Our sense of smell is just as important as other senses available in our body. But although smell serves a powerful function for the body, it is often overlooked. One thing that makes the sense of smell unique is the consistency of its ability to recognize various objects whenever, wherever.
The sense of smell is an effective medium to preserve certain information regarding a material that, if stored properly, could be detailed by an individual on occasions possible. For example, a cup of coffee has a distinct smell that stays the same whenever presented under any climate or in any place with other scents present.
Locusts Help to Explain Why Scent of Objects are Not Influenced by External Conditions
In this picture taken on February 23, 2020, a locust in seen in the grass at a farm in Pipli Pahar village in Pakistan's central Punjab province. - Pakistan's farmers are struggling to combat the worst locust plague in nearly three decades as insect swarms decimate entire harvests in the country's agricultural heartlands and send food prices soaring.
It may seem basic to know that any scent of materials detected by our smelling functions is consistent without the influence of other elements. But experts have been figuring out why this natural phenomenon happens regardless of environmental factors. To know more about the mystery of smells, McKelvey School of Engineering scholars from the prestigious Washington University in St. Louis conducted a study. The investigation was made possible through the help of locust subjects.
Biomedical engineering expert and author of the study Barani Rama said that what they found in the research was "surprisingly simple," per EurekAlert. Their team had been observing various locust subjects for years. Many of their previous studies involved the neurological functions of the species and how it relates to the behavioral activities of the locusts.
Among the main interests of the experts is to identify how locusts could smell. With the previous findings, the authors are on the progress of unique research in which the locusts could be engineered similarly to bomb-sniffing canines. Along with the progress of this long-term study, the experts were able to gather a significant amount of information about the corresponding biological mechanisms that revolve around the animal's sense of smell.
Experts based the study on how locusts could smell objects and recognize them regardless of the conditions from the previous investigations held by the famous Ivan Pavlov. The authors trained the locusts to be familiarized with certain smells like the odors of their food such as the natural blades of grass.
Neural Response During Smell Recognition
When food supply was controlled, the locusts were provided with odors composed of isoamyl acetate and hexanol. Within six repetitions of the experiment, the locusts became associated with the routine, allowing their sensory appendages called palps to open in anticipation of receiving food.
When the activity was perfected, the neurons of the subjects were examined in the hopes to single out the specified ones responsible for opening their palps. Raman said that neural responses observed from the locusts were highly variable.
To extract the pattern from the animal's behavior, the team utilized a machine-learning algorithm. In this way, they have predicted both the stable and inconsistent intervals of the neural response. The experts categorized ON and OFF neurons through the readings, which translates to spikes whenever the training odorant is exposed or not. The difference between the neural spikes was the data that served as a threshold for predicting the locust's sense of smell.
In conclusion, there are several objects with specific scents that people are undoubtedly familiar with. As long as the significance of the features becomes intense, they are recognized by the neurons, even if most of the item's deal-breakers are not presented in the object itself. The ON neurons convey what smell we want to associate with the item, and the OFF neurons become silent whenever there is an absence of any deal-breakers. The study was published in the journal PNAS, titled "Invariant odor recognition with ON-OFF neural ensembles."
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