Taste and olfactory representations in the human brain
The aim of this Thesis is to investigate the functional neuroanatomy of taste and olfactory processing in the human brain, including where taste-olfactory convergence is represented and which areas respond to these stimuli as a function of their value as reinforcers. Taste and olfactory representati...
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| Format: | Thesis |
| Language: | English |
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2003
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| _version_ | 1797109289003778048 |
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| author | de Araujo, IET |
| author2 | Rolls, E |
| author_facet | Rolls, E de Araujo, IET |
| author_sort | de Araujo, IET |
| collection | OXFORD |
| description | The aim of this Thesis is to investigate the functional neuroanatomy of taste and olfactory processing in the human brain, including where taste-olfactory convergence is represented and which areas respond to these stimuli as a function of their value as reinforcers. Taste and olfactory representations in the human brain were investigated in five functional Magnetic Resonance Imaging studies. First, we have shown that umami tastants activate similar cortical regions of the human taste system to those activated by a prototypical taste stimulus (glucose) and that the psychophysical enhacement produced by combinations of umami tastants is represented in the orbitofrontal cortex. Second, we found that three pleasant (but not unpleasant) odours activated a medial part of the rostral orbitofrontal cortex and that a correlation was found between the subjective pleasantness ratings of the six odours with activation in this medial region of the orbitofrontal cortex. In contrast, the primary olfactory (but not orbital) cortex was correlated with the intensity ratings. Third, unimodal taste and (both retronasal and orthonasal) olfactory inputs were found to converge into a region of the far anterior, agranular insula, where it adjoins the caudal part of the orbitofrontal cortex. Moreover, the pleasantness of flavour is represented in a medial part of the rostral orbitofrontal cortex. Fourth, the medial orbitofrontal cortex was also activated by intra-venous administration of amphetamine, implying that this region is generally involved in reward processing. Fifth, we have shown that water in the mouth activates the same general areas involved in taste processing including the primary taste cortex, and that the medial orbitofrontal cortex and a part of the mid insula respond to water in the mouth as a function of thirst levels whereas the anterior parts of the insular cortex including taste cortex respond to water independently of thirst levels. These new findings imply that the medial part of the human orbitofrontal cortex is a reward-related area involved in particular in the representation of the reinforcing properties of taste and olfactory stimuli (including water in the mouth) whereas a part of the far anterior, agranular insula and adjoining caudal orbitofrontal cortex encode for the sensory properties of these stimuli, in particular taste-olfactory convergence. |
| first_indexed | 2024-03-07T07:39:42Z |
| format | Thesis |
| id | oxford-uuid:ab80f624-bc75-454d-b535-bd112fb3d161 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T07:39:42Z |
| publishDate | 2003 |
| record_format | dspace |
| spelling | oxford-uuid:ab80f624-bc75-454d-b535-bd112fb3d1612023-04-13T09:36:12ZTaste and olfactory representations in the human brainThesishttp://purl.org/coar/resource_type/c_db06uuid:ab80f624-bc75-454d-b535-bd112fb3d161Human brain anatomyHuman brain functionEnglishHyrax Deposit2003de Araujo, IETRolls, EThe aim of this Thesis is to investigate the functional neuroanatomy of taste and olfactory processing in the human brain, including where taste-olfactory convergence is represented and which areas respond to these stimuli as a function of their value as reinforcers. Taste and olfactory representations in the human brain were investigated in five functional Magnetic Resonance Imaging studies. First, we have shown that umami tastants activate similar cortical regions of the human taste system to those activated by a prototypical taste stimulus (glucose) and that the psychophysical enhacement produced by combinations of umami tastants is represented in the orbitofrontal cortex. Second, we found that three pleasant (but not unpleasant) odours activated a medial part of the rostral orbitofrontal cortex and that a correlation was found between the subjective pleasantness ratings of the six odours with activation in this medial region of the orbitofrontal cortex. In contrast, the primary olfactory (but not orbital) cortex was correlated with the intensity ratings. Third, unimodal taste and (both retronasal and orthonasal) olfactory inputs were found to converge into a region of the far anterior, agranular insula, where it adjoins the caudal part of the orbitofrontal cortex. Moreover, the pleasantness of flavour is represented in a medial part of the rostral orbitofrontal cortex. Fourth, the medial orbitofrontal cortex was also activated by intra-venous administration of amphetamine, implying that this region is generally involved in reward processing. Fifth, we have shown that water in the mouth activates the same general areas involved in taste processing including the primary taste cortex, and that the medial orbitofrontal cortex and a part of the mid insula respond to water in the mouth as a function of thirst levels whereas the anterior parts of the insular cortex including taste cortex respond to water independently of thirst levels. These new findings imply that the medial part of the human orbitofrontal cortex is a reward-related area involved in particular in the representation of the reinforcing properties of taste and olfactory stimuli (including water in the mouth) whereas a part of the far anterior, agranular insula and adjoining caudal orbitofrontal cortex encode for the sensory properties of these stimuli, in particular taste-olfactory convergence. |
| spellingShingle | Human brain anatomy Human brain function de Araujo, IET Taste and olfactory representations in the human brain |
| title | Taste and olfactory representations in the human brain |
| title_full | Taste and olfactory representations in the human brain |
| title_fullStr | Taste and olfactory representations in the human brain |
| title_full_unstemmed | Taste and olfactory representations in the human brain |
| title_short | Taste and olfactory representations in the human brain |
| title_sort | taste and olfactory representations in the human brain |
| topic | Human brain anatomy Human brain function |
| work_keys_str_mv | AT dearaujoiet tasteandolfactoryrepresentationsinthehumanbrain |