This book by Oliver Sacks (a noted neurologist) outlines several cases he saw where damage to the brain led to 'losses' or 'excesses'. An extremely good read, especially considering that until medical imaging (MRI, PET) became possible the brain could only really be studied by seeing what happened when it was damaged. In the book (which is a collection of case studies) he touches on proprioception, autism and Tourette's syndrome amongst others.