Health and Medical News and Resources

General interest items edited by Janice Flahiff

Aging memories may not be ‘worse,’ just ‘different’

From The August 20, 2020 news release of the Washington University in St. Louis

Excerpts
“Memory is the first thing to go.”

Everyone has heard it, and decades of research studies seem to confirm it: While it may not always be the first sign of aging, some faculties, including memory, do get worse as people age.

It may not be that straightforward…..

….Much of the activity he was interested in is in an area of the brain referred to as the posterior medial network — which includes regions in the midline and toward the backside of the brain. In addition to memory, these areas are heavily involved in representing context and situational awareness. Some of those areas showed decreased activity in the older adults.

We do think the differences are memory-related,” Reagh said. At the boundaries, they saw differences in the levels of activity in the hippocampus that was related to memory in a different measurement — “story memory,” he called it.

“There might be a broad sense in which the hippocampus’s response to event boundaries predicts how well you are able to parse and remember stories and complex narratives,” no matter one’s age, Reagh said.

But for older adults, closer to the front of the brain, particularly the medial prefrontal cortex, things were looking up.

Activity in that area of the brain was ramped up in older adults. This area is implicated in broad, schematic knowledge — what it’s like to go to grocery store as opposed to a particular grocery store.

“What might be happening is as older adults lose some responsiveness in posterior parts of the brain, they may be shifting away from the more detailed contextual information,” Reagh said. But as activity levels heighten in the anterior portions, “things might become more schematic. More ‘gist-like.’”

In practice, this might mean that a 20-year-old noting an event boundary in a movie might be more focused on the specifics — what specific room are the characters in? What is the exact content of the conversation? An older viewer might be paying more attention to the broader picture — What kind of room are the characters in? Have the characters transitioned from a formal dinner setting to a more relaxed, after-dinner location? Did a loud, tense conversation resolve into a friendly one?

“Older adults might be representing events in different ways, and transitions might be picked up differently than, say, a 20-year-old,” Reagh said.

“An interesting conclusion one could draw is maybe healthy older adults aren’t ‘missing the picture.’ It’s not that the info isn’t getting in, it’s just it’s getting in differently.”

August 17, 2020 Posted by | biology | , , , | Leave a comment

Sex redefined : Nature News & Comment

The idea of two sexes is simplistic
Biologists now think there is a wider spectrum than that

From the February 18, 2015 Nature News Feature

““The main problem with a strong dichotomy is that there are intermediate cases that push the limits and ask us to figure out exactly where the dividing line is between males and females,” says Arthur Arnold at the University of California, Los Angeles, who studies biological sex differences. “And that’s often a very difficult problem, because sex can be defined a number of ways.”

The article goes on to explain DSDs (Differences/Disorders in Sexual Development) both in and out of the womb.

Read the entire news item here

August 13, 2020 Posted by | biology | , , , , , , , , , | Leave a comment

How psychedelic drug psilocybin works on brain

From the June 4, 2020 article at Johns Hopkins University Medicine

Research Story Tip:
Psychedelic Drug Psilocybin Tamps Down Brain’s Ego Center

Excerpt:
“Perhaps no region of the brain is more fittingly named than the claustrum, taken from the Latin word for “hidden or shut away.” The claustrum is an extremely thin sheet of neurons deep within the cortex, yet it reaches out to every other region of the brain. Its true purpose remains “hidden away” as well, with researchers speculating about many functions. For example, Francis Crick of DNA-discovery fame believed that the claustrum is the seat of consciousness, responsible for awareness and sense of self.”

What is known is that this region contains a large number of receptors targeted by psychedelic drugs such as LSD or psilocybin — the hallucinogenic chemical found in certain mushrooms. To see what happens in the claustrum when people are on psychedelics, Johns Hopkins Medicine researchers compared the brain scans of people after they took psilocybin with their scans after taking a placebo.

Their findings were published online on May 23, 2020, in the journal NeuroImage.

The scans after psilocybin use showed that the claustrum was less active, meaning the area of the brain believed responsible for setting attention and switching tasks is turned down when on the drug. The researchers say that this ties in with what people report as typical effects of psychedelic drugs, including feelings of being connected to everything and reduced senses of self or ego.

“Our findings move us one step closer to understanding mechanisms underlying how psilocybin works in the brain,” says Frederick Barrett, Ph.D., assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine and a member of the school’s Center for Psychedelic and Consciousness Research. “This will hopefully enable us to better understand why it’s an effective therapy for certain psychiatric disorders, which might help us tailor therapies to help people more.”

Read the whole article at https://www.hopkinsmedicine.org/news/newsroom/news-releases/research-story-tip-psychedelic-drug-psilocybin-tamps-down-brains-ego-center

August 13, 2020 Posted by | biology, Psychiatry | , , , , | Leave a comment

National Survey Shows Different Bacteria on Cellphones and Shoes

From the June 9, 2020 article at UC Davis

Microbes Mostly Harmless, Include Groups Barely Known to Science

“They found that shoes and cellphones from the same person consistently had distinct communities of microbes. Cellphone microbes reflected those found on people, while shoes carried microbes characteristic of soil. This is consistent with earlier results.

The shoe microbes were also more diverse than those found on a person’s phone.”…

…”Surprisingly, a substantial proportion of the bacteria came from groups that researchers call “microbial dark matter.” These microbes are difficult to grow and study in a lab setting and thus have been compared to invisible “dark matter” that astronomers think makes up much of the universe.

Since they are so difficult to grow in a lab, these dark matter groups have only been discovered as scientists have used genetic sequencing technology to look for microbes in the world around us. Although many of the dark microbial groups come from remote or extreme environments, such as boiling acid springs and nutrient-poor underground aquifers, some have been found in more mundane habitats, such as soil.

“Perhaps we were naïve, but we did not expect to see such a high relative abundance of bacteria from these microbial dark matter groups on these samples,” Eisen said. 

A number of these dark microbe groups were found in more than 10 percent of samples, with two groups, Armatimonadetes and Patescibacteria, being found in almost 50 percent of swabs and somewhat more frequently in those from shoes than those from phones. Armatimonadetes is known to be widespread in soil.  

“A remarkable fraction of people are traveling around with representatives from these uncultured groups on commonplace objects,” Coil said.”

August 13, 2020 Posted by | biology | , , , , , | Leave a comment

Are viruses alive? Perhaps we’re asking the wrong question

From the June 8, 2020 article at The Conversation

“The truth is, we don’t fully understand viruses, and we’re still trying to understand life. Some properties of living things are absent from viruses, such as cellular structure, metabolism (the chemical reactions that take place in cells) and homeostasis (keeping a stable internal environment).

This sets viruses apart from life as we currently define it. But there are also properties that viruses share with life. They evolve, for instance, and by infecting a host cell they multiply using the same cellular machinery.”

Read the entire article at https://theconversation.com/are-viruses-alive-perhaps-were-asking-the-wrong-question-139639

August 13, 2020 Posted by | biology | , , , | Leave a comment

   

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