Connectionists: neural mechanisms of autism

[Stephen Grossberg]

The following article is now available at 
http://www.cns.bu.edu/Profiles/Grossberg

Grossberg, S. and Seidman, D. (2006). Neural dynamics of autistic 
behaviors: Cognitive, emotional, and timing substrates. Psychological 
Review, in press.

ABSTRACT
  What brain mechanisms underlie autism and how do they give rise to 
autistic behavioral symptoms? This article describes a neural model, 
called the iSTART model, which proposes how cognitive, emotional, 
timing, and motor processes that involve brain regions like 
prefrontal and temporal cortex, amygdala, hippocampus, and cerebellum 
may interact together to create and perpetuate autistic symptoms. 
These model processes were originally developed to explain data 
concerning how the brain controls normal behaviors. The iSTART model 
shows how autistic behavioral symptoms may arise from prescribed 
breakdowns in these brain processes, notably a combination of 
underaroused emotional depression in the amygdala and related 
affective brain regions, learning of hyperspecific recognition 
categories in temporal and prefrontal cortices, and breakdowns of 
adaptively timed attentional and motor circuits in the hippocampal 
system and cerebellum. The model clarifies how malfunctions in a 
subset of these mechanisms can, though a system-wide vicious circle 
of environmentally mediated feedback, cause and maintain problems 
with them all.

Key words: autism, learning, categorization, depression, 
hypervigilance, adaptive resonance theory, adaptive timing, amygdala, 
frontal cortex, hippocampus, cerebellum