It is not yet known how the immune system’s discovery of the pathogens leads to a change in behavior. “As this learned food avoidance can be found in all species, we investigated this question in a model organism – the fruit fly Drosophila,” explains the senior author. “Within this model, we can clarify how the brain and body interact with each other to trigger an avoidance reaction that is vital for survival.”

In the current study, the group had their test animals choose between two food sources. One of them was contaminated with the pathogenic bacterium Pseudomonas entomophila. The other contained a harmless Pseudomonas strain. The two food sources were otherwise completely identical.

Flies that have not yet had any bad experiences with the pathogen prefer the harmful food because they find its odor attractive. “As this is life-threatening for the animals, we wondered how animals that have consumed these bacteria with their food behave,” explains the scientist.

The pathogens did not remain undiscovered among the flies for long: The animals’ innate immune system has sensors that raise the alarm in cases such as this. “In our experiment, receptors were activated in them that respond to components of the bacterial cell wall,” explains another author.

These sensors mainly respond to the harmful Pseudomonas strain, but hardly respond at all to the harmless strain. Many of them sit on the surface of special neurons located near the fly’s throat. Via their branches, these neurons are connected not only to the fly’s brain but also to a fat store in the fly’s head. If the receptors raise the alarm in the presence of harmful microorganisms, this leads to the release of the neurotransmitter octopamine in the neurons, which is closely related to adrenaline. This travels through the neuronal branches to the fat store.

“The octopamine then triggers the formation of another neurotransmitter, dopamine, in the fat cells,” says the author. “The dopamine, in turn, is transported into the fly’s brain, where it causes the continuous, increased activation of neuronal networks that are important for learning and trigger an avoidance response.” The animals then tend to be deterred by the odor of pathogenic bacteria. “We were able to show that the flies chose the food source with the harmless germs following their experience with the spoiled food,” explains the scientist.

The adipose tissue is significantly involved in this learned behavioral change. But why is that so? “We still do not have a definitive answer,” says the author. “However, the flies’ decision may be linked to their nutritional status.”

Researchers at the University of Sussex, in collaboration with scientists from different institutes worldwide, have identified a blood test capable of early diagnosis of the most aggressive form of brain tumor. The technology has the potential to save lives. Lead author Professor Georgios Giamas and his team have identified distinctive biomarkers (molecules that act as signs of normal processes, diseases, or responses to treatment) within patient blood samples, which could signal the presence of glioblastoma, one of the most aggressive forms of brain tumor.

The study published in Cell Reports Medicine investigated whether a simple blood test—analyzing the cargo of tiny particles called small extracellular vesicles (sEVs) that are released by cells into the bloodstream—could accurately detect and classify these tumors.

More than 11,000 people are diagnosed with a primary brain tumor in the U.K. each year. Glioblastoma is the most common high grade primary brain tumor in adults, which means it can grow and spread exceptionally quickly. Currently, diagnosing glioma often requires risky brain surgery.

Horner’s syndrome (HS) occurs when there is interruption of the oculosympathetic pathway (OSP). This article reviews the anatomy of the OSP and clinical findings associated with lesions located at various positions along this pathway. The imaging findings of lesions associated with HS at various levels of the OSP, classified as preganglionic HS (first-and second-order neuron HS) or postganglionic HS (third-order neuron HS), are demonstrated.

The authors discovered that training mice to exhibit a placebo effect with one type of pain produces marked relief of several different types of pain, including pain caused by injury.

To establish that the native opioid peptides actually drive pain relief, similar to opioid painkillers such as morphine, the researchers employed a light-activated drug developed in Banghart’s lab called PhNX, for photoactivatable naloxone. Naloxone, also known as Narcan, is the medicine used to reverse opioid overdoses by blocking opioid receptors. Using light, they were able to precisely control the site and timing of opioid signaling interference. Using PhNX, the scienists found that both morphine-induced pain relief and placebo pain relief rely on opioid signaling in the vlPAG brain region.

Co-first author: “We essentially trained a mouse brain to create its own broad-spectrum painkillers on demand, precisely where they are needed to treat pain, without the off-target effects of opioid-based painkillers.”

“These results increase the translational relevance of rodent placebo models to clinical contexts, in which patients’ prior experiences with drugs and treatment settings can generalize to broader expectations of improvement,” the researchers conclude in their paper. ScienceMission sciencenewshighlights.

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Placebo effects, in which patients experience relief without therapeutic treatment, increasingly have been considered as potentially powerful clinical treatments for ailments such as depression and pain. Yet the neurological mechanisms underlying such processes are not fully understood.

Now, a multi-institutional team has pinpointed the brain circuitry responsible for placebo pain relief. Their findings, reported in the journal Neuron, describe brain regions that support placebo effects and identify sites where endogenous opioid neuropeptides (commonly referred to as endorphins) provide signals that are critical for placebo pain relief.