Samuelsen Lab

About 

What we choose to eat or drink depends upon a complex interaction between sensory information, experience, and state. Trying a new food is a very different experience than eating an old favorite. Similarly, your perception of a chocolate bar can vary depending on if you haven’t eaten anything all day or you just finished a big meal. The interplay between chemosensory processing and physiological/ psychological state is key to understanding how, when, and why we choose what to eat. 

To this end, our lab investigates the neural substrates underlying the integration of smell and taste (flavor) and how physiological/psychological state modulates this multisensory processing. We explore these fundamental network and circuit mechanisms using a combination of awake-behaving electrophysiology, optogenetics, anatomical tracing, and behavior. Our long-term goal is to better understand these complex interactions in order to address eating-related diseases, including eating disorders, obesity, and diabetes. 

Current Projects

• Representation of gustatory and olfactory signals in GC. It had long been thought that primary sensory cortices (i.e., the first cortical areas that respond to sensory information) could only process information from a single sense (e.g., visual cortex could only respond to light). However recent experiments have shown that these areas respond to information from many modalities. We are using in vivo multielectrode recordings in behaving rats to characterize the neural activity of single neurons in gustatory cortex (the primary cortical area for taste) in response to tastes and odors.
• Modulation of chemosensory responses by experience with flavor. After experiencing a flavor (a mixture of taste and odor), an odor becomes associated with that taste. This is experience is why many odors are describe using taste qualities (e.g., vanilla smells “sweet”). We are using in vivo multielectrode recordings in behaving rats to investigate how experience with a flavor modulates the response of neurons in gustatory cortex to tastes and odors. In particular, we are interested in understanding how the response to the combination of a taste and odor (flavor) is different than that of the response to the taste or odor alone. 
• Modulation of chemosensory activity by mismatching odor-tastes mixtures. While the taste and odor components of a flavor act synergistically, when a taste is mismatched with an odor (e.g., pairing a “sweet” odor with a sour taste) the perception of both components are disrupted. In vivo multielectrode recordings in behaving rats are being used to determine how mismatching odors and tastes modulates neural activity in areas important for flavor.  

Recent Publications

• The role of the mediodorsal thalamus in chemosensory preference and consummatory behavior in rats. 

  Gartner KE, Samuelsen CL.Chem Senses. 2024 Jan 1;49:bjae027. doi: 10.1093/chemse/bjae027.PMID: 38985657 

• Multisensory Integration Underlies the Distinct Representation of Odor-Taste Mixtures in the Gustatory Cortex of Behaving Rats. 

  Stocke S, Samuelsen CL.J Neurosci. 2024 May 15;44(20):e0071242024. doi: 10.1523/JNEUROSCI.0071-24.2024.PMID: 38548337 

• Neural Representation of Intraoral Olfactory and Gustatory Signals by the Mediodorsal Thalamus in Alert Rats. 

  Fredericksen KE, Samuelsen CL.J Neurosci. 2022 Oct 26;42(43):8136-8153. doi: 10.1523/JNEUROSCI.0674-22.2022.PMID: 36171086  

• Cortical Hub for Flavor Sensation in Rodents. 

  Samuelsen CL, Vincis R.Front Syst Neurosci. 2021 Nov 15;15:772286. doi: 10.3389/fnsys.2021.772286. eCollection 2021.PMID: 34867223  

• A drivable optrode for use in chronic electrophysiology and optogenetic experiments. 

  Stocke SK, Samuelsen CL.J Neurosci Methods. 2021 Jan 15;348:108979. doi: 10.1016/j.jneumeth.2020.108979. Epub 2020 Oct 21.PMID: 33096153  

Team 

• John Hourigan, Cooperative Intern Temp