GRIN2A and Anxiety: One clinical study by Tsang demonstrated that the NMDA receptor NR2A(N-methyl,D-aspartate receptor subunit 2A subunit)was significantly reduced in the orbitofrontal gyrus of high-anxiety Alzheimer's patients in comparison to low anxiety patients, indicating that changes in the expression of NMDA receptors in the brain may modulate an anxiety-like activity [12].