It’s a Sunday morning and you’re hiking by Taughannock when suddenly you’re confronted by an eight foot grizzly bear. Before you can form a coherent thought, you find yourself fleeing back towards campus. This instinctual response, aptly named the fight-or-flight response, is triggered by a hormone released in situations of stress or danger: norepinephrine.
A lesser known function of norepinephrine is currently being explored by Prof. Christiane Linster, neurobiology and behavior. Linster used behavior, electrophysiology, and computational modeling to research how modulation of norepinephrine affects the olfactory system, the sensory system used for smelling.
Linster elaborated on her lab’s work in an interview with The Sun last week.
“In other sensory systems, researchers have suggested that [norepinephrine] improves signal-to-noise ratio, which means that the hormone makes sensory signals clearer while suppressing irrelevant signal,” she said.
Linster conducted an experiment with the rat olfactory system to help determine the effects of norepinephrine.
“We started with behavioral research and found that if we increased norepinephrine in the rat olfactory system, rats could detect much lower odor concentrations than if we hadn’t. And if we decreased the hormone concentrations, the rats didn’t do so well,” she said.
Linster has also additionally developed a computational model of the olfactory system. In doing so, the Linster Lab found that the principal neuron firing would indeed be suppressed in the absence of odors but stimulated in the presence of odors.
The applications of this research extend far beyond the hormone’s correlation to sense of smell. Linster suggested that her work could potentially shed light on post-traumatic stress disorder, otherwise known as PTSD.
PTSD is a mental health condition which is a result of a person witnessing or experiencing a traumatic event. Symptoms include intense flashbacks, severe anxiety, and uncontrollable thoughts about the occurrence. Often times, a PTSD episode can be triggered by a seemingly innocuous sound or sight.
“People with PTSD have learned to focus on certain stimuli which seem to take on a greater importance in their lives, which is intriguing because norepinephrine plays a role in learning and plasticity,” Linster said.
Linster discussed a study trying to compare the effect of stress on rats on their ability to remember odors.
“We found that stressing them led to the rats remembering the odor for longer periods of time,” she said.
The power of coupling computational modeling and behavioral studies to elucidate the mysteries of noradrenergic modulation has far reaching applications. When asked what she sees as the future of this research, Linster emphasized that her lab will aim to push past the olfactory system to look into other sensory systems and to possibly take a look at norepinephrine’s influence on short-term and long-term memory.