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Project

Noninvasive neuromodulation: Animal models to understand basic neural mechanisms

Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation method in which DC current is passed through scalp electrodes with the aim of altering brain activity. The current passes through the scalp, skull, and cerebrospinal fluid (CSF), before a small fraction reaches the brain. The recent surge in interest, combined with tDCS noninvasive nature and low-cost, mean that a wide range of potential clinical applications are under investigation: tDCS is currently under investigation as a treatment for addiction, depression, schizophrenia and cognitive decline. However, in spite of these significant resources the neurophysiological mechanism underpinning the observed tDCS effects is currently very poorly understood. Additionally, and perhaps because of this lack of mechanistic understanding, there is contentious debate within the field about tDCS effectiveness and reproducibility. That said, there is a now growing consensus that the most reliable and reproducible tDCS effects are on motor learning, mediated by tDCS boosting synaptic plasticity. Although it must also be stressed that very similar improvements in motor learning can be achieved via other general mechanisms that boost synaptic plasticity - such as exercise or noradrenaline (i.e. norepinephrine) released by the sympathetic nervous system. Understanding the transcranial alternating current stimulation (tACS) mechanisms has advanced that field. We have recently shown, using a series of animal and human experiments, that tACS motor system effects  can be caused by transcutaneous stimulation of peripheral nerves in the scalp. Our results, together with those of others, question the effectiveness of the weak electric field in the brain. Understanding the tDCS will do the same Given the wide-ranging effects of tDCS in humans, it appears unlikely that just one mechanisms can account for all these effects. Just as with tACS, evidence suggests that tDCS effects may are also mediated by a range of different transcranial and potentially transcutaneous mechanisms. However, we are currently not aware of any published research that directly attempts to dissect and understand the relative roles of these mechanisms. In this project we propose a series of innovative animal and human experiments that will provide a clearer, improved, understanding of the tDCS mechanisms.

Date:28 Jan 2021 →  Today
Keywords:neuromodulation, tDCS, Mechanism, rat
Disciplines:Cognitive neuroscience
Project type:PhD project