Appropriate attention levels are pivotal for cognitive processes, and individual differences in attentional functioning are related to variations in the interplay of neurotransmitters. In the present study, the role of variation in GRIN2B, which encodes the NR2B subunit of N-methyl-d-aspartate (NMDA) receptors, was explored.
The study focuses on the regulation of arousal and attention by comparing the efficiency of the three attention networks alerting, orienting and conflicting as measured with the Attention Network Test (ANT). Two synonymous SNPs in GRIN2B, rs1806201 (T888T) and rs1806191 (H1178H) were genotyped in 324 young Caucasian adults. Results revealeda highly specific modulatory influence of SNP rs1806201 on alerting processes with subjects homozygous for the frequent C allele displaying higher alerting network scores as compared to the other two genotype groups (CT and TT). This result can be further explained by faster reaction times in the no-cue condition of the ANT (tonic alertness) in participants carrying at least one of the rare T alleles, possibly as a result of more effective glutamatergic neurotransmission.

Schulz, S., Arning, L., Pinnow, M., Epplen, J.T., Beste, C. (2012). N-methyl-d-aspartate receptor 2B subunit (GRIN2B) gene variation is associated with alerting, but not with orienting and conflicting in the attention network test. Neuropharmacology, 63, 259-265.