Specific brain disorders can affect the perception of music in a very specific way. Experi

ments done on epileptics decades ago showed that stimulating certain areas of the temporal lobe on both sides of the brain awakened "musical memories"—vivid re-creations of melodies that the patients had heard years earlier. Lesions in the temporal lobe can result in so-called musicogenic epilepsy, an extremely rare form. of the disorder in which seizures are triggered by the sound of music. Autism offers an even greater puzzle. People with this condition are mentally deficient, yet most are proficient musicians; some are "musical savants" possessed of extraordinary talent.

The opposite is true of the less than 1 percent of the population who suffer from amusia, or tree tone deafness. They literally cannot recognize a melody, let alone tell two of them apart, and they are incapable of repeating a song (although they think they are doing correctly). Even simple, familiar tunes such as Frere Jacques and Happy Birthday are mystifying to musics, but when the lyrics are spoken rather than sung, musics are able to recognize the song immediately.

But for instrumentalists, at least, music can evidently trigger physical changes in the brain's wiring. By measuring faint magnetic field emitted by the brains of professional musicians, a team led by Christo Pantev of the University of Muenster's Institute of Experimental Audiology in Germany has shown that intensive practice of an instrument leads to discernible enlargement of parts of the cerebral cortex, the layer of gray matter most closely associated with higher brain function.

As for music's emotional impact, there is some indication that music can affect levels of various hormones, including cortisol (involved in arousal and stress), testosterone (aggression and arousal) and oxytocin (nurturing behavior) as well as trigger release of the natural opiates known as endorphins. Using PET canners, Zatorre has shown that the parts of the brain involved in processing emotion seem to light up with activity when a subject hears music.

As tantalizing as these nits of research are, they barely begin to address the mysteries of music and the brain, including the deepest question of all: Why do we appreciate music？ Did our musical ancestors have an evolutionary edge over their tin-eared fellow？ Or is music, as M. I. T. neuroscientist Steven Pinker asserts, just "auditory cheesecake," with no biological value？ Given music's central role in most of our lives, it's time that scientists found the answers.

Specific brain disorders can ______ .

A．affect the understanding of music in almost every possible way

B．stimulate the memorizing of music he/she knew before

C．hinder musical understanding of the brain in some special ways

D．restrain the memorizing of music he/she knew before