Bigger Brains - Insect Consciousness? - Queasy Vs Hunger - Touch Vs. Pain - P

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Apr 20, 2024, 9:15:51 AMApr 20

https://www.scientificamerican.com/article/human-brains-may-be-getting-bigger/

Human Brains May Be Getting Bigger

By Diana Kwon

Overall, people in U.S. live longer than they did a hundred years ago. The growing number of people reaching old age has meant an increased proportion are at risk of developing dementia or Alzheimer’s disease, illnesses that typically strike later in life. However, researchers have found that, in the U.S. and elsewhere, dementia risk may actually be decreasing, at least in a subset of the population. A new study provides a potential explanation for this trend: Human brains may be getting larger—and thus more resilient to degeneration—over time.

Several large population studies in countries including the U.S. and Great Britain have found that, in recent decades, the number of new cases, or incidence, of dementia has declined. Among these is the Framingham Heart Study, which has been collecting data from individuals living in Framingham, Massachusetts since 1948. Now accommodating a third generation of participants, the study includes data from more than 15,000 people.

In 2016, Sudha Seshadri, a neurologist at UT Health San Antonio and her colleagues published findings revealing that while the prevalence—the total number of people with dementia—had increased, the incidence had declined since the late 1970s. “That was a piece of hopeful news,” Seshadri says. “It suggested that over 30 years, the average age at which somebody became symptomatic had gone up.”

These findings left the team wondering: What was the cause of this reduced dementia risk? While the cardiovascular health of the Framingham residents and their descendants—which can influence the chances of developing dementia—had also improved over the decades, this alone could not fully explain the decline. On top of that, the effect only appeared in people who had obtained a high school diploma, which, according to Seshadri, pointed to the possibility that greater resilience against dementia may result from changes that occur in early life.

https://www.quantamagazine.org/insects-and-other-animals-have-consciousness-experts-declare-20240419/

Insects and Other Animals Have Consciousness, Experts Declare

By Dan Falk

In 2022, researchers at the Bee Sensory and Behavioral Ecology Lab at Queen Mary University of London observed bumblebees doing something remarkable: The diminutive, fuzzy creatures were engaging in activity that could only be described as play. Given small wooden balls, the bees pushed them around and rotated them. The behavior had no obvious connection to mating or survival, nor was it rewarded by the scientists. It was, apparently, just for fun.

The study on playful bees is part of a body of research that a group of prominent scholars of animal minds cited today, buttressing a new declaration that extends scientific support for consciousness to a wider suite of animals than has been formally acknowledged before. For decades, there’s been a broad agreement among scientists that animals similar to us — the great apes, for example — have conscious experience, even if their consciousness differs from our own. In recent years, however, researchers have begun to acknowledge that consciousness may also be widespread among animals that are very different from us, including invertebrates with completely different and far simpler nervous systems.

The new declaration, signed by biologists and philosophers, formally embraces that view. It reads, in part: “The empirical evidence indicates at least a realistic possibility of conscious experience in all vertebrates (including all reptiles, amphibians and fishes) and many invertebrates (including, at minimum, cephalopod mollusks, decapod crustaceans and insects).” Inspired by recent research findings that describe complex cognitive behaviors in these and other animals, the document represents a new consensus and suggests that researchers may have overestimated the degree of neural complexity required for consciousness.

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https://www.nature.com/articles/d41586-024-01037-0

Why queasiness kills hunger: brain circuit identified

By Gillian Dohrn

No one wants to eat when they have an upset stomach. To pinpoint exactly where in the brain this distaste for eating originates, scientists studied nauseated mice.

The work, published in Cell Reports on 27 March1, describes a previously uncharacterized cluster of brain cells that fire when a mouse is made to feel nauseous, but don’t fire when the mouse is simply full. This suggests that responses to satiety and nausea are governed by separate brain circuits.

“With artificial activation of this neuron, the mouse just doesn’t eat, even if it is super hungry,” says Wenyu Ding at the Max Planck Institute for Biological Intelligence in Martinsried, Germany, who led the study.

Ding and colleagues suspected that this group of neurons was involved in processing negative experiences, such as feeling queasy, so they injected the mice with a chemical that induces nausea and then scanned the animals’ brains. This confirmed that the neurons are active when mice feel nauseous.

Using a light-based technique called optogenetics, the team artificially activated the neurons of mice that had been deprived of food in the hours before the experiment. When the neurons were ‘off’, the mice ate. When the researchers turned them on, the mice walked away mid-chow.

These brain cells could influence how fast you eat — and when you stop

Researchers also blocked the activity of these neurons in nauseated mice that were hungry and found that the mice overcame their nausea to eat.

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https://www.quantamagazine.org/pleasure-or-pain-he-maps-the-neural-circuits-that-decide-20240416/

Pleasure or Pain? He Maps the Neural Circuits That Decide.

By Ingrid Wickelgren

Ishmail Abdus-Saboor has been fascinated by the variety of the natural world since he was a boy growing up in Philadelphia. The nature walks he took under the tutelage of his third grade teacher, Mr. Moore, entranced him. “We got to interact and engage with wildlife and see animals in their native environment,” he recalled. Abdus-Saboor also brought a menagerie of creatures — cats, dogs, lizards, snakes and turtles — into his three-story home, and saved up his allowance to buy a magazine that taught him about turtles. When adults asked him what he wanted to be when he grew up, “I said I wanted to become a scientist,” he said. “I always raised eyebrows.”

Abdus-Saboor did not stray from that goal. Today, he is an associate professor of biological sciences at the Mortimer B. Zuckerman Mind Brain Behavior Institute at Columbia University, where he studies how the brain determines whether a touch to the skin is painful or pleasurable. “Although this question is fundamental to the human experience, it remains puzzling to explain with satisfying molecular detail,” he said. Because the skin is our largest sensory organ and a major conduit to our environment, it may hold clues for treating conditions from chronic pain to depression.

To find those clues, Abdus-Saboor probes the nervous system at every juncture along the skin-to-brain axis. He does not focus on skin alone or home in on only the brain as many others do. “We merge these two worlds,” he said. That approach, he added, requires mastering two sets of techniques, reading two sets of literature and attending two sets of scientific meetings. “It gives us a unique leg up,” he said. It has led to a landmark paper published last year in Cell that laid out the entire neural circuit for pleasurable touch.

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https://www.sciencenews.org/article/aimee-grant-autism-research-healthcare

Aimee Grant investigates the needs of autistic people

By Saima S. Iqbal

Before becoming a researcher, Aimee Grant worked as a caregiver for six years in Cornwall, England, supporting autistic adults in group homes. But only more than a decade later, after befriending an autistic colleague at a sociology conference, did she realize she was autistic herself.

The stereotypical view of autism as a brain impairment more commonly found in men made it difficult for Grant to make sense of her internal world. From an early age, she struggled to pick up on important social cues and found the sounds and scents in her environment distractingly painful. But like many children in her generation, she says, she grew accustomed to either dismissing or disguising her discomfort. It was by listening to some of the stories of her female peers that Grant saw that the label could fit.

Receiving a diagnosis in 2019 prompted her to “reframe [my] entire life,” she says. She began working with her mind rather than against it. She no longer felt the same pressure to seem as nonautistic as possible with friends and family members, and she began to make use of accommodations at work, such as a light filter for her computer monitor.

Today, as a public health researcher at Swansea University in Wales, Grant aims to uncover the lived experience of autistic people. Many scientists and clinicians see autism as a developmental disorder that hinders a person’s ability to understand and communicate with others. Grant believes that their work often obscures the heterogeneity of autism. And because many studies view autism as a disease, they overlook the reality that autistic people can feel more disabled by widespread misunderstanding and a lack of accommodations than by autistic traits themselves.

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