Abnormalities in brainstem microstructure are correlated with sensory challenges in Autism
I had the pleasure of talking to Brittany Travers about her new research on Autism, specifically targeting the brain stem. Unsatisfied with previous diffusion tensor imaging data collection methods, they developed a novel way to capture high quality images of the brainstem.
Diffusion tensor imaging (DTI) is a technique I had heard of but not really understood. Brittany kindly helped me understand. In DTI, one “images” by measuring the direction of water flow in the brain. In her study, they focused on Fractional Anisotropy, which measures how much water is flowing along a fiber tract in the brain. Water flows along a tract because myelination prevents the water from flowing through. In this way, scientists can locate and quantify abnormalities in the microstructure of brain regions.
In their study, Travers and her colleagues showed that fractional anisotropy (FA) in the medial lemniscus of the brain stem is positively correlated with hyporesponsivity scores in the Autism cohort only. A common feature of children with Autism is either (or both) hyperresponsiveness to sensory stimuli and hyporesponsiveness to sensory stimuli. However, hyperresponsivity was not correlated with FA in either the medial lemniscus or the pyramidal tract. They chose to focus on the medial lemniscus and the pyramidal tract in order to understand a major input and a major output structure. The medial lemniscus carries somatosensory information from the skin to the thalamus, and the pyramidal tract contains upper motor neurons travelling from the cerebral cortex to the brainstem and spinal cord. However, their dataset now allows them to specifically analyze any structure in the brainstem, which is where they are going next.
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