Thermal taster status: evidence of cross-modal integration

Hort, Joanne; Ford, Rebecca A.; Eldeghaidy, Sally; Francis, Susan T.

Abstract

Thermal taster status refers to the finding that, in some individuals, thermal stimulation of the tongue elicits a phantom taste. Little is known regarding the mechanism for this, it is hypothesised to be a result of cross-wiring between gustatory and trigeminal nerves whose receptors co-innervate papillae on the tongue.
To address this, we use functional magnetic resonance imaging to perform the first study of whether the cortical response to gustatory-trigeminal samples is altered with thermal taster status. We study the response to cold (6°C) gustatory (sweet) samples at varying levels of trigeminal stimulation elicited by CO2 (no CO2, low CO2, high CO2) in thermal taster (TT) and thermal non-taster (TnT) groups, and evaluate associated behavioural measures.
Behaviourally, the TT group perceived gustatory and trigeminal stimuli significantly more intense than TnTs, and were significantly more discriminating of CO2 level. fMRI data revealed elevated cortical activation to the no CO2 sample for the TT group compared to TnT group in taste, oral somatosensory and reward areas. In TnTs, a significant positive modulation in cortical response with increasing level of CO2 was found across taste, somatosensory and reward areas. In contrast, in TTs, a reduced positive modulation with increasing level of CO2 was found in somatosensory areas (SI, SII), whilst a significant negative modulation was found in taste (anterior insula) and reward (ACC) areas. This difference in cortical response to trigeminal stimuli supports cross-modal integration in TTs, with gustatory and trigeminal nerves highly stimulated by cold gustatory samples due to their intertwined nature.

Citation

Hort, J., Ford, R. A., Eldeghaidy, S., & Francis, S. T. (2016). Thermal taster status: evidence of cross-modal integration. Human Brain Mapping, 37(6), 2263-2275. https://doi.org/10.1002/hbm.23171

• Journal Article Type: Article
• Acceptance Date: Feb 23, 2016
• Online Publication Date: Mar 7, 2016
• Publication Date: Jun 30, 2016
• Deposit Date: Apr 18, 2016
• Publicly Available Date: Apr 18, 2016
• Journal: Human Brain Mapping
• Print ISSN: 1065-9471
• Electronic ISSN: 1097-0193
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 37
• Issue: 6
• Pages: 2263-2275
• DOI: https://doi.org/10.1002/hbm.23171
• Keywords: fMRI; BOLD; taste; thermal taster status; insula; oral somatosensory; trigeminal
• Public URL: https://nottingham-repository.worktribe.com/output/781163
• Publisher URL: http://onlinelibrary.wiley.com/doi/10.1002/hbm.23171/abstract
• Additional Information: "This is the peer reviewed version of the following article: Hort, J., Ford, R. A., Eldeghaidy, S. and Francis, S. T. (2016), Thermal taster status: Evidence of cross-modal integration. Hum. Brain Mapp. doi: 10.1002/hbm.23171, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/hbm.23171/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving
• Contract Date: Apr 18, 2016