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+--- Thread: Brainless single-cell seems able to "change its mind" + How microbiomes affect fear (/thread-7908.html)
Brainless single-cell seems able to "change its mind" + How microbiomes affect fear - C C - Dec 6, 2019
How microbiomes affect fear
https://www.quantamagazine.org/how-microbiomes-affect-fear-20191204/
EXCERPT: Our brains may seem physically far removed from our guts, but in recent years, research has strongly suggested that the vast communities of microbes concentrated in our digestive tract open lines of communication between the two. The intestinal microbiome has been shown to influence cognition and emotion, affecting moods and the state of psychiatric disorders, and even information processing. But how it could do so has been elusive.
[...] Focusing on fear, and specifically on how fear fades over time, researchers have now tracked how behavior differs in mice with diminished microbiomes. They identified differences in cell wiring, brain activity and gene expression, and they pinpointed a brief window after birth when restoring the microbiome could still prevent the adult behavioral deficits. They even tracked four particular compounds that may help to account for these changes. While it may be too early to predict what therapies could arise once we understand this relationship between the microbiome and the brain, these concrete differences substantiate the theory that the two systems are deeply entwined.
Pinning down these mechanisms of interaction with the brain is a central challenge in microbiome research, said Christopher Lowry, an associate professor of integrative physiology at the University of Colorado, Boulder. “They have some tantalizing leads,” he added... (MORE - details)
Brainless single-celled organism seems capable of changing its mind
https://newatlas.com/science/single-celled-organisms-complex-decision-making/
EXCERPT: . . . “They do the simple things first, but if you keep stimulating, they ‘decide’ to try something else,” says Jeremy Gunawardena, lead author of the study. “S. roeselii has no brain, but there seems to be some mechanism that, in effect, lets it ‘change its mind’ once it feels like the irritation has gone on too long. This hierarchy gives a vivid sense of some form of relatively complex, decision-making calculation going on inside the organism, weighing whether it’s better to execute one behavior versus another.”
The researchers speculate that single-celled organisms like S. roeselii may possess some form of cellular “cognition” that allows them to process complex information and make decisions. The research was published in the journal Current Biology. The team describes the work in the video below. (MORE - details)
RE: Brainless single-cell seems able to "change its mind" + How microbiomes affect fear - Yazata - Dec 7, 2019
It seems to me that these biologists are grievously anthropomorphizing their protozoa. They say, "We consider the behavior hierarchy as a form of sequential decision-making, in the sense that, when given similar stimulation repeatedly, the organism "changes its mind" about which response to give..."
In my opinion it's probably mechanical as opposed to mental. Perhaps stimulation excites chemical transmitters in the cell, and various events that the authors seemingly are interpreting as decisions simply have different activation thresholds. A relatively low concentration of this hypothetical chemical associated with stimulation elicits the bending behavior. A greater concentration produces the contraction behavior (the bending might be an incomplete contraction only on one side). And still more concentration produces the detachment, which combined with continued ciliary movement would result in the thing swimming away. Certainly it's easy to see how evolution might select for these kind of cellular physiological effects.
https://www.cell.com/action/showPdf?pii=S0960-9822%2819%2931431-9
I'll add that when I was looking a brackish pond-water with my microscope, Stentor was easily the most impressive protozoan in there. They are (comparatively) huge, compared to smaller things like Euglena. And they are obviously complex by single-celled standards, with lots of organelles and even something of a mouth with its cilia creating current to direct small food items in. They aren't fast-moving like Paramecium though, since they are fixed by a stalk-like appendage to physical objects. Paramecia are free-swimmers and dart around.
I like Stentors. They seem like one of the most advanced single-celled organisms to appear before multicellularity started hogging the spotlight. That being said, I'm not really comfortable with attributing psychological terms to them.
https://en.wikipedia.org/wiki/Stentor_(ciliate)
RE: Brainless single-cell seems able to "change its mind" + How microbiomes affect fear - confused2 - Dec 9, 2019
This is with reference to gut bacteria and fear - I find mine generally bother other people more than they bother me.
I'm pretty sure the brain has enough neural plasticity (a Syne theme) to deal with most things. Once you stop knowing where your towel is all kinds of unpleasantness follows. Unfortunately that same plasticity can allow and perpetuate internal storms of nightmarish proportions.
https://www.urbandictionary.com/define.php?term=Towel