Understanding olfactory representations and behavior
My laboratory studies neural representations of the sense of smell. In particular, we are interested in how sensory representations acquire meaning that is used to inform behavior. Thus, we study circuits involved in both innate and learned mouse olfactory behaviors. We use 2-photon endoscopic calcium imaging to monitor odor-evoked activity coupled with optogenetic manipulations to determine causality.
Olfactory perception is initiated upon the recognition of odorants by a large repertoire of receptors in the sensory epithelium. Neurons expressing a given receptor are randomly distributed within zones of the epithelium but project with precision to two spatially invariant glomeruli in the olfactory bulb. This invariant glomerular map in the bulb is transformed in the representations in higher olfactory centers. For instance, the piriform cortex receives distributed input from seemingly random sets of glomeruli in the olfactory bulb, and is implicated in learned associations. In contrast, the cortical amygdala receives topographically organized input from the olfactory bulb, and in recent work I have demonstrated that the neurons in this pathway mediate innate attraction and avoidance to odors (Root et al., Nature 2014). Going forward, my lab is interested in determining circuit mechanisms that integrate leaning with instinct to afford flexible behaviors.
Ko KI, Root CM, Lindsay SA, Zaninovich OA, Shepherd AK, Wasserman SA, Kim SM, Wang JW. Starvation promotes concerted modulation of appetitive olfactory behavior via parallel neuromodulatory circuits. Elife. 2015; 4. PMID: 26208339.
Root CM, Denny CA, Hen R, Axel R. The participation of cortical amygdala in innate, odour-driven behaviour. Nature. 2014 Nov 13; 515(7526):269-73. PMID: 25383519.
Root CM, Ko KI, Jafari A, Wang JW. Presynaptic facilitation by neuropeptide signaling mediates odor-driven food search. Cell. 2011 Apr 1; 145(1):133-44. PMID: 21458672; NIHMSID: NIHMS272219.
Root CM, Masuyama K, Green DS, Enell LE, Nässel DR, Lee CH, Wang JW. A presynaptic gain control mechanism fine-tunes olfactory behavior. Neuron. 2008 Jul 31; 59(2):311-21. PMID: 18667158; NIHMSID: NIHMS63994.
Root CM, Semmelhack JL, Wong AM, Flores J, Wang JW. Propagation of olfactory information in Drosophila. Proc Natl Acad Sci U S A. 2007 Jul 10; 104(28):11826-31. PMID: 17596338; PMCID: PMC1913902.