A crucial function of the central nervous system is to bias behavior toward events and outcomes that hold relevance for survival. It is well recognized that odors have a strong effect on animal behavior, as they guide food search and selection, maternal bonding, and mate selection. Even though humans do not consider olfaction to be a dominant sense, humans are similarly swayed by the rewarding properties of smells. With recent developments in the pattern-based analysis of functional magnetic resonance imaging (fMRI) data, we are now in a position to explore the neural mechanisms of olfactory reward processing in humans. The objective of the current research proposal is to capitalize on these novel methods in order to understand the neural mechanisms of odor-guided behavior in humans. Specifically, we will use functional and structural brain imaging in combination with olfactory psychophysics to reveal the functional anatomy and coding mechanisms of olfactory reward processing. The proposed studies will examine predictive neural representations of food odor identity and reward value, and their importance for olfactory reward-based behavior and learning. Complementary studies will track the anatomical pathways between olfactory and limbic brain regions, and delineate the specific information that is transmitted via these connections. Together these experiments will open a new window into understanding olfactory reward processing in the human brain at the functional, mechanistic, and anatomical level, with implications for neuroscientific research on adaptive behavior in general. Moreover, the findings of this research can lead to a better understanding of the olfactory and behavioral deficits described in a variety of neurodegenerative disorders, including Alzheimer's disease and frontotemporal dementia, and may ultimately provide insights into the development of novel diagnostic and therapeutic clinical approaches.
The proposed research will combine cutting-edge neuroimaging and olfactory psychophysics to identify the neural principles of olfactory reward processing in the human brain. The findings from this research may be important for clarifying the effects of odors on human decision-making. Moreover, they may have particular clinical relevance for patients with frontotemporal dementia and other neurodegenerative diseases, where fundamental changes in olfactory hedonic processing may underlie symptoms of altered food preferences, hyperorality, and consumption of non-foods.
| Howard, James D; Kahnt, Thorsten (2018) Identity prediction errors in the human midbrain update reward-identity expectations in the orbitofrontal cortex. Nat Commun 9:1611 |
| Howard, James D; Kahnt, Thorsten (2017) Identity-Specific Reward Representations in Orbitofrontal Cortex Are Modulated by Selective Devaluation. J Neurosci 37:2627-2638 |
| Kahnt, Thorsten; Tobler, Philippe N (2017) Dopamine Modulates the Functional Organization of the Orbitofrontal Cortex. J Neurosci 37:1493-1504 |
