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Category: neuroscience – Page 33

Brain circuit controlling compulsive behavior mapped

Researchers at Karolinska Institutet in Sweden have identified a brain circuit that can drive repetitive and compulsive behaviors in mice, even when natural rewards such as food or social contact are available. The study has been published in the journal Science Advances and may contribute to increased knowledge about obsessive-compulsive disorder and addiction.

Both animals and humans can become stuck in certain behaviors, but exactly how this is regulated in the brain has been unknown. Now, researchers have been able to show that a specific nerve circuit in the brain can put behaviors into a kind of “repeat mode,” where mice continue to perform the same actions over and over again, even when there is no longer any reward.

The researchers investigated a that runs from the , part of the brain’s reward system, to a region in the hypothalamus, which in turn is connected to the , an area that processes unpleasant experiences. By activating this circuit using optogenetics, a method in which are controlled by light, the researchers were able to induce a negative state in mice that led to repetitive behaviors such as digging and sniffing—even when food or other rewards were available.

ENeuro Blog

These images have been selected to showcase the art that neuroscience research can create.

As described by the authors: The cacophony voltage-gated calcium channel serves as the primary conduit for the calcium that triggers neurotransmitter release at countless synapses across the fruit fly (Drosophila) nervous system. To support this role at different synapse types, alternate splicing confers different biophysical properties upon cacophony. However, conventional techniques that might discriminate splice isoforms, such as antibodies, toxins, and pharmacological agents, are poorly suited for identifying splice isoforms across multiple neurons in a living nervous system.

This image demonstrates the transgenic expression of a bichromatic fluorescent exon reporter in most neurons of the fly brain. Green fluorescent protein (GFP) fluorescence was particularly bright relative to red fluorescent protein (TagRFP) in the α, β, and γ lobes of the mushroom body (MB), indicating a bias towards the inclusion of exon 11 at the expense of exon 10. Differences were also evident between neurons of the optic lobes.

How the cheese-noodle principle could help counter Alzheimer’s

Researchers at the Paul Scherrer Institute PSI have clarified how spermine—a small molecule that regulates many processes in the body’s cells—can guard against diseases such as Alzheimer’s and Parkinson’s: It renders certain proteins harmless by acting a bit like cheese on noodles, making them clump together. This discovery could help combat such diseases. The study has now been published in the journal Nature Communications.

Our life expectancy keeps rising—and as it does, age-related illnesses, including neurodegenerative diseases such as Alzheimer’s and Parkinson’s, are becoming increasingly common. These diseases are caused by accumulations in the brain of harmful protein structures consisting of incorrectly folded amyloid proteins. Their shape is reminiscent of fibers or spaghetti. To date, there is no effective therapy to prevent or eliminate such accumulations.

Yet a naturally occurring molecule in the body called spermine offers hope. In experiments, researchers led by study leader Jinghui Luo, in the Center for Life Sciences at the Paul Scherrer Institute PSI, have discovered that this substance is capable of extending the lifespan of small nematode worms, improving their mobility in old age, and strengthening the powerhouses of their cells—the mitochondria. Specifically, the researchers observed how spermine helps the body’s immune system eliminate nerve-damaging accumulations of amyloid proteins.

An Autism Epidemic?

The CDC website now says: “The claim ‘vaccines do not cause autism’ is not an evidence-based claim…” Psychologist David Myers from Hope College summarizes the relevant evidence.

You are an educated reader, so I know that you know that vaccines do not cause autism. However, you probably have also read headlines such as the recent U.S. Health and Human Services release, “Autism Epidemic Runs Rampant.”

Uptake, Adherence, and Attrition in Clinical Trials of Depression and Anxiety Apps: A Systematic Review and Meta-Analysis

A meta-analysis of RCTs found high uptake (92%) but moderate adherence (62%) to mental health apps among participants with depression or anxiety; posttest attrition averaged 18% and follow-up attrition 28%. Trials that included reminders, human contact, and omitted gamification saw lower dropout rates.

Question What are the expected rates of uptake, attrition, and adherence in randomized clinical trials of mental health apps for depression and anxiety?

Findings This systematic review and meta-analysis of 79 randomized trials found high rates of app uptake (94%) and moderate adherence (62%) among participants with depression or anxiety. Posttest attrition averaged 17%, and follow-up attrition was 27%.

Meaning These findings highlight the need to optimize app design and trial protocols to improve engagement and reduce attrition in digital interventions for depression and anxiety.

New on-switch for pain signaling pathway could lead to safer treatment and relief

Researchers at Tulane University, with a team of colleagues from eight other universities, have discovered a new nerve cell signaling mechanism that could transform our understanding of pain and lead to safer, more effective treatments.

The study, co-led by Matthew Dalva, director of the Tulane Brain Institute and professor of cell and in the School of Science and Engineering and Ted Price at the University of Texas at Dallas, reveals that neurons can release an enzyme outside the cell that switches on pain signaling after injury. The work, published in Science, offers new insight into how strengthen their connections during learning and memory.

“This finding changes our fundamental understanding of how neurons communicate,” Dalva said. “We’ve discovered that an enzyme released by neurons can modify proteins on the outside of other cells to turn on pain signaling—without affecting normal movement or sensation.”

Aging alters the protein landscape in the brain — diet can counteract this

A study by the Leibniz Institute on Aging – Fritz Lipmann Institute (FLI) in Jena shows that the chemical composition of proteins in the brain undergoes fundamental changes with aging. In particular, ubiquitylation—a process that marks proteins and thus controls their activity and degradation—undergoes drastic changes in the aging brain. Interestingly, a change in nutrition, such as short-term dietary restriction, can partially revert some of these molecular patterns. These findings open up new opportunities to better understand the aging process of the brain and related diseases.

Cerebrospinal fluid motion in the brain captured in remarkable detail

Cerebrospinal fluid (CSF) is a clear and watery liquid that flows in and around the brain and spinal cord. Its functions include protecting parts of the nervous system, delivering nutrients and removing metabolic waste.

Some neurological diseases, including Alzheimer’s disease, have been linked to the abnormal accumulation of proteins in the brain, which can cause damage to neurons. This accumulation of proteins could potentially be linked to variations in the flow of CSF in specific brain regions.

Researchers at Leiden University Medical Center, University of Amsterdam and the German Center for Neurodegenerative Diseases (DZNE) recently developed a new approach to study the motion of CSF, which is based on the widely used imaging technique magnetic resonance imaging (MRI).

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