Neurophysiology: Hodgkin and Huxley model — still standing?

Arising from: B. Naundorf, F. Wolf & M. Volgushev 440, 1060–1063 (2006); Naundorf et al. replyAction potentials in cortical neurons show a variable threshold and a sudden rise in membrane potential at initiation. Naundorf et al. fail to explain these features using single- or double-compartment Hodgkin–Huxley-style models, suggesting instead that they could arise from cooperative opening of Na+ channels, although there is no direct biological evidence to support this. Here we show that these so-called unique features are to be expected from Hodgkin–Huxley models if the spatial geometry and spike initiation properties of cortical neurons are taken into account — it is therefore unnecessary to invoke exotic channel-gating properties as an explanation.

[1]  J. Eccles,et al.  The generation of impulses in motoneurones , 1957, The Journal of physiology.

[2]  D. Johnston,et al.  Axonal Action-Potential Initiation and Na+ Channel Densities in the Soma and Axon Initial Segment of Subicular Pyramidal Neurons , 1996, The Journal of Neuroscience.

[3]  T. Sejnowski,et al.  [Letters to nature] , 1996, Nature.

[4]  B. Sakmann,et al.  Action potential initiation and propagation in rat neocortical pyramidal neurons , 1997, The Journal of physiology.

[5]  A. Destexhe,et al.  Impact of spontaneous synaptic activity on the resting properties of cat neocortical pyramidal neurons In vivo. , 1998, Journal of neurophysiology.

[6]  M. Komada,et al.  βIV-spectrin regulates sodium channel clustering through ankyrin-G at axon initial segments and nodes of Ranvier , 2002, The Journal of cell biology.

[7]  C. Colbert,et al.  Ion channel properties underlying axonal action potential initiation in pyramidal neurons , 2002, Nature Neuroscience.

[8]  Andrea Hasenstaub,et al.  Barrages of Synaptic Activity Control the Gain and Sensitivity of Cortical Neurons , 2003, The Journal of Neuroscience.

[9]  G. Stuart,et al.  Site of Action Potential Initiation in Layer 5 Pyramidal Neurons , 2006, The Journal of Neuroscience.

[10]  G. Baranauskas,et al.  Sodium Currents Activate without a Hodgkin and Huxley-Type Delay in Central Mammalian Neurons , 2006, The Journal of Neuroscience.

[11]  J. DeFelipe,et al.  Voltage-gated ion channels in the axon initial segment of human cortical pyramidal cells and their relationship with chandelier cells. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[12]  D. McCormick,et al.  Modulation of intracortical synaptic potentials by presynaptic somatic membrane potential , 2006, Nature.

[13]  M. Volgushev,et al.  Unique features of action potential initiation in cortical neurons , 2006, Nature.

[14]  Yuguo Yu,et al.  Properties of action-potential initiation in neocortical pyramidal cells: evidence from whole cell axon recordings. , 2007, Journal of neurophysiology.

[15]  R. Rosenfeld.  Nature , 2009, Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery.