 There appear to be three different types of gating circuits – one that is controlled by the cortex, one that is controlled by the association nuclei in the thalamus, and one that is controlled by circuits spanning the basal ganglia, cortex, and the thalamus.Strong evidence has concluded that gating from thalamus impacts the prefrontal cortex response from the hippocampus.This is seen as either an enhancement or a suppression illustrating the bistability of the process.