Nonlinear Analysis of Neural Activity of Prefrontal Cortex of the Rat Injected Methamphetamine

We analyzed neural activity of the prefrontal cortex of rats injected a psychotic drug methamphetamine by using nonlinear dynamics and chaos theory. Although correlation dimensions of the attractors generated by using interspike intervals (ISI) of the observed neural spikes showed little difference before and after drug injection, the ISI distribution revealed a noticeable dierence. Before and after drug injection the correlation dimension was found to be approximately 7, which means that the neural activity is governed by a high-dimensional dynamics. By comparing analysis results of the original ISI data and its surrogate data, we also conrmed that the ISI has determinicity.