Elsevier

Neuroscience Letters

Volume 183, Issues 1–2, 2 January 1995, Pages 143-146
Neuroscience Letters

Visual cortex activation in blind humans during sound discrimination

https://doi.org/10.1016/0304-3940(94)11135-6Get rights and content

Abstract

We used a whole-scalp magnetometer with 122 planar gradiometers to study the activity of the visual cortex of five blind humans deprived of visual input since early infancy. Magnetic responses were recorded to pitch changes in a sound sequence when the subjects were either counting these changes or ignoring the stimuli. In two of the blind subjects, magnetic resonance images were also obtained, showing normal visual cortex macroanatomy. In these subjects, the magnetic responses to counted pitch changes were located at visual and temporal cortices whereas ignored pitch changes activated the temporal cortices almost exclusively. Also in two of the other three blind, the visual-cortex activation was detectable in the auditory counting task. Our results suggest that the visual cortex of blind humans can participate in auditory discrimination.

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This research was supported by the University of Helsinki and Academy of Finland.

1

We thank Mr. V. Jousmäki for assistance in data transfer, Professor S.J. Williamson, Professor V. Virsu, Dr. P. Laurinen, and Mr. P. May for critical comments on the manuscript, and Professor ON. Lounasmaa, Head of the Low Temperature Laboratory, Helsinki University of Technology, for providing us with acces to the magnetometer and the magnetically shielded room.

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