What’s better for me? :: Fundamental role for habenula in subjective decision biases
Colin Stopper & Stan Floresco, Brain Research Centre, University of British Columbia :: Nature Neuroscience, Vol. 17, No. 1, January 2014
Summary and review of the above paper
The lateral habenula (LHb) had traditionally been seen as an ‘aversion centre’. The LHb’s neurons respond to aversive events or the lack of expected rewards. However, in this study, the LHb is seen as being important as a preference centre involved is subjective decision biases.
When the LHb is inactivated subjects become indifferent to the costs of obtaining rewards or their subjective values. The subjective value of rewards can be tempered by delays or costs incurred in obtaining such rewards. The lateral habenula is also seen as important in the brain’s dopamine system, and it is known to project to both dopamine and serotonin neurons, although the change in bias sensitivity relates to the dopamine neurons. This study shows that the LHb has a direct effect on reward seeking. When it is inactivated choice biases as between different rewards cease, and subjects’ responses are randomised.
The inactivation of the lateral habenula did not alter the preference for larger rewards as opposed to smaller rewards. What it altered was preferences for rewards that involved varying costs in obtaining them, or which had differing subjective values. The LHb is seen as having a selective role in situations where a larger reward has an offsetting drawback in terms of the costs associated with it. This study suggests that the lateral habenula has an important role in the cost/benefit analysis of possible actions, and the expression of preference for one course of action over another.