We performed neurochemical quantitation of the catecholamines dopamine (DA), norepinephrine (NE) and epinephrine (E) and their major metabolites 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylethylene glycol (MHPG) in 22 cortical regions of 6 postmortem human brains. Statistical analysis indicated a clear regional difference for NE and E while DA and all the metabolites under study are homogeneously distributed over the cortex. These consistent regional differences suggest the possible role of NE and E as neurotransmitters or neuromodulators in human cerebral cortex.