The impact of language proficiency on task-dependent neural activity and functional connectivity: insights from deafness.

Our study investigates how language proficiency impacts cognitive processing in the brain. We focused on congenitally and early deaf adults, where individual differences in language access during development significantly influence language proficiency and cognitive function. This variability in language backgrounds and skills allows us to explore the influence of early language experience on the large-scale brain networks that support cognition. We used functional MRI in a group of deaf adults with diverse language backgrounds and a control group of hearing participants. We hypothesized that differences in language skills would modulate neural responses and functional connectivity in task-related networks during the execution of demanding working memory and planning tasks. Our study revealed that differences in language proficiency, independently of language modality (signed or spoken), are positively correlated with neural activity and functional connectivity within the task-positive network during working memory in deaf adults. Furthermore, compared to hearing participants, the deaf group showed distinct patterns of neural activity and connectivity in task-dependent regions in the working memory experiment. Our findings emphasize the profound impact of early environmental experiences on brain responses during cognitive processing. Specifically, they highlight the role of language proficiency in shaping and supporting higher-order cognition.