The sense of smell is more than just appreciating the scents; it is also a survival tool for animals and humans to determine if a new environment is safe or dangerous, and plays a crucial role in reproduction. According to a news release, this inspired researchers at the University of Rochester's Del Monte Institute for Neuroscience to learn more about the olfactory system.
They hypothesize that the olfactory sensory system assists in assessing danger and learning which scent could be a potential threat. Julian Meeks, Ph.D., chief investigator of the Chemosensation and Social Learning Laboratory said that they are trying to figure out how animals interact with scent and how it affects their behavior toward hazardous social and non-social contexts.
Learning Which Scent Poses Significant Threat
The recent study, titled "Arc-Expressing Accessory Olfactory Bulb Interneurons Support Chemosensory Social Behavioral Plasticity" published in The Journal of Neuroscience, gives scientists a valuable tool to use in future studies as they connect specific sets of neurons in the olfactory system to the memory associated with social threats.
Researchers noted that the scent could influence how a brain responds to a hazardous object or situation as they discovered in their experiment using mice. They identified a unique collection of neurons in the supplementary olfactory system that can memorize the smell of another mouse, which signals a threat.
The study's first author, Kelsey Zuk, Ph.D., explained that a resident male who is frequently presented with another male could lead to the rise of territorial aggression. Studies have shown that this behavior is due to social smells, but the new study takes it one further by pinpointing the location of its origin in the olfactory system.
They found that plasticity occurs across neurons and that the aggression happening between two male mice may have been triggered by odor memory. More so, they found that "inhibitory" neurons in a brain region are responsible for interpreting social smells to become active when males repeatedly see other males and increase their territorial aggression.
Researchers reveal that disrupting the neurons linked to neuroplasticity could decrease territorial aggression and changes cellular function in the pheromone-sensing circuitry of the brain, which leads to changes in the behavior toward social threats.
Sense of Smell Assess the Level of Threat Based on Their Scents
A similar report from Neuroscience News reveals that animals assess the threat in a new environment using their sense of smell, especially to predators who they never encountered. Researchers found that a new predator's smell could cause another to engage in a threat assessment behavior that is neither fearful nor safe.
In a separate paper in eNeuro, the team from Chemosensation and Social Learning Laboratory said that their findings offer clues on how predators give off their scents to stimulate their prey's threat assessment system. They identified patterns of animal behavior to better understand how threatening smells are processed in the brain.
They tracked the behavior of mice using video to observe their movement and posture while exploring environments with varying odors, such as mice and snakes. The team developed a machine learning approach to uncover that mice respond to novel predator odors that are different from the ones they never encountered yet and observed how they reacted to non-predator odors.
The team believes that the findings will be valuable for future research into how the blends of chemical odorants given off by predators could trigger threat assessment in the brain.
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