¬¬¬The Arcuate Fasciculus (AF) is a white matter tract connecting the posterior temporal region involved in the comprehension of language with the inferior frontal gyrus involved in language production (Broca’s region). Several studies have used diffusion Magnetic Resonance Imaging (MRI) to reconstruct the AF in vivo in the human brain. Diffusion MRI reconstructions often mix the AF with the Superior Longitudinal Fasciculus (SLF) which originates from the inferior parietal lobule and courses parallel to the AF towards the frontal region. Petrides and Pandya (2009) demonstrated distinct connection profiles to the inferior frontal region in the macaque monkey based on anatomical tract tracing studies from the posterior temporal and the inferior parietal lobule. Thus, the AF and two distinct branches of the SLF could be clearly distinguished. The present study aimed to improve the reconstruction of the AF originating from the posterior temporal region and SLF II and III originating in the inferior parietal lobule. The reconstructions were carried out in 37 right-handed healthy volunteers (age 18-34, M=24.5) who had been scanned with MRI (diffusion and anatomical). The diffusion MRI images were preprocessed using FSL and the tracts were reconstructed with Diffusion Toolkit and Trackvis using Regions of Interests drawn on the diffusion and coregistered anatomical scans. The AF was successfully reconstructed in all participants and separated from SLF II and III. Furthermore, resting state connectivity permitted differentiation of the inferior frontal targets of these pathways. These results refine knowledge of connectivity of the language regions.

REFINING THE RECONSTRUCTION OF WHITE MATTER TRACTS CONNECTING SPECIFIC TEMPORO-PARIETAL AREAS TO BROCA'S REGION