Dopamine and cannabinoid modulation of emotional memory in the amygdala-prefrontal cortical circuit

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To make sense of the world around us, the brain must constantly filter a barrage of incoming sensory information and accurately interpret the emotional significance and relevance of these inputs. In the mammalian brain, the basolateral amygdala (BLA), ventral tegmental area (VTA) and medial prefrontal cortex (mPFC) are critical for the processing and integration of emotionally salient sensory information, learning and memory formation. These neural regions are functionally interconnected and contain high concentrations of cannabinoid and dopamine (DA) receptors, two neurotransmitter systems that are critical in the processing of emotional processing and learning. The primary goal of our research project involves the neurophysiological, behavioural and neurochemical characterization of neural mechanisms involved in the processing of emotionally salient sensory information. Using in vivo electrophysiological associative conditioning and neural plasticity recording procedures, we examine emotional associative learning within single neurons of the rodent BLA and mPFC by examining neuronal responses to odour cues that have been associatively paired with emotionally salient experiences (footshock). Our research program will explore this neural circuitry by examining the roles of specific DA receptor subtypes and cannabinoid signaling systems during distinct phases of emotional memory encoding, recall and extinction. Using an integrative combination of behavioural pharmacology and in vivo, multi-unit recordings in awake, behaving rodents, we will examine how inputs from the VTA and BLA functionally interact to mediate the processing of emotional associative learning and memory encoding in single neurons and neuronal ensembles within the mPFC, BLA and VTA circuitry. Understanding how this neural circuitry may be involved in the encoding of emotionally salient learned associations will provide fundamental insights into how both single neurons and distributed neural networks may encode and express emotional memory and identify the specific neural mechanisms that control how the brain assigns emotional salience to incoming sensory signals.