MIT Researchers Discover Neurons in The Brain of Primates that Weigh Costs and Benefits to Drive Formation of Habits

This week, Massachusetts Institute of Technology (MIT) researcher, Ann M. Graybiel, Ph.D. whose laboratory is part of MIT’s McGovern Institute for Brain Research and is focused on studying brain structures that are important for normal brain function but are also implicated in Parkinson’s disease, released results from a study showing that the formation of habits is a product of neuron activity associated with cost and reward, in a laboratory animal model. The study, entitled, “Habit Learning by Naive Macaques Is Marked by Response Sharpening of Striatal Neurons Representing the Cost and Outcome of Acquired Action Sequences,” was published in the latest edition of the journal Neuron.

Dr. Gaybiel and her team gave a group of Macaques (type of monkey that is most often used by laboratory investigators) a sequential saccade task, one that requires rapid movement of the eyes between fixated points, and analyzed the potential neurological signals attributed to the animals’ habituated learning. They found that there was a specific spike in neuron activity after each experimental task that corresponded to a cost-benefit signal, which was highly correlated with habit formation learning by the monkeys.

In an institutional press release, Dr. Graybiel stated, “The brain seems to be wired to seek some near optimality of cost and benefit. We’re interested in repetitive behavior because our creative brain is resting on this giant glacier of habit. It’s this wonderful mechanism that frees us up. But also it would be a dream to be able to learn more about diseases that involve unhealthy repetitive behavior by understanding the wiring and what can go wrong.”

Dr. Graybiel’s enthusiasm was shared by her colleague and lead study author, Dr. Theresa M. Desrochers, PhD, “This strong correlation suggests that both reward and cost are represented in these neurons, and are driving the habit-forming behavior.” The results from this study are the first to show that habit formation is associated with cost considerations in laboratory animals. The researchers are optimistic that future studies could provide important insights into neurologic disorders such as Parkinson’s disease, in which problems caused by repetitive behaviour are primary facets of disease pathology.

To watch a brief video about the study click here.