Activation response and functional connectivity change in rat cortex after bilateral transcranial direct current...

Area of Science:

• Neuroscience
• Medical Engineering
• Brain Stimulation

Background:

• Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation technique.
• Bilateral tDCS may offer enhanced motor learning benefits compared to unilateral stimulation.
• Investigating tDCS effects on brain networks requires simultaneous monitoring techniques.

Purpose of the Study:

• To develop an experimental model for simultaneous magnetic resonance imaging (MRI) and bilateral tDCS in rats.
• To measure the immediate and resultant effects of bilateral tDCS on brain network activity and connectivity.
• To explore the potential of bilateral tDCS as an adjunct therapy for motor function improvement.

Main Methods:

• Developed an MRI-compatible setup for concurrent bilateral tDCS in Sprague-Dawley rats.
• Acquired functional MRI (fMRI) during stimulation and resting-state fMRI and perfusion MRI before and after stimulation.
• Compared a tDCS group (n=7) with a sham stimulation group (n=6).

Main Results:

• Bilateral tDCS induced a hemodynamic activation response with increased blood oxygenation level-dependent signal in cortical areas, including sensorimotor regions.
• Resting-state functional connectivity within the sensorimotor network showed dynamic changes across multiple stimulation sessions.
• No significant alterations in cerebral blood flow were detected via perfusion MRI post-tDCS.

Conclusions:

• Successfully demonstrated an MRI-compatible bilateral tDCS system in an animal model.
• Bilateral tDCS can acutely modulate local neuronal activity and functional connectivity.
• These findings support the potential therapeutic applications of bilateral tDCS in neurological disorders affecting motor function.