The left inferior frontal gyrus is causally linked to vocal feedback control: evidence from high-definition transcranial alternating current stimulation.

Current models of speech motor control propose a role for the left inferior frontal gyrus (IFG) in feedforward control of speech production. There is evidence, however, that has implicated the functional relevance of the left IFG for the neuromotor processing of vocal feedback errors. The present event-related potential (ERP) study examined whether the left IFG is causally linked to auditory feedback control of vocal production with high-definition transcranial alternating current stimulation (HD-tACS). After receiving active or sham HD-tACS over the left IFG at 6 or 70 Hz, 20 healthy adults vocalized the vowel sounds while hearing their voice unexpectedly pitch-shifted by ±200 cents. The results showed that 6 or 70 Hz HD-tACS over the left IFG led to larger magnitudes and longer latencies of vocal compensations for pitch perturbations paralleled by larger ERP P2 responses than sham HD-tACS. Moreover, there was a lack of frequency specificity that showed no significant differences between 6 and 70 Hz HD-tACS. These findings provide first causal evidence linking the left IFG to vocal pitch regulation, suggesting that the left IFG is an important part of the feedback control network that mediates vocal compensations for auditory feedback errors.

Effect of Rhythmically Cued Exercise Interventions on Functions in Patients With Parkinson Disease: A Meta-Analysis.

OBJECTIVE: The purpose of this review was to investigate the efficacy of rhythmically cued exercise interventions on motor function, cognition, and mental state in patients with Parkinson disease. METHODS: PubMed, Cochrane Database, Web of Science, Embase, and CINAHL were searched June 15, 2023. Original studies investigating the efficacy of rhythmically cued exercise interventions on the functions of patients with Parkinson disease were included. The Cochrane risk-of-bias assessment tool was used to evaluate the risk of bias. The protocol was registered in PROSPERO (CRD42022371203). RESULTS: A total of 38 original studies involving 1486 participants were included. Rhythmically cued exercise interventions demonstrated superior effects on motor function compared to exercise therapy without rhythm (standardized mean difference [SMD] = -0.31). However, no significant improvements were observed in cognition and mental state. Overall, significant improvements were observed in motor examination (SMD = -0.61), Timed "Up & Go" Test (mean difference [MD] = -0.91), activities of daily living (SMD = -0.49), balance (SMD = 0.59), walking velocity (MD = 0.06), step length (MD = 2.65), and stride length (MD = 0.04) following rhythmically cued exercise interventions. No significant improvements were observed in freezing of gait and cadence. Assessment of publication bias showed no significant evidence of publication bias. Meta-regression analyses revealed a significant association between treatment duration and improvement in motor function. Furthermore, adverse events and dropout rates did not significantly differ between the 2 groups. CONCLUSION: Rhythmically cued exercise interventions are effective in improving motor function in the early to middle stages of Parkinson disease. More than 10 weeks of intervention yielded better results. However, these interventions do not have a significant impact on cognition and mental states. Importantly, rhythmically cued exercise interventions are safe and well tolerated. Large-scale trials are needed for further confirmation. IMPACT: This study contributes to the development of safe and reliable home rehabilitation programs, aiming to enhance the quality of life for patients with Parkinson disease.

Comparative efficacy of transcranial magnetic stimulation on different targets in Parkinson's disease: A Bayesian network meta-analysis.

Background/Objective: The efficacy of transcranial magnetic stimulation (TMS) on Parkinson's disease (PD) varies across the stimulation targets. This study aims to estimate the effect of different TMS targets on motor symptoms in PD. Methods: A Bayesian hierarchical model was built to assess the effects across different TMS targets, and the rank probabilities and the surface under the cumulative ranking curve (SUCRA) values were calculated to determine the ranks of each target. The primary outcome was the Unified Parkinson's Disease Rating Scale part-III. Inconsistency between direct and indirect comparisons was assessed using the node-splitting method. Results: Thirty-six trials with 1,122 subjects were included for analysis. The pair-wise meta-analysis results showed that TMS could significantly improve motor symptoms in PD patients. Network meta-analysis results showed that the high-frequency stimulation over bilateral M1, bilateral DLPFC, and M1+DLPFC could significantly reduce the UPDRS-III scores compared with sham conditions. The high-frequency stimulation over both M1 and DLPFC had a more significant effect when compared with other parameters, and ranked first with the highest SCURA value. There was no significant inconsistency between direct and indirect comparisons. Conclusion: Considering all settings reported in our research, high-frequency stimulation over bilateral M1 or bilateral DLPFC has a moderate beneficial effect on the improvement of motor symptoms in PD (high confidence rating). High-frequency stimulation over M1+DLPFC has a prominent beneficial effect and appears to be the most effective TMS parameter setting for ameliorating motor symptoms of PD patients (high confidence rating).

Identification and Characterization of the Lysine-Rich Matrix Protein Family in Pinctada fucata: Indicative of Roles in Shell Formation.

Mantle can secret matrix proteins playing key roles in regulating the process of shell formation. The genes encoding lysine-rich matrix proteins (KRMPs) are one of the most highly expressed matrix genes in pearl oysters. However, the expression pattern of KRMPs is limited and the functions of them still remain unknown. In this study, we isolated and identified six new members of lysine-rich matrix proteins, rich in lysine, glycine and tyrosine, and all of them are basic matrix proteins. Combined with four members of the KRMPs previously reported, all these proteins can be divided into three subclasses according to the results of phylogenetic analyses: KRMP1-3 belong to subclass KPI, KRMP4-5 belong to KPII, and KRMP6-10 belong to KPIII. Three subcategories of lysine-rich matrix proteins are highly expressed in the D-phase, the larvae and adult mantle. Lysine-rich matrix proteins are involved in the shell repairing process and associated with the formation of the shell and pearl. What's more, they can cause abnormal shell growth after RNA interference. In detail, KPI subgroup was critical for the beginning formation of the prismatic layer; both KPII and KPIII subgroups participated in the formation of prismatic layer and nacreous layer. Compared with different temperatures and salinity stimulation treatments, the influence of changes in pH on KRMPs gene expression was the greatest. Recombinant KRMP7 significantly inhibited CaCO3 precipitation, changed the morphology of calcite, and inhibited the growth of aragonite in vitro. Our results are beneficial to understand the functions of the KRMP genes during shell formation.