The neural mechanisms responsible for decreased in motivation, as is often observed in depression, are poorly understood. A new study by Christophe Proulx of the CERVO Brain Research Center sheds new light on the areas of the brain involved in motivation. Published in the journal Proceedings of the National Academy of Sciences of the USA, the study exposes a neural pathway that controls the motivation to make an effort.
This study reveals that the lateral habenula, a nucleus known to be hyperactive in depressive states, plays an important role in motivation. Specifically, Dr. Proulx's study shows that signaling of lateral habenula to the rostromedial tegmental nucleus, a nucleus that inhibits dopaminergic neurons, increases when an animal becomes immobile in a test requiring sustained effort. In addition, the activation of this signaling pathway promotes immobility, while its inhibition produces the opposite effect.
These results show the important role played by this neural pathway in controlling the motivation to make a sustained effort in demanding contexts. The hyperactivity of this pathway could contribute to the decreased motivation commonly seen in depressed people and paves the way for the development of new avenues of treatment.
Read the original research article in PNAS (subscription required – contact us for a copy of the article):
Proulx CD, Aronson S, Milivojevic D, Molina C, Loi A, Monk B, Shabel SJ, Malinow R. A neural pathway controlling motivation to exert effort. Proc Natl Acad Sci U S A. 2018 May 11. pii: 201801837. doi: 10.1073/pnas.1801837115.