Non-invasive brain stimulation and the autonomic nervous system

The effect of transcranial direct current stimulation of the motor cortex on exercise-induced pain

“…However, the analgesic effect observed in our study is unlikely to be caused by a reduction of activity in the somatosensory cortex, but rather through an alteration of the cold signaling pathway in the thalamus or insular cortex following anodal stimulation of the motor cortex (Zandieh et al 2013). Indeed, investigations on animal models indicate an anatomical connection between the motor cortex with insula and thalamus (Schestatsky et al 2013;Stepniewska et al 1994), and so the effect of tDCS may be extended to other brain regions distant from the targeted area (i.e., spatial effect) as previously hypothesized by Zandieh et al (2013). Therefore, the tDCS-induced analgesia demonstrated in the current study could be due to an inhibition of the nociceptive center at the ventroposterior and medial thalamic nuclei via corticothalamic pathway, which would have a greater antinociceptive action for thermal pain signaling (Stepniewska et al 1994;Zandieh et al 2013).…”

“…Although not assessed in the current study, it is generally accepted that sensitivity to somatosensory inputs is reduced after cathodal tDCS administration to the motor and somatosensory cortex, probably because of the alteration of the resting membrane potential in the targeted area Schestatsky et al 2013). However, the analgesic effect observed in our study is unlikely to be caused by a reduction of activity in the somatosensory cortex, but rather through an alteration of the cold signaling pathway in the thalamus or insular cortex following anodal stimulation of the motor cortex (Zandieh et al 2013).…”

Cytokines plasma levels during antidepressant treatment with sertraline and transcranial direct current stimulation (tDCS): results from a factorial, randomized, controlled trial

“…Nonetheless, the effects of rTMS and tDCS on the HPA and SAM axes, which are directly linked to the neuroimmunological response, have been evaluated in healthy volunteers and neuropsychiatric disorders. On this matter, two recent reviews (Sampaio et al 2012; Schestatsky et al 2013) found mixed evidence regarding possible neuromodulatory effects on these systems, with positive results obtained from studies generally employing designs in which participants were submitted to physiological or psychological stress (e.g., (Brunoni et al 2013c)). Using data from SELECT-TDCS, we observed that tDCS-only and combined with sertraline did not modulate heart rate variability, a marker of sympathetic/parasympathetic activity, throughout the trial (Brunoni et al 2013a) and also, that these therapies had no specific antidepressant effects on vegetative symptoms (Brunoni et al, in press), as similarly observed in another tDCS trial (Alonzo et al 2013).…”

Nonlinear effects of respiration on the crosstalk between cardiovascular and cerebrovascular control systems

“…HR variability measures indicated that rTMS produced significantly greater reduction than serotonergic agents (taken by a second group of 25 patients) in the sympathetic/parasympathetic ratio, suggesting improvement in sympathovagal balance [124]. However, a recent review on the topic failed to demonstrate conclusive evidences that rTMS might impact on autonomic function at a clinically useful degree [125]. This might be due to several, non-mutually exclusive factors: the heterogeneity of stimulation parameters (cortical target, frequency intensity and duration of stimulation), and patients' characteristics and design of the studies not including a systematic evaluation of cardiovascular variables among their primary or secondary aims.…”

“…Despite this promising scenario and modelling work suggesting its feasibility in humans, just a handful of studies have investigated the application of tDCS for the modulation of cardiovascular human functions [125], with current literature showing very conflicting results [143,144]. Most of the studies involved the delivery of tDCS using a classic bipolar, cephalic electrode montage (i.e.…”