Our work addresses the psychological and brain mechanisms driving symptoms of mental illness, especially depression. Work at the Centre has been funded by a Wellcome Investigator Award and an MRC New Investigator Research Grant. We focus on the brain’s reward system, which controls motivated behaviour and is likely to make an important contribution to symptoms such as anhedonia. Over the past 5 years my group has led landmark studies examining the role of a small, little studied brain structure called the habenula in controlling both aversive and appetitive processing.
Due to the habenula’s small size, this required important MRI development, performed by the Centre Physics team, to create high-resolution fMRI sequences. Consistent with prior work in experimental animals, we showed that the habenula tracks a key computational quantity, negative associative value (here the negative outcomes were painful electric shocks (Lawson et al., 2014)).
In a subsequent study using a similar design we found that, surprisingly, individuals with depression exhibit the opposite pattern of habenula responses (Lawson et al., 2017). More recent work has expanded on this finding by investigating the role of the habenula in controlling action in the face of aversive stimuli, in particular active avoidance. We showed that the habenula activates both during the anticipation of aversive stimuli and when action is required to avoid them, which may help to understand our earlier findings in depression.
Finally, an ongoing study is examining the role of dopamine in effort-based decision-making in depression. We are using the drug L-DOPA (usually used to treat Parkinson’s Disease) to boost dopamine synthesis in an experimental medicine study in depressed individuals, who perform an effort-based decision-making task while being scanned.
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