Chad Samuelsen, Ph.D.

Chad Samuelsen, Ph.D.

Assistant Professor, Department of Anatomical Sciences & Neurobiology

Office: MDR 434A
Phone: (502) 852-5169

Research Focus

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, the perception of a chocolate bar can be very different depending on if you haven’t eaten anything all day or have just finished a fabulous meal. The interplay between chemosensory processing and physiological/psychological state is a significant key in understanding how, when, and why we choose what to eat.

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

Current Research

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. 

Key Publications

Samuelsen CL, Fontanini A (2017) Processing of intraoral olfactory and gustatory signals in the gustatory cortex of awake rats. J. Neurosci 37(2):244-257.

Samuelsen CL, Gardner MP, Fontanini A (2013) Thalamic contribution to cortical processing of taste and expectation. J Neurosci33(5):1815-27.

Samuelsen CL*, Gardner MP*, Fontanini A (2012) Effects of cue-triggered expectation on cortical processing of taste. Neuron 74: 410-422.

Samuelsen CL, Meredith M (2011) Oxytocin antagonist disrupts male mouse medial amygdala response to chemical-communication signals. Neuroscience 180: 96-104.

Samuelsen CL, Meredith M (2009) The vomeronasal organ is required for the male mouse medial amygdala response to chemical-communication signals, as assessed by immediate early gene expression. Neuroscience 164: 1468-1476.

Mast TG, Samuelsen CL (2009) Human pheromone detection by the vomeronasal organ: unnecessary for mate selection? Chem Senses 34: 529-531.

Samuelsen CL, Meredith M (2009) Categorization of biologically relevant chemical signals in the medial amygdala. Brain Res 1263: 33-42.