms of outliers allows understanding the involvement of individual differences in fear conditioning and extinction. We recently developed an innovative experimental model of individual differences in approach and avoidance behaviors, classifying the mice as Approaching, Balancing or Avoiding animals according to their responses to conflicting stimuli. The approach and avoidance behaviors appear to be the primary reactions to rewarding and threatening stimuli and may represent predictors of vulnerability (or resilience) to fear. We submitted the three mice phenotypes to Contextual Fear Conditioning. In comparison to Balancing animals, Approaching and Avoiding mice exhibited no middle- or long-term fear extinction. The two non-extinguishing phenotypes exhibited potentiated glutamatergic neurotransmission (spontaneous excitatory postsynaptic currents/spinogenesis) of pyramidal neurons of medial prefrontal cortex and basolateral amygdala. Basing on the a priori individuation of outliers, we demonstrated that the maintenance of aversive memories is linked to increased spinogenesis and excitatory signaling in the amygdala-prefrontal cortex fear matrix.
authors.affiliation: IRCCS Fondazione Santa Lucia, Rome, Italy.|Department of Psychology, University Sapienza of Rome, Rome, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Laricchiuta
authors.affiliation: IRCCS Fondazione Santa Lucia, Rome, Italy.|Department of Neuroscience, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Luana
authors.initials: L
authors.lastname: Saba
authors.affiliation: IRCCS Fondazione Santa Lucia, Rome, Italy.|Department of Sociological and Psychopedagogical Studies, University Guglielmo Marconi of Rome, Rome, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: De Bartolo
authors.affiliation: IRCCS Fondazione Santa Lucia, Rome, Italy.|Department of Neuroscience, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Caioli
authors.affiliation: IRCCS Fondazione Santa Lucia, Rome, Italy.|Department of Neuroscience, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Zona
authors.affiliation: IRCCS Fondazione Santa Lucia, Rome, Italy.|Department of Psychology, University Sapienza of Rome, Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Petrosini
mesh_terms: D000679:Amygdala / Q000502:physiology*; D000818:Animals; D001362:Avoidance Learning / Q000502:physiology; D003214:Conditioning, Classical; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005239:Fear / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D051379:Mice; D010641:Phenotype; D017397:Prefrontal Cortex / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology