Does prefrontal cortex transcranial direct current stimulation influence the oxygen uptake at rest and post-exercise?

Effects of smartphone use before resistance exercise on inhibitory control, heart rate variability, and countermovement jump

BACKGROUND

The effect of MF induced by exposure time to social media smartphone apps on inhibitory control, heart rate variability (HRV), and high-intensity physical effort following a resistance exercise session might indicate whether strength and conditioning professionals should suggest avoiding smartphone usage before a resistance exercise session.

AIM

The objective of this study was to analyze the effect of mental fatigue on inhibitory control, HRV, and countermovement jump (CMJ) in trained adults after resistance exercise.

METHODS

A total of 16 trained males (21.4 ± 3.3 years) volunteered in this study. The participants performed resistance exercises with and without mental fatigue. The Stroop Task, countermovement jump, and heart rate variability were evaluated before and after the resistance exercise. The participants used smartphones in the mental fatigue condition, whereas the participants watched TV in the control condition.

RESULTS

No condition × time interaction was found for the Stroop accuracy (p = 0.87), CMJ (p = 0.68), SDNN (p = 0.15), or pNN50 (p = 0.15) in the heart rate variability. An interaction was found for Stroop response time (p = 0.01) with a higher response time for the mental fatigue condition (p = 0.01).

CONCLUSIONS

Mental fatigue impaired the inhibitory control performance after a resistance exercise session in trained adults.

Effects of single session transcranial direct current stimulation on aerobic performance and one arm pull-down explosive force of professional rock climbers

Objective: To explore the effects of single-session transcranial direct current stimulation (tDCS) on aerobic performance and explosive force in the one-arm pull-down of long-term trained rock climbers. Method: Twenty athletes (twelve male and eight female) from the Rock Climbing Team of Hunan province (Hunan, China) were selected for a randomized double-blind crossover study. After baseline tests, All subjects visited laboratories twice to randomly receive either sham or a-tDCS at a current intensity of 2 mA for 20 min. The two visits were more than 72 h apart. Immediately after each stimulation, subjects completed a 9-min 3-level-load aerobic test and a one-arm pull-down test. Results: Differences in the heart rate immediately after 9-min incremental aerobic exercises revealed no statistical significance between each group (p > 0.05). However, the decrease in heart rate per unit time after exercise after real stimulation was significantly better than before stimulation (p < 0.05), and no statistical significance was observed between after sham stimulation and before stimulation (p > 0.05). One-arm pull-down explosive force on both sides after real stimulation was improved by a-tDCS compared with before stimulation, but with no significant difference (p > 0.05). Real stimulation was significantly improved, compared with sham stimulation on the right side (p < 0.05). Conclusion: Single-session tDCS could potentially benefit sports performance in professional athletes.

A pilot randomized clinical trial of tDCS for increasing exercise engagement in individuals with elevated depressive symptoms: Rationale, design, and baseline characteristics

Regular exercise protects against overweight/obesity as well as numerous chronic diseases. Yet, less than half of Americans exercise sufficiently. Elevated levels of depressive symptoms have been identified as an important correlate of physical inactivity as well as poor adherence to exercise programs. Individuals with depression are less sensitive to rewards and demonstrate an attentional bias toward negative stimuli. These, and other features of depression, may place them at increased risk for effectively managing the affective experience of exercise. Lower baseline levels of activation of the left (vs right) frontal cortex, an area implicated in affect regulation, have also been found in depression, potentially pointing to this region as a potential target for intervening on affect regulation during exercise. Transcranial direct current stimulation (tDCS) has shown promise in impacting a variety of cognitive and affective processes in a large number of individuals, including people with depression. Some findings have suggested that tDCS targeting the left dorsolateral prefrontal cortex (DLPFC), specifically, may improve emotion regulation. Transcranial direct current stimulation could theoretically be a novel and potentially promising approach to improving the affective experience of exercise, thereby increasing exercise adherence among individuals with depressive symptoms. Here we present the rationale, design, and baseline characteristics of a pilot randomized controlled trial of tDCS versus sham delivered 3x/week for 8 weeks in the context of supervised aerobic exercise (AE) program among 51 low-active individuals with elevated depressive symptoms (86.3% female; mean age = 49.5). Follow-up assessments were conducted at end of treatment, and three and six months after enrollment to examine changes in levels of objectively-measured moderate-to-vigorous physical activity (MVPA). If effective, this approach could have high public health impact on preventing obesity and chronic diseases among these at-risk individuals.

Beyond the target area: an integrative view of tDCS-induced motor cortex modulation in patients and athletes

Transcranial Direct Current Stimulation (tDCS) is a non-invasive technique used to modulate neural tissue. Neuromodulation apparently improves cognitive functions in several neurologic diseases treatment and sports performance. In this study, we present a comprehensive, integrative review of tDCS for motor rehabilitation and motor learning in healthy individuals, athletes and multiple neurologic and neuropsychiatric conditions. We also report on neuromodulation mechanisms, main applications, current knowledge including areas such as language, embodied cognition, functional and social aspects, and future directions. We present the use and perspectives of new developments in tDCS technology, namely high-definition tDCS (HD-tDCS) which promises to overcome one of the main tDCS limitation (i.e., low focality) and its application for neurological disease, pain relief, and motor learning/rehabilitation. Finally, we provided information regarding the Transcutaneous Spinal Direct Current Stimulation (tsDCS) in clinical applications, Cerebellar tDCS (ctDCS) and its influence on motor learning, and TMS combined with electroencephalography (EEG) as a tool to evaluate tDCS effects on brain function.

The Effect of Anodal Transcranial Direct Current Stimulation Over Left and Right Temporal Cortex on the Cardiovascular Response: A Comparative Study

Background: Stimulation of the right and left anterior insular cortex, increases and decreases the cardiovascular response respectively, thus indicating the brain’s lateralization of the neural control of circulation. Previous experiments have demonstrated that transcranial direct current stimulation (tDCS) modulates the autonomic cardiovascular control when applied over the temporal cortex. Given the importance of neural control for a normal hemodynamic response, and the potential for the use of tDCS in the treatment of cardiovascular diseases, this study investigated whether tDCS was capable of modulating autonomic regulation.

Methods: Cardiovascular response was monitored during a post-exercise muscle ischemia (PEMI) test, which is well-documented to increase sympathetic drive. A group of 12 healthy participants performed a PEMI test in a control (Control), sham (Sham) and two different experimental sessions where the anodal electrode was applied over the left temporal cortex and right temporal cortex with the cathodal electrode placed over the contralateral supraorbital area. Stimulation lasted 20 min at 2 mA. The hemodynamic profile was measured during a PEMI test. The cardiovascular parameters were continuously measured with a transthoracic bio-impedance device both during the PEMI test and during tDCS.

Results: None of the subjects presented any side effects during or after tDCS stimulation. A consistent cardiovascular response during PEMI test was observed in all conditions. Statistical analysis did not find any significant interaction and any significant main effect of condition on cardiovascular parameters (all ps > 0.316) after tDCS. No statistical differences regarding the hemodynamic responses were found between conditions and time during tDCS stimulation (p > 0.05).

Discussion: This is the first study comparing the cardiovascular response after tDCS stimulation of left and right TC both during exercise and at rest. The results of the current study suggest that anodal tDCS of the left and right TC does not affect functional cardiovascular response during exercise PEMI test and during tDCS. In light of the present and previous findings, the effect of tDCS on the cardiovascular response remains inconclusive.