Distinct Effects of Brain Activation Using tDCS and Observational Practice: Implications for Motor Rehabilitation.

Complex motor skills can be acquired while observing a model without physical practice. Transcranial direct-current stimulation (tDCS) applied to the primary motor cortex (M1) also facilitates motor learning. However, the effectiveness of observational practice for bimanual coordination skills is debated. We compared the behavioural and brain causal connectivity patterns following three interventions: primary motor cortex stimulation (M1-tDCS), action-observation (AO) and a combined group (AO+M1-tDCS) when acquiring a bimanual, two-ball juggling skill. Thirty healthy young adults with no juggling experience were randomly assigned to either video observation of a skilled juggler, anodal M1-tDCS or video observation combined with M1-tDCS. Thirty trials of juggling were performed and scored after the intervention. Resting-state EEG data were collected before and after the intervention. Information flow rate was applied to EEG source data to measure causal connectivity. The two observation groups were more accurate than the tDCS alone group. In the AO condition, there was strong information exchange from (L) parietal to (R) parietal regions, strong bidirectional information exchange between (R) parietal and (R) occipital regions and an extensive network of activity that was (L) lateralized. The M1-tDCS condition was characterized by bilateral long-range connections with the strongest information exchange from the (R) occipital region to the (R) temporal and (L) occipital regions. AO+M1-tDCS induced strong bidirectional information exchange in occipital and temporal regions in both hemispheres. Uniquely, it was the only condition that was characterized by information exchange between the (R) frontal and central regions. This study provides new results about the distinct network dynamics of stimulating the brain for skill acquisition, providing insights for motor rehabilitation.

Blink-related EEG oscillations are neurophysiological indicators of subconcussive head impacts in female soccer players: a preliminary study.

Introduction: Repetitive subconcussive head impacts can lead to subtle neural changes and functional consequences on brain health. However, the objective assessment of these changes remains limited. Resting state blink-related oscillations (BROs), recently discovered neurological responses following spontaneous blinking, are explored in this study to evaluate changes in BRO responses in subconcussive head impacts. Methods: We collected 5-min resting-state electroencephalography (EEG) data from two cohorts of collegiate athletes who were engaged in contact sports (SC) or non-contact sports (HC). Video recordings of all on-field activities were conducted to determine the number of head impacts during games and practices in the SC group. Results: In both groups, we were able to detect a BRO response. Following one season of games and practice, we found a strong association between the number of head impacts sustained by the SC group and increases in delta and beta spectral power post-blink. There was also a significant difference between the two groups in the morphology of BRO responses, including decreased peak-to-peak amplitude of response over left parietal channels and differences in spectral power in delta and alpha frequency range post-blink. Discussion: Our preliminary results suggest that the BRO response may be a useful biomarker for detecting subtle neural changes resulting from repetitive head impacts. The clinical utility of this biomarker will need to be validated through further research with larger sample sizes, involving both male and female participants, using a longitudinal design.

Better Hemodynamic Profile of Laryngeal Mask Airway Insertion Compared to Laryngoscopy and Tracheal Intubation.

BACKGROUND: Laryngoscopy and tracheal intubation can cause serious cardiovascular responses in patients such as hypertension, tachycardia, and arrhythmias. Alternative airway maintenance techniques may attenuate these hemodynamic stress responses. OBJECTIVES: This study aimed to compare the immediate hemodynamic effects of the insertion of laryngeal mask airway supreme (LMA-S) and classic (LMA-C) with laryngoscopy and Endotracheal Intubation (ETT). PATIENTS AND METHODS: This study was a prospective, double-blind, and randomized clinical trial conducted on 150 patients aged 18 to 50 years with ASA I (American Society of Anesthesiologists), in the general operating room of Shahid Mohammadi hospital, Hormozgan university of medical sciences, Bandar Abbas, Iran. In the ETT group, endotracheal intubation was performed using the Macintosh laryngoscope; while for the LMA-C and LMA-S groups, LMA Classic and LMA Supreme were inserted, respectively. The induction and maintenance of anesthesia were similar in all patients. The hemodynamic parameters such as heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured before (baseline) and after induction of anesthesia at 4 different time points. The statistical analysis was done and P value less than 0.05 was considered significant. RESULTS: Participants in all groups were similar in terms of gender, age, weight, height, and Mallampati class. The mean ± SD of SBPs (105.62 ± 12.12, 112.90 ± 12.2, and 112.48 ± 15.14 mm Hg, respectively for ETT, LMA-C, and LMA-S) and DBPs (64.64 ± 10.23, 73.78 ± 9.70, and 71.20 ± 12.27 mm Hg, respectively for ETT, LMA-C, and LMA-S) were significantly lower in the ETT group compared to LMA groups 5 minutes after device insertion (P < 0.01 for SBPs and P < 0.001 for DBPs); however these values were lower than the baseline values in all groups. There were no differences in the mean SBP and DBPs between the three groups at the other time points. The mean ± SD heart rates in the ETT group, compared to the LMA-C and LMA-S groups, were considerably higher in the first minute (100.06 ± 18.27, 82.50 ± 10.52, and 82.00 ± 13.60 bpm, respectively for ETT, LMA-C, and LMA-S), third minute (91.04 ± 17.12, 78.84 ± 11.23, and 78.90 ± 13.41 bpm, respectively for ETT, LMA-C, and LMA-S) and fifth minute (85.82 ± 16.01, 75.78 ± 11.73, and 75.04 ± 13.90 bpm, respectively for ETT, LMA-C, and LMA-S) after intubation (P < 0.001). There were no significant differences between the LMA-C and LMA-S groups in terms of hemodynamic parameters. CONCLUSIONS: Maintaining the airway using laryngeal mask airway is associated with less cardiovascular responses compared to direct laryngoscopy and tracheal intubation.

Effect of mineral trioxide aggregates and Portland cements on inflammatory cells.

INTRODUCTION: Recently, some studies have compared mineral trioxide aggregate (MTA) with Portland cements, concluding that the principal ingredients of Portland cements are similar to those of MTA. The purpose of the present study was to evaluate the effect of gray MTA, white MTA, and gray and white Portland cements on inflammatory cells in rats. METHODS: Fresh mixtures mixed with distilled water were placed in polyethylene tubes, which were implanted in the dorsal subcutaneous connective tissue of 60 Sprague-Dawley rats along with empty tubes as controls. Tissue specimens were collected after the rats were sacrificed after 7, 15, 30, 60, and 90 days. The specimens were fixed, stained, processed, and histologically evaluated under a light microscope. Inflammatory reactions were classified as grade 0: without inflammatory cells, grade I: sporadic infiltration of inflammatory cells, grade II: moderate infiltration (<25 cells), grade III: dense and severe infiltration (25-125 cells), and grade IV: very dense and severe infiltration (>125 cells). Data were analyzed with the nonparametric (two factor) analysis of variance and Kruskal-Wallis H-test. RESULTS: All the groups showed grade III inflammation after 7 and 15 days; there was a decrease in the inflammatory process after 30, 60, and 90 days. After 90 days, gray MTA, white MTA, and control groups had grade 0 inflammatory process, but gray Portland cement and white Portland cement groups showed grade 0 to grade I inflammatory processes. CONCLUSION: MTAs were more biocompatible; however, more studies are required.