Researchers identify possible physiological cause of brain deficits with aging

brain
Left hemisphere of J. Piłsudski's brain, lateral view. Credit: public domain

Like scratchy-sounding old radio dials that interfere with reception, circuits in the brain that grow noisier over time may be responsible for ways in which we slow mentally as we grow old, according to the results of new studies from UC San Francisco on young and older adults.

The new intracranial and electroencephalogram (EEG) research, published online September 22, 2015, in The Journal of Neuroscience, supports the neural noise hypothesis, which proposes that the signal-to-noise ratio in nerve circuits diminishes with aging and leads to worse performance. The studies were designed and conducted by Brad Voytek, PhD, when he was a postdoctoral research fellow working in the lab of Adam Gazzaley, MD, PhD, professor of neurology, physiology and psychiatry at the UCSF Center for Integrative Neuroscience.

In two new experiments, Voytek, now an assistant professor of cognitive science and neuroscience at UC San Diego, found that background noise in key cortical regions of the brain responsible for higher functions was associated with poorer memorization of visual information, and that this noise also was associated with age. He concluded that might be the mechanism behind aging-associated loss of cognitive ability, slowing of behavioral responses, uncertain memories and wavering concentration.

"Our measurement of noise seems to show up in aging, just as we thought it would," Voytek said.

The noise measured in the studies was random signaling that did not fit the pattern of the brain's natural oscillations. These oscillations are rhythmic patterns of electrical activity generated by nerve cells, or neurons, linked within the brain's circuitry. This activity occurs in addition to electrical signals generated by individual neurons.

In recent years brain oscillations have become an intense focus of research by Voytek and others seeking to discover any functional roles they might play. Emerging evidence suggests that oscillations might prime nerve circuits to respond more efficiently to stimuli.

"Imagine that are like surfers," Voytek said. "Nearby surfers experience the same waves, which are like the oscillations linking neurons in the brain. But like noise, additional interfering factors often disrupt the perfect wave at different times and different spots along the beach."

In one experiment on 15 consenting subjects, Voytek collected and analyzed voltage measurements from electrodes placed directly in contact with cortical regions of the brain during surgery by neurosurgeons searching for the specific location that triggered each patient's seizures. The intracranial study design eliminated detection of confounding signals from muscle. The alert study subjects performed a listening task, which in one of Voytek's earlier human studies resulted in a high degree of coordinated brain oscillations in these regions. In the new experiment Voytek's research team found that noise in the frontal cortex and in the temporal cortex was associated with age.

In the second experiment, the researchers collected data from EEG electrodes placed on the scalps of 11 healthy participants between the ages of 20 and 30 and 13 healthy participants between the ages of 60 and 70, while the research subjects performed a visual memorization test.

Researchers flashed one, two or three colored squares for less than one-fifth of a second, gave the subjects almost one second to memorize the colors, and then flashed a second display and asked the participants if the colors matched. The researchers used mathematical algorithms to extract measures of noise in the oscillations from data collected during the interval when the subjects were trying to memorize the colors.

On average, older subjects performed worse than younger subjects. The scientists determined that this poorer performance was due to additional noise in nerve circuits in the visual cortex; neurons did not appear to coordinate as well in generating lower-frequency oscillations. When the researchers accounted for the , age was no longer an independent, significant factor in performance in this experiment.

Voytek suggested an analogy. "A big group of friends can have a fairly normal conversation at home," he said, "but in a crowded bar everyone keeps asking each other, 'What did you say?' Similarly, instead of having a normal conversation, the that make up the memory networks in seemed to be talking over one another, leading to a communication breakdown and degrading their memory performance.

"I think these types of experiments will allow neuroscientists to explore the neural underpinnings of cognitive changes across normal aging and in a variety of disease states, including autism, Parkinson's and schizophrenia, each of which is associated with breakdowns in neural ."


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It don't mean a thing if the brain ain't got that swing

Journal information: Journal of Neuroscience

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JVK
Sep 22, 2015
Excerpt: "The noise measured in the studies was random signaling that did not fit the pattern of the brain's natural oscillations. These oscillations are rhythmic patterns of electrical activity generated by nerve cells, or neurons, linked within the brain's circuitry. This activity occurs in addition to electrical signals generated by individual neurons."

All signaling is progressively disrupted by the accumulation of viral microRNAs that link viruses from entropic elasticity to genomic entropy. The first effects of the viruses are on the de novo creation of olfactory receptor genes, which is why it is important to understand how to avoid DNA damage that can be repaired during RNA-mediated events.

See: Linking Viral Discovery with Causality http://labroots.c...r/id/136

This webinar will help you to link viruses to effects of food odors and pheromones on the physiology of reproduction in health and pathology.

JVK
Sep 22, 2015
See also: http://phys.org/n...die.html

Virus-perturbed RNA-mediated protein folding is linked to all pathology. That's why loss of the sense of smell predicts dysfunction associated with Alzheimer's, Parkinson's, and other neurodegenerative diseases.

See also: Pheromones and the luteinizing hormone for inducing proliferation of neural stem cells and neurogenesis http://www.freshp...8009.php

Claims that human pheromones do not exist may have led researchers to abandon this patent. I often wonder who or what motivates pseudoscientists to claim that human pheromones don't exist. Could it just be the ignorance of evolutionary theorists or are big bang cosmologists and drug manufacturers also part of the problem?

Sep 22, 2015
"Virus-perturbed RNA-mediated protein folding is linked to all pathology."

Repeating a lie doesn't make it true.

JVK
Sep 22, 2015
Repeating a lie doesn't make it true.


Does that mean you won't be watching the webinar and will probably forever remain a biologically uninformed science idiot?

Excerpt: The majority of emerging diseases are infections with viruses that jump species barriers from wildlife or domestic animals to humans. The advent of molecular methods like high-throughput sequencing dramatically scaled viral discovery in humans and animals. Efficient and (nearly) unbiased discovery has expanded our understanding of the complexity of viral families, can inform individualized medicine, can quickly identify emerging disease, and even potentially can anticipate emergence. Many of these novel viruses are innocuous, so along with powerful discovery tools comes a responsibility in the medical research community to uncover viral pathogenesis and to clearly define associations, if present, with disease.

JVK
Sep 22, 2015
The picture placed into the context of ecological variation and ecological adaption reveals that common functions of viral miRNAs across divergent families include: autoregulation of virus gene expression, regulation of viral persistence/latency, alteration of the cell cycle, and avoidance of host defenses.

Only serious scientists and at least one science fiction author have seen this emerging picture. Creationists are among the serious scientists, but so far no evolutionary theorist or theoretical physicist seems to have learned enough about biologically-based cause and effect to see the nose on their face and/or link olfaction and pheromones to feedback loops and RNA-mediated cell type differentiation in species from microbes to humans.

http://medicalxpr...man.html

Sep 23, 2015

Creationists are among the serious scientists,

@JVK

I like that, damning yourself with your own words. It's going to follow you.

JVK
Sep 23, 2015
I like that, damning yourself with your own words. It's going to follow you.
.

Thanks. See also:

http://www.theatl...s_thread

"Going forward, we can combine techniques like this with portable sequencing and have a diagnostic device which provides incredibly rich data for clinicians and epidemiologists. Ultimately what we would like is an entirely unbiased method that captured all pathogens—known and unknown—with exquisite sensitivity."

Re: "...an entirely unbiased method that captured all pathogens—known and unknown—with exquisite sensitivity.

I do not think it is possible for theorists to behave as if they were serious scientists and/or creationists. Theorists start with a biased view of life and ridiculous claims that refute what is known about physics, chemistry, and molecular epigenetics.

If we continue to let them do that, they will kill us all.

Sep 23, 2015
I often wonder ...claim that human pheromones don't exist
@jk
you still can't read?
THE EVIDENCE DOESN'T SUPPORT YOUR CLAIMS
there is no robust bioassay-led evidence for the widely published claims that four steroid molecules are human pheromones: androstenone, androstenol, androstadienone and estratetraenol. In the absence of sound reasonsto test the molecules, positive results in studies need to be treated with scepticism as these are highly likely to be false positives. Common problems include small sample sizes, an overestimate of effect size (as no effect can be expected), positive publication bias and lackof replication. Instead, if we are to find human pheromones, we need to treat ourselves as if we were a newly discovered mammal, and use the rigorous methods already proven successful in pheromone research on other species.
http://rspb.royal...full.pdf

Sep 23, 2015
Creationists are among the serious scientists, but so far no evolutionary theorist or theoretical physicist seems to have learned enough about
REPEATING PSEUDOSCIENCE doesn't make you a serious scientist, nor does it advocate actual evidence based science
it LABELS you a PSEUDOSCIENTIST
If we continue to let them do that, they will kill us all.
the only reason you continue to repeat THIS claim is because you want people to react and side with your position out of fear and ignorance

here is the problem you have:
1- you DO NOT UNDERSTAND THE SCIENTIFIC METHOD

2- you DO NOT UNDERSTAND what ANY scientific theorist builds upon or generates hypothesis about

3- you DO NOT UNDERSTAND what a scientific theory is nor how it becomes a theory or validated

so Vietvet is right: repeating a lie doesn't make it true any more than flying over Rome makes you a Ferrari

(and owning a sports car doesn't make you a racecar driver, either)
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