Thesis defense Yanfen Chen (Donders series 385)

3 September 2019

Promotor: prof. dr. B. Roozendaal, Co-promotor: dr. N. Nadif Kasri

Emotional arousal effects on object recognition memory: Role of amygdala-insular cortex interactions

I investigated functional interactions between the basolateral amygdala and insular cortex in regulating emotional arousal effects on object recognition memory. The tight regulation of emotional memories is usually considered to be highly adaptive and pivotal for survival. However, highly intense or traumatic experiences or maladaptive processing of emotionally arousing information also lies at the core of several fear-related disorders, including post-traumatic stress disorder and phobias. Extensive evidence indicates that emotional arousal induces activation of the basolateral amygdala, and that this subsequently strengthens neural plasticity and information storage processes in other brain regions. Whereas several studies have investigated how basolateral amygdala activation facilitates hippocampal function and memory, little isknown concerning the influence of basolateral amygdala activity on other memory systems. The aim of the research described in this thesis is to investigate, in rodents, whether the basolateral amygdala interacts with the insular cortex in enhancing recognition memory for novel objects. The main findings are thatthe basolateral amygdala is predominantly interconnected with the anterior division of the insular cortex, and that basolateral amygdala activity reduces,rather than increases, neuronal activity within the anterior insular cortex.Such functional connectivity between the basolateral amygdala and anterior insular cortexby emotional arousal does not only increase the ability to assess the familiarity of the objects, but also increases the ability to detect a novel stimulus, possibly reflecting an effect on memory accuracy. These findings indicating an intimate functional crosstalk between the basolateral amygdala and insular cortex yield fundamental insight into the broader effects of emotional arousal on brain network dynamics and memory formation.