据统计有10%的人先天五音不全，唱歌跑调。最新一项研究证明这可能由于大脑回路缺陷造成。
一种被称为弓状束的神经纤维链接大脑中知觉和运动区域，如果这条连接受损，就会导致不能准确控制音准，这项研究发表在最新的神经科学杂志上面。
研究人员通过核磁共振弥散张量成像技术检测大脑右颞和额叶间的联系，发现弓状束参与链接发音感知和发音控制。经过检测的20人中有一半以上的人被查出不能准确发声。在发声不准的人中，弓状束一般体积较小，纤维含量低。以最先进的方法在右半脑中都无法检测出弓状束分支存在，研究人员推测可能是弓状束分支完全缺失或者变形。
根据以往的研究和最新研究结果，研究人员表示发声不准的人不能自主的听见自己歌声，所以造成唱歌跑调。（生物谷Bioon.com）
生物谷推荐原始出处：
The Journal of Neuroscience, August 19, 2009, 29(33):10215-10220; doi:10.1523/JNEUROSCI.1701-09.2009
Tone Deafness: A New Disconnection Syndrome?
Psyche Loui,1 David Alsop,2 and Gottfried Schlaug1
Departments of 1Neurology and 2Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215
Communicating with one's environment requires efficient neural interaction between action and perception. Neural substrates of sound perception and production are connected by the arcuate fasciculus (AF). Although AF is known to be involved in language, its roles in non-linguistic functions are unexplored. Here, we show that tone-deaf people, with impaired sound perception and production, have reduced AF connectivity. Diffusion tensor tractography and psychophysics were assessed in tone-deaf individuals and matched controls. Abnormally reduced AF connectivity was observed in the tone deaf. Furthermore, we observed relationships between AF and auditory–motor behavior: superior and inferior AF branches predict psychophysically assessed pitch discrimination and sound production perception abilities, respectively. This neural abnormality suggests that tone deafness leads to a reduction in connectivity resulting in pitch-related impairments. Results support a dual-stream anatomy of sound production and perception implicated in vocal communications. By identifying white matter differences and their psychophysical correlates, results contribute to our understanding of how neural connectivity subserves behavior.
