Brains of blind people store visual information

William Atkins
Friday, 23 May 2008 07:42

Science - Biology

The researchers conclude that when people become blind, the visual part of the brain is changed so that it is used for other senses. However, that visual part maintains its original ability to detect motion even years after being blinded.

Saenz stated, "Sight-recovery patients can face many challenges in using restored vision because of brain reorganization that occurs during prolonged blindness. Understanding this brain adaptation will be useful for helping patients make the best use of their restored vision.” [CalTech news release: “Sight Recovery After Blindness Offers New Insights on Brain Reorganization”]

Koch stated, "This study demonstrates the plasticity inherent in even adult brains and the very tight linkage between neural activity in particular pieces of gray matter and the subject's perception in the privacy of his and her mind.” [CalTech news release]

The researchers contend that patients in the future who undergo surgery to restore their vision could likely regain full use of their vision.

The abstract of their paper states, “Using functional magnetic resonance imaging, we found that cortical visual motion area MT+/V5 responded to auditory motion in two rare subjects who had been blind since early childhood and whose vision was partially recovered in adulthood.”

And, “Visually normal control subjects did not show similar auditory responses. These auditory responses in MT+ were specific to motion compared with other complex auditory stimuli including frequency sweeps and speech.”

In conclusion, “Thus, MT+ developed motion-specific responses to nonvisual input, suggesting that cross-modal plasticity can be influenced by the normal functional specialization of a cortical region. Regarding sight recovery after early blindness, our results further demonstrate that cross-modal responses coexist with regained visual responses within the visual cortex.”