1. Modeling of an isolated rhythm-generating population.
Modeling of an isolated rhythm-generating population. A, Raster plot of the activity of 50 neurons from the 200-neuron population. Each horizontal line represents a neuron, and each dot represents a spike. B, Integrated population activity represented by the average histogram of population activity [spikes/(neuron × s), bin = 100 ms]. In A and B, the average leakage reversal potential (ĒL) defining the average level of neuronal excitation was linearly increased from −70 to −58 mV for 400 s. Voltage regions of silence, bursting, and tonic activity are denoted at the bottom. Bursting emerges at lower values of ĒL in a limited number of neurons. With increasing ĒL, more neurons become involved and the population bursting becomes strongly synchronized. A further increase of ĒL leads to a transition to tonic activity. C and D, respectively, show the frequency of and amplitude of population activity as functions of ĒL. E and F, respectively, show the frequency and amplitude of NMDA/5-HT-evoked locomotor activity in the isolated mouse spinal cord recorded in vitro from the flexor ventral root as a function of NMDA (red circles) or d-glutamate (black squares) concentration (the amplitude was normalized with respect to the maximal amplitude). Graphs display the mean ± SD (n = 20 each). G shows changes of ĒL for flexor (ĒLF, red line) and extensor (ĒLE, blue line) RG centers during increasing neuronal excitation with an increase in drug concentration [defined by parameter α, (ĒLi = ĒLiO · (1 − α))] across areas for silence (white), bursting (blue), and tonic (yellow) population activity. This figure is reproduced from Shevtsova et al. (2015), their Figure 2, with permission.
Ilya A. Rybak et al. eneuro 2015;2:ENEURO
©2015 by Society for Neuroscience