Thursday, April 11, 2013

Will Karl Deisseroth and company bring "clarity" to uncovering the etiology of autism?

I was interested to read a piece in today's L.A. times about a Stanford University scientist named Karl Deisseroth who has developed a new technique to see better inside human brains.  Neurons (brain cells) have a covering over the part called the axon which is a myelin sheath or white matter which helps transport electrical impulses down them so that they can communicate with other neurons.  The myelin sheath is made of fatty materials which cause postmortem brains to be opaque so that certain details cannot be seen.

The Stanford scientists developed  a technique where they replaced the fatty myelin tissue with substances that included acrylamide, bisacrylamide and formaldehyde.  These don't interfere with light diffraction the way the fatty tissue of myelin does, enabling various parts of a postmortem brain to be viewed that couldn't be otherwise.

The researchers call this technique CLARITY (Clear Lipid-exchanged Anatomically Rigid Imaging/immunostaining compatible Tissue hYdrogel).

They initially studied mouse brains.

One of the first human brains they studied belonged to an autistic individual.  They found a neuron that apparently looped back onto itself rather than communicating with adjoining cells.  Also neurons in the frontal lobe of this individual  revealing "ladder-like" patterns in the neurons.  They stated this was similar to a finding in Down's syndrome.  This is in spite of the fact that in my reading of some stuff by Dr. Manuel Casanova, Down's syndrome brains are much smaller than normal and autistic brains are initially larger, undergoing an abnormal period of growth during a child's initial development and then tapering off.

I don't have the times article online handy, but another articlesummarizes this research well.

Dr. Deisseroth seemed to think it was not unquestionable that this finding could be key in understanding the etiology of autism, though I'm skeptical myself.

Prior to this, brains were sliced into small millimeter segments.  It was difficult to see how various cells or circuits connected to each other.  Also, the tissue could not be used for subsequent experiments.   This new technique may help resolve these problems. 

I'd also be interested in knowing what glial cell abnormalities they might find in autistic individuals since scientists have begun to recognize the importance of glia.  Previously, they were just thought to provide supporting functions to neurons. 

Here's hoping that this technique will help revolutionize our understanding of the etiology of autism so that we know what causes it and make it more likely a cure will be found at some point in time. 

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