Functional heterogeneity in the prefrontal cortex of adult and developing marmosets: insight into the individual variation in depression and its symptoms

Depressed people find themselves beset with many symptoms including sadness, despair, and anhedonia. The severity of these symptoms and how they combine varies greatly between individuals, and the success of current treatments is likewise highly variable with limited new treatment prospects on the horizon. We hypothesise that a key contributor to variability in aetiology and treatment is altered activity across functionally distinct domains of a brain region called the prefrontal cortex (PFC). Thus, we aim to uncover the causal role of these distinct domains in the cardinal symptoms of depression, both in adulthood but also development, mainly adolescence, when depression often has its onset. These distinct domains will be transiently activated/inactivated in experimental animals whilst performing behavioural tasks akin to those used in humans and will reveal the psychological consequences of dysregulated PFC activity related to depression symptoms and provide critical insights into individual variation in diagnosis and treatment strategies.