Summary: Disruptions in how the body converts cholesterol into bile acids may play a key role in the development of dementia.
Source: PLOS
The blood-brain barrier is impermeable to cholesterol, yet high blood cholesterol is associated with increased risk of Alzheimer’s disease and vascular dementia. However, the underlying mechanisms mediating this relationship are poorly understood.
The psychological reasons why novelty—from visiting new places to socializing—makes us happier and healthier people.
There’s already a strong link between sleep and memory, and scientists have just found out more about how that relationship works: there are specific patterns of brain activity that open up windows on our past experiences, fixing them in our long-term memory.
These patterns involve the slow oscillations (SOs) of brain waves that normally accompany sleep, and the sharper sleep spindle bursts of activity that happen during dreamless slumber. It now seems that the precise way these two types of brain activity coordinate with each other makes a big difference in how well we remember something.
Our memories are essentially being reactivated during sleep via these two brain activity patterns, the researchers suggest, making us more likely to remember them. The stronger the reactivation, the more likely we are to be able to recall a memory later on.
More on thymus regeneration. Unless I understood wrong one patient’s epigenetic clock went from his mid 50’s to early 40’s.
Foresight Biotech & Health Extension Meeting sponsored by 100 Plus Capital.
2021 program & apply to join: https://foresight.org/biotech-health-extension-program/
Circa 2016
Accumulated evidence from genetic animal models suggests that the brain, particularly the hypothalamus, has a key role in the homeostatic regulation of energy and glucose metabolism. The brain integrates multiple metabolic inputs from the periphery through nutrients, gut-derived satiety signals and adiposity-related hormones. The brain modulates various aspects of metabolism, such as food intake, energy expenditure, insulin secretion, hepatic glucose production and glucose/fatty acid metabolism in adipose tissue and skeletal muscle. Highly coordinated interactions between the brain and peripheral metabolic organs are critical for the maintenance of energy and glucose homeostasis. Defective crosstalk between the brain and peripheral organs contributes to the development of obesity and type 2 diabetes. Here we comprehensively review the above topics, discussing the main findings related to the role of the brain in the homeostatic regulation of energy and glucose metabolism.
In normal individuals, food intake and energy expenditure are tightly regulated by homeostatic mechanisms to maintain energy balance. Substantial evidence indicates that the brain, particularly the hypothalamus, is primarily responsible for the regulation of energy homeostasis.1 The brain monitors changes in the body energy state by sensing alterations in the plasma levels of key metabolic hormones and nutrients. Specialized neuronal networks in the brain coordinate adaptive changes in food intake and energy expenditure in response to altered metabolic conditions ( Figure 1 ).2, 3.
The hormone, which is well known for regulating appetite, appears to influence neuronal development—a finding that could shed light on disorders such as autism that involve dysfunctional synapse formation.
Various insect species serve as valuable model systems for investigating the cellular and molecular mechanisms by which a brain controls sophisticated behaviors. In particular, the nervous system of Drosophila melanogaster has been extensively studied, yet experiments aimed at determining the number of neurons in the Drosophila brain are surprisingly lacking. Using isotropic fractionator coupled with immunohistochemistry, we counted the total number of neuronal and non-neuronal cells in the whole brain, central brain, and optic lobe of Drosophila melanogaster. For comparison, we also counted neuronal populations in three divergent mosquito species: Aedes aegypti, Anopheles coluzzii and Culex quinquefasciatus. The average number of neurons in a whole adult brain was determined to be 199380 ±3400 cells in D. melanogaster, 217910 ±6180 cells in Ae. aegypti, 223020 ± 4650 cells in An. coluzzii and 225911±7220 cells in C. quinquefasciatus. The mean neuronal cell count in the central brain vs. optic lobes for D. melanogaster (101140 ±3650 vs. 107270 ± 2720), Ae. aegypti (109140 ± 3550 vs. 112000 ± 4280), An. coluzzii (105130 ± 3670 vs. 107140 ± 3090), and C. quinquefasciatus (108530 ±7990 vs. 110670 ± 3950) was also estimated. Each insect brain was comprised of 89% ± 2% neurons out of its total cell population. Isotropic fractionation analyses did not identify obvious sexual dimorphism in the neuronal and non-neuronal cell population of these insects. Our study provides experimental evidence for the total number of neurons in Drosophila and mosquito brains.
Citation: Raji JI, Potter CJ (2021) The number of neurons in Drosophila and mosquito brains. PLoS ONE 16: e0250381. https://doi.org/10.1371/journal.pone.
Editor: Matthieu Louis, University of California Santa Barbara, UNITED STATES.
A brain–computer interface enables rapid communication through neural decoding of attempted handwriting movements in a person with paralysis.
Some of the most devastating health effects of a stroke or heart attack are caused by oxygen deprivation in the brain. Now, researchers at Massachusetts General Hospital (MGH) have identified an enzyme that may naturally protect the brain from oxygen deprivation damage, which could be a potential drug target to prevent issues arising from strokes or heart attacks.
Like many scientific breakthroughs, the new discovery came about while investigating something else entirely. The team was looking into a study from 2005 that found that a state of “suspended animation” could be induced in mice by having them inhale hydrogen sulfide. In the new study, the researchers set out to investigate the longer-term effects of that exposure.
The team exposed groups of mice to hydrogen sulfide for four hours a day, for five consecutive days. The suspended animation-like state followed, with the animals’ movement slowing and body temperatures dropping.
The biological clock is present in almost all cells of an organism. As more and more evidence emerges that clocks in certain organs could be out of sync, there is a need to investigate and reset these clocks locally. Scientists from the Netherlands and Japan introduced a light-controlled on/off switch to a kinase inhibitor, which affects clock function. This gives them control of the biological clock in cultured cells and explanted tissue. They published their results on 26 May in Nature Communications.
Life on Earth has evolved under a 24-hour cycle of light and dark, hot and cold. “As a result, our cells are synchronized to these 24-hour oscillations,” says Wiktor Szymanski, Professor of Radiological Chemistry at the University Medical Center Groningen. Our circadian clock is regulated by a central controller in the suprachiasmatic nucleus, a region in the brain directly above the optic nerve, but all our cells contain a clock of their own. These clocks consist of an oscillation in the production and breakdown of certain proteins.
