Search

Objective: We studied age-related dynamics of information sharing among cortical language regions with electrocorticographic high-gamma modulation during picture-naming and story-listening tasks., Methods: Seventeen epilepsy patients aged 4-19 years, undergoing extraoperative monitoring with left-hemispheric subdural electrodes, were included. Mutual information (MI), a nondirectional measure of shared information, between 16 pairs of cortical regions of interest, was computed from trial-averaged 70-150 Hz power modulations during language tasks. Impact of age on pairwise MI between language regions and their determinants were ascertained with regression analysis., Results: During picture naming, significant increase in MI with age was seen between pairwise combinations of Broca's area, inferior precentral gyrus (iPreC), and frontal association cortex (FAC); Wernicke's area and posterior association cortex (PAC); and Broca's and Wernicke's areas. During story listening, significant age-related increase in MI was seen between Wernicke's area and either Broca's area, FAC, or PAC; and between Broca's area and FAC. Significant impact of baseline intelligence quotient was seen on the relationship between age and MI for all pairs, except between Broca's area and iPreC. The mean MI was higher during naming compared to listening for pairs including iPreC with Broca's area, FAC, or PAC and was lower for pairs of Wernicke's area or PAC with anterior language regions., Significance: Information sharing matures with age "within" frontal and temporoparietal language cortices, and "between" Broca's and Wernicke's areas. This study provides evidence for distinct patterns of developmental plasticity within perisylvian language cortex and has implications for planning epilepsy surgery., (Wiley Periodicals, Inc. © 2019 International League Against Epilepsy.)

Aim: Previous functional imaging studies demonstrate that people who stutter (PWS) exhibit over- and under-activation of Broca's and Wernicke's areas and their right hemisphere homologues when speaking. However, it is unclear whether this altered activation represents the neural cause of speech dysfluency or a secondary compensatory activation in PWS. To clarify the functional significance of the altered activation pattern in classic language areas and their right homologues, we examined whether the severity of stuttering was affected when the activation of these areas was modulated by brain stimulation., Methods: While PWS read passages aloud, we applied transcranial direct current stimulation (tDCS) using electrode montages that included an anodal or cathodal electrode placed over one of the language areas and its right hemisphere homologue, with the second electrode placed over the contralateral supraorbital region. Each participant underwent both anodal and cathodal tDCS sessions, each of which included a sham stimulation. Effects of stimulation polarity and electrode location on the frequency of stuttering were analyzed., Results: We observed a significant interaction between polarity and location on the frequency of stuttering. Follow-up analyses revealed that a tDCS montage including the cathodal electrode over right Broca's area (RB) significantly reduced the frequency of stuttering., Conclusion: The results indicated that stuttering severity was ameliorated when overactivation in RB was reduced by tDCS. This observation further suggests that speech dysfluency in PWS may be caused either by functional alteration in RB or by abnormal activation in speech motor control areas that are connected with RB., (© 2018 The Authors. Psychiatry and Clinical Neurosciences © 2018 Japanese Society of Psychiatry and Neurology.)