We study how the nervous system encodes and processes sensory information, with a special focus on the olfactory system. In other words, how does the brain identify smells? This is a tough problem because most smells are complex mixtures of different odor molecules, because the number of different smells that an animal must detect and identify is huge, and because the olfactory environment is highly varied over time and space. Because of the unique nature of the problem that odors pose for the nervous system, studying olfactory processing may lead to novel insights into how the brain processes complex information in general.
We use optical tools to directly visualize neural activity in genetically- and anatomically-defined neuron populations and to investigate how neurons process olfactory information as an animal smells an odor. We also use optical and other genetic tools to manipulate activity in neuron populations in order to assess how different elements of olfactory circuitry shape odor coding and odor perception. Other projects that overlap with the training goals of the Molecular Biology program include understanding the role of particular neurotransmiter signalling pathways in neural circuit function and mapping odorant receptor expression among sensory neurons to their targets in the olfactory bulb.
References (Selected Publications)
- Bozza T, McGann JP, Mombaerts P, Wachowiak M. (2004). In vivo imaging of neuronal activity by targeted expression of a genetically encoded probe in the mouse. Neuron, 42(1), 9-21. https://pubmed.ncbi.nlm.nih.gov/15066261/
- Rothermel M, Brunert D, Zabawa C, Díaz-Quesada M, Wachowiak M (2013) Transgene Expression in Target-Defined Neuron Populations Mediated by Retrograde Infection with Adeno-Associated Viral Vectors. J Neurosci. 33:15195-15206 https://pubmed.ncbi.nlm.nih.gov/24048849/
- Wachowiak M, Economo MN, Díaz-Quesada M, Brunert D, Wesson DW, White JA, Rothermel M. (2013). Optical dissection of odor information processing in vivo using GCaMPs expressed in specified cell types of the olfactory bulb. J Neurosci. 33:5285-300. PMCID: PMC3690468. https://pubmed.ncbi.nlm.nih.gov/23516293/
- Economo MN, Hansen KR, Wachowiak M (2016) Control of Mitral/Tufted Cell Output by Selective Inhibition among Olfactory Bulb Glomeruli. Neuron 91:397-411. PMCID: PMC6474342 https://pubmed.ncbi.nlm.nih.gov/27346531/
- Brunert D, Tsuno Y, Rothermel M, Shipley MT, Wachowiak M (2016) Cell-Type-Specific Modulation of Sensory Responses in Olfactory Bulb Circuits by Serotonergic Projections from the Raphe Nuclei. J Neurosci 36:6820-6835 https://pubmed.ncbi.nlm.nih.gov/27335411/
- Short SM, Wachowiak M. Temporal Dynamics of Inhalation-Linked Activity across Defined Subpopulations of Mouse Olfactory Bulb Neurons Imaged In Vivo. eNeuro. 2019 https://pubmed.ncbi.nlm.nih.gov/31209151/
- Eiting TP, Wachowiak M. Differential impacts of repeated sampling on odor representations by genetically-defined mitral and tufted cell subpopulations in the mouse olfactory bulb. J Neurosci. 2020 Jun 29;. doi: 10.1523/JNEUROSCI.0258-20.2020. https://pubmed.ncbi.nlm.nih.gov/32601245/