PROVIDENCE, R.I. [Brown University] A new study finds that mice have a distinct neural subsystem that links the nose to the brain and is associated with instinctually important smells such as those emitted by predators. That insight, published online this week in Proceedings of the National Academy of Sciences, prompts the question whether mice and other mammals have specially hardwired neural circuitry to trigger instinctive behavior in response to certain smells.
In the series of experiments and observations described in the paper, the authors found that nerve cells in the nose that express members of the gene family of trace amine-associated receptors (TAAR) have several key biological differences from the much more common and diverse neurons that express members of the olfactory receptor gene family. Those other nerve cells detect a much broader range of smells, said corresponding author Gilad Barnea, the Robert and Nancy Carney Assistant Professor of Neuroscience at Brown University.
The differences between TAAR neurons and olfactory receptor neurons led Barnea and his co-authors to conclude that they form an independent subsystem for certain smells.
"Our observations suggest that the TAAR-expressing sensory neurons constitute a distinct olfactory subsystem that extracts specific environmental cues that then elicit innate responses," Barnea said.
Different circuits and genes
The newly found differences include the way TAAR neurons are wired to structures called glomeruli in the olfactory bulb, which is the brain area that initially processes smells. The glomeruli relay smell signals deeper into the brain where the perception of smell occurs and behavioral responses are initiated.
Graduate students Mark A. Johnson and Lulu Tsai at the Barnea laboratory visualized TAAR neurons in the nose and their projections to the olfactory bulb by generating specific antibodies that could detect TAA
|Contact: David Orenstein|