Why Are Some People Tone Deaf? Investigating the Causes

[Priyadarshini]

Why are some people tone deaf? I read that there is a neural disconnection between two sections of the brain, but what causes this disconnection? Does this disconnection occur over time by chemicals acting on the neurones? Or are people born simply without the connection?

 

[DaveC426913]

Sonuvagun, there does seem to be a physiological basis for it - an actual missing piece of the brain.

"In nine of ten tone-deaf people, the superior arcuate fasciculus in the right hemisphere could not be detected, suggesting a disconnection between the posterior superior temporal gyrus and the posterior inferior frontal gyrus."
https://en.wikipedia.org/wiki/Tone_deafness

"The arcuate fasciculus (Latin, curved bundle) is a bundle of axons that forms part of the superior longitudinal fasciculus. The arcuate bidirectionally connects caudal temporal cortex and inferior parietal cortex to locations in the frontal lobe."
https://en.wikipedia.org/wiki/Arcuate_fasciculus

Essentially a bundle of axons connecting Broca's area with Wernicke's area.

 

[Priyadarshini]

Sonuvagun, there does seem to be a physiological basis for it - an actual missing piece of the brain.

"In nine of ten tone-deaf people, the superior arcuate fasciculus in the right hemisphere could not be detected, suggesting a disconnection between the posterior superior temporal gyrus and the posterior inferior frontal gyrus."
https://en.wikipedia.org/wiki/Tone_deafness

"The arcuate fasciculus (Latin, curved bundle) is a bundle of axons that forms part of the superior longitudinal fasciculus. The arcuate bidirectionally connects caudal temporal cortex and inferior parietal cortex to locations in the frontal lobe."
https://en.wikipedia.org/wiki/Arcuate_fasciculus

Essentially a bundle of axons connecting Broca's area with Wernicke's area.

But how exactly is there an entire piece missing? I mean, is it something to do with having no codes for it in one's DNA due to some sort of mutation? Or that that area is so underdeveloped that it is considered missing?

 

[DaveC426913]

But how exactly is there an entire piece missing? I mean, is it something to do with having no codes for it in one's DNA due to some sort of mutation? Or that that area is so underdeveloped that it is considered missing?

I wondered the same thing.

 

[litup]

And the opposite, do people with perfect pitch have some extra mass in their brains? I have heard you can be trained to have perfect pitch but don't know anyone personally who has learned this gift.