Effects of direct current stimulation on synaptic plasticity in a single neuron

Area of Science:

• Neuroscience
• Neurophysiology
• Computational Neuroscience

Background:

• Transcranial direct current stimulation (DCS) is known to induce lasting effects.
• These effects are potentially mediated by enhanced synaptic long-term potentiation (LTP).

Purpose of the Study:

• To investigate if DCS-induced LTP enhancement stems from direct modulation of postsynaptic somatic spiking.
• To differentiate between direct neuronal effects and indirect network effects of DCS on LTP.

Main Methods:

• In-vitro patch-clamp recordings of CA1 pyramidal neurons in rodents.
• Induction of LTP using theta-burst stimulation (TBS) concurrent with DCS.
• Manipulation of somatic polarization via current injections and computational modeling.

Main Results:

• Anodal DCS and depolarizing current injections enhanced TBS-induced LTP.
• Increased somatic spiking in postsynaptic neurons correlated with LTP enhancement.
• DCS effects were partially explained by increased spiking, but network activity also played a role.

Conclusions:

• DCS enhances synaptic plasticity primarily by increasing postsynaptic somatic spiking.
• Network activity modulated by DCS can both enhance and limit LTP potentiation.