Highlights
- •Anodal stimulation increases responsiveness of a neuron to a given synaptic input, while cathodal stimulation reduces responsiveness, albeit to a lesser degree.
- •A computational neuron model suggests that opposing polarization in soma and dendrite acts synergistically for anodal stimulation but cancel for cathodal stimulation due to a shift in spike generation to the dendrite.
Abstract
Background
Direct current stimulation (DCS) affects both neuronal firing rate and synaptic efficacy.
The neuronal input/output (I/O) function determines the likelihood that a neuron elicits
an action potential in response to synaptic input of a given strength. Changes of
the neuronal I/O function by DCS may underlie previous observations in animal models
and human testing, yet have not been directly assessed.
Objective
Test if the neuronal input/output function is affected by DCS
Methods
Using rat hippocampal brain slices and computational modeling, we provide evidence
for how DCS modulates the neuronal I/O function.
Results
We show for the first time that DCS modulates the likelihood of neuronal firing for
a given and fixed synaptic input. Opposing polarization of soma and dendrite may have
a synergistic effect for anodal stimulation, increasing the driving force of synaptic
activity while simultaneously increasing spiking probability at the soma. For cathodal
stimulation, however, the opposing effects tend to cancel. This results in an asymmetry
in the strength of the effects of stimulation for opposite polarities.
Conclusions
Our results may explain the asymmetries observed in acute and long term effects of
transcranial direct current stimulation.
Keywords
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Article info
Publication history
Published online: September 01, 2016
Accepted:
August 30,
2016
Received in revised form:
August 16,
2016
Received:
May 13,
2016
Footnotes
Funding: This work is supported by grants from the National Institutes of Health (R01MH092926), National Institutes of Health - National Institute of Biomedical Imaging and Bioengineering (R21-5R21EB017510-02), and DoD (UAF, #FA9550-13-1-0073).
Identification
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