Departing the Vacuousness

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All things brain...

Started by Claireliontamer, July 12, 2017, 08:18:49 PM

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Quote from: Magdalena on February 11, 2021, 06:11:48 AM
Quote from: Icarus on February 10, 2021, 03:47:32 AM
I wonder whether Mags and Hermes has had to put up with similar dimwits.
Oh, yes.
  :picard facepalm:

I was telling a young lady that I used to work with that when I was a kid in El Salvador, my friends and I used to play around quicksand. She asked me,
" do you know where your loved ones are buried, then?"  :headscratch:
I said,
"We have cemeteries."

:picard facepalm: :lol:
I am what survives if it's slain - Zack Hemsey


"I've had several "spiritual" or numinous experiences over the years, but never felt that they were the product of anything but the workings of my own mind in reaction to the universe." ~Recusant


Here is an interesting article that explains some of the brain stuff that xSP has not told us about. Seems that there are some involuntary noises going on inside our skulls.


From memory (with an assist from the web) a post lost in the most recent downtime and re-boot of the site:

This thread has been snoozing for a while (despite a recent near miss). This seems an appropriate story to rouse it with.

"Escape from Oblivion: How the Brain Reboots after Deep Anesthesia" | University of Michigan Health Lab

QuoteMillions of surgical procedures performed each year would not be possible without the aid of general anesthesia, the miraculous medical ability to turn off consciousness in a reversible and controllable way.

Researchers are using this powerful tool to better understand how the brain reconstitutes consciousness and cognition after disruptions caused by sleep, medical procedures requiring anesthesia, and neurological dysfunctions such as coma.

In a new study published in the journal eLife, a team led by anesthesiologists George Mashour, M.D., Ph.D. of University of Michigan Medical School, Michigan Medicine, Max Kelz, M.D., Ph.D. of the University of Pennsylvania Medical School, and Michael Avidan, MBBCh of the Washington University School of Medicine used the anesthetics propofol and isoflurane in humans to study the patterns of reemerging consciousness and cognitive function after anesthesia.

In the study, 30 healthy adults were anesthetized for three hours. Their brain activity was measured with EEG and their sleep-wake activity was measured before and after the experiment. Each participant was given cognitive tests—designed to measure reaction speed, memory, and other functions—before receiving anesthesia, right after the return of consciousness, and then every 30 minutes thereafter.

The study team sought to answer several fundamental questions: Just how does the brain wake up after profound unconsciousness—all at once or do some areas and functions come back online first? If so, which?

"How the brain recovers from states of unconsciousness is important clinically but also gives us insight into the neural basis of consciousness itself," says Mashour.

After the anesthetic was discontinued and participants regained consciousness, cognitive testing began. A second control group of study participants, who did not receive general anesthesia and stayed awake, also completed tests over the same time period.

[Continues . . .]

The paper is open access:

"Recovery of consciousness and cognition after general anesthesia in humans" | eLife


Understanding how the brain recovers from unconsciousness can inform neurobiological theories of consciousness and guide clinical investigation. To address this question, we conducted a multicenter study of 60 healthy humans, half of whom received general anesthesia for 3 hr and half of whom served as awake controls. We administered a battery of neurocognitive tests and recorded electroencephalography to assess cortical dynamics.

We hypothesized that recovery of consciousness and cognition is an extended process, with differential recovery of cognitive functions that would commence with return of responsiveness and end with return of executive function, mediated by prefrontal cortex. We found that, just prior to the recovery of consciousness, frontal-parietal dynamics returned to baseline.

Consistent with our hypothesis, cognitive reconstitution after anesthesia evolved over time. Contrary to our hypothesis, executive function returned first. Early engagement of prefrontal cortex in recovery of consciousness and cognition is consistent with global neuronal workspace theory.

[¶ added - R]
"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


Another connection in the network. You've gotta love it.

"A Never-Before-Seen Type of Signal Has Been Detected in The Human Brain" | Science Alert

QuoteScientists have discovered a unique form of cell messaging occurring in the human brain that's not been seen before. Excitingly, the discovery hints that our brains might be even more powerful units of computation than we realized.

Early last year, researchers from institutes in Germany and Greece reported a mechanism in the brain's outer cortical cells that produces a novel 'graded' signal all on its own, one that could provide individual neurons with another way to carry out their logical functions.

By measuring the electrical activity in sections of tissue removed during surgery on epileptic patients and analysing their structure using fluorescent microscopy, the neurologists found individual cells in the cortex used not just the usual sodium ions to 'fire', but calcium as well.

This combination of positively charged ions kicked off waves of voltage that had never been seen before, referred to as a calcium-mediated dendritic action potentials, or dCaAPs.

[Continues . . .]

The paper is open access:

"Dendritic action potentials and computation in human layer 2/3 cortical neurons" | Science


The active electrical properties of dendrites shape neuronal input and output and are fundamental to brain function. However, our knowledge of active dendrites has been almost entirely acquired from studies of rodents.

In this work, we investigated the dendrites of layer 2 and 3 (L2/3) pyramidal neurons of the human cerebral cortex ex vivo. In these neurons, we discovered a class of calcium-mediated dendritic action potentials (dCaAPs) whose waveform and effects on neuronal output have not been previously described.

In contrast to typical all-or-none action potentials, dCaAPs were graded; their amplitudes were maximal for threshold-level stimuli but dampened for stronger stimuli. These dCaAPs enabled the dendrites of individual human neocortical pyramidal neurons to classify linearly nonseparable inputs—a computation conventionally thought to require multilayered networks.

[ ¶ added. -R]
"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


WOW!   There is much for we mortals to learn.


I agree, Icarus. It's a genuine pleasure to see what we learn, at least in the field of science, and for the most part.

* * *

We had something just upthread about the brain as it becomes "conscious," and here's something about the brain as it becomes less conscious.

"Going 'Blank' Looks a Lot Like Parts of The Brain Falling Asleep, Neuroscientists Find" | Science Alert

QuoteIt's easy to get distracted - whether you're daydreaming about a special someone while you should be working, or completely going blank and just taking a brain break.

Now, scientists have gained a better idea of what actually happens in our brains when we 'zone out', and it looks a lot like a part of the brain is... sort-of falling asleep.

"Attentional lapses occur commonly and are associated with mind wandering, where focus is turned to thoughts unrelated to ongoing tasks and environmental demands, or mind blanking, where the stream of consciousness itself comes to a halt," the team – led by neuroscientist Thomas Andrillon – wrote in their new paper.

"Our results suggest attentional lapses share a common physiological origin: the emergence of local sleeplike activity within the awake brain."

When you go to sleep, your brain experiences 'slow waves' of brain activity in the delta (1–4 Hz) or theta (4–7 Hz) ranges during non-rapid eye movement sleep. This is the slow descent before you get to the deep, dream-filled rapid eye movement (REM) sleep.

In contrast, there's this 'sleeplike activity' while you're awake – called local sleep by scientists. It's relatively well studied by researchers and it happens while you're completely awake, but localized brain activity enters a state which resembles sleep.

There are pretty specific times when we know that local sleep happens, particularly when we're really, really tired. But the researchers discovered something that looks very similar to local sleep in well-rested volunteers when their minds were wandering or blanking.

[Continues . . .]

The paper is open access:

"Predicting lapses of attention with sleep-like slow waves" | Nature Communications

I'd quote the abstract, but the quoted portion of the pop-sci article does that fairly thoroughly.
"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


Colloquial among a certain specialty of science, this "second brain" stuff. I've heard the term before, but might give you a blank look if you said, "Hey, did you know you have a second brain?" Nonetheless it is a part of the nervous system. In the fanciful way of a dear friend, I will go so far as to say that it may even have a sort of personality.   :thumbsup2:

"The 'Second Brain' in Your Gut Might Have Evolved Before The Brain in Your Head" | Science Alert

QuoteThe enteric nervous system (ENS) in our gut operates a lot like other neural networks in the brain and the spinal cord – so much so that it's often called the 'second brain'. Now a new study has revealed more about how exactly the ENS works.

Using a recently developed technique combining high-resolution video recordings with an analysis of biological electrical activity, scientists were able to study the colons of mice, and in particular the way that the gut moves its contents along.

One of the key findings was discovering how the thousands of neurons inside the ENS communicate with each other, causing contractions in the gastrointestinal tract to aid the digestive process. Up until now, it wasn't clear how these neurons were able to join forces to do this.

"Interestingly, the same neural circuit was activated during both propulsive and non-propulsive contractions," says neurophysiologist Nick Spencer from Flinders University in Australia.

The team found large bunches of connecting neurons firing to propel the contents of the colon further down the gut, via both excitatory (causing action) and inhibitory (blocking action) motor neurons.

The discovery means the ENS is made up of a more advanced network of circuitry, covering a wider section of the gut and involving a greater amount of different types of neurons working in tandem than had previously been thought.

Another important finding is that this activity is significantly different from the propulsion that's seen in other muscle organs around the body that don't have a built-in nervous system, such as lymphatic vessels, ureters, or the portal vein.

"The mechanism identified is more complex than expected and vastly different from fluid propulsion along other hollow smooth muscle organs," the researchers explain in their paper.

The team says it backs up the hypothesis that the ENS is in fact the 'first brain' rather than the second one – suggesting that it may have evolved in animals a long time before our actual brains took their current form.

[Continues . . .]

The paper appears to be open access.

"Long range synchronization within the enteric nervous system underlies propulsion along the large intestine in mice" | Nature Communications Biology


How the Enteric Nervous System (ENS) coordinates propulsion of content along the gastrointestinal (GI)-tract has been a major unresolved issue. We reveal a mechanism that explains how ENS activity underlies propulsion of content along the colon.

We used a recently developed high-resolution video imaging approach with concurrent electrophysiological recordings from smooth muscle, during fluid propulsion. Recordings showed pulsatile firing of excitatory and inhibitory neuromuscular inputs not only in proximal colon, but also distal colon, long before the propagating contraction invades the distal region.

During propulsion, wavelet analysis revealed increased coherence at ~2 Hz over large distances between the proximal and distal regions. Therefore, during propulsion, synchronous firing of descending inhibitory nerve pathways over long ranges aborally acts to suppress smooth muscle from contracting, counteracting the excitatory nerve pathways over this same region of colon. This delays muscle contraction downstream, ahead of the advancing contraction.

The mechanism identified is more complex than expected and vastly different from fluid propulsion along other hollow smooth muscle organs; like lymphatic vessels, portal vein, or ureters, that evolved without intrinsic neurons.

[¶ added. - R]

"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken

Ecurb Noselrub

I've always known that my gut has its own personality. It's a bit like a wolf - growling, howling, tearing at its prey.  It has certain demands and often overcomes the executive functions of my upstairs brain. It's a beast.


Mine definitely doesn't always listen to me.
Always question all authorities because the authority you don't question is the most dangerous... except me, never question me.

Dark Lightning

I guess this lends some scientific basis for the claim that some people talk out their asses.

I'm grinding my way Through Steven Pinker's "The Better Angels of our Nature". The brain stuff is quite interesting. He discusses regions and what they generally do. I was an electrical and then mechanical design and test engineer (though my degree is in physics) and I never went into the biological side.


From a second brain in the gut to mini-brains in glass, with proto-mini-eyeballs. 👀

"Scientists Grew Stem Cell 'Mini Brains'. Then, The Brains Sort-of Developed Eyes" | Science Alert


Brain organoid with optic cups at day 60 of development.
Image credit: Gabriel et al., Cell Stem Cell

Mini brains grown in a lab from stem cells have spontaneously developed rudimentary eye structures, scientists report in a fascinating new paper.

On tiny, human-derived brain organoids grown in dishes, two bilaterally symmetrical optic cups were seen to grow, mirroring the development of eye structures in human embryos. This incredible result will help us to better understand the process of eye differentiation and development, as well as eye diseases.

"Our work highlights the remarkable ability of brain organoids to generate primitive sensory structures that are light sensitive and harbor cell types similar to those found in the body," said neuroscientist Jay Gopalakrishnan of University Hospital Düsseldorf in Germany.

"These organoids can help to study brain-eye interactions during embryo development, model congenital retinal disorders, and generate patient-specific retinal cell types for personalized drug testing and transplantation therapies."

[Continues . . .]

The paper appears to be open access:

"Human brain organoids assemble functionally integrated bilateral optic vesicles" | Cell Stem Cell

"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


Always question all authorities because the authority you don't question is the most dangerous... except me, never question me.

Dark Lightning

:lol: Googly eyes on the brain? Where's Silver!?


Quote from: Dark Lightning on August 27, 2021, 05:36:42 PM
:lol: Googly eyes on the brain? Where's Silver!?

:lol: I'm here, trying to catch up! :grin:

I saw that article about the mini-brain with Googly eyes a few days ago, and I thought the exact same thing!  :P
I am what survives if it's slain - Zack Hemsey