Computational Model Explains Outlasting Effects of Periodic Stimulation.

<p>(A) Schematic of computational model that includes the different components and interactions among them. The region of the cortex being stimulated is denoted by a gray circle encompassing excitatory and inhibitory neurons. The model neurons exhibit reciprocal as well as recurrent connections. The cortico-thalamic and cortico-cortical interactions are also modeled to be reciprocal. (B) Membrane potential observed from excitatory neurons in the model shows task-dependent differences in stimulation effect. During the eyes-closed state (blue trace), a strong oscillation is observed in the alpha frequency range. Stimulation onset does not alter the dynamics significantly. In the eyes-open state (magenta trace), an oscillation is still observed in the alpha frequency range. However, the strength is decreased compared to the eyes-closed state. Stimulation onset causes the amplification of this oscillation, which persists after stimulation offset and then slowly decays. In the task-engaged state (yellow trace), no strong oscillation is observed due to the external inputs that model task-related input. In this state, stimulation causes the network to oscillate at the stimulation frequency, which persists and decays in the epoch after stimulation. (C) Spectral analysis of membrane potential reveals state-dependent effect of stimulation. Refer to <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1002424#pbio.1002424.s001" target="_blank">S1 Fig</a> for dynamics in the absence of cortico-thalamic and cortico-cortical interactions. The data shown in this figure are available online: <a href="http://dx.doi.org/10.5281/zenodo.45811" target="_blank">http://dx.doi.org/10.5281/zenodo.45811</a>