White matter integrity in right hemisphere predicts pitch-related grammar learning

• Published in: NeuroImage (Orlando, Fla.) Vol. 55; no. 2; pp. 500 - 507
• Main Authors: Loui, Psyche, Li, H. Charles, Schlaug, Gottfried
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.03.2011; Elsevier Limited
• Subjects: Adult; Attention deficit hyperactivity disorder; Behavior; Brain; Brain Mapping; Cerebrum - anatomy & histology; Cerebrum - physiology; Diffusion Tensor Imaging; Female; Grammar; Humans; Hypotheses; Image Interpretation, Computer-Assisted; Language; Learning; Learning - physiology; Linguistics; Male; Memory; Music; Neural Pathways - anatomy & histology; Neural Pathways - physiology; Pitch; Pitch Perception - physiology; Plasticity; Reading comprehension; Studies; White matter; Young Adult; Learning; Memory; Music; Plasticity; Pitch; Grammar; White matter; Diffusion tensor imaging
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2010.12.022

White matter plays an important role in various domains of cognitive function. While disruptions in white matter are known to affect many domains of behavior and cognition, the ability to acquire grammatical regularities has been mostly linked to the left hemisphere, perhaps due to its dependence on linguistic stimuli. The role of white matter in the right hemisphere in grammar acquisition is yet unknown. Here we show for the first time that in the domain of pitch, intact white matter connectivity in right-hemisphere analogs of language areas is important for grammar learning. A pitch-based artificial grammar learning task was conducted on subjects who also underwent diffusion tensor imaging. Probabilistic tractography using seed regions of interest in the right inferior frontal gyrus and right middle temporal gyrus showed positive correlations between tract volume and learning performance. Furthermore, significant correlations were observed between learning performance and FA in white matter underlying the supramarginal gyrus, corresponding to the right temporal–parietal junction of the arcuate fasciculus. The control task of recognition did not correlate with tract volume or FA, and control tracts in the left hemisphere did not correlate with behavioral performance. Results show that the right ventral arcuate fasciculus is important in pitch-based artificial grammar learning, and that brain structures subserving learning may be tied to the hemisphere that processes the stimulus more generally. ► Human subjects underwent DTI and behavioral testing on pitch learning and memory. ► Volume of right arcuate fasciculus correlated with grammar-learning ability. ► FA of right temporal–parietal junction predicted grammar-learning. ► Right temporal–parietal junction of arcuate fasciculus is important for learning.