title: Neural correlates of olfactory processing in congenital blindness.
abstract: Adaptive neuroplastic changes have been well documented in congenitally blind individuals for the processing of tactile and auditory information. By contrast, very few studies have investigated olfactory processing in the absence of vision. There is ample evidence that the olfactory system is highly plastic and that blind individuals rely more on their sense of smell than the sighted do. The olfactory system in the blind is therefore likely to be susceptible to cross-modal changes similar to those observed for the tactile and auditory modalities. To test this hypothesis, we used functional magnetic resonance imaging to measure changes in the blood-oxygenation level-dependent signal in congenitally blind and blindfolded sighted control subjects during a simple odor detection task. We found several group differences in task-related activations. Compared to sighted controls, congenitally blind subjects more strongly activated primary (right amygdala) and secondary (right orbitofrontal cortex and bilateral hippocampus) olfactory areas. In addition, widespread task-related activations were found throughout the whole extent of the occipital cortex in blind but not in sighted participants. The stronger recruitment of the occipital cortex during odor detection demonstrates a preferential access of olfactory stimuli to this area when vision is lacking from birth. This finding expands current knowledge about the supramodal function of the visually deprived occipital cortex in congenital blindness, linking it also to olfactory processing in addition to tactile and auditory processing.
authors: Institute of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2300 Copenhagen, Denmark. ron@pet.rh.dk
authors: R
authors: R
authors: Kupers
authors: M
authors: M
authors: Beaulieu-Lefebvre
authors: F C
authors: FC
authors: Schneider
authors: T
authors: T
authors: Kassuba
authors: O B
authors: OB
authors: Paulson
authors: H R
authors: HR
authors: Siebner
authors: M
authors: M
authors: Ptito
mesh_terms: D000328:Adult; D000679:Amygdala / Q000502:physiology; D001766:Blindness / Q000151:congenital* / Q000503:physiopathology / Q000523:psychology*; D005260:Female; D005625:Frontal Lobe / Q000502:physiology; D006321:Heart / Q000502:physiology; D006624:Hippocampus / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D020645:Mediodorsal Thalamic Nucleus / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D009778:Occipital Lobe / Q000502:physiology; D009812:Odorants; D010092:Oximetry; D010100:Oxygen / Q000097:blood; D011597:Psychomotor Performance / Q000502:physiology; D015656:Respiratory Mechanics / Q000502:physiology; D012903:Smell / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology; D013268:Stimulation, Chemical; D014793:Visual Cortex / Q000502:physiology
chemical_list: D010100:Oxygen