Medium spiny neurons and “sticking” to bad habits
By Alexandra Fuller
By the time March rolls around, New Year’s resolutions to ditch the expensive lattes and spend less time (and money) shopping online are often far behind us. Activity within the nucleus accumbens, a region of the brain implicated in motivation and addiction, may be at play. Recent work from the labs of Brad Grueter, associate professor of pharmacology and molecular physiology and biophysics, and Heidi Hamm, Aileen M. Lange and Annie Mary Lyle Chair in Cardiovascular Research and professor of pharmacology, reveals processes that may disrupt communication between the NA and other areas of the brain. When you experience an event, chemical messages released throughout the brain are gathered by neurons in the NA and interpreted as pleasant or unpleasant, which may ultimately impact how you respond to similar events in the future. The researchers set out to better understand how responses in the NA are fine-tuned by studying interactions between medium spiny neurons of the NA and other neuron types. They discovered that inhibitory neurons impair the release of incoming chemical messages from other areas of the brain, making medium spiny neurons less likely to activate; this happens through activation of receptor called GABABR. The researchers found that some neuron pairings were more sensitive to interference by inhibitory neurons than others. Molecular studies that characterize interactions between neurons help to form a bigger picture of how our brains interpret events and drive us to seek the habits that we wish to avoid.This knowledge may advance our understanding (and treatment options) for addiction and other psychiatric disorders, or may help us come up with resolutions we can actually stick to.