Sign Language Learning Alters Brain Activity, Predicts Long-Term Retention

A study investigated how learning Israeli Sign Language (ISL) modifies brain activity in hearing adults. The research isolated neural activity related to ISL's linguistic components: sentence-level, lexical, and phonological. Findings indicate that learning a new language causes widespread changes in brain activity patterns. These changes involve the recruitment of distinct brain regions for processing different linguistic components. Specifically, initial phonological processing activated the left precentral gyrus, occipital cortex, and bilateral fusiform gyrus. Lexical processing activated the left angular gyrus, inferior parietal cortex, precuneus, and bilateral MTG and inferior temporal gyrus (ITG). Sentence-level processing activated Broca's area, left temporal and inferior parietal regions. Activation patterns after learning, particularly those related to sentence processing, strongly predicted long-term learning success, measured six months later. The study also noted that ISL syntax differs from Hebrew, featuring sentence-final wh-elements and negative markers following the verb. Researchers used fMRI to monitor brain activity and ANOVA to compare learning and control groups, confirming that observed changes resulted from the ISL course. The study used a 1-s inter-stimulus interval in the fMRI task, but task conditions were as long as 15 s.