22 Introduction to Autism Spectrum Disorders
Hind brainHind brainMid brain
Mid brainMid brainMid brainFore brainFore brainSpinal cordSpinal cordTypical child
Cerebral hemisphereCerebral hemisphereCerebellumCerebellumPonsPonsMedullaMedulla25 days25 days35 days35 days40 days40 days50 days50 days100 days100 days9 months9 months5 months5 monthsAutistic childFigure 1.12 Development of a typical human and an autistic human fetal brain from 25
days to 5 months of gestation. In the majority of autism cases, the problems arise during the
very early stages of the fetal brain development. A few progenitor neurons, destined to
mature into a specialized faculty are killed or mutated, resulting in ASD. An autistic child’s
brain is larger but has parts missing (see text for details). (See insert for color representation of
this figure.)