There have been many world-class blind musicians over the years including Stevie Wonder and Ray Charles. It turns out that their exception musical talent may have been matched by a sharpened sense of hearing.
Researchers have found that individuals who are born blind or become blind later in life achieve a heightened sense of hearing. Those who are born blind or become blind later in life can often hear the nuances of music more easily and track moving objects in their minds much more easily.
Intuitively enough, researchers explored areas of the brain which might underlie these qualitative findings. Functional magnetic resonance imagery (fMRI) was used to determine which parts of the brain were active as blind participants listened to segments of sound.
https://www.sciencedaily.com/releases/2019/04/190422151020.htm
Sounds were varied up such that researchers could gauge subjects’ sensitivity to particular nuances and the associated areas of the brain that were engaging with particular auditory frequencies. The end goal, then, wasn’t measuring the rate at which neurons fired; rather, the researchers looked for how responsive groups of neurons and brain regions were to particular frequencies.
The results showed that blind individuals displayed more narrow neural tuning when it came to discerning minute differences in a range of sound frequencies.
The study is considered a landmark and a watershed moment in neuroscience in the sense that it demonstrates how blindness can result in neuronal plasticity and a change in the ways in which the auditory cortex processes information.
The study further showed that blind participants were more able to discern where objects were in their immediate environment. An area of the brain known as hMT+ is normally used by sighted individuals to mentally map visual objects in space. In blind individuals this same region of the brain is used in a different way: to track the motion and timing of auditory signals in order to recreate what’s likely going on in the real world.
Results from the Proceedings of the National Academy of Sciences are the first of their kind to show how particular areas of the brain can be “recruited” to do different tasks with blind individuals. Namely, the study provided vindication that normal-sighted and blind participants use the hMT+ region of the brain differently and that blind individuals, whether congenital or acquired, recruited this region to mentally map and orient towards the world based on subtle nuances in sound. Truly a monumental study.
