A Deficiency of Amygdala Neurons in Autism?

EurekAlert

"Authors Cynthia Schumann, PhD, of the University of California, San Diego, and David Amaral, PhD, director of the M.I.N.D. Institute at the University of California, Davis, counted and measured neurons in the amygdala of nine postmortem autistic male brains and 10 age-matched male postmortem non-autistic brains. Ages ranged from 10 to 44 years old. Unlike previous postmortem studies, the sample excluded brains of individuals with epilepsy or similar disorders associated with cell loss in the amygdala.
Paradoxically, past research using magnetic resonance imaging with children has shown that the amygdala in young males with autism is abnormally large in volume due to precocious maturation. 'It is somewhat surprising, therefore, that there are ultimately fewer neurons in the autistic amygdala,' says Schumann."

This study points to a deficit of grey matter; below is the Carnegie Mellon research pointing to problems with white matter.