Previous studies suggested that gamma oscillations in the brain are associated with higher order cognitive function including selective visual attention, motor task planning, sensory perception, working memory and dreaming REM sleep. These oscillations are mainly observed in cortical regions and also occurs in neocortical and subcortical areas and the hippocampus. In this paper, we investigate the influence of acute exposure to 2-APB exposure on the complexity of hippocampal gamma gamma oscillations. Our central hypothesis is that acute exposure to 2 APB significantly reduce the hippocampal gamma oscillations. In order to test this hypothesis, we use brain-slice recordings and the advanced nonlinear dynamical analysis method based on the Lempel-Ziv estimator. Our nonlinear dynamical analysis of brain slice recordings results suggested that 2-APB exposure significantly reduces the hippocampal gamma oscillations.