When two are better than one: Bilateral mesial temporal lobe contributions associated with better vocabulary skills in children and adolescents

Abstract

This study considered the involvement of the mesial temporal lobe (MTL) in language and verbal memory functions in healthy children and adolescents. We investigated 30 healthy, right-handed children and adolescents, aged 7-16, with a fMRI language paradigm and a comprehensive cognitive test battery. We found significant MTL activations during language fMRI in all participants; 63% of them had left lateralized MTL activations, 20% exhibited right MTL lateralization, and 17% showed bilateral MTL involvement during the fMRI language paradigm. Group analyses demonstrated a strong negative correlation between the lateralization of MTL activations and language functions. Specifically, children with less lateralized MTL activation showed significantly better vocabulary skills. These findings suggest that the mesial temporal lobes of both hemispheres play an important role in language functioning, even in right-handers. Our results furthermore show that bilateral mesial temporal lobe involvement is advantageous for vocabulary skills in healthy, right-handed children and adolescents.

Atypical language representation is unfavorable for language abilities following childhood stroke

“…Previous literature in healthy children and adolescents found an association between language lateralization and functioning, but conflicting findings were reported regarding the nature of this relationship: some studies found a positive correlation between language lateralization towards the left hemisphere and verbal abilities, 43, 44 whereas others reported better language performance related to less lateralization and more involvement of the contralateral hemisphere. 29, 30, 45–47 The contradictory findings of these studies may be the result of different imaging methods and different tasks testing different functions. The relationship between lateralization and cognitive functioning has been reported as dependent on task demands.…”

“…This paradigm has shown robust language lateralization in healthy children and typically involves inferior and middle frontal regions, middle and superior temporal regions, as well as mesial temporal areas including the hippocampal formation. 26–30 In the auditory description definition condition, the participants listen to the definition of an object followed by a noun and are instructed to press a button each time the definition incorrectly described the noun. For instance, “A long yellow fruit is a banana.” (correct) or “Something you sit on is a spaghetti.” (incorrect).…”

The role of the corpus callosum in language network connectivity in children

“…During fMRI assessment, the German version of an auditory description definition task was administered (Bartha‐Doering, Kollndorfer, et al, 2018; Bartha‐Doering, Novak, et al, 2018; Berl et al., 2014; Sepeta et al., 2016). In the auditory description definition condition, the participants heard the definition of an object followed by a noun and were instructed to press a button each time the definition truly described the noun.…”

“…Each block lasted for 40 s and consisted of 10 sentences presented every 4 s. Total fMRI scan time was 6 min 40 s. Task performance was evaluated by the overall accuracy in the language condition and the control task separately. Detailed description of the fMRI paradigm can be found in Bartha‐Doering, Kollndorfer, et al (2018), Bartha‐Doering, Novak, et al (2018), or Bartha‐Doering et al. (2019).…”

“…For our language nodes, we included regions that were involved in paradigms of speech, semantics, syntax, and phonology, while we excluded regions that were only involved in orthography. In addition, we included the hippocampi and parahippocampal gyri within both hemispheres as their involvement in semantic language processing was shown in previous research (Bartha et al., 2003, 2005; Bartha‐Doering, Novak, et al, 2018). In sum, we obtained 29 ROIs within each hemisphere and a total of 58 ROIs (Figure 2).…”