Banca de DEFESA: ELIS HERCULANO DUARTE

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ELIS HERCULANO DUARTE
DATE: 30/06/2026
TIME: 13:30
LOCAL: INSTITUTO DO CEREBRO - AUDITORIO
TITLE:

Implementation and validation of a semi-automated pipeline for fear conditioning assessment in rats

KEY WORDS:

Aversive memory; Memory extinction; Freezing; Fear conditioning; Automated behavior analysis;

PAGES: 78
BIG AREA: Ciências Biológicas
AREA: Fisiologia
SUMMARY:

Fear is a fundamental adaptive defensive state for the survival of living organisms, as it allows threat detection, the formation of aversive memories, and behavioral adjustment in response to potentially harmful stimuli. In rodents, one of the main responses observed during fear expression is freezing behavior, which is widely used as a behavioral marker in aversive conditioning protocols. However, despite its broad use, the quantification of freezing still presents important methodological variations.
In this work, we implemented and validated a conditioned fear protocol in rats over five days, composed of habituation, conditioning, extinction, and aversive memory recall sessions in two distinct contexts. Initially, we characterized the temporal dynamics of freezing in relation to the onset of the aversive conditioned stimulus (CS+), aiming to define an appropriate window for its quantification. We observed that the freezing response does not increase instantaneously, but follows a progressive increase over the seconds following stimulus onset. Therefore, we adopted a window that captured the highest freezing values, defined as the final 10 seconds of the stimulus and the 10 seconds immediately following its offset.
Based on this definition, we compared freezing levels across the five experimental sessions, observing the highest expression of this behavior on the day following conditioning, especially during the initial CS+ presentations. In addition, we observed a reduction in freezing levels in the context in which the animal had not been conditioned, consistent with the formation of extinction memory. To support these analyses, we developed a semi-automated workflow based on body tracking with DeepLabCut and supervised classification using Random Forest, which was used as a screening tool to separate candidate episodes of immobility and movement.
Taken together, the results show that the protocol was effective in inducing different stages of aversive memory, while also allowing a more rigorous analysis of the freezing response. Furthermore, the semi-automated workflow contributed to reducing the burden of manual analysis and standardizing the selection of behavioral episodes. These findings provide a methodological basis for future studies involving conditioned fear protocols and the quantification of freezing in rodents.

COMMITTEE MEMBERS:
Presidente - 1721223 - ADRIANO BRETANHA LOPES TORT
Externo ao Programa - 2190521 - HINDIAEL AERAF BELCHIOR - UFRNExterno à Instituição - RAMÓN HYPOLITO LIMA - IIN-ELS