Neuroimaging data provides inconsistent evidence as to whether hippocampal development is impacted in individuals with PEA140, 141, 161. A small study reported asymmetric hippocampal size following PEA, with right hippocampal volumes larger than left, however the study was not case controlled161. Other studies report relative sparing of hippocampus and amygdala following PEA, especially when whole brain volumes are taken into account140, 162. The hippocampus and amygdala are components of the limbic system and are functionally implicated in formation of long term memories and emotion, respectively. Considering their functional implications, further studies clarifying the involvement of these structures following PEA are warranted. Several studies have reported disproportionate volume reductions of the BG (basal ganglia) in subjects with PEA. However, when overall brain volume was taken into account, only reductions in caudate volume remained significant140, 162, 163. The volumes of lenticular and accumbens nuclei were relatively spared140, 163.
