PT - JOURNAL ARTICLE AU - Daniel S. Reich AU - Jonathan D. Victor AU - Bruce W. Knight TI - The Power Ratio and the Interval Map: Spiking Models and Extracellular Recordings AID - 10.1523/JNEUROSCI.18-23-10090.1998 DP - 1998 Dec 01 TA - The Journal of Neuroscience PG - 10090--10104 VI - 18 IP - 23 4099 - http://www.jneurosci.org/content/18/23/10090.short 4100 - http://www.jneurosci.org/content/18/23/10090.full SO - J. Neurosci.1998 Dec 01; 18 AB - We describe a new, computationally simple method for analyzing the dynamics of neuronal spike trains driven by external stimuli. The goal of our method is to test the predictions of simple spike-generating models against extracellularly recorded neuronal responses. Through a new statistic called the power ratio, we distinguish between two broad classes of responses: (1) responses that can be completely characterized by a variable firing rate, (for example, modulated Poisson and gamma spike trains); and (2) responses for which firing rate variations alone are not sufficient to characterize response dynamics (for example, leaky integrate-and-fire spike trains as well as Poisson spike trains with long absolute refractory periods). We show that the responses of many visual neurons in the cat retinal ganglion, cat lateral geniculate nucleus, and macaque primary visual cortex fall into the second class, which implies that the pattern of spike times can carry significant information about visual stimuli. Our results also suggest that spike trains of X-type retinal ganglion cells, in particular, are very similar to spike trains generated by a leaky integrate-and-fire model with additive, stimulus-independent noise that could represent background synaptic activity.