Institute of Biomedical Sciences

Title

Extinction of Blood Pressure and Heart Rate Responses to Conditioned Fear

Poster Number

12

Document Type

Poster

Status

Graduate Student - Doctoral

Publication Date

Spring 2018

Abstract

Background: Post-traumatic stress disorder (PTSD) is characterized by an impaired ability to extinguish fear associations that trigger exaggerated neurophysiological responses, which may contribute to increased cardiovascular (CV) risk. The objective of this study was to evaluate the effects of learned inhibition or extinction on the conditioned cardio-autonomic response during fear memory recall. We hypothesized that extinction training would lead to a temporary reduction of conditioned heart rate (HR) and systolic blood pressure (SBP) responses.

Methods: In male C57BL/6 mice, Pavlovian fear conditioning combined with simultaneous in-vivo telemetry was used to assess CV and behavioral measures in home-cage and testing contexts. The conditioned CV response was evaluated during short-term (STR) (1-hour post-extinction) and long- term recall (LTR) (2 weeks post-extinction) of the CS in the home-cage.

Results: Freezing in response to the CS from Day 1 to Day 2 was reduced in fear conditioned mice (80% ± 7 vs. 57% ± 11; p

Conclusions: These data demonstrate that both short and long-term recall of fear memory elicit a conditioned blood pressure response that can be temporarily attenuated by extinction training. Furthermore, these data suggest that conditioned blood pressure and heart rate responses may vary in their sensitivity to inhibitory learning.

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Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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Extinction of Blood Pressure and Heart Rate Responses to Conditioned Fear

Background: Post-traumatic stress disorder (PTSD) is characterized by an impaired ability to extinguish fear associations that trigger exaggerated neurophysiological responses, which may contribute to increased cardiovascular (CV) risk. The objective of this study was to evaluate the effects of learned inhibition or extinction on the conditioned cardio-autonomic response during fear memory recall. We hypothesized that extinction training would lead to a temporary reduction of conditioned heart rate (HR) and systolic blood pressure (SBP) responses.

Methods: In male C57BL/6 mice, Pavlovian fear conditioning combined with simultaneous in-vivo telemetry was used to assess CV and behavioral measures in home-cage and testing contexts. The conditioned CV response was evaluated during short-term (STR) (1-hour post-extinction) and long- term recall (LTR) (2 weeks post-extinction) of the CS in the home-cage.

Results: Freezing in response to the CS from Day 1 to Day 2 was reduced in fear conditioned mice (80% ± 7 vs. 57% ± 11; p

Conclusions: These data demonstrate that both short and long-term recall of fear memory elicit a conditioned blood pressure response that can be temporarily attenuated by extinction training. Furthermore, these data suggest that conditioned blood pressure and heart rate responses may vary in their sensitivity to inhibitory learning.