Sustained human chemosignal unconsciously alters brain function

Abstract

The human chemosignal, Delta 4,16-androstadien-3-one modulates psychological state without being consciously discernible as an odor. This study demonstrates that Delta 4,16-androstadien-3-one (androstadienone) alters cerebral glucose utilization both in subcortical regions and in areas of the neocortex not exclusively associated with olfaction. These widely distributed changes are consistent with modulation of an integrated neural network for regulation of emotional and attentional states. This is the first study to demonstrate the effects of a sustained chemosignal on brain metabolism and to show that they are similar to those of long acting chemical substances that affect psychological states. Moreover, this provides the first evidence that a human chemosignal has distributed effects on cortical processes and brain metabolism even when it is not detected consciously.

Dynamic functional evolution of an odorant receptor for sex-steroid-derived odors in primates

“…Various studies point to the potential effect of the steroidal odorants on human physiology and behavior (11)(12)(13), although there is no evidence for a behavioral role of these odorants in a primate species other than human. As an OR for sex-steroid derived compounds, OR7D4 is not likely to be involved in food detection or toxicity avoidance.…”

“…In the domestic pig, androstenone has been identified as a male pheromone that induces a receptive mating stance in estrous females (10). In humans, androstenone is found in saliva, sweat, and urine and olfactory exposure to androstadienone has been reported to affect physiological responses (11)(12)(13). However, their effects on human reproductive activities remain controversial (14).…”

Neurobehavioral functional deficits following closed head injury in the neonatal pig

“…The same ontogeny of olfactory relative to visual systems is likely to apply to swine. Jacob et al demonstrated in humans that olfactory signals modulate emotional and attentional states through the activation of widely distributed regions of neocortex not specifically dedicated to olfactory function, including prefrontal cortex, amygdala, visual cortex and cerebellum (Jacob 2001). Thus, our findings on neurobehavioral measures could be explained, at least in part, by the finding of damage to olfactory systems, which may impair performance on tasks involving olfaction directly, or indirectly by affecting motivation, attention, and visual-motor integration, while leaving primary motor systems unaffected.…”

Evidence that androstadienone, a putative human chemosignal, modulates women’s attributions of men’s attractiveness

“…The presentation method and concentrations were chosen to allow comparison with existing literature (e.g. Jacob and McClintock, 2000;Jacob et al, 2001b;Lundström et al, 2003a;Lundström and Olsson, 2005). …”

“…At the physiological level, androstadienone inhalation precedes measurable changes in endocrine state (Wyart et al, 2007) and autonomic activations (Bensafi et al, 2004a;Grosser et al, 2000;Jacob et al, 2001a;Monti-Bloch and Grosser, 1991) that may be specific to women (Boulkroune et al, 2007). Neurologically, female response to androstadienone extends beyond the olfactory system, activating areas of the brain associated with attention, social cognition, emotional processing, and sexual behavior Jacob et al, 2001b;Savic et al, 2001;Savic et al, 2005). A functional consideration of these types of findings has led to the suggestion that androstadienone might have a sexual function, and be able to elicit behavioral responses in women towards men in such a manner as to facilitate partnership formation (Bensafi et al, 2004a;Hays, 2003;Lundström and Olsson, 2005), but so far specific evidence in support of this suggestion has been lacking (e.g.…”