Neuroimmunology Center - Dennett & Consciousness - Exercise & Brain - Anger & Heart
Breedlove, S
https://www.nature.com/articles/d41586-024-01259-2
Found: the dial in the brain that controls the immune system
By Giorgia Guglielmi
A population of neurons in the brain stem, the stalk-like structure that connects the bulk of the brain to the spinal cord, acts as the master dial for the immune system.Credit: Voisin/Phanie/Science Photo Library
Scientists have long known that the brain plays a part in the immune system — but how it does so has been a mystery. Now, scientists have identified cells in the brainstem that sense immune cues from the periphery of the body and act as master regulators of the body’s inflammatory response.
The results, published on 1 May in Nature1, suggest that the brain maintains a delicate balance between the molecular signals that promote inflammation and those that dampen it — a finding that could lead to treatments for autoimmune diseases and other conditions caused by an excessive immune response.
The discovery is akin to a black-swan event — unexpected but making perfect sense once revealed, says Ruslan Medzhitov, an immunologist at Yale University in New Haven, Connecticut. Scientists have known that the brainstem has many functions, such as controlling basic processes such as breathing. However, he adds, the study “shows that there is whole layer of biology that we haven’t even anticipated”.
The brain is watching
After sensing an intruder, the immune system unleashes a flood of immune cells and compounds that promote inflammation. This inflammatory response must be controlled with exquisite precision: if it’s too weak, the body is at greater risk of becoming infected; if it’s too strong, it can damage the body’s own tissues and organs.
Previous work has shown that the vagus nerve, a large network of nerve fibres that links the body with the brain, influences immune responses. However, the specific brain neurons that are activated by immune stimuli remained elusive, says Hao Jin, a neuroimmunologist at the US National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, who led the work.
© 2024 Springer Nature Limited
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10 Brilliant Insights from Daniel Dennett
By Dan Falk
Daniel Dennett, who died in April at the age of 82, was a towering figure in the philosophy of mind. Known for his staunch physicalist stance, he argued that minds, like bodies, are the product of evolution. He believed that we are, in a sense, machines—but astoundingly complex ones, the result of millions of years of natural selection.
Dennett wrote more than a dozen books, some of them aimed at a scholarly audience but many of them directed squarely at the inquisitive non-specialist—including bestsellers like Consciousness Explained, Breaking the Spell, and Darwin’s Dangerous Idea. Reading his works, one gets the impression of a mind jammed to the rafters with ideas. As Richard Dawkins put it in a blurb for Dennett’s last book, a memoir titled I’ve Been Thinking: “How unfair for one man to be blessed with such a torrent of stimulating thoughts.”
Dennett spent decades puzzling over the existence of minds. How does non-thinking matter arrange itself into matter that can think, and even ponder its own existence? A long-time academic nemesis of Dennett’s, the philosopher David Chalmers, dubbed this the “Hard Problem” of consciousness. But Dennett felt this label needlessly turned a series of potentially-solvable problems into one giant unsolvable one: He was sure the so-called hard problem would evaporate once the various lesser (but still difficult) problems of understanding the brain’s mechanics were figured out.
Because he viewed brains as miracle-free mechanisms, he saw no barrier to machine consciousness, at least in principle. Yet he had no fear of Terminator-style AI doomsday scenarios, either. (“The whole singularity stuff, that’s preposterous,” he once told an interviewer for The Guardian. “It distracts us from much more pressing problems.”)
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https://www.scientificamerican.com/article/exercise-helps-your-brain-as-much-as-your-body/
Exercise Helps Your Brain as Much as Your Body
By J. David Creswell
Let’s start thinking differently about exercise.
Decades of exercise science research show that when people or animals are given a new exercise routine, they get healthier. But when thinking about the benefits of exercise, most people hold a strong body bias; they focus on how regular exercise builds more lean body mass, helps increase their strength and balance, or improves heart health. Exercise matters even more for our brains, it turns out, in ways that are often overlooked.
Here’s how we know. Animal exercise studies typically run rats for weeks on running wheels. The animals gleefully run every night, sprinting several miles over the course of an evening. There are wonderful health benefits in these studies of voluntary running—improved muscle tone and cardiovascular health, and many brain benefits too. But in some studies, there’s an additional experimental condition where some rats exercise with one crucial difference: it’s no longer voluntary exercise. Instead of a freestanding running wheel, rats run on a mechanized wheel that spins, forcing the animals to cover the same distance as the voluntary runners.
What happens? When the rats are forced to exercise on a daily basis for several weeks, their bodies become more physically fit, but their brains suffer. Animals regularly forced to exercise have the equivalent of an anxiety disorder, behaving on new tasks in highly anxious and avoidant ways. These animals are more anxious not only compared to the voluntary runners, but also to animals that are not given an opportunity to exercise at all. Yes, forced exercise might be worse than no exercise at all. This work suggests something important about the health benefits of exercise: it is not just about making our muscles work, but what exercise does to our brains. When exercise gives us a sense of control, mastery and joy, our brains become less anxious. If we take that away, by forcing exercise, we can shift it from helpful to harmful.
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https://www.nytimes.com/2024/04/30/us/politics/justice-department-reclassify-marijuana.html
Justice Dept. Recommends Easing Restrictions on Marijuana
By Eileen Sullivan, Glenn Thrush and Zolan Kanno-Youngs
The Justice Department said on Tuesday that it had recommended easing restrictions on marijuana in what could amount to a major change in federal policy.
Even though the move, which kicks off a lengthy rule-making process, does not end the criminalization of the drug, it is a significant shift in how the government views the safety and use of marijuana for medical purposes. It also reflects the Biden administration’s effort to liberalize marijuana policy in a way that puts it more in line with the public as increasingly more Americans favor legalizing the drug.
The decision comes at an opportune time for President Biden, who is trailing the presumptive Republican nominee, former President Donald J. Trump, as they approach the November election, according to a recent CNN poll.
It could also lead to the softening of other laws and regulations that account for the use or possession of cannabis, including sentencing guidelines, banking and access to public housing.
People familiar with the recommendation, speaking on the condition of anonymity, said Attorney General Merrick B. Garland planned to tell the White House Office of Management and Budget that the government should change the drug’s categorization. After the office assesses the recommendation, it will still face a long road before taking effect, including being subject to public comment.
The Associated Press earlier reported the Justice Department decision.
For more than half a century, marijuana has been considered a Schedule I drug, classified on the same level as highly addictive substances like heroin that the Drug Enforcement Administration describes as having no currently accepted medical use. Moving marijuana to Schedule III, as the Department of Health and Human Services recommended in August, would put it alongside less addictive substances like Tylenol with codeine, ketamine and testosterone, meaning that it would be subject to fewer restrictions on production and research, and that eventually it could be prescribed by a doctor.
© 2024 The New York Times Company
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https://www.washingtonpost.com/health/2024/05/01/anger-heart-disease-nih/
Anger has been linked to heart disease. A new study suggests why.
By Sabrina Malhi
The phrase “anger kills” might have a more literal meaning: New research suggests a possible reason frequent anger has been linked to an increased risk of cardiovascular disease. The study, published Wednesday in the Journal of the American Heart Association, emphasizes the potential health risks associated with intense anger and illuminates the influence of negative emotions on our overall well-being.
Funded by the National Institutes of Health, the study involved 280 healthy adults who were randomly assigned to a different eight-minute task, each designed to elicit feelings of anger, anxiety, sadness or neutrality. Before and after these emotional tasks, researchers assessed the participants’ endothelial health. Endothelial cells, which line the insides of blood vessels, are essential for maintaining vessel integrity and are vital for proper circulation and cardiovascular health.
The findings revealed that anger had a significant negative impact on endothelial function, limiting the blood vessels’ ability to dilate. The response was not as pronounced with anxiety or sadness.
According to Daichi Shimbo, a cardiologist and professor of medicine at Columbia University Irving Medical Center and the lead study author, this research marks a step toward understanding how different negative emotions particularly affect physical health.
“It's fascinating that anxiety and sadness did not have the same effect as anger, suggesting that the ways in which negative emotions contribute to heart disease differ,” Shimbo said.
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https://www.nature.com/articles/d41586-024-01207-0
Why it’s essential to study sex and gender, even as tensions rise
In 2023, students protested against a new policy in Texas, where parents would be notified if their child asks to be identified as transgender.Credit: Brett Coomer/Houston Chronicle/Getty
This week, Nature is launching a collection of opinion articles on sex and gender in research. Further articles will be published in the coming months. The series will highlight the necessity and challenges of studying a topic that is both hugely under-researched and, increasingly, the focus of arguments worldwide — many of which are neither healthy nor constructive.
Some scientists have been warned off studying sex differences by colleagues. Others, who are already working on sex or gender-related topics, are hesitant to publish their views. Such a climate of fear and reticence serves no one. To find a way forward we need more knowledge, not less.
Nearly 20 researchers from diverse fields, including neuroscience, psychology, immunology and cancer, have contributed to the series, which provides a snapshot of where scholars studying sex and gender are aligned — and where they are not. In time, we hope this collection will help to shape research, and provide a reference point for moderating often-intemperate debates.
In practice, people use sex and gender to mean different things. But researchers studying animals typically use sex to refer to male and female individuals, as defined by various anatomical and other biological features. In studies involving humans, participants are generally asked to identify their own sex and/or gender category. Here, gender usually encompasses social and environmental factors, including gender roles, expectations and identity.
© 2024 Springer Nature Limited
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