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Reduced EEG alpha activity over parieto-occipital brain areas in congenitally blind adults
Anne Kriegseis1, Erwin Hennighausen, Frank Rösler
1Department of Psychology, Philipps University of Marburg, Marburg, Germany.
Objective:
Goal of the present study was to compare the amplitude and topography of EEG alpha activity between congenitally blind and sighted adults both in a primarily sensory and a primarily cognitive task.
Methods:
Congenitally blind and blindfolded sighted adults performed a somatosensory perception task (experiment 1), which required to discriminate tactile stimuli at different fingers, and a mental imagery task (experiment 2), in which a previously haptically encoded map had to be mentally scanned. The EEG was recorded with 61 electrodes and was analyzed with the Fast Fourier Transformation (FFT).
Results:
Results showed a significant reduction of alpha power in the blind compared to the sighted controls over parieto-occipital recording sites in both tasks.
Conclusions:
It is speculated that brain structures, which have been associated with the generation of posterior alpha rhythms in sighted adults, including the geniculo-cortical pathway, depend on visual input and might either be reorganized or atrophied following blindness from birth.
Significance:
The present study demonstrates that oscillatory activity of the brain might serve as a marker of cortical reorganization.
