Biotechnology

Fruit flies have more complex cognitive abilities than previously known

The virtual reality arena has been combined with an image of fluorescent brain activity in vivo to observe the neural dynamics of brain structures involved in learning and memory formation during conditioning. Credit: Dhruv Grover, UC San Diego KIBM

While they annoyingly buzz around a batch of bananas in our kitchens, fruit flies seem to have little to do with mammals. But as a model species for science, researchers are finding growing similarities between us and small insects that love fruit.


In a new study, researchers from the Cowley Institute of Brain and Mind (KIBM) at the University of California, San Diego, found that fruit flies (Drosophila melanogaster) have more developed cognitive abilities than previously thought. Using a specially created virtual reality environment with immersion, neurogenetic manipulation and visualization of brain activity in real time in vivo, scientists present new evidence on February 16 in the journal Nature about the excellent connections between the cognitive abilities of flies and mammals.

The multi-level approach of their investigations found attention, worked memory and conscious abilities to consciousness in fruit flies, cognitive abilities are usually tested only in mammals. The researchers were able to observe the formation, distraction and final extinction of traces of memory in their tiny brains.

“Despite the lack of obvious anatomical similarities, this study speaks to our daily cognitive functioning – what we pay attention to and how we do it,” said Ralph Greenspan, senior author of the study, a professor in California’s San Diego Department of Biological Sciences and an associate professor. director of KIBM. “Because all brains evolved from a common ancestor, we can draw a correspondence between areas of the brain of a fly and a mammal based on molecular characteristics and how we store our memories.”

Flies have more complex cognitive abilities than previously known

Researchers have created a panoramic arena of virtual reality, where flies are trained to associate the image of a vertical “T” with a negative thermal stimulus and an inverted “T” without heat. Credit: Dhruv Grover, UC San Diego KIBM

To get to the heart of their new findings, the researchers created an exciting virtual reality environment to test the fly’s behavior with visual stimulation and combined the reflected images with an infrared laser as a reverse thermal stimulus. The 360-degree panoramic arena allowed Drosophila to flutter its wings freely while remaining tethered, and virtual reality was constantly updated based on the movement of their wings (analyzed in real time using high-speed machine vision cameras) giving flies the illusion of free flight in the world. This gave researchers the opportunity to train and test flies to perform conditioning tasks, allowing insects to navigate from an image associated with a negative thermal stimulus to a second image unrelated to heat.

They tested two conditioning options: one in which the flies received visual stimulation by overlapping in time with heat (delayed conditioning), both ending together, or the other, conditioning the trail, waiting 5 to 20 seconds to deliver heat after showing and removing visual stimulation. The intermediate time is considered to be the “trace” interval during which the fly retains “traces” of visual stimulus in its brain, a feature that indicates attention, working memory, and consciousness in mammals.

Researchers have also found the brain to monitor calcium activity real time using a fluorescent molecule they genetically introduced into their brain cells. This allowed the researchers to record the formation and duration of the fly’s living memory, as they saw how the trace stored in the fly’s short-term (working) memory blinks and turns off. They also found that the distraction introduced during training – soft breathing – caused visual memory to disappear faster, which was the first time researchers had been able to prove such distraction in flies and suggested the need for attention in Drosophila memory formation.

“This work demonstrates not only that flies are capable of this higher form of trail conditioning and that learning is distracting for both mammals and humans, but also nervous activity The underlying processes of attention and working memory in flies show striking similarities to processes in mammals, “said Dhruv Grover, research faculty at UC San Diego KIBM and lead author of the new study.” This work shows that fruit flies can serve as a powerful model for the study of higher cognitive functions. Simply put, the fly continues to amaze how smart it is. ”

Flies have more complex cognitive abilities than previously known

The blows of the fly’s wings were mapped and analyzed in real time (200 Hz) to determine if they were flying straight (left), turning clockwise (center) or counterclockwise (right). The virtual reality images were then rotated to reflect the orientation of the flying fly. Credit: Dhruv Grover, UC San Diego KIBM

Scientists have also identified the area of ​​the fly’s brain where memory was formed and extinguished – an area known as the ellipsoidal body of the central complex of the fly, a place that corresponds to the cerebral cortex in the human brain.

In addition, the research team found that neurochemical dopamine is required for such training and higher cognitive functions. The data showed that reactions to dopamine increasingly occurred earlier in the learning process, ultimately anticipating future thermal stimuli.

Researchers are now exploring the details of how attention is physiologically coded in brain. Grover believes that the lessons learned from this model system are likely to directly help our understanding of human cognition strategies and the nervous disorders that disrupt them, but also contribute to new engineering approaches that lead to performance breakthroughs in artificial intelligence designs.


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Additional information:
Dhruv Grover et al., Differential mechanisms underlie the conditioning of traces and delays in Drosophila, Nature (2022). DOI: 10.1038 / s41586-022-04433-6

Citation: fruit flies have better cognitive abilities than previously known (2022, February 17), obtained February 17, 2022 from https://phys.org/news/2022-02-fruit-flies-sophisticated-cognitive -potentials.html

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