Effect of early visual deprivation on olfactory perception: psychophysical and low resolution electromagnetic tomography (LORETA) investigation.
Isabel Cuevas, Paula Plaza, Philippe Rombaux, Jean Delbeke, Olivier Collignon, Anne G De Volder, Laurent Renier
Poster
Last modified: 2008-05-13
Abstract
Several studies provided evidence of structural and functional reorganization of the occipital cortex in early blind (EB) people, associated with superior abilities in auditory and tactile tasks. However, little is known about odor perception in this population. The purpose of the present study was to investigate the olfactory capacities, as well as the brain areas recruited during olfactory stimulation, in EB subjects. Methods: Eight EB and eight sighted control participants were tested using the Sniffin’s Sticks Test ® and a retronasal olfactory test. The cerebral cartography was obtained by Low Resolution Electromagnetic Tomography (LORETA®) through Event-Related Potentials recorded during olfactory (rose) and trigeminal (CO2) passive stimulation using an olfactometer. Results: In the psychophysical tests, EB obtained better scores for “threshold perception� (p=0.017) and “ odor discrimination� (p > 0.05). The cerebral cartography showed high activity in the precuneus (BA 7), cuneus (BA 19) and lingual gyrus (BA 18) in EB. Discussion: these findings indicate that EB subjects have an advantage in odor detection (but not in odor discrimination or identification). Furthermore, olfactory passive stimulation induced activation in EB occipital cortex, supporting the principle of functional reorganization of this cortex after visual deprivation, for the olfactory modality.