title: Localization of the primary taste cortex by contrasting passive and attentive conditions.
abstract: The primary taste cortex is located in the insula. However, exactly where in the insula the human primary taste cortex is located remains a controversial issue. Human neuroimaging studies have shown prominent variation concerning the location of taste-responsive activation within the insula. A standard protocol for gustatory testing in neuroimaging studies has not been developed, which might underlie such variations. In order to localize the primary taste cortex in an fMRI experiment, we used a taste delivery system to suppress non-taste stimuli and psychological effects. Then, we compared brain response to taste solution during a passive tasting task condition and a taste quality identification task condition to verify whether this cognitive task affected the location of taste-responsive activation within the insula. To examine which part of insula is the primary taste area, we performed dynamic causal modeling (DCM) to verify the neural network of the taste coding-related region and random-effects Bayesian model selection (BMS) at the family level to reveal the optimal input region. Passive tasting resulted in activation of the right middle insula (MI), and the most favorable model selected by DCM analysis showed that taste effect directly influenced the MI. Additionally, BMS results at the family level suggested that the taste inputs entered into the MI. Taken together, our results suggest that the human primary taste cortex is located in the MI.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. nakamura@rad.dent.kyushu-u.ac.jp
authors.forename: Yuko
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Kenji
authors.initials: K
authors.lastname: Tokumori
authors.forename: Hiroki C
authors.initials: HC
authors.lastname: Tanabe
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshiura
authors.forename: Koji
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Honda
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yoshiura
authors.forename: Tazuko K
authors.initials: TK
authors.lastname: Goto
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D015984:Causality; D004192:Discrimination, Psychological; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D009039:Motion Perception / Q000502:physiology; D017711:Nonlinear Dynamics; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D012965:Sodium Chloride / Q000494:pharmacology; D012970:Sodium Glutamate / Q000494:pharmacology; D013003:Somatosensory Cortex / Q000098:blood supply / Q000502:physiology*; D013649:Taste / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology; D055815:Young Adult
chemical_list: D012965:Sodium Chloride; D010100:Oxygen; D012970:Sodium Glutamate