At all times, behaviors have been guided by smells, including returning “home”, avoiding predators or looking for food and mates. This study by a team from the University of Montreal, presented in the journal PLoS Biology, helps to shed light on the processes underlying these olfactomotor behaviors. This work, carried out on the lamprey, a primitive fish, identifies a neural pathway extending from the middle part of the olfactory bulb to the locomotor control centers of the brainstem, via a single relay in the caudal diencephalon. This lifelong olfactomotor pathway could be responsible for motor behaviors induced by smell, at all stages of life.
In all animals and in humans, the sense of smell, the oldest and probably the most developed of the 5 senses, plays a predominant role in many behaviors essential to survival and reproduction. Multiple studies have also linked smell more broadly to cognitive abilities. However, the neural pathways and mechanisms responsible for odor-induced behavior remain poorly understood. This identification of a neural pathway linking the olfactory and motor centers in the lamprey constitutes a first step towards a better understanding of our behaviors in response to odors.
Scientists from Montreal and the University of Windsor (Ontario) precisely showed that an inhibitory circuit that releases the neurotransmitter GABA in the olfactory bulb strongly modulates behavioral responses to odors in lamprey. The study of this mechanism reveals a new pathway linking the olfactory and motor centers of the brain.
This discovery demonstrates, in animals, that odors are indeed activating factors of the locomotor centers. Data perhaps (?) in favor of the stimulating properties as well as the better known soothing properties of aromatherapy. With the need for much additional research in animals, and clinical trials in humans.
