How blindness shapes sound processing

How blindness shapes sound processing
Figure 1 (left) shows tonotopic maps in auditory cortex for four example subjects. Tonotopic organization did not differ significantly across datasets. Figure 4 (right) shows tuning width maps in auditory cortex. Q estimates (for successfully fitted voxels, see Methods), are shown for the left hemisphere for two sighted subjects (A-B), and example individuals who are early blind (C) and anophthalmic (D). Credit: Huber et al., JNeurosci (2019)

Adults who lost their vision at an early age have more refined auditory cortex responses to simple sounds than sighted individuals, according to new neuroimaging research published in JNeurosci. The study is among the first to investigate the effects of early blindness on this brain region, which may contribute to superior hearing in the blind.

Loss of visual input from an early age is thought to reorganize how the brain processes sound. This plasticity has been observed in , where parts of the brain that usually respond to vision may take on new roles to handle . Auditory cortex itself may also become more specialized to support a blind individual's increased reliance on sound to interact with their environment.

Kelly Chang and colleagues at the University of Washington and the University of Oxford compared response to pure tones in blind and sighted individuals. Although the two groups had similarly-sized auditory cortices, this area was more finely tuned to specific auditory frequencies in people who became blind early in life or whose eyes failed to develop at all.

Further research in people who lost—and in some cases recovered—their vision as adults may reveal the mechanisms underlying these changes.


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Rewired visual input to sound-processing part of the brain leads to compromised hearing

More information: Early Blindness Shapes Cortical Representations of Auditory Frequency Within Auditory Cortex, JNeurosci (2019). DOI: 10.1523/JNEUROSCI.2896-18.2019
Journal information: Journal of Neuroscience

Citation: How blindness shapes sound processing (2019, April 22) retrieved 19 June 2019 from https://medicalxpress.com/news/2019-04-how-blindness-shapes-sound-processing.html
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