Corticostriatal control over hippocampal and amygdala-dependent appetitive learning and memory systems. (360G-Wellcome-078197_Z_05_Z)

There is growing evidence that multiple, interactive learning and memory systems provide the basis of behaviour, and that disruptions or imbalances within these systems result in the manifestation of abnormal behaviour. Considerable effort is currently being directed at characterising the key neural structures comprising these systems, and this project will investigate the neural and neurochemical basis of the competitive interaction between hippocampal and amygdala-dependent learning and memory processes in rodents, using a systems and multidisciplinary approach. I hypothesise that this interaction occurs in regions of the corticostriatal system that receive converging inputs from the HPC and amygdala, and is modulated by dopaminergic and glutamatergic systems. The first set of experiments will validate the causal roles of the ventral and dorsal HPC in appetitive conditioning and establish the functional connectivity of specific limbic-accumbens pathways using selective permanent or temporary lesions and electrophysiological recordings. The neural loci of interactions between HPC and BLA-mediated information processing will then be investigated using reversible inactivationand in vivo voltammetry targeting the prelimbic-infralimbic cortical regions, orbitofrontal cortex, and rostral pole of the NAc. Finally, the neurochemical mechanism of the competition will be established using intra-cerebral infusions of neuropharmacological agents manipulating the dopaminergic and glutamatergic systems.