Impact of the activation rate of the hyperpolarization- activated current on the neuronal membrane time constant and synaptic potential duration
Vollum Institute, Oregon Health & Science University, Portland, OR, USA
2 Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, New Jersey, NJ, USA
3 Department of Physics, School of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
Accepted: 7 May 2021
Published online: 11 June 2021
The temporal dynamics of membrane voltage changes in neurons is controlled by ionic currents. These currents are characterized by two main properties: conductance and kinetics. The hyperpolarization-activated current () strongly modulates subthreshold potential changes by shortening the excitatory postsynaptic potentials and decreasing their temporal summation. Whereas the shortening of the synaptic potentials caused by the conductance is well understood, the role of the kinetics remains unclear. Here, we use a model of the current model with either fast or slow kinetics to determine its influence on the membrane time constant ( of a CA1 pyramidal cell model. Our simulation results show that the with fast kinetics decreases and attenuates and shortens the excitatory postsynaptic potentials more than the slow . We conclude that the activation kinetics is able to modulate and the temporal properties of excitatory postsynaptic potentials (EPSPs) in CA1 pyramidal cells. To elucidate the mechanisms by which kinetics controls , we propose a new concept called “time scaling factor”. Our main finding is that the kinetics influences by modulating the contribution of the derivative conductance to .
© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2021