Monday, 22 July 2013

Language Tractography

Ant Left, Post. Right


Have been performing a large number of Frontal Aslant Tract (FAT) dissections recently and felt like I needed a change in my dissection, to keep me fresh (and sane). Here is an image of the structural networks associated with linguistic processing; the arcuate fasciculus (in Red) and the parallel perisylvian pathways (ant. segment in green, post. segment in yellow).

Predominantly involved with the production and comprehension of language. These tracts originate in the inferior frontal gyrus, known as Broca's area, damage to the cortex hear results in difficulties in the production of language, whilst sparing the ability to comprehend language. Following the course of the arcuate fasciculus, and half way between the bundles origin and destination, the anterior segment of the parallel perisylvian pathway compose fibers that terminate in Geschwind's terrritory. Located in the Inferior parietal lobule, this region appears to a densely connected hub between Broca's and Wernicke's that may be involved with the acquisition of language and of the emotional sensory processing associated with language tone, subtext and gesturing etc. Following on from Geschwind's territory, the posterior segment follows the arcuate's descent into the posterior temporal lobe, where both sets of fibers terminate in Wernicke's. A region most associated with the comprehension of language.

Dissections were performed on the very easy to use Trackvis (download for free @ http://www.trackvis.org/download/).


Acquisition
3T GE scanner 
Spin-Echo-EPI Diffusion weighted imaging
32 directions
b = 1300 s/mm2
40 mT/m
2.4 mm isotropic voxels