Astrocytes, for instance, may play a role in depression and anxiety
, if they think about the matter at all, probably think of thinking as something done by the huge network of specialised, electrically conductive cells that occupies the upper half of their skulls. And, as far as it goes, that is true. The 86bn neurons in a human brain do indeed do much of the cognitive heavy lifting. But not all of it.cell—microglia, oligodendrocytes and astrocytes—collectively called glial cells .
For example, axons carrying signals from the left and right ears to a particular part of the auditory cortex will differ in length, so those signals might be expected to take different amounts of time to arrive. Oligodendrocyte fine-tuning compensates for this, meaning that any remaining difference reflects the actual interval between the times of a sound’s arrival at each ear. And it is that real difference which the brain uses to locate from where a sound has come.
Biopsies suggest that astrocytes regulate between 50% and 90% of human-brain synapses in this way. Astrocytes’ meddling is thus the rule, not the exception. Many researchers therefore now talk explicitly of the “tripartite synapse” as the standard synapse in the brain. It is this three-element composition that makes it transistor-like, with one element regulating the passage of signals between the other two .
The emerging picture of the brain, then, is less an aristocracy—with neurons looking down on their glial inferiors—than a democratic society of cells working together to produce thoughts. In 2022 Alexey Semyanov and Alexei Verkhratsky of the Russian Academy of Sciences dubbed this idea the “active milieu” within the brain.
Current thinking is that misfiring microglia in those with autism fail to prune synapses thoroughly enough during brain development, resulting in overconnected brains with heightened sensitivity to stimuli, both sensory and emotional. Moreover, the effect that Dr Xu found disproportionately affects male mice—a bias that, perhaps not coincidentally, is also a feature of autism in human beings.
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Transient Receptor Potential Ankyrin-1-expressing vagus nerve fibers mediate IL-1β induced hypothermia and reflex anti-inflammatory responses - Molecular MedicineBackground Inflammation, the physiological response to infection and injury, is coordinated by the immune and nervous systems. Interleukin-1β (IL-1β) and other cytokines produced during inflammatory responses activate sensory neurons (nociceptors) to mediate the onset of pain, sickness behavior, and metabolic responses. Although nociceptors expressing Transient Receptor Potential Ankyrin-1 (TRPA1) can initiate inflammation, comparatively little is known about the role of TRPA1 nociceptors in the physiological responses to specific cytokines. Methods To monitor body temperature in conscious and unrestrained mice, telemetry probes were implanted into peritoneal cavity of mice. Using transgenic and tissue specific knockouts and chemogenetic techniques, we recorded temperature responses to the potent pro-inflammatory cytokine IL-1β. Using calcium imaging, whole cell patch clamping and whole nerve recordings, we investigated the role of TRPA1 during IL-1β-mediated neuronal activation. Mouse models of acute endotoxemia and sepsis were used to elucidate how specific activation, with optogenetics and chemogenetics, or ablation of TRPA1 neurons can affect the outcomes of inflammatory insults. All statistical tests were performed with GraphPad Prism 9 software and for all analyses, P ≤ 0.05 was considered statistically significant. Results Here, we describe a previously unrecognized mechanism by which IL-1β activates afferent vagus nerve fibers to trigger hypothermia, a response which is abolished by selective silencing of neuronal TRPA1. Afferent vagus nerve TRPA1 signaling also inhibits endotoxin-stimulated cytokine storm and significantly reduces the lethality of bacterial sepsis. Conclusion Thus, IL-1β activates TRPA1 vagus nerve signaling in the afferent arm of a reflex anti-inflammatory response which inhibits cytokine release, induces hypothermia, and reduces the mortality of infection. This discovery establishes that TRPA1, an ion channel known previously as a pro-inf
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Glasgow's Nailzone founder caught covid in middle of treatment for brain tumourKaren Kaye was put on a ventilator for four weeks after being rushed to hospital on Christmas Day in 2020. She died from her cancer diagnosis one year later.
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