Scientists have identified a feedback mechanism in the brain’s sense of smell center that appears to help associate smells and sounds with their contexts. This feedback loop may aid animals in modifying their behaviors in reaction to new sensory experiences.
Kaboom! For most of us, the first exposure to the sound of an explosion occurs in films. Experiencing that sound in real life—even from a distance—triggers a significantly different reaction. Why is this? It all comes down to context. Our responses to sounds and other sensory inputs depend on how they are presented to us. Often, we don’t know how we will react to something until we actually encounter it, and the sensation can greatly differ from our expectations. Thus, the brain needs to adapt swiftly.
Professor Florin Albeanu from Cold Spring Harbor Laboratory (CSHL) elaborates: “In natural environments, animals must navigate various engagement rules. The same sensory inputs can convey different meanings based on the surrounding context. Therefore, it’s not surprising that one needs to respond to these varying rules and evaluate what actions are appropriate. What associations does the stimulus hold concerning specific outcomes?”
New research conducted by Albeanu and postdoctoral researcher Diego Hernandez Trejo sheds light on this process. Their findings reveal unprecedented quick-updating signals within a feedback loop between the olfactory cortex and the olfactory bulb in the brain. These signals may allow for the reinterpretation of odors and sounds in different contexts. This feedback system seems to enable an animal’s brain to rapidly adjust to changes, allowing for precise modifications in physical responses.
Hernandez Trejo and his team performed a series of behavioral tests to observe how mice reacted to various smells and sounds. The mice were conditioned to link rewards with one type of stimulus but not another, and this was only for a limited time. Notably, the researchers altered the rules once the mice appeared to grasp them. Expertly trained mice adapted easily to these changes, Albeanu notes. “The animal can perceive this shift. Within seconds, it will act in a way that reflects its understanding. Intriguingly, we found that signals from the olfactory cortex—which provides information about the reward value—are transmitted to the olfactory bulb, irrespective of whether the stimulus is a sound or an odor.”
The olfactory cortex is responsible for processing scents, yet it seems to consider auditory signals as well. This aligns with another discovery from CSHL, which illustrated how sensory inputs are integrated within the brain. It also prompts fascinating questions.
How do reward signals come into play? Does this feedback loop also integrate visual and tactile information? “There is an entire realm of possibilities,” says Albeanu. He looks forward to continuing this exploration alongside colleagues Andrei Ciuparu and Raul Muresan from TINS in Romania, understanding that every piece of information brings us closer to understanding our shared world and the perceptions that influence it.
