Person:

Qin, Yuqi

Many animals use their olfactory systems to learn to avoid dangers, but how neural circuits encode naive and learned olfactory preferences, and switch between those preferences, is poorly understood. Here, we map an olfactory network, from sensory input to motor output, which regulates the learned olfactory aversion of Caenorhabditis elegans for the smell of pathogenic bacteria. Naive animals prefer smells of pathogens but animals trained with pathogens lose this attraction. We find that two different neural circuits subserve these preferences, with one required for the naive preference and the other specifically for the learned preference. Calcium imaging and behavioral analysis reveal that the naive preference reflects the direct transduction of the activity of olfactory sensory neurons into motor response, whereas the learned preference involves modulations to signal transduction to downstream neurons to alter motor response. Thus, two different neural circuits regulate a behavioral switch between naive and learned olfactory preferences.

One essential function of the nervous system is to modulate behavioral response based on experience. In the past decades, increasing amount of studies has characterized the mechanisms underlying experience-dependent modulation of neural circuits. However, it is not entirely clear how the nervous system translates experience into a modulatory signal. The over-arching goal of my thesis work is to contribute to our understanding of this important neuroscience question.