Skip to comments.Perspective: Brain scans need a rethink
Posted on 11/05/2012 7:51:16 PM PST by neverdem
One of the most popular and widely accepted theories on the cause of autism spectrum disorders attributes the condition to disrupted connectivity between different regions of the brain. This 'connectivity hypothesis' claims that the social and cognitive abnormalities in people with autism can be explained by a dearth of connections between distant regions of the brain1. Some flavours of this theory also predict more connections between nearby brain regions.
Recent studies, however, have found that when a person moves their head while undergoing functional magnetic resonance imaging (fMRI) |[mdash]| a method that maps how different neuroanatomical structures of the brain interact in real time, its functional connectivity |[mdash]| it looks like the neural activity observed in autism. That's a sobering discovery: it means that a major source of evidence for a leading hypothesis on autism, and one that several research teams have pursued for years, may arise from an artefact.
Many studies have investigated functional connectivity in the brains of people with autism, and most have reported evidence supporting the connectivity hypothesis. These findings are consistent with results from some animal models of autism, and from studies using diffusion tensor imaging, which measures the bundles of fibres connecting parts of the brain.
But three studies published in 2012 have come to the same conclusion: head motion leads to systematic biases in fMRI-based analyses of functional connectivity2, 3, 4...
(Excerpt) Read more at nature.com ...
What's with this |[mdash]| business?
In an autistic patient, this would require general anesthesia. That's an increased risk & an increased expense. And for what? This does not help anybody in the short term. It's all related to research.
The correct code is: "&Mdash;", which should display as " — "...
“mdash”? Oh, that’s a British thing like calling cookies biscuits.
They will dig out the old wood vice and clamp that sucker down.
Coulda fooled me... '-)
What’s with this |[mdash]| business?
That happened because you moved your head.
Maybe in those on the more profound end of autistic spectrum disorder, but this connectivity hypothesis is also proposed for Asperger syndrome, IIRC.
I think it’s midrash, what I get on my stomach in the summer.