The Effect of Neural Noise on Spike Time Precision in a Detailed CA3 Neuron Model
Figure 2
Voltage-gated channel noise and the effect of system memory of the model. (a) States of the model and its input were resumed as they were at times before the expected occurrence of each AP cluster and simulated for periods lasting ms repeatedly times () for each AP cluster. Bar heights in each of nine traces represent AP clusters’ values for increasing value of (top-down). (b) An example of superimposed voltage AP courses of the second AP for increasing values of (top-down). The traces end up at the end of simulation segments lasting . (c) Aligned courses taken from all AP clusters merged altogether. (d) Correlations between values and courses of different intervals . (e) courses obtained under varying are aligned here for each AP cluster. The small misalignment of shapes of given AP cluster is due to the voltage-gated channel noise incurring a small scattering of the resulting AP times collected under various durations of simulation segments. (f) Relationship between the and estimated minimal, mean and maximal value with both somadendritic (SD) and axonal channel noise switched on. (g) The LOWESS quadratic fit matching the dependence between values and interspike interval ISI, constructed by processing the data from 30 s long continuous stimulations. The fitted curve shows the average value of for each given ISI (the effect of variable trajectory influencing the AP time precision is averaged by the fitting procedure). (h) The effects of various types of somadendritic voltage-gated channel noise on AP time precision. (i) The effect of axonal initial segment voltage-gated channel noise on AP time precision. (j) Mean value of for various numbers N (on abscissa) of engaged presynaptic neurons mimicking various levels of synchrony among presynaptic neurons is demonstrated here. In panels ((h), (i), and (j)), the 95% confidence interval is indicated by red bars (obtained from simulations generating from 30 to 40 AP clusters). At the top of each bar, the black bars represent the ± standard deviation of values obtained over all AP clusters.
