Prof. Sumantra Chattarji
Synaptic plasticity in the amygdala: implications for stress & developmental disorders
Memories come in many different flavors, some more potent than others. Emotionally significant experiences tend to be well remembered, and the amygdala has a pivotal role in this process. But the rapid and efficient encoding of emotional memories can become maladaptive — severe stress often turns them into a source of chronic anxiety. What are the cellular mechanisms underlying these powerful emotional symptoms? To answer this question, we have been using a range of behavioral, morphometric, in vitro and in vivo electrophysiological tools to identify neural correlates of stress-induced modulation of amygdala structure and function — from cellular and synaptic mechanisms to their behavioural consequences in rodents. Our findings point to unique features of stress-induced plasticity in the amygdala, which are in striking contrast to those seen in the hippocampus and cortex (1), and could have long-term consequences for pathological fear and anxiety exhibited in people with affective disorders.
In addition to behavioral experience, the genes we inherit can also cause cognitive and emotional dysfunction. Strikingly, individuals afflicted with certain types of autism spectrum disorder often exhibit impaired cognitive function alongside high anxiety and mood lability. Hence, we are extending our analyses to genetically engineered mice to identify cellular and molecular targets that can be used to correct symptoms of Fragile X Syndrome, the leading genetic cause of autism.