Role of habenula in reward circuitry?

The habenula plays a notable role in the brain's reward circuitry by providing inhibitory input to the mesolimbic reward pathway, which is rich in dopamine-releasing neurons. This pathway includes areas like the ventral segmental area and the nucleus accumbens. The habenula's function is to regulate the reward pathway by inhibiting it, which can influence mood and motivation, acting in some ways as an antidepressant under certain conditions 1.

For instance, during the use of ketamine, which is known to lessen the inhibitory output from the habenula, the reward pathway becomes more receptive to engagement from daily life activities. However, the effects of such a modulation highly depend on reinforcing these neural circuit changes with appropriate behaviors and activities that stimulate the reward circuitry. This ensures that the changes induced by drug treatments like ketamine are beneficial and sustained in the context of mental health 1.