The lateral habenula is a very small part of the brain, located near the stalk of the pineal gland. It has been linked to depression and negative behavior, but that might not be all it does. As it turns out, this little region could have a big fundamental role in how decisions are made. The research was led by Colin Stopper of the University of British Columbia’s Department of Psychology and Brain Research Centre and was published yesterday in Nature Neuroscience.
We are faced with decisions all day, ranging from small things like what to wear up to deciding whether or not to get married or change careers. The area of the brain responsible for these potentially life-altering choices has not been well known.
Because the lateral habenula (LHb) has previously been associated with negative behaviors and feelings, it was assumed that it was a punishment center. After a choice-based study using rats, Stopper and his colleague Stan Floresco learned that this is not the case and it could be the basis of subjective preference. For the experiement, the LHb was inactivated in rats who could either receive one food pellet often or four food pellets after an extended period of time. Researchers had assumed that the rats would choose the larger reward of four food pellets, but were surprised to see that the rats didn’t really care either way and the choice was made at random.
This research could have implications for treating depression symptoms, but not necessarily the cause of depression itself. By stimulating the LBh in humans to inactivate it, the symptoms subside, but researchers aren’t sure if it represents an actual cure for the depression. Floresco notes: “Our findings suggest these improvements may not be because patients feel happier. They may simply no longer care as much about what is making them feel depressed."