Last week an interesting study was published (online) that provides evidence that music exposure facilitates neuroplasticity in rats. While I feel quite uncomfortable with using animals for these studies (especially if you read the explicit method sections of these kind of neurobiological papers :-\) , the results could well contribute to a better insight in how music might be functional in the neurohabilitation of humans.
About sixty rats were divided in four groups, two of which had callosotomy performed on them: a small section of the brain was removed just after they were born, an area that is considered important for e.g. spatial memory. The research elaborates on earlier studies that showed music to have an effect on hippocampal neurogenesis, as well as facilitated spatial memory (e.g., Kim et al., 2006).
The authors conclude that an enriched sound environment -exposing rats to piano music- helps the recovery from neural damage. Rats with a damaged brain showed signs of recovery after about fifty days of listening to Mozart piano sonates for about 12 hours a day. Compared to rats that also had brain damage, but that did not listen to music, they performed significantly better in a spatial memory task (finding their way in a maze) and in their emotional reactivity (using a marble burying task).
While it remains unclear whether sounds other than music would have the same effect, the study is a striking example of research showing that music has a larger role in shaping the brain than previously thought.
Amagdei, A., Balteş, F., Avram, J., & Miu, A. (2009). Perinatal exposure to music protects spatial memory against callosal lesions International Journal of Developmental Neuroscience DOI: 10.1016/j.ijdevneu.2009.08.017