Slide 2

Electric fields influence the membrane potential of cylinders, such as neurons with elongated dendrites.

Figure 2. Uniform extracellular field causes polarization of neurons that are aligned with the direction of the electric field. We here used a simplified model (uniform cable) to demonstrate the effect of an applied uniform electric field on a neuron. The cable was portioned into individual segments to allow for a numerical solution of the cable equation. Transmembrane voltage Vm (green) is defined as the difference between the intracellular and extracellular voltage. The applied electric field defines the extracellular voltage Ve (blue). As a result of the applied field, ionic charge within the cable rearranges which results in a potential gradient Vi within the cable/neuron (red). The overall effect is a depolarization of the cable end that corresponds to the soma and a hyperpolarization of the cable end that corresponds to the distal end of the apical dendrites. B. Membrane voltage traces for three cable lengths as a function of time (shown for 10 compartments that span the cable).