Abstract
In animals, emotional memory is classically assessed through pavlovian fear conditioning in which a neutral novel stimulus (conditioned stimulus) is paired with an aversive unconditioned stimulus. After conditioning, the conditioned stimulus elicits a fear response characterized by a wide range of behavioral and physiological responses. Despite the existence of this large repertoire of responses, freezing behavior is often the sole parameter used for quantifying fear response, thus limiting emotional memory appraisal to this unique index. Interestingly, respiratory changes and ultrasonic vocalizations (USV) can occur during fear response, yet very few studies investigated the link between these different parameters and freezing. The aim of the present study was to design an experimental setup allowing the simultaneous recording of respiration, USV, and behavior (RUB cage), and the offline synchronization of the collected data for fine-grain second by second analysis. The setup consisted of a customized plethysmograph for respiration monitoring, equipped with a microphone capturing USV, and with four video cameras for behavior recording. In addition, the bottom of the plethysmograph was equipped with a shock-floor allowing foot-shock delivery, and the top received tubing for odor presentations. Using this experimental setup we first described the characteristics of respiration and USV in different behaviors and emotional states. Then we monitored these parameters during contextual fear conditioning and showed that they bring complementary information about the animal's anxiety state and the strength of aversive memory. The present setup may be valuable in providing a clearer appraisal of the physiological and behavioral changes that occur during acquisition as well as retrieval of emotional memory.
Highlights
In animals, emotional memory is classically assessed through pavlovian fear conditioning
We monitored these parameters during contextual fear conditioning and showed that they bring complementary information about the animal’s anxiety state and the strength of aversive memory.The present setup may be valuable in providing a clearer appraisal of the physiological and behavioral changes that occur during acquisition as well as retrieval of emotional memory
In order to validate this setup in the context of emotional memory, we investigated whether respiration and ultrasonic vocalizations (USV) are modulated by contextual fear learning, and can be used as reliable indices of anxiety and aversive memory
Summary
Emotional memory is classically assessed through pavlovian fear conditioning. The conditioned stimulus elicits a wide range of behavioral and physiological responses that usually occur when an animal encounters a danger (LeDoux, 2000; Maren, 2001) These responses include freezing, potentiated acoustic startle, increased heart rate and blood pressure, breathing modulation, ultrasonic vocalizations (USV), and glucocorticoids release. Respiratory changes and USV can occur during fear response, yet very few studies have addressed the question of the link between these different parameters and freezing and even less studies have correlated them using a fine-grained temporal scale. The reason for this is that no commercial device is available for such an investigation on adult animals
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
