Banca de DEFESA: MOISES DOS SANTOS CORREA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MOISES DOS SANTOS CORREA
DATE: 15/12/2022
TIME: 13:00
LOCAL: Sala S17 do Bloco Delta do Campus de São Bernardo do Campo da Universidade Federal do ABC
TITLE:

Does the intensity of an aversive event matter? How do features of the stress response modulate systems consolidation and specificity of fear memories in rats

PAGES: 150
BIG AREA: Ciências Humanas
AREA: Psicologia
SUBÁREA: Psicologia Fisiológica
SPECIALTY: Psicobiologia
SUMMARY:

The ability to retrieve contextual fear memories depends on the coordinated activation of a brain-wide circuitry of memory engram cells. The transition from recent to remote memories seems to involve the reorganization of this global circuitry, a process called systems consolidation that has been associated with time-dependent fear generalization. Fear or contextual generalization seems to involve a loss of dependence on the hippocampus and increased dependence on neocortical regions, and memory becomes less specific to the original context where the event took place. However, it is unknown whether emotional memories acquired under different stress levels can undergo different systems consolidation processes, and the relationship between glucocorticoids and time-dependent fear generalization is also not very well understood. Here, we describe how increasing contextual fear conditioning intensities elicit time-dependent fear generalization only after moderate or strong footshocks, and this process is linearly associated with post-training corticosterone levels. This dissociation between mild and strong fear conditioning is accompanied by different patterns of functional connectivity between key brain regions associated with the Salience and Default-Mode networks during memory retrieval, with mild training maintaining high connectivity between the networks and strong training eliciting low connectivity between them at remote timepoints. Also, the post-training treatment with corticosterone seems to promote contextual discrimination after mild contextual fear training, even at remote timepoints, whereas the same treatment facilitates time-dependent fear generalization after moderate conditioning trainings. Lastly, post-training infusions of mifepristone, a glucocorticoid and progesterone receptor antagonist, into the prelimbic cortex seems to interfere with the negative feedback look of the hypothalamic-pituitary-adrenal axis and to be associated with higher, generalized freezing times at remote timepoints; and the rate of corticosterone recovery to basal levels and generalization in the mifepristone treated group seem to be positively correlated at recent timepoints but negatively correlated at a remote timepoint. This set of data points to an association between glucocorticoid release in response to an aversive event and the consolidation of contextual features into the memory trace, possibly acting synergically with other stress mediators to either promote contextual discrimination or facilitate time-dependent fear generalization, and this effect is possibly amplified by a dependence on global brain functional connectivity. These results open avenues for the identification of novel treatments for pathological overgeneralized fear memories, seen in Post-Traumatic Stress and Generalized Anxiety disorders.

BANKING MEMBERS:
Presidente - Interno ao Programa - 1893240 - RAQUEL VECCHIO FORNARI
Membro Titular - Examinador(a) Interno ao Programa - 2139904 - CLAUDINEI EDUARDO BIAZOLI JUNIOR
Membro Titular - Examinador(a) Externo à Instituição - DEBORAH SUCHECKI - UNIFESP
Membro Titular - Examinador(a) Externo à Instituição - CAROLINA DEMARCHI MUNHOZ - USP
Membro Titular - Examinador(a) Externo à Instituição - MARIA GABRIELA MENEZES DE OLIVEIRA - UNIFESP
Membro Suplente - Examinador(a) Interno ao Programa - 1887027 - FERNANDO AUGUSTO DE OLIVEIRA RIBEIRO
Membro Suplente - Examinador(a) Externo à Instituição - CARLA DALMAZ - UFRGS
Membro Suplente - Examinador(a) Externo à Instituição - LEANDRO JOSÉ BERTOGLIO - UFSC