Brain structure & function
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Consequential works in cognitive neuroscience have led to the formulation of an interactive dual-stream model of language processing: the dorsal stream may process the phonological aspects of language, whereas the ventral stream may process the semantic aspects of language. While it is well-accepted that the dorsal route is subserved by the arcuate fasciculus, the structural connectivity of the semantic ventral stream is a matter of dispute. Here we designed a longitudinal study to gain new insights into this central but controversial question. ⋯ Furthermore, a negative correlation was observed between semantic fluency scores and the infiltration volumes in this fasciculus (r = -0.4, P = 0.029). Postoperatively, VLSM analyses were inconclusive. Taken as a whole and when combined with the literature data, our findings strengthen the view that the IFOF plays an essential role in semantic processing and may subserve the direct ventral pathway of language.
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The 30-amino acid peptide Y-P30, generated from the N-terminus of the human dermcidin precursor protein, has been found to promote neuronal survival, cell migration and neurite outgrowth by enhancing the interaction of pleiotrophin and syndecan-3. We now show that Y-P30 activates Src kinase and extracellular signal-regulated kinase (ERK). Y-P30 promotes axonal growth of mouse embryonic stem cell-derived neurons, embryonic mouse spinal cord motoneurons, perinatal rat retinal neurons, and rat cortical neurons. ⋯ Levels of total Src kinase, actin, GAP-43, cortactin and the glutamate receptor subunit GluN2B were not altered. When exposed to semaphorin-3a, Y-P30 protected a significant fraction of growth cones of cortical neurons from collapse. These results suggest that Y-P30 promotes axonal growth via Src- and ERK-dependent mechanisms which stabilize growth cones and confer resistance to collapsing factors.