Skip to main content

Effects of polarization induced by non-weak electric fields on the excitability of elongated neurons with active dendrites


An externally-applied electric field can polarize a neuron, especially a neuron with elongated dendrites, and thus modify its excitability. Here we use a computational model to examine, predict, and explain these effects. We use a two-compartment Pinsky-Rinzel model neuron polarized by an electric potential difference imposed between its compartments, and we apply an injected ramp current. We vary three model parameters: the magnitude of the applied potential difference, the extracellular potassium concentration, and the rate of current injection. A study of the Time-To-First-Spike (TTFS) as a function of polarization leads to the identification of three regions of polarization strength that have different effects. In the weak region, the TTFS increases linearly with polarization. In the intermediate region, the TTFS increases either sub- or super-linearly, depending on the current injection rate and the extracellular potassium concentration. In the strong region, the TTFS decreases. Our results in the weak and strong region are consistent with experimental observations, and in the intermediate region, we predict novel effects that depend on experimentally-accessible parameters. We find that active channels in the dendrite play a key role in these effects. Our qualitative results were found to be robust over a wide range of inter-compartment conductances and the ratio of somatic to dendritic membrane areas. In addition, we discuss preliminary results where synaptic inputs replace the ramp injection protocol. The insights and conclusions were found to extend from our polarized PR model to a polarized PR model with I h dendritic currents. Finally, we discuss the degree to which our results may be generalized.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16
Fig. 17
Fig. 18
Fig. 19
Fig. 20
Fig. 21


  1. Traub et al. (1991) presents an abstract model of intracellular calcium where each compartment’s rate of absorption can be varied by varying the thickness of an imagined sub-cellular membrane. This coefficient was fine-tuned to best match experimental data.

  2. R 2≡ 1- (sum square of residuals)/ (sum square of differences of the dependent variable from the mean).

  3. The rate of change of the somatic and dendritic membrane potentials are appreciably different only in a 1-2 millisecond period after the TTFS and during an action potential.


Download references


We wish to thank the reviewers for their careful review and insightful suggestions.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Robert I. Reznik.

Ethics declarations

Conflict of interests

The authors declare that they have no conflict of interest.

Additional information

Action Editor: Gaute T. Einevoll

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Reznik, R.I., Barreto, E., Sander, E. et al. Effects of polarization induced by non-weak electric fields on the excitability of elongated neurons with active dendrites. J Comput Neurosci 40, 27–50 (2016).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • Electric fields
  • Excitability
  • Hippocampus
  • Pyramidal neurons