Conference on Cognitive Computational Neuroscience

Negative biases, which are thought to play a key role in the maintenance of depression, are hypothesised to be caused by altered reinforcement learning processes. Depression has been associated with deficits in adjusting learning rates to the informativeness of outcomes, and with increased punishment vs. reward learning rates. In this study, we tested whether transcranial direct current stimulation (tDCS), a potential novel antidepressant therapy, might normalise these learning processes in individuals with low mood. Compared to healthy controls, Individuals with low mood showed decreased adjustment of loss learning rates to the volatility of outcome associations. TDCS applied to dorsolateral prefrontal cortex normalised this deficit. This finding is of clinical interest, since deficits in adjusting learning rates to informativeness of outcomes is hypothesised to cause negative biases in depression. Future studies are needed to test for a causal relationship between learning rate adjustment and mood.