SingleIhChannels in Pyramidal Neuron Dendrites: Properties, Distribution, and Impact on Action Potential Output

• DOI: 10.1523/jneurosci.3664-05.2006
• Publication Date: 2006-02-08T21:27:56Z
• Authors: Maarten H. P. Kole; Stefan Hallermann; Greg J. Stuart
• Keywords: HCN channel; Hyperpolarization

The hyperpolarization-activated cation current ( I h ) plays an important role in regulating neuronal excitability, yet its native single-channel properties the brain are essentially unknown. Here we use variance-mean analysis to study of single channels apical dendrites cortical layer 5 pyramidal neurons vitro . In these neurons, find that have average unitary conductance 680 ± 30 fS n = 18). Spectral simulated and showed there is little or no channel flicker below kHz. contrast uniformly distributed conductance, number increases exponentially with distance, reaching densities as high ∼550 channels/μm 2 at distal dendritic sites. These generate significant membrane voltage noise. By incorporating a stochastic model gating into morphologically realistic neuron, show this noise higher compartments increased threefold 10-fold (6.8 pS) but constant density. addition, demonstrate fluctuations attributable impact on action potential output, greater spike-timing precision models experimentally determined conductance. data suggest that, face densities, small critical for maintaining fidelity output.