Posts tagged sniffing
Articles and news from the latest research reports.
Rats take high-speed multisensory snapshots
When animals are on the hunt for food they likely use many senses, and scientists have wondered how the different senses work together.
New research from the laboratory of CSHL neuroscientist and Assistant Professor Adam Kepecs shows that when rats actively use the senses of smell (sniffing) and touch (through their whiskers) those two processes are locked in synchronicity. The team’s paper, published today in the Journal of Neuroscience, shows that sniffing and “whisking” movements are synchronized even when they are running at different frequencies.
Studies in the 1960s suggested these two sensory activities were coordinated: sniffing, a sharp, profound intake of air; and whisking, the back-and-forth movement of the whiskers to sample the near environment, akin to the sensation of touch as felt through the fingers in humans. Such coordination could be important for decisions that depend on multiple types of sensory information, for instance, locating food. “The question is how two very different streams of sensory information, touch and smell, are integrated into a single multisensory “snapshot” of the environment,” says Kepecs.
These snapshots can be taken at high frequency, up to 12 times a second. To determine whether these two sensorimotor rhythms are indeed phase-locked, Kepecs’ team, including postdocs Sachin Ranade and Balázs Hangya, simultaneously monitored sniffing and whisking in rats freely foraging for food pellets.
At different frequencies occurring between 4-12 times per second they found strong 1:1 phase locking — in other words, every time the rats extended their whiskers to feel their vicinity, they also smelled it. Surprisingly, they found even when the sniffing and whisking rhythms operating at different fundamental frequencies they were locked in phase. Key to this is that the phases of the sensory input – the start of inhalation and onset of whisking – are aligned, which facilitates multisensory integration.
This is similar to how a person’s breathing rhythm settles into place while running and is synchronized to the steps. In both cases, the coordination could be advantageous in terms of energy efficiency. A crucial difference, though, is that in humans, the breathing rate has to catch up to the running rhythm after changes in pace, while for sniffing and whisking in rats they lock into phase immediately.
Even though human behavior doesn’t seem to be overtly tied to rhythms, there are hints that it could be. “Underneath the smoothly executed movements of humans there are rhythm generators, which are sometimes revealed in some diseases, for example the tremors seen in Parkinson’s disease, or in the brain waves that result from the synchronized firing of neurons,” says Kepecs. Studying the rhythms of multisensory inputs in rodents could provide clues to a fundamental principle underlying sensory and brain rhythms that are essential to all animals, including humans.
(Source: cshl.edu)
New Form of Animal Communication Discovered
Sniffing, a common behavior in dogs, cats and other animals, has been observed to also serve as a method for rats to communicate—a fundamental discovery that may help scientists identify brain regions critical for interpreting communications cues and what brain malfunctions may cause some complex social disorders.
Researchers have long observed how animals vigorously sniff when they interact, a habit usually passed off as simply smelling each other. But Daniel W. Wesson, PhD, of Case Western Reserve University School of Medicine, whose research is published in Current Biology, found that rats sniff each other to signal a social hierarchy and prevent aggressive behavior.
Wesson, who drew upon previous work showing that, similar to humans, rodents naturally form complex social hierarchies, used wireless methods to record and observe rats as they interacted. He found that, when two rats approach each other, one communicates dominance by sniffing more frequently, while the subordinate signals its role by sniffing less. Wesson found that if the subordinate didn’t do so, the dominant rat was more likely to become aggressive to the other.
Wesson theorized the dominant rat was displaying a “conflict avoidance signal,” similar to a large monkey walking into a room and banging its chest. In response, the subordinate animal might cower and look away, or in the case of the rats, decrease its sniffing.
“These novel and exciting findings show that how one animal sniffs another greatly matters within their social network,” said Wesson, an associate professor of neurosciences. “This sniffing behavior might reflect a common mechanism of communication behavior across many types of animals and in a variety of social contexts. It is highly likely that our pets use similar communication strategies in front of our eyes each day, but because we do not use this ourselves, it isn’t recognizable as ‘communication’.”
Wesson’s findings represent the first new form of communication behavior in rats since it was discovered in the 1970s that they communicate through vocal ultrasonic frequencies. The research provides a basis for understanding how neurological disorders might impact the brain’s ability to conduct normal, appropriate social behaviors.
Wesson’s laboratory will use these findings to better understand how certain behaviors go awry. Ultimately, the hope is to learn whether this new form of communication can help explain how the brain controls complex social behaviors and how these neural centers might inappropriately deal with social cues.
Animals learn to fine-tune their sniffs
Animals use their noses to focus their sense of smell, much the same way that humans focus their eyes, new research at the University of Chicago shows.
A research team studying rats found that animals adjust their sense of smell through sniffing techniques that bring scents to receptors in different parts of the nose. The sniffing patterns changed according to what kind of substance the rats were attempting to detect.
The sense of smell is particularly important for many animals, as they need it to detect predators and to search out food. “Dogs, for instance, are quite dependent on their sense of smell,” said study author Leslie Kay, associate professor of psychology and director of the Institute for Mind & Biology at the University of Chicago. “But there are many chemicals in the smells they detect, so detecting the one that might be from a predator or an explosive, for instance, is a complex process.”
Kay was joined in writing the paper by Daniel Rojas-Líbano, a postdoctoral scholar at the University of Chile in Santiago, who received his PhD from UChicago in 2011. Rojas-Líbano, who did the work as a doctoral scholar, was the first author on the publication. Their results are published in an article, “Interplay Between Sniffing and Odorant Properties in the Rat,” in the current issue of the Journal of Neuroscience.