Functional and structural abnormalities of the speech disorders: a multimodal activation likelihood estimation meta-analysis.

Speech disorders are associated with different degrees of functional and structural abnormalities. However, the abnormalities associated with specific disorders, and the common abnormalities shown by all disorders, remain unclear. Herein, a meta-analysis was conducted to integrate the results of 70 studies that compared 1843 speech disorder patients (dysarthria, dysphonia, stuttering, and aphasia) to 1950 healthy controls in terms of brain activity, functional connectivity, gray matter, and white matter fractional anisotropy. The analysis revealed that compared to controls, the dysarthria group showed higher activity in the left superior temporal gyrus and lower activity in the left postcentral gyrus. The dysphonia group had higher activity in the right precentral and postcentral gyrus. The stuttering group had higher activity in the right inferior frontal gyrus and lower activity in the left inferior frontal gyrus. The aphasia group showed lower activity in the bilateral anterior cingulate gyrus and left superior frontal gyrus. Across the four disorders, there were concurrent lower activity, gray matter, and fractional anisotropy in motor and auditory cortices, and stronger connectivity between the default mode network and frontoparietal network. These findings enhance our understanding of the neural basis of speech disorders, potentially aiding clinical diagnosis and intervention.

Greater Pattern Similarity between Mother Tongue and Second Language in the Right ATL Facilitates Understanding of Written Language.

Previous research has mapped out the brain regions that respond to semantic stimuli presented visually and auditorily, but there is debate about whether semantic representation is modality-specific (only written or only spoken) or modality-invariant (both written and spoken). The mechanism of semantic representation underlying native (L1) and second language (L2) comprehension in different modalities as well as how this mechanism is influenced by L2 proficiency, remains unclear. We used functional magnetic resonance imaging (fMRI) data from the OpenNEURO database to calculate neural pattern similarity across native and second languages (Spanish and English) for different input modalities (written and spoken) and learning sessions (before and after training). The correlations between behavioral performance and cross-language pattern similarity for L1 and L2 were also calculated. Spanish-English bilingual adolescents (N = 24; ages 16-17; 19 girls) participated in a 3-month English immersion after-school program. As L2 proficiency increased, greater cross-language pattern similarity between L1 and L2 spoken words was observed in the left pars triangularis. Cross-language pattern similarity between L1 and L2 written words was observed in the right anterior temporal lobe. Brain-behavior correlations indicated that increased cross-language pattern similarity between L1 and L2 written words in the right anterior temporal lobe was associated with L2 written word comprehension. This study identified an effective neurofunctional predictor related to L2 written word comprehension.