Effects of taurine acute intake on cortical excitability and post-exercise facilitation: A TMS study.

Taurine (TAU) is one of the most abundant amino acids in the brain. It has many important physiological functions. The effects of TAU supplementation on brain function need to be further characterized in humans. The purpose of this study was to investigate whether a single dose of Taurine (TAU) intake would modulate corticospinal excitability and post-exercise facilitation (PEF) of the motor evoked potentials (MEP).

Exploring the effect of adaptogenic Rhodiola Rosea extract on neuroplasticity in humans.

OBJECTIVES: Rhodiola rosea extract is one of the most common herbal treatment for stress. Its mechanism of action in humans still need to be determined. We investigated the effect of a single dose intake of Rhodiola rosea extract on the plastic after-effects induced by anodal and cathodal motor cortex transcranial Direct Current Stimulation in humans. METHODS: Twenty-eight healthy volunteers were required to intake 500 mg of either RRE or placebo. Transcranial Magnetic Stimulation was used to investigate cortical excitability. Motor threshold, recruitment of motor-evoked potentials, cortical silent period, short-interval intracortical inhibition and intracortical facilitation were assessed at different time points. Spinal excitability and peripheral nerve conduction were measured by F-response and M-wave. Furthermore, we assessed the modulation of cortical plasticity using transcranial direct current stimulation after-effects on Motor Evoked Potentials amplitudes. RESULTS: Rhodiola rosea extract acute intake prevented cathodal transcranial Direct Current Stimulation-induced Long-term depression-like plasticity. The extract intake did not affect cortical excitability. CONCLUSIONS: Our findings suggest that a single oral dose of Rhodiola rosea extract intake modulates cortical plasticity in humans preventing the activity-dependent reduction in the efficacy of neuronal synapses. These results suggest that the adaptogenic and antidepressant effects of Rhodiola rosea extract might be based on its modulation of brain plasticity.

Hypericum perforatum extract modulates cortical plasticity in humans.

BACKGROUND: Hypericum perforatum (HYP) extract is one of the most commonly used complementary alternative medicines (CAMs) for the treatment of mild-to-moderate depression. Non-invasive brain stimulation protocols can be used to investigate the effect of psychoactive substances on the human brain. In this study, we explored the effect of a single dose of HYP extract (WS 5570) intake on corticospinal excitability and plasticity in humans. METHODS: Twenty-eight healthy subjects were required to intake 900 mg of either HYP extract or placebo. Cortical excitability was assessed using single and paired transcranial magnetic stimulation (TMS). The electrophysiological parameters of motor threshold, recruitment of motor-evoked potentials (MEPs), cortical silent period (CSP), short interval intracortical inhibition (SICI), and intracortical facilitation (ICF) were tested before and 2 and 5 h after the oral intake. Spinal and neuromuscular excitability and peripheral nerve excitability were measured by F response and M-wave. Cortical plasticity was induced using transcranial direct current stimulation (tDCS). Subjects received either HYP extract or placebo before anodal and cathodal tDCS of the primary motor cortex. Plasticity was assessed by MEP amplitudes. RESULTS: HYP extract reversed cathodal tDCS-induced long-term depression (LTD)-like plasticity into facilitation, as compared to placebo. HYP extract did not have a significant effect on anodal tDCS-induced plasticity and TMS measures of motor cortex and spinal/neuromuscular excitability. CONCLUSIONS: Our findings suggest that a single oral dose of HYP extract modulates cortical plasticity in healthy subjects and provide new insight into its possible mechanism of action in humans.

Valeriana officinalis Root Extract Modulates Cortical Excitatory Circuits in Humans.

BACKGROUND: Valeriana officinalis extract (VE) is a popular herbal medicine used for the treatment of anxiety and sleep disorders. Although the anxiolytic and sedative effects are mainly attributed to the modulation of GABA-ergic transmission, the mechanism of action has not been fully investigated in humans. Noninvasive brain stimulation protocols can be used to elucidate the mechanisms of action of psychoactive substances at the cortical level in humans. In this study, we investigated the effects of a single dose of VE on cortical excitability as assessed with transcranial magnetic stimulation (TMS). METHODS: Fifteen healthy volunteers participated in a double-blind, randomized, cross-over, placebo-controlled study. Subjects were required to take either 900 mg of VE (valerenic acid 0.8%) or placebo (an equal dose of vitamin E). Motor cortex excitability was studied by single and paired TMS before and at 1 h and 6 h after the oral administration. Cortical excitability was assessed using different TMS parameters: resting motor threshold, motor-evoked potential amplitude, cortical silent period, short-interval intracortical inhibition, and intracortical facilitation. Furthermore, we assessed sensorimotor integration by short-latency and long-latency afferent inhibition. RESULTS: We found a significant reduction in ICF, without any significant changes in other TMS measures of motor cortex excitability. The amount of ICF returned to baseline value 6 h after the intake of the VE. CONCLUSION: A single oral dose of VE modulates intracortical facilitatory circuits. Our results in healthy subjects could be predictive markers of treatment response in patients and further support the use of pharmaco-TMS to investigate the neuropsychiatric effects of herbal therapies in humans.

Acute effects of self-myofascial release and stretching in overhead athletes with GIRD.

OBJECTIVE: To examine the acute effects of self-myofascial release (SMR), static stretching (SS), and the combination of self-myofascial release and static stretching (SMR + SS) on glenohumeral internal rotation range of motion (GH IR ROM) in overhead athletes with glenohumeral internal rotation deficit (GIRD). PARTICIPANTS: Twelve asymptomatic adult male amateur softball position players exhibiting GIRD. RESULTS: All three methods significantly improved GH IR ROM. Post hoc testing revealed that SS alone and SMR + SS improved GH IR ROM significantly more than SMR alone. However, there were no significant differences in GH IR ROM between SS alone and SMR + SS. CONCLUSIONS: If an athlete has a limited time to perform a warm-up (e.g., 3-4 min), SS alone is recommended to improve GH IR ROM. However, if the athlete has more time available to warm up (e.g., 7-8 min), combining SMR + SS may result in a greater increase in GH IR ROM.

Perceived Stress and Coffee and Energy Drink Consumption Predict Poor Sleep Quality in Podiatric Medical Students A Cross-sectional Study.

BACKGROUND: A cross-sectional survey administered to first- and second-year podiatric medical students aimed to investigate the effect of coffee intake, energy drink consumption, and perceived stress on sleep quality in medical students during their preclinical studies. METHODS: Ninety-eight of 183 students contacted (53.6%) completed a questionnaire comprising standard instruments measuring sleep quality (Pittsburgh Sleep Quality Index), daytime sleepiness (Epworth Sleepiness scale), and perceived stress (ten-item Perceived Stress Scale). Furthermore, we investigated coffee and energy drink consumption. Logistic regression was conducted to identify factors associated with poor sleep quality and the relation between sleep quality and academic performance (grade point average). RESULTS: High prevalences of poor sleep quality, excessive daytime sleepiness, and perceived stress were reported. In addition, higher odds of developing poor sleep quality were associated with coffee and energy drink intake, perceived stress, and excessive daytime sleepiness. The total Pittsburgh Sleep Quality Index score was inversely correlated with grade point average. CONCLUSIONS: First- and second-year podiatric medical students have poor sleep quality. Further research is needed to identify effective strategies to reduce stress and decrease coffee and energy drink intake to minimize their negative effect on sleep quality and academic performance in podiatric medical students.

n-3 fatty acids prevent impairment of neurogenesis and synaptic plasticity in B-cell activating factor (BAFF) transgenic mice.

OBJECTIVE: Autoimmune-prone B-cell activating factor transgenic mice, a mouse model of systemic lupus erythematosus and Sjögren's syndrome exhibit neuroinflammation, anxiety-like phenotype, deficit in adult hippocampal neurogenesis and impaired neurogenesis-dependent and neurogenesis-independent dentate gyrus long-term potentiation. Given that n-3 polyunsaturated fatty acids regulate hippocampal plasticity and inflammatory responses, we investigated whether n-3 polyunsaturated fatty acids-enriched diet might prevent age-dependent hippocampal changes in B-cell activating factor transgenic mice. METHODS: B-cell activating factor transgenic mice were fed for 12 weeks with either n-3 polyunsaturated fatty acids-enriched or control diet and we tested the effect of this dietary supplementation on hippocampal inflammation, progenitor cell proliferation and neurogenesis-dependent and neurogenesis-independent long-term potentiation. RESULTS: Dietary supplementation with n-3 polyunsaturated fatty acids significantly decreased hippocampal microglial activation and increased the density of bromodeoxyuridine and doublecortin-positive newly-formed cells in the subventricular zone of hippocampus. Furthermore, B-cell activating factor transgenic mice fed with n-3 polyunsaturated fatty acids-enriched diet displayed normal long-term potentiation at the medial perforant pathway/dentate gyrus connections. CONCLUSIONS: The results indicate that n-3 fatty acids prevent neuroinflammation and deficits of hippocampal plasticity in B-cell activating factor transgenic mice and suggest that increased n-3 fatty acids intake might represent a potential therapeutic option to prevent neuropsychiatric symptoms associated with autoimmune diseases.

Corticomotor Excitability during Observation and Imagination of a Work of Art.

We examine the effects of the artistic representation - here exemplified by Michelangelo's Expulsion from Paradise - of an action on the motor system. Using single and paired- pulse transcranial magnetic stimulation we analyze corticomotor excitability during observation of an action in the painting, during imagery of the painting, and during observation of a photograph of the same pose. We also analyze the effects of observation of two further paintings, one showing the same muscles at rest, and in the other in a more overtly emotional context. Both observation of the Expulsion and of imagery of the painting increased cortical excitability. Neither the relaxed pose of Michelangelo's Creation nor the flexed posture in the highly emotional context of Bellini's Dead Christ increased cortical excitability. Observation of a photograph of the same extended pose did not increase cortical excitability either. Moreover, intracortical inhibition was reduced during imagery of the painting. Our results offer clear motor correlates of the relationship between the esthetic quality of a work and the perception of implied movement within it.

Hypericum perforatum treatment: effect on behaviour and neurogenesis in a chronic stress model in mice.

BACKGROUND: Extracts of Hypericum perforatum (St. John's wort) have been traditionally recommended for a wide range of medical conditions, in particular mild-to-moderate depression. The present study was designed to investigate the effect of Hypericum perforatum treatment in a mouse model of anxiety/depressive-like behavior, induced by chronic corticosterone administration. METHODS: CD1 mice were submitted to 7 weeks corticosterone administration and then behavioral tests as Open Field (OF), Novelty-Suppressed Feeding (NSF), Forced Swim Test (FST) were performed. Cell proliferation in hippocampal dentate gyrus (DG) was investigated by both 5-bromo-2'-deoxyuridine (BrdU) and doublecortin (DCX) immunohistochemistry techniques and stereological procedure was used to quantify labeled cells. Golgi-impregnation method was used to evaluate changes in dendritic spines in DG. Hypericum perforatum (30 mg/Kg) has been administered for 3 weeks and then neural development in the adult hippocampus and behavioral changes have been examined. RESULTS: The anxiety/depressive-like state due to chronic corticosterone treatment was reversed by exogenous administration of Hypericum perforatum; the proliferation of progenitor cells in mice hippocampus was significantly reduced under chronic corticosterone treatment, whereas a long term treatment with Hypericum perforatum prevented the corticosterone-induced decrease in hippocampal cell proliferation. Corticosterone-treated mice exhibited a reduced spine density that was ameliorated by Hypericum perforatum administration. CONCLUSION: These results provide evidence of morphological adaptations occurring in mature hippocampal neurons that might underlie resilient responses to chronic stress and contribute to the therapeutic effects of chronic Hypericum perforatum treatment.

Transcranial direct current stimulation for major depression: a general system for quantifying transcranial electrotherapy dosage.

There has been a recent resurgence of interest in therapeutic modalities using transcranial weak electrical stimulation through scalp electrodes, such as trans-cranial direct current stimulation (tDCS), as a means of experimentally modifying and studying brain function and possibly treating psychiatric conditions. A range of electrotherapy paradigms have been investigated, but no consistent method has been indicated for reporting reproducible stimulation "dosage." Anecdotal reports, case studies, and limited clinical trials with small numbers suggest that tDCS may be effective in treating some patients with depression, but methods for selecting the optimal stimulation parameters ("dosage") are not clear, and there is no conclusive indication that tDCS is an effective treatment for depression. Larger, controlled studies are necessary to determine its safety and efficacy in a clinical setting. If tDCS can be established as an effective treatment for depression, it would represent a particularly attractive electrotherapy option, as it is a relatively benign and affordable treatment modality. An accurate system for describing reproducible treatment parameters is essential so that further studies can yield evidence-based guidelines for the clinical use of transcranial current stimulation. Development of appropriate parameters requires a biophysical understanding of how electrotherapy affects brain function and should include different paradigms for different clinical applications. As with any dosage guidelines, such a system does not supersede physician judgment on safety.

Long lasting effects of transcranial direct current stimulation on motor imagery.

Transcranial magnetic stimulation (TMS) was employed to probe the modulatory effects of transcranial direct current stimulation of motor cortex on motor evoked responses (MEPs) produced during motor imagery. MEP amplitudes at rest and during motor imagery were assessed before and for a period of 60 min after transcranial direct current stimulation (tDCS) applied over the primary motor cortex at 1 mA for 5 min. Cathodal stimulation induced a decrease of about 30% of MEP amplitude at rest and a 50% reduction of MEP size during imagery. Ten minutes after tDCS, MEPs at rest returned to baseline values while MEPs during motor imagery were suppressed for up to 30 min. No changes in MEP amplitude during imagery were found after anodal stimulation. tDCS could represent a powerful tool to modulate the excitability of motor areas involved in mental practice and motor imagery.