A portion of the brain called the interpeduncular nucleus (IPN) is at the heart of a neural circuit that controls a person’s interest in new things, leading him or her to explore them further. This novelty preference behavior can be abnormal in disorders including schizophrenia, ADHD, autism spectrum disorder and addiction. The study describing the key role of the IPN in novelty preference was published online July 17 in the journal Nature Neuroscience.

A University of Massachusetts Medical School team used beams of colored laser light to switch specific neurons on and off in mice in order to explore how the IPN helps the brain signal the familiarity -- or novelty -- of new items in the environment. They discovered that silencing neurons in the IPN caused the mice to pay more attention to, and to interact with, familiar objects as well as mice they lived with, as if they were new. Conversely, activating those same neurons caused the mice to treat new animals and objects as if already familiar. Control of this circuit depends on both familiarity and novelty signals generated in parts of the brain called the habenula and ventral tegmental area.

The team, led by 2016 Independent Investigator Andrew R. Tapper, Ph.D., concluded that the IPN “acts as a brake” that can by itself reduce the urge to explore familiar items. The researchers say that dysregulation of the IPN circuit could play a role in several disorders, where patients may shy away from new social interactions -- in autism, for example -- or prefer novel sensation seeking – as in addiction. “Thus, targeting components of this circuit may provide novel therapeutic strategies for treating several neuropsychiatric conditions,” Dr. Tapper and his colleagues conclude.