Representative 9.4 Tesla anterior cingulate cortex 31P MRS spectrum with peaks for PME and PDE, Pi, PCr, β-NTP (primarily adenosine triphosphate), γ-NTP, and α-NTP (respectively). 31P MRS, phosphorus magnetic resonance spectroscopy; α-NTP, α-nucleoside triphosphate; β-NTP, β-nucleoside triphosphate; γ-NTP, γ-nucleoside triphosphate; PCr, phosphocreatine; PDE, phosphodiesters; Pi, inorganic phosphate; PME, phosphomonoesters.