セミナー情報

Our main goal is to map the neural mechanisms of behaviour at the circuit level. To this end, we chose to study behaviours which are ethologically relevant as they are likely to have shaped their underlying neural circuits throughout evolution. The major goal in my laboratory is to unravel the mechanisms of fear. In particular, we are studying how past experience and the environment, including the social environment, modulate fear responses.
To address these issues we are studying the neural mechanisms of classical fear conditioning and of social transmission of fear. Classical conditioning is a function of the temporal features of stimulus presentation. However, how time affects the neural circuit underlying associative learning remains largely unknown. I will discuss our results looking at the role of amygdala, mPFC and dorsal hippocampus in learning the association between a tone and a shock while varying the length of the interval that separates the two stimuli. Learning to fear cues that are associated with an experienced threat may be crucial for survival as these cues can be used to avoid future threats. However, many animal species are also able to use social cues to avoid danger, such as alarm calls and alarm pheromones, a defense mechanism that may be less costly than learning from self-experience. We developed a behavioural paradigm to study transmission of fear in rats to examine the cues that mediate this process. By systematically probing for the sensory cues that trigger transmission of fear, we found that observer rats respond to an auditory cue which signals the sudden immobility of the demonstrator rat ﾐ the cessation of the sound of motion. I will discuss our evidence supporting the hypotheses that silence, or other signals of the sudden absence of motion, constitute a public cue that can be used by any animal in the ecosystem to detect impeding danger.