Stress influences the dynamics of hippocampal structural remodeling associated with fear memory extinction

BENDER, CRHISTIAN LUIS; GIACHERO, MARCELO; COMAS-MUTIS, RAMIRO; MOLINA, VICTOR ALEJANDRO; CALFA, GASTÓN DIEGO

NEUROBIOLOGY OF LEARNING AND MEMORY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2018 vol. 155 p. 412 - 412

1074-7427

ear extinction is defined as a decline in fear-conditioned responses following non-reinforced exposure to a fear conditioned stimulus, therefore the conditioned stimulus gains new predictive properties. Patients with anxiety related disorders (e.g.: PTSD) subjected to extinction-like exposure treatments often experience a relapse of symptoms. Stress is a risk factor for those psychiatric disorders and a critical modulator of fear learning that turns the memory resistant to the extinction process. Dendritic spines are the anatomical sites where neuronal activity reshapes brain networks during learning and memory processes. Thus, we planned to characterize the dynamics of synaptic remodeling before and after contextual fear extinction in the dorsal hippocampus (DH), and how this process is affected by a previous stress experience. Animals with or without previous stress were contextually fear conditioned and one day later trained in an extinction paradigm. Rats were sacrificed one day a