The University of Tennessee Health Science Center announced today that Jordan Ross, graduate student in the Department of Anatomy and Neurobiology in the College of Medicine, is the recipient of a National Institutes of Health Fellowship. Ross will investigate the underlying mechanisms of sensory processing and plasticity, or changes, as they relate to fear learning in the olfactory bulb which is the first site of odor processing in the brain.
Associative fear learning, a fundamental cause of disorders such as Post-Traumatic Stress Disorder (PTSD), involves the pairing of a stimulus with a negative outcome. This combination causes robust fear responses to the conditioned stimulus. Upon detecting a smell, the olfactory neurons in the upper part of the nose create an impulse which is passed to the brain along the olfactory nerve. This information is transmitted to the olfactory bulb first, which processes the signal and then passes information about the smell to other areas closely connected to it, including parts of the limbic system.
Odor-evoked memories, such as those formed during olfactory fear learning, are attained quickly, are long-lasting, and are apparent in olfactory bulb glomeruli, the initial sites of odor processing in the brain. Ross’s investigation aims to understand how a learning event can change the way the brain processes sensory stimuli in the early stages of sensory information coming into the brain.
“If I teach an animal to fear an odor, I want to know how is the representation of that odor changed at the level of the olfactory bulb,” Ross said. “We know it changes not only the conditioned stimulus, but other odors that they have never been taught to fear before are also feared. We want to know when is this association change happening in the olfactory bulb and is it learning dependent.”
Research in her lab shows that when the animals learn to fear certain odors through classical conditioning over time they also begin to fear closely related odors, or generalize odors. Ross’s novel research project titled, “Fear learning-induced transformations of olfactory bulb odor representations and behavioral generalization,” is expected to provide insight into underlying mechanisms of behavioral fear generalization with potential clinical implications in PTSD as well as other sensory processing mechanisms.
“These findings could be applied to investigators doing work with patients who suffer from PTSD or anxiety,” Ross said. “Specifically, for PTSD, the prevailing theory is that fear learning is happening in higher order areas of the brain. However, our work shows that fear learning could be happening in the first areas of sensory representation meaning therapies should focus on this part of the brain too.”
Ross has been with UTHSC’s Department of Anatomy and Neurobiology since 2013. Her award, totaling $87,152, will be distributed over two years.