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Category: neuroscience – Page 602

Using new technique, researchers make surprising discoveries about how flies’ brains respond to tastes

Taste matters to fruit flies, just as it does to humans: like people, the flies tend to seek out and consume sweet-tasting foods and reject foods that taste bitter. However, little is known about how sweet and bitter tastes are represented by the brain circuits that link sensation to behavior.

In a new study published in Current Biology, researchers at Brown University described how they developed a new imaging technique and used it to map the neural activity of fruit flies in response to sweet and bitter tastes.

“These results show that the way fly brains encode the taste of food is more complex than we had anticipated,” said study author Nathaniel Snell, who earned his Ph.D. in neuroscience from Brown in 2021 and conducted the research as part of his thesis.

‘No Other Material Behaves in This Way’: Scientist Identify a Compound With a Memory

It isn’t alive, and has no structures even approaching the complexity of the brain, but a compound called vanadium dioxide is capable of ‘remembering’ previous external stimuli, researchers have found.

This is the first time this ability has been identified in a material; but it may not be the last. The discovery has some pretty intriguing implications for the development of electronic devices, in particular data processing and storage.

“Here we report electronically accessible long-lived structural states in vanadium dioxide that can provide a scheme for data storage and processing,” write a team of researchers led by electrical engineer Mohammad Samizadeh Nikoo of École Polytechnique Fédérale de Lausanne in Switzerland in their paper.

Researchers discover a material that can learn like the brain

EPFL researchers have discovered that Vanadium Dioxide (VO2), a compound used in electronics, is capable of “remembering” the entire history of previous external stimuli. This is the first material to be identified as possessing this property, although there could be others.

Mohammad Samizadeh Nikoo, a Ph.D. student at EPFL’s Power and Wide-band-gap Electronics Research Laboratory (POWERlab), made a chance discovery during his research on in Vanadium Dioxide (VO2). VO2 has an insulating phase when relaxed at , and undergoes a steep insulator-to-metal transition at 68 °C, where its lattice structure changes. Classically, VO2 exhibits a : “the material reverts back to the insulating state right after removing the excitation” says Samizadeh Nikoo. For his thesis, he set out to discover how long it takes for VO2 to transition from one state to another. But his research led him down a different path: after taking hundreds of measurements, he observed a effect in the material’s structure.

Brains cells born together wire and fire together for life

Brain cells with the same “birthdate” are more likely to wire together into cooperative signaling circuits that carry out many functions, including the storage of memories, a new study finds.

Led by researchers from NYU Grossman School of Medicine, the new study on the brains of mice developing in the womb found that () with the same birthdate showed distinct connectivity and activity throughout the animals’ , whether they were asleep or awake.

Published online August 22 in Nature Neuroscience, the findings suggest that evolution took advantage of the orderly birth of neurons—by gestational day—to form localized microcircuits in the hippocampus, the region that forms memories. Rather than attempting to create each new from scratch, the researchers suggest, the brain may exploit the stepwise formation of neuronal layers to establish neural templates, like “Lego pieces,” that match each new experience to an existing template as it is remembered.

Human Skin Cells Reprogrammed Into Aged Neurons To Study Neurodegenerative Disorders

“We took skin biopsies from patients living with Huntington’s disease and reprogrammed the skin biopsies into neurons. We then compared these neurons with reprogrammed neurons from healthy people. The results are very interesting. We have found several defects that explain some of the disease mechanisms in neurons from patients with Huntington’s disease. Among other things, we observed that neurons from patients with Huntington’s disease show problems in breaking down and recycling a particular kind of protein – which can lead to a lack of energy in these cells”, says Johan Jakobsson, professor of neuroscience at Lund University.

The researchers have also measured the biological age of the cells and observed that the reprogrammed neurons retain their biological age, which is significant if they are to be used for research in the new model system.

Functional (ir)Relevance of Posterior Parietal Cortex during Audiovisual Change Detection

The posterior parietal cortex (PPC) plays a key role in integrating sensory inputs from different modalities to support adaptive behavior. Neuronal activity in PPC reflects perceptual decision-making across behavioral tasks, but the mechanistic involvement of PPC is unclear. In an audiovisual change detection task, we tested the hypothesis that PPC is required to arbitrate between the noisy inputs from the two different modalities and help decide in which modality a sensory change occurred. In trained male mice, we found extensive single-neuron and population-level encoding of task-relevant visual and auditory stimuli, trial history, as well as upcoming behavioral responses. However, despite these rich neural correlates, which would theoretically be sufficient to solve the task, optogenetic inactivation of PPC did not affect visual or auditory performance. Thus, despite neural correlates faithfully tracking sensory variables and predicting behavioral responses, PPC was not relevant for audiovisual change detection. This functional dissociation questions the role of sensory-and task-related activity in parietal associative circuits during audiovisual change detection. Furthermore, our results highlight the necessity to dissociate functional correlates from mechanistic involvement when exploring the neural basis of perception and behavior.

SIGNIFICANCE STATEMENT The posterior parietal cortex (PPC) is active during many daily tasks, but capturing its function has remained challenging. Specifically, it is proposed to function as an integration hub for multisensory inputs. Here, we tested the hypothesis that, rather than classical cue integration, mouse PPC is involved in the segregation and discrimination of sensory modalities. Surprisingly, although neural activity tracked current and past sensory stimuli and reflected the ongoing decision-making process, optogenetic inactivation did not affect task performance. Thus, we show an apparent redundancy of sensory and task-related activity in mouse PPC. These results narrow down the function of parietal circuits, as well as direct the search for those neural dynamics that causally drive perceptual decision-making.

How Scientists Revived Organs in Pigs an Hour After They Died

Yes, it does. Although OrganEx helps revitalize pigs’ organs, it’s far from a deceased animal being brought back to life. Rather, their organs were better protected from low oxygen levels, which occur during heart attacks or strokes.

“One could imagine that the OrganEx system (or components thereof) might be used to treat such people in an emergency,” said Porte.

The technology could also help preserve donor organs, but there’s a long way to go. To Dr. Brendan Parent, director of transplant ethics and policy research at NYU Grossman School of Medicine, OrganEx may force a rethink for the field. For example, is it possible that someone could have working peripheral organs but never regain consciousness? As medical technology develops, death becomes a process, not a moment.