In voltage-clamp experiments, incomplete space clamp distorts the recorded currents, rendering accurate analysis impossible. Here, we present a simple numerical algorithm that corrects such distortions. The method enabled accurate retrieval of the local densities, kinetics, and density gradients of somatic and dendritic channels. The correction method was applied to two-electrode voltage-clamp recordings of K currents from the apical dendrite of layer 5 neocortical pyramidal neurons. The generality and robustness of the algorithm make it a useful tool for voltage-clamp analysis of voltage-gated currents in structures of any morphology that is amenable to the voltage-clamp technique.
Model Type: Neuron or other electrically excitable cell
Cell Type(s): Neocortex M1 L5B pyramidal pyramidal tract GLU cell
Currents: I K; I K,leak; I M; I Potassium
Model Concept(s): Parameter Fitting; Influence of Dendritic Geometry; Detailed Neuronal Models
Simulation Environment: NEURON
Implementer(s): Schaefer, Andreas T [andreas.schaefer at crick.ac.uk]
References:
Schaefer AT, Helmstaedter M, Sakmann B, Korngreen A. (2003). Correction of conductance measurements in non-space-clamped structures: 1. Voltage-gated K+ channels. Biophysical journal. 84 [PubMed]
Schaefer AT et al. (2007). Dendritic voltage-gated K+ conductance gradient in pyramidal neurones of neocortical layer 5B from rats. The Journal of physiology. 579 [PubMed]