title: Rapid language-related plasticity: microstructural changes in the cortex after a short session of new word learning.
abstract: Human brain imaging revealed that the brain can undergo structural plasticity following new learning experiences. Most magnetic resonance imaging (MRI) uncovered morphometric alternation in cortical density after the long-term training of weeks to months. A recent diffusion tensor imaging (DTI) study has found changes in diffusion indices after 2 h of training, primarily in the hippocampus. However, whether a short learning experience can induce microstructural changes in the neocortex is still unclear. Here, we used diffusion MRI, a method sensitive to tissue microstructure, to study cortical plasticity. To attain cortical involvement, we used a short language task (under 1 h) of introducing new lexical items (flower names) to the lexicon. We have found significant changes in diffusivity in cortical regions involved in language and reading (inferior frontal gyrus, middle temporal gyrus, and inferior parietal lobule). In addition, the difference in the values of diffusivity correlated with the lexical learning rate in the task. Moreover, significant changes were found in white matter tracts near the cortex, and the extent of change correlated with behavioral measures of lexical learning rate. These findings provide first evidence of short-term cortical plasticity in the human brain after a short language learning task. It seems that short training of less than an hour of high cognitive demand can induce microstructural changes in the cortex, suggesting a rapid time scale of neuroplasticity and providing additional evidence of the power of MRI to investigate the temporal and spatial progressions of this process.
authors.affiliation: Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Shir
authors.initials: S
authors.lastname: Hofstetter
authors.affiliation: Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.|Language and Brain Lab, School of Education, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Naama
authors.initials: N
authors.lastname: Friedmann
authors.affiliation: Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel. assafyan@post.tau.ac.il.|Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel. assafyan@post.tau.ac.il.
authors.forename: Yaniv
authors.initials: Y
authors.lastname: Assaf
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007802:Language; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D010775:Photic Stimulation; D014706:Verbal Learning / Q000502:physiology*; D066127:White Matter / Q000502:physiology; D055815:Young Adult
keywords: DTI; Language; Lexical learning; Neuroplasticity