Anodal tDCS Over the Left Prefrontal Cortex Does Not Cause Clinically Significant Changes in Circulating Metabolites.

BACKGROUND: Transcranial direct current stimulation (tDCS), a putative treatment for depression, has been proposed to affect peripheral metabolism. Metabolic products from brain tissue may also cross the blood-brain barrier, reflecting the conditions in the brain. However, there are no previous data regarding the effect of tDCS on circulating metabolites. OBJECTIVE: To determine whether five daily sessions of tDCS modulate peripheral metabolites in healthy adult men. METHODS: This double-blind, randomized controlled trial involved 79 healthy males (aged 20-40 years) divided into two groups, one receiving tDCS (2 mA) and the other sham stimulated. The anode was placed over the left dorsolateral prefrontal cortex and the cathode over the corresponding contralateral area. Venous blood samples were obtained before and after the first stimulation session, and after the fifth stimulation session. Serum levels of 102 metabolites were determined by mass spectrometry. The results were analysed with generalised estimating equations corrected for the family-wise error rate. In addition, we performed power calculations estimating sample sizes necessary for future research. RESULTS: TDCS-related variation in serum metabolite levels was extremely small and statistically non-significant. Power calculations indicated that for the observed variation to be deemed significant, samples sizes of up to 11,000 subjects per group would be required, depending on the metabolite of interest. CONCLUSION: Our study found that five sessions of tDCS induced no major effects on peripheral metabolites among healthy men. These observations support the view of tDCS as a safe treatment that does not induce significant changes in the measured peripheral metabolites in healthy male subjects.

[Methods of brain stimulation based on weak electric current--future tool for the clinician?]. / Heikkoon sähkövirtaan perustuvat aivojen stimulaatiomenetelmät--tulevaisuuden kliinikon työkalu?

Methods of brain stimulation based on a weak electric current are non-invasive neuromodulation techniques. They include transcranial direct current, alternating current and random noise stimulation. These methods modify the membrane potential of neurons without triggering the action potential, and have been successfully utilized to influence cognition and regulation of emotions in healthy experimental subjects. In clinical studies, indications of the efficacy of these techniques have been obtained in the treatment of depression, schizophrenia, memory disorders and pain as well as in stroke rehabilitation. It is hoped that these techniques will become established as part of the care and rehabilitation of psychiatric and neurologic patients in the future.

Effect of transcranial direct current stimulation on semantic discrimination eyeblink conditioning.

BACKGROUND: Transcranial direct current stimulation (tDCS) is a neuromodulation method that has been used to modulate learning. We tested whether anodal tDCS targeted at the left DLPFC could enhance learning in a semantic variant of discrimination eyeblink conditioning, i.e., whether the stimulation would have a specific effect on the discrimination ability, rate of acquisition, amplitude of the conditioned response (CR), or all of these. METHODS: Immediately prior to the eyeblink conditioning, the participants received either active stimulation of 1 mA for 10 min or sham stimulation. The anode was placed over F3 and the cathode over the right supraorbital area. The conditioned stimuli (CSs) were common Finnish male and female names that were presented as text. Male names were reinforced with an unconditioned stimulus. RESULTS: Stimulation had no effect on the learning rate or discrimination ratio, but the stimulated participants showed steeper CR acquisition in the initial phase of the experiment. Nevertheless, the participants in the stimulation group showed greater eyeblink CRs to the non-reinforced CS. DISCUSSION: Contrary to our initial hypothesis, the magnitude and rate of CRs to non-reinforced CS was higher in the active stimulation group than in the sham stimulation group, which may suggest deterioration of discrimination and contingency awareness in the used task. Our observations may suggest a lack of effect on the participants' ability to discriminate between two different types of CS. Furthermore, cathodal modulation of the right prefrontal cortex may explain the change in magnitude and rate of CRs to non-reinforced CS.

Effect of statin use on outcome of symptomatic cholelithiasis: a case-control study.

BACKGROUND: Statins can modify bile cholesterol and, thus, the formation of gallstones. We examined whether statin use also modifies the severity of symptomatic gallstone disease and its treatment. METHODS: A total of 1,140 consecutive patients with symptomatic gallstone disease were recruited during 2008-2010 at Kuopio university hospital, Finland. Case-control analysis matched the patients using (n = 272) or not using (n = 272) statins by age and sex. The baseline characteristics of the patients, need and type of surgical treatment, duration of operation, perioperative bleeding, postoperative complications and overall mortality rate were compared statistically between the study groups. RESULTS: Morbidity and subsequent polypharmacy occurred more frequently among the patients with statins compared to the patients without statins. There were no significant differences between the statin users and non-users regarding surgical treatment (open vs. laparoscopic cholecystectomy). The mean operation time for laparoscopic cholecystectomy was 10% shorter for the patients with statin use than for the patients without. In addition, there was a non-significant tendency for statin users to bleed less during laparoscopic operations than the non-users. There were no differences in other procedure-related parameters (e.g., operation urgency, conversions, choledochotomies, complications and mortality) in patients with or without statins. CONCLUSIONS: Compared to no treatment, statin treatment was associated with a shorter operation time for laparoscopy cholecystectomy. Other surgical outcome parameters were similar in patients with or without statins, although statin users had more polypharmacy and circulatory illnesses than non-users.