Posts tagged foraging
Articles and news from the latest research reports.
Game Technology Teaches Mice and Men to Hear Better in Noisy Environments
The ability to hear soft speech in a noisy environment is difficult for many and nearly impossible for the 48 million in the United States living with hearing loss. Researchers from the Massachusetts Eye and Ear, Harvard Medical School and Harvard University programmed a new type of game that trained both mice and humans to enhance their ability to discriminate soft sounds in noisy backgrounds. Their findings will be published in PNAS Online Early Edition the week of June 9-13, 2014.
In the experiment, adult humans and mice with normal hearing were trained on a rudimentary ‘audiogame’ inspired by sensory foraging behavior that required them to discriminate changes in the loudness of a tone presented in a moderate level of background noise. Their findings suggest new therapeutic options for clinical populations that receive little benefit from conventional sensory rehabilitation strategies.
“Like the children’s game ‘hot and cold’, our game provided instantaneous auditory feedback that allowed our human and mouse subjects to hone in on the location of a hidden target,” said senior author Daniel Polley, Ph.D., director of the Mass. Eye and Ear’s Amelia Peabody Neural Plasticity Unit of the Eaton-Peabody Laboratories and assistant professor of otology and laryngology at Harvard Medical School. “Over the course of training, both species learned adaptive search strategies that allowed them to more efficiently convert noisy, dynamic audio cues into actionable information for finding the target. To our surprise, human subjects who mastered this simple game over the course of 30 minutes of daily training for one month exhibited a generalized improvement in their ability to understand speech in noisy background conditions. Comparable improvements in the processing of speech in high levels of background noise were not observed for control subjects who heard the sounds of the game but did not actually play the game.”
The researchers recorded the electrical activity of neurons in auditory regions of the mouse cerebral cortex to gain some insight into how training might have boosted the ability of the brain to separate signal from noise. They found that training substantially altered the way the brain encoded sound.
In trained mice, many neurons became highly sensitive to faint sounds that signaled the location of the target in the game. Moreover, neurons displayed increased resistance to noise suppression; they retained an ability to encode faint sounds even under conditions of elevated background noise.
“Again, changes of this ilk were not observed in control mice that watched (and listened) to their counterparts play the game. Active participation in the training was required; passive listening was not enough,” Dr. Polley said.
These findings illustrate the utility of brain training exercises that are inspired by careful neuroscience research. “When combined with conventional assistive devices such as hearing aids or cochlear implants, ‘audiogames’ of the type we describe here may be able to provide the hearing impaired with an improved ability to reconnect to the auditory world. Of particular interest is the finding that brain training improved speech processing in noisy backgrounds – a listening environment where conventional hearing aids offer limited benefit,” concluded Dr. Jonathon Whitton, lead author on the paper. Dr. Whitton is a principal investigator at the Amelia Peabody Neural Plasticity Unit and affiliated with the Program in Speech Hearing Bioscience and Technology, Harvard–Massachusetts Institute of Technology Division of Health, Sciences, and Technology.
(Source: masseyeandear.org)
Bumblebees are anything but bumbling: The insects quickly figure out the optimal route for visiting five far-flung flowers, a computational task that even human brains find challenging.
That result suggests that an elaborate mental map isn’t necessary to travel efficiently in unknown territory. Finding a way to mimic the bumblebee’s navigation system may allow programmers to develop robots that adeptly maneuver through unfamiliar places.
The new study, published online September 20 in PLOS Biology, pulls together several lines of previous research into one grand experiment. After training bumblebees to associate artificial flowers with a reward, scientists from the University of Sydney, Rothamsted Research in Harpenden, England and Queen Mary University of London arranged five flowers in a pentagon with sides 50 meters long. One at a time, bumblebees outfitted with a little radar antenna were released from the nest. The bees’ movements were tracked by radar, and motion-sensing cameras on the flowers recorded each visiting bee.
A computer analysis of the bees’ movements suggested that the insects were doing some quick comparing. If a bee went from flower A to B and later went from flower A to C, it would compare those routes, adding the one that was shorter to its itinerary and abandoning longer paths. The bees also made adjustments when a flower was moved to a different location. These results suggest that bees don’t need a big-picture map to search their surroundings, says team member Mathieu Lihoreau, a behavioral ecologist at the University of Sydney.
“It’s amazing that these little creatures are as flexible as they are and have evolved these solutions that make maximum use of these little brains they are carrying around,” says behavioral biologist Fred Dyer of Michigan State University in East Lansing.
In a study published in The American Naturalist, a group of scientists led by the Zoological Society of London (ZSL) have used a technique developed to study human consumer choices to investigate what influences a baboon’s foraging decisions. The technique, known as discrete choice modelling, has rarely been used before in animal behaviour research. It showed how baboons not only consider many social and non-social factors when making foraging decisions, but also how they change these factors depending on their habitat and their own social traits.
On the surface, ants and the Internet don’t seem to have much in common. But two Stanford researchers have discovered that a species of harvester ants determine how many foragers to send out of the nest in much the same way that Internet protocols discover how much bandwidth is available for the transfer of data. The researchers are calling it the “anternet.”