The Nucleus Accumbens (NAc) is an area of the brain that is part of the Basal Ganglia system. It is divided into two subregions: the core and the shell. As you can imagine, the core region is nested within the shell. The NAc is primarily composed of neurons that contain GABA, the primary inhibitory neurotransmitter. These neurons make up ~95% of NAc neurons and contain a variety of neurotransmitter receptors, such as opioid and dopamine. These receptors are affected by a variety of drugs of abuse, including alcohol, cocaine, opioids, and many others. The NAc is well known for its role in motivation and reward learning, including drug abuse and addiction. As such, this makes the NAc an integral part of addiction research and a major target for developing potential treatments.
This image shows neurons in the NAc core from a transgenic rat. The blue marker is dapi, which is a fluorescent stain that binds to DNA, marking all of the neurons in this area. The red marker shows fibers of passage, which are nerve fibers transporting dopamine. These fibers are marked using a stain for Tyrosine Hydroxylase (TH), which helps make dopamine. In yellow is a subpopulation of neurons that contain Gad1, a gene that helps make GABA. The yellow comes from a virus marked with yellow fluorescent protein (YFP) that was injected into the brain of this transgenic rat. If you want to learn more about how this YFP virus tags this specific population of neurons, check out my previous post on the Ventral Pallidum here. The “branches” protruding from the cell body are called dendrites, which are where the neuron receives information from other neurons it is connected with. The longer extension from the cell body is the axon, which transports this information when the cell is activated. Since these neurons are GABAergic, meaning they produce GABA, the signals they send are inhibitory, so when they are activated they will inhibit the neurons with which they connect. Together the research tools used in this image allow scientists to investigate the role of the NAc and its GABAergic neurons in drug abuse and addiction. Drug abuse and addiction affects millions of people across the United States, including my own family. Researching these GABAergic neurons in the NAc, as well as other brain regions and neurotransmitters, is essential to developing therapies for the prevention and treatment of drug abuse and addiction.
Contributed by Maddie Ray, a third year PhD graduate student at Boston College, and our Featured Artist for the fall of 2018. To meet Maddie and see more of her art, click here.