Sustained human chemosignal unconsciously alters brain function

The human chemosignal, Delta4,16-and rostadien-3-one modulates psychologica l state without being consciously discernible as an odor. This study demons trates that Delta4,16-androstadien-3-one (androstadienone) alters cerebral glucose utilization both in subcortical regions and in areas of the neocort ex not exclusively associated with olfaction. These widely distributed chan ges are consistent with modulation of an integrated neural network for regu lation of emotional and attentional states. This is the first study to demo nstrate the effects of a sustained chemosignal on brain metabolism and to s how that they are similar to those of long acting chemical substances that affect psychological states. Moreover, this provides the first evidence tha t a human chemosignal has distributed effects on cortical processes and bra in metabolism even when it is not detected consciously. NeuroReport 12:2391 -2394 (C) 2001 Lippincott Williams & Wilkins.