Regeneration of specific nerve cells in lesioned visual cortex of the human brain: an indirect evidence after constant stimulation with different spots of light.

The defective parts of the visual field of two brain-injured patients were stimulated with different spots of light. There is evidence for at least five independent visual functions which can be restored due to constant stimulation of the blind part of the visual field: (1) The constant stimulation of the blind part of the visual field with spots of white light leads to an increase of the visual field for the perception of white light only. (2) The constant stimulation with spots of light of different wavelengths leads to an increase of the visual field for different color perception. To enlarge the visual field for the perception of the color red, a light stimulus with the wavelength of 656 nanometers (nm) was used; for the visual field for the perception of the color green 525 nm; for yellow 578 nm; and for blue 450 nm. (3) The constant stimulation of the blind visual field with black and white light bars of different orientations and constellations leads to an increase of the foveal acuity and an improvement of form perception in the periphery of the visual field. The results suggest that the recovery of visual functions, different color perception and form perception, may depend upon neuronal regeneration in the human visual cortex; regeneration occurs with adequate and constant stimulation of its specific neurons.