One nose, one brain: contribution of the main and accessory olfactory system to chemosensation

Abstract

The accessory olfactory system is present in most tetrapods. It is involved in the perception of chemical stimuli, being implicated also in the detection of pheromones. However, it is sensitive also to some common odorant molecules, which have no clear implication in intraspecific chemical communication. The accessory olfactory system may complement the main olfactory system and may contribute different perceptual features to the construction of a unitary representation, which merges the different chemosensory qualities. Crosstalk between the main and accessory olfactory systems occurs at different levels of central processing, in brain areas where the inputs from the two systems converge. Interestingly, centrifugal projections from more caudal brain areas are deeply involved in modulating both main and accessory sensory processing. A high degree of interaction between the two systems may be conceived and partial overlapping appears to occur in many functions. Therefore, the central chemosensory projections merge inputs from different organs to obtain a complex chemosensory picture.

Major unsolved points in adult neurogenesis: doors open on a translational future?

“…These two brain regions are essential for behavioral outputs critical for survival of the individuals and species (Mucignat-Caretta et al, 2012; Snyder and Cameron, 2012). Accordingly, AN is assumed as a mechanism which promotes life-long adaptability of individuals to environmental complexity and novelty (Freund et al, 2013).…”

Airborne molecules released from male mouse urine affect female exploratory behavior

“…These stimuli differentially activate the main and accessory olfactory systems, inducing selective responses to urine from different donors (Veyrac et al, 2011). The initial differential processing of chemicals by the main and accessory olfactory systems is partly compensated by the high degree of interaction between their downstream projection areas (Kang et al, 2009;Mucignat-Caretta et al, 2012), so that chemosignals may lead to complex effects. In the present paper we analyzed the exploratory behavior of estrus female mice exposed to the smell of adult male mouse urine, sMUP, or water.…”

Parenting Behavior

“…2 Although maternal responding in olfaction-disrupted nulliparous rats is impressively hastened, it is not the only inhibitor of mothering because administration of ovarian hormones makes anosmic females even more responsive to pups. 429,430 Third, olfactory disruption in mammals broadly affects endocrine function, including thyroid, pineal, pituitary, gonadal, and adrenal hormones. First, the ability of intranasal irrigation of zinc sulfate to produce anything other than a brief (<72 h) and incomplete anosmia in rats has long been questioned.…”