Brain transcranial direct current stimulation modulates motor excitability in mice

Area of Science:

• Neuroscience
• Neurophysiology
• Brain Stimulation

Background:

• Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique.
• Previous studies in humans show tDCS alters corticospinal excitability.
• Anodal tDCS typically enhances motor-evoked potentials (MEPs), while cathodal tDCS reduces them.

Purpose of the Study:

• To investigate the effects of anodal and cathodal tDCS on motor cortex excitability in mice.
• To compare tDCS effects in mice with existing human findings.
• To assess the feasibility of using tDCS in mouse models for neurological diseases.

Main Methods:

• 12 C57BL/6 mice were anesthetized with sevoflurane.
• Motor-evoked potentials (MEPs) were recorded from forelimbs.
• Anodal and cathodal tDCS (10-minute duration) were applied, with MEPs recorded before and after stimulation (0, 5, 10 min).
• Sham stimulation served as a control.

Main Results:

• Immediately after anodal tDCS, MEP size significantly increased compared to sham.
• Cathodal tDCS significantly reduced MEP size by approximately 20% compared to sham.
• These tDCS-induced changes returned to baseline levels within 10 minutes.
• The direction of tDCS effects on MEPs in mice was consistent with human studies.

Conclusions:

• tDCS can modulate corticospinal excitability in mice in a polarity-dependent manner.
• The findings support the consistency of tDCS effects across species.
• tDCS is a feasible technique for animal models, potentially aiding research into brain polarization therapies for neurological disorders.