Quantitative MRI Used to Map Visual Sensory Thalamus

Neuroscientists at Technische Universität Dresden used structural quantitative MRI (qMRI) methods to investigate the visual sensory thalamus, a point of origin of visual difficulties in diseases such as dyslexia and glaucoma. Their methodology could provide an in-depth understanding of visual sensory processing in both health and disease in the near future.

The visual sensory thalamus contains two major compartments that are tiny and located very deep inside the brain, which has hampered thorough investigation. Christa Müller-Axt, first author on a paper  published in NeuroImage recently, discovered structures that she thought might resemble the two visual sensory thalamus compartments in neuroimaging data. The neuroimaging data was unique because it had an unprecedented high spatial resolution obtained via qMRI. She followed up this discovery in a series of novel experiments involving analysis of high spatial resolution in vivo and post-mortem MRI data as well as post-mortem histology and uncovered the two major compartments of the visual sensory thalamus.

The results showed that the two major compartments of the visual sensory thalamus are characterized by different amounts of brain white matter. This information can be detected in the qMRI data and thus, can be used to investigate the two compartments of the visual sensory thalamus in living humans.

“Post-mortem studies in developmental dyslexia have shown that there are alterations specifically in one of the two compartments of the visual sensory thalamus. However, there are very few of these post-mortem studies, so it is difficult to say whether all dyslexics are characterized by these kind of visual sensory thalamus alterations,” Müller-Axt explains. “Also, post-mortem data cannot reveal anything about the functional impact of these alterations and their specific contribution to developmental dyslexia symptoms. Therefore, we expect that our novel in vivo approach will be a great asset in facilitating research on the role of the visual sensory thalamus in developmental dyslexia.”