What sends the signals to your brain, allowing you to distinguish one sound from another?
http://www.ipam.ucla.edu/programs/es2005/
http://www.google.com/search?q=signals+ear+brain+distinguish+sounds&rls=com.microsoft:en-us:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7SUNA
