Struggling with Naurobiology

Hi all,

I am home for the summer recuperating from shoulder replacement surgery. As such, I have a rather large agenda. One item is to read neurobiological literature on autism to try to shore up my very limited understanding. Another is to read more about perspective-taking, joint attention, and the research supporting/refuting DIR/Floortime. And so today I read and took notes on several articles, most of which I had to go back and forth between Google to find definitions/examples for some of the brain related words. But! Here is a beginner's view on some of this.

Christpher Gillberg has presented a summary of the known literature on where in the brain is autism? Autopsy and imaging studies suggest: cerebella dysfunction (cerebellum: a region of the brain that plays an important role in motor control, cognitive functions such as attention and language, and probably in some emotional responses such as regulating fear and pleasure responses). Within the cerebellum are Purkinje cells, which receive more synaptic input than any other type of cell in the brain. Purkinje cells use GABA as their neurotransmitter, and exert inhibitory effects on their targets. Bauman and Kemper (2005) have demonstrated in their post-mortem studies that children and adults with autism have significantly reduced numbers of Purkinje cells. However, in other post-mortem studies,  additional abnormalities have been found in other areas of the brain, often in the cerebellum.  The reduced number of Purkinje cells has to have happened prenatally, before 28-30 weeks gestation. Minshew and Williams (2007) characterize autism as a "polygenetic developmental neurobiologic disorder with multiorgan involvement", although it predominantly involves the central nervous system. They state that autism is primarily a disorder of connectivity, involving hemispheric connectivity. It appears that deficits in high-functioning persons with autism occur in processing that places high demands on integration of information and coordination or multiple neural systems. Intact abilities share a dependence on low information processing demands and local neural connections.

So - autism is not a disorder of one area of the brain, or even of two. It appears to involve the connections made between areas of the brain, that demonstrate problems in central coherence, executive function, and aberrant reading of facial expression. "Polygenetic" refers to the current research that indicates many genes appears to be affected at different levels of expression and at places on the genome. Although there is a heritability component, determining the inheritance aspects are far less simple than  what we know about Fragile X syndrome.

Gillberg also references frontotemporal lobe dysfunction suggested by autopsy studies, functional imaging studies and neuropsychological studies. More on that later!