SHANK2 and Anxiety: Shank2 clusters were found to colocalize extensively with the excitatory synaptic vesicular glutamate transporter 1 (VGluT1), which is expressed selectively in parallel fibers as opposed to climbing fibers (Hioki et al., 2003), indicating postsynaptic localization of Shank2 at the PF-PC synapses This is associated with a decrease in the frequency of spontaneous excitatory synaptic currents in PCs, suggesting a net reduction of GC excitatory input into PCs that affects anxiety behavior.