GLP1 & Nausea - Night Owls - Migraines - Deciding Hand
Breedlove, S
Weight loss drugs without the nausea? Mouse study suggests it may be possible
By Mitch Leslie
Millions of people have taken glucagon-like peptide-1 (GLP-1) agonist drugs such as Ozempic to lose weight, despite the fact that the drugs can cause severe nausea and vomiting. But a new mouse study shows distinct groups of neurons in the brain diminish appetite and trigger nausea, a finding that could lead to less stomach-turning treatments that activate one set of cells and not the other.
“It’s a very solid paper,” says neuroscientist Chuchu Zhang of the University of California, Los Angeles, who wasn’t connected to the study. “It shows us something new” about the activity of GLP-1 agonists.
Scientists haven’t pinned down exactly how GLP-1 agonist drugs work, and previous studies have produced conflicting results on where they exert their effects. Some research suggests the drugs curb appetite by targeting the hypothalamus, a control center for physiological functions such as thirst and hunger that is located in the center of the brain. Other findings point to the rear portion of the brain, known as the hindbrain, and still others implicate the vagus nerve, which carries messages to and from organs such as the stomach and heart. All of these locations contain cells bearing GLP-1 receptors, to which the drugs bind.
Another key question is whether the drugs cause weight loss primarily because people feel full or because they feel nauseated—a side effect suffered by more than half of individuals who take the drugs. “Do we need the nausea and aversion [to food] to see the appetite suppression and weight loss?” asks neuroscientist Amber Alhadeff of the Monell Chemical Senses Center.
To answer that question, she and her colleagues first tried to pinpoint where GLP-1 agonists act. Using a genetically modified virus containing genes for either of two cell-killing molecules, they selectively eliminated cells bearing GLP-1 receptors in the hypothalamus, the hindbrain, or the vagus nerve. Only destroying the hindbrain cells prevented weight loss when mice received a GLP-1 agonist, suggesting this region curtails appetite. In a follow-up experiment, the researchers stimulated cells in the hindbrain and found that even slender mice lost weight.
© 2024 American Association for the Advancement of Science.
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Night owls’ cognitive function ‘superior’ to early risers, study suggests
Anna Bawden
The idea that night owls who don’t go to bed until the early hours struggle to get anything done during the day may have to be revised.
It turns out that staying up late could be good for our brain power as research suggests that people who identify as night owls could be sharper than those who go to bed early.
Researchers led by academics at Imperial College London studied data from the UK Biobank study on more than 26,000 people who had completed intelligence, reasoning, reaction time and memory tests.
They then examined how participants’ sleep duration, quality, and chronotype (which determines what time of day we feel most alert and productive) affected brain performance.
They found that those who stay up late and those classed as “intermediate” had “superior cognitive function”, while morning larks had the lowest scores.
Going to bed late is strongly associated with creative types. Artists, authors and musicians known to be night owls include Henri de Toulouse-Lautrec, James Joyce, Kanye West and Lady Gaga.
But while politicians such as Margaret Thatcher, Winston Churchill and Barack Obama famously seemed to thrive on little sleep, the study found that sleep duration is important for brain function, with those getting between seven and nine hours of shut-eye each night performing best in cognitive tests.
© 2024 Guardian News & Media Limited
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https://www.nature.com/articles/d41586-024-02222-x
What causes migraines? Study of ‘brain blackout’ offers clues
By Miryam Naddaf
About one-third of people who suffer from migraines experience a phenomenon known as aura before the headache.Credit: Tunatura/Getty
For one billion people worldwide, the symptoms can be debilitating: throbbing head pain, nausea, blurred vision and fatigue that can last for days. But how brain activity triggers these severest of headaches — migraines — has long puzzled scientists.
A study1 in mice, published in Science on 4 July, now offers clues about the neurological events that spark migraines. It suggests that a brief brain ‘blackout’ — when neuronal activity shuts down — temporarily changes the content of the cerebrospinal fluid, the clear liquid that surrounds the brain and spinal cord. This altered fluid, researchers suggest, travels through a previously unknown gap in anatomy to nerves in the skull where it activates pain and inflammatory receptors, causing headaches.
“This work is a shift in how we think the headaches originate,” says Gregory Dussor, a neuroscientist at the University of Texas at Dallas in Richardson. “A headache might just be a general warning sign for lots of things happening inside the brain that aren’t normal.”
“Migraine is actually protective in that way. The pain is protective because it’s telling the person to rest and recover and sleep,” says study co-author Maiken Nedergaard, a neuroscientist at the University of Copenhagen.
The brain itself has no pain receptors; the sensation of headaches comes from areas outside the brain that are in the peripheral nervous system. But how the brain, which is not directly linked to the peripheral nervous system, triggers nerves to cause headaches is poorly understood, making them difficult to treat.
© 2024 Springer Nature Limited
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Think you’ve decided what to buy? Actually, your brain is still deciding
Tijl Grootswagers Genevieve L Quek Manuel Varlet
You are standing in the cereal aisle, weighing up whether to buy a healthy bran or a sugary chocolate-flavoured alternative.
Your hand hovers momentarily before you make the final grab.
But did you know that during those last few seconds, while you’re reaching out, your brain is still evaluating the pros and cons – influenced by everything from your last meal, the health star rating, the catchy jingle in the ad, and the colours of the letters on the box?
Our recently published research shows our brains do not just think first and then act. Even while you are reaching for a product on a supermarket shelf, your brain is still evaluating whether you are making the right choice.
Read news coverage based on evidence, not tweets
Further, we found measuring hand movements offers an accurate window into the brain’s ongoing evaluation of the decision – you don’t have to hook people up to expensive brain scanners.
What does this say about our decision-making? And what does it mean for consumers and the people marketing to them?
There has been debate within neuroscience on whether a person’s movements to enact a decision can be modified once the brain’s “motor plan” has been made.
Our research revealed not only that movements can be changed after a decision – “in flight” – but also the changes matched incoming information from a person’s senses.
To study how our decisions unfold over time, we tracked people’s hand movements as they reached for different options shown in pictures – for example, in response to the question “is this picture a face or an object?”
Put simply, reaching movements are shaped by ongoing thinking and decision-making.
© 2010–2024, The Conversation US, Inc.
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