The membrane time constant ($\tau_{RC}$ or $\tau_m$) is the product of the membrane's resistance and capacitance, which makes it proportional to the surface area. This page gives values for the time constant.

Summary

• Most neurons: 20 ms

Details

Primary Sources

• Geiger, J. R. P., Lübke, J., Roth, A., Frotscher, M., and Jonas, P. (1997). Submillisecond AMPA receptor-mediated signaling at a principal neuron-interneuron synapse. Neuron, 18, 1009-1023.
  • BC: $\tau_m$ = 8.4 $\pm$ 0.7 ms (range 6.7-10.6; n = 5)
• Isokawa, M. (1997). Membrane time constant as a tool to assess cell degeneration. Brain Research Protocols. 1(2), 114-116. doi:10.1016/S1385-299X(96)00016-5
  • Also notes that membrane time constant is related to neuron size
  • $\tau_m$ = 21.2 ms
• Jonas, P., Major, G., and Sakmann, B. (1993). Quantal components of unitary EPSCs at the mossy fibre synapse on CA3 pyramidal cells of rat hippocampus. J. Physiol. (London), 472, 615-663.
  • Capacitance of 0.683 $\mu$F cm$^2$; resistance of 164 k$\Omega$
  • $\tau_m$ = 112 ms
• McCormick, D.A., Connors, B.W., Lighthall, J.W., and Prince, D.A. (1985). Comparative electrophysiology of pyramidal and sparsely spiny stellate neurons of the neocortex. J. Neurophysiol. 54: 782-806.
  • Neocortical neurons:
    • Regular spiking: $\tau_m$ = 20.2 $\pm$ 14.6 (n = 12)
    • Bursting: $\tau_m$ = 16.6 $\pm$ 5.9 (n = 9)
    • Fast spiking: $\tau_m$ = 11.9 $\pm$ 6.5 (n = 15)
• Miles, R. (1990). Synaptic excitation of inhibitory cells by single CA3 hippocampal pyramidal cells of the guinea-pig in vitro. J. Physiol. 428: 61-77.
  • CA3 IN: $\tau_m$ = 9.2 $\pm$ 3.2 ms (n = 12)

Secondary Sources

• Carter, A. G., and Regehr, W. G. (2002). Quantal events shape cerebellar interneuron firing. Nature Neurosci., 5, 1309-1318.
• Bartos, M., Vida, I., Frotscher, M., Geiger, J. R. P., and Jonas, P. (2001). Rapid signaling at inhibitory synapses in a dentate gyrus interneuron network. J. Neurosci., 21(8), 2687-2698.

Potential Sources

• Dendritic attenuation of synaptic potentials and currents: the role of passive membrane properties.
• Plenz, D., and Kitai, S. (1998). Up and Down States in Striatal Medium Spiny Neurons Simultaneously Recorded with Spontaneous Activity in Fast-Spiking Interneurons Studied in Cortex-Striatum-Substantia Nigra. Journal of Neuroscience, 18(1):266-283.