[ExI] Possible seat of consciousness found

William Flynn Wallace foozler83 at gmail.com
Fri Feb 14 13:39:44 UTC 2020

Perhaps they stimulated the ascending reticular activating system?  RAS.
bill w

On Fri, Feb 14, 2020 at 2:53 AM Stuart LaForge via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

> According to a study published in Neuron, the thalamus modulates
> consciousness. The thalamus is a small portion of the brain that is
> located just above the brain stem and is associated with relaying
> sensory information to the cerebral cortex. Experimenters found this
> out by anaesthetizing monkeys and electrically stimulating various
> portions of the brain. When the researchers stimulated their thalamus,
> the anaesthetized monkeys opened their eyes, reached for things, and
> acted like they were awake, but when the stimulation ceased, they went
> back to being unconscious.
> https://www.cell.com/neuron/fulltext/S0896-6273(20)30005-2#secsectitle0025
> Abstract:
> "Functional MRI and electrophysiology studies suggest that
> consciousness depends on large-scale thalamocortical and
> corticocortical interactions. However, it is unclear how neurons in
> different cortical layers and circuits contribute. We simultaneously
> recorded from central lateral thalamus (CL) and across layers of the
> frontoparietal cortex in awake, sleeping, and anesthetized macaques.
> We found that neurons in thalamus and deep cortical layers are most
> sensitive to changes in consciousness level, consistent across
> different anesthetic agents and sleep. Deep-layer activity is
> sustained by interactions with CL. Consciousness also depends on
> deep-layer neurons providing feedback to superficial layers (not to
> deep layers), suggesting that long-range feedback and intracolumnar
> signaling are important. To show causality, we stimulated CL in
> anesthetized macaques and effectively restored arousal and wake-like
> neural processing. This effect was location and frequency specific.
> Our findings suggest layer-specific thalamocortical correlates of
> consciousness and inform how targeted deep brain stimulation can
> alleviate disorders of consciousness."
> Popular science article:
> https://www.inverse.com/mind-body/tiny-area-of-the-brain-could-enable-consciousness
> Excerpt:
> "In a wild new experiment conducted on monkeys, scientists discovered
> that a tiny, but powerful area of the brain may enable consciousness:
> the central lateral thalamus. Activation of the central lateral
> thalamus and deep layers of the cerebral cortex drives pathways in the
> brain that carry information between the parietal and frontal lobe in
> the brain, the study suggests.
> This brain circuit works as a sort-of “engine for consciousness,” the
> researchers say, enabling conscious thought and feeling in primates.
> To zero in on this brain circuit, a scientific team put macaque
> monkeys under anesthesia, then stimulated different parts of their
> brain with electrodes at a frequency of 50 Hertz. Essentially, they
> zapped different areas of the brain and observed how the monkeys
> responded. When the central lateral thalamus was stimulated, the
> monkeys woke up and their brain function resumed — even though they
> were STILL UNDER ANESTHESIA. Seconds after the scientists switched off
> the stimulation, the monkeys went right back to sleep."
> Stuart LaForge
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