The Journal of Neuroscience, June 21, 2006, ():
The Properties and Implications of NMDA Spikes in Neocortical Pyramidal Cells
J. Neurosci. Rhodes
26: 6704
Supplemental data
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Supplemental Figure 1
The affect of lowering membrane resistance and cytoplasmic resistivity on NMDA spike generation. Some studies of pyramidal cells (Stuart and Spruston 1998) have suggested lower values of the passive resistive parameters than those adopted (Rm = 50,000 Ωcm2, Ri = 150 Ωcm) in this study. To examine the affect of lower values, simulated NMDA spikes were generated at two locations in the dendritic tree, in 1 mM Mg2+, with values of Rm and Ri of 10,000 Ωcm2 and 70 Ωcm respectively. The results indicated that threshold NMDA conductance increased in concert with the reduction in Rm and Ri, with threshold NMDA conductance at the location in the right panel 12 nS, whereas it was approximately 7 nS with the values of Rm and Ri used in the text. NMDA spike generation at another dendritic location, different from those illustrated in the text, is shown at left; at this location threshold was about 16 nS with the lower passive parameters. In both locations the characteristics of both the dendritic and somatic voltage wave-forms associated with the NMDA spike were similar to those at higher Rm and Ri, suggesting that the mechanisms of NMDA spike generation explored in the text were not dependent upon the choice of passive resistive parameters.
Stuart, G, and Spruston, N (1998) Determinants of voltage attenuation in neocortical pyramidal neuron dendrites. J Neurosci 18: 3501-10.
