Using in vivo probabilistic tractography to reveal two segregated dorsal 'language-cognitive' pathways in the human brain.
Primate studies have recently identified the dorsal stream as constituting multiple dissociable pathways associated with a range of specialized cognitive functions. To elucidate the nature and number of dorsal pathways in the human brain, the current study utilized in vivo probabilistic tractography to map the structural connectivity associated with subdivisions of the left supramarginal gyrus (SMG). The left SMG is a prominent region within the dorsal stream, which has recently been parcellated into five structurally-distinct regions which possess a dorsal-ventral (and rostral-caudal) organisation, postulated to reflect areas of functional specialisation. The connectivity patterns reveal a dissociation of the arcuate fasciculus into at least two segregated pathways connecting frontal-parietal-temporal regions. Specifically, the connectivity of the inferior SMG, implicated as an acoustic-motor speech interface, is carried by an inner/ventro-dorsal arc of fibres, whilst the pathways of the posterior superior SMG, implicated in object use and cognitive control, forms a parallel outer/dorso-dorsal crescent.
Neuroscience and Aphasia Research Unit (NARU), School of Psychological Sciences, University of Manchester, UK. Electronic address: Lauren.Cloutman@manchester.ac.uk.
Lauren L
LL
Cloutman
Richard J
RJ
Binney
David M
DM
Morris
Geoffrey J M
GJ
Parker
Matthew A
MA
Lambon Ralph
D000328:Adult; D001921:Brain / Q000033:anatomy & histology*; D001931:Brain Mapping / Q000379:methods*; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007802:Language; D008297:Male; D009434:Neural Pathways / Q000033:anatomy & histology*; D011597:Psychomotor Performance; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult
Arcuate fasciculus; Connectivity; Dual stream model; Functional specialization; Language production; Performance feedback; Repetition; Sensory-motor integration; Supramarginal gyrus; Tool use