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I'm a Ph.D student in Cognitive Science and I'm currently writing my dissertation on the topic of conscious perception. I think this study is pretty damn inter

I'm a Ph.D student in Cognitive Science and I'm currently writing my dissertation on the topic of conscious perception. I think this study is pretty damn interesting because the cingulate cortex (ACC & PCC) along with the thalamus are implicated in states of consciousness (i.e. wake/sleep/coma/vegetation/etc) and also in "access consciousness" (i.e.: “consciousness” in the sense of “I am conscious of such and such”). Subjects dosed with psilocybin have decreased BOLD (blood-oxygen level-dependent) signals in these regions. BOLD signal essentially tells you how active a brain region is (the more active the region, the more energy it needs, so the more irrigation it requires), so this tells us that the thalamic and cingulate regions are relatively suppressed by psilocybin. This is congruent with a longstanding (albeit simplistic) theory on how hallucinogens work. The idea is that hallucinogens would actually be inhibitory in their function, but they would selectively inhibit regions that are, themselves, inhibitory. So in a hand-wavy way, you can think of the ACC as keeping imagination in check. It inhibits perceptual areas (that are also activated by imagination) so that when you imagine a tiger, you don’t actually _see_ a tiger. With psilocybin & LSD, this function is suppressed so you see the tiger. Again, I'm simplifying to the point of risking a collective beat-down from my colleagues and lab-mates, but I thought it might help illustrate what's groovy about this study.

d33 11y ago
Interesting! Is there a brain region related to telling apart results of imagination and our actual perception that would work as a fail-safe mechanism?
- Balgair 11y ago
  The ACC. Brains are squishy and evolved from fish, especially the basal ganglia parts like the ACC. They don't have fail-safe parts. Whatever gets 'routed' is going to synapse regardless of if it is 'real' or not. You cause a neuron to fire and it fires and sends it's signal onwards, it does not care why it fired. Caution, hand-waving abounds in this comment.
  - conceit 11y ago
    That's a bold claim indeed, especially with that attempt at an explanation. > You cause a neuron to fire and it fires Tautology much? > it does not care why it fired. That's not even good English grammar. I mean, it's a very informal style, that I only understand because the information is redundant. Of course there are fail-safe parts. I don't even need to study to see that redundancy is a vital feature of the nervous system. In the same way, the ACC probably isn't the only point of failure for certain perceptions of the environment.
- omginternets 11y ago
  The ACC is implicated in many, many, many things, but it always seems to rear its head when error-monitoring of some sort is involved. Any time you want to respond to a mis-prediction, an error of judgement, or some sort of high-level mismatch, you're pretty much guaranteed to see ACC involvement. The theory goes that beyond some differential threshold, the ACC detects the mismatch between the perception (the tiger in my example) and the sensation (the actual input into the system) and then "does something". We're not sure what that "something" is: it could -- to proceed by computational analogy -- raise an exception and signal some other process to regulate the system, or it may directly inhibit certain early visual neurons in an attempt to downplay percept. This theory could also be completely wrong.
mettamage 11y ago
I forgot where I read the idea but some neuroscientists proposed that consciousness in the brain is more a measure of interconnectivity of activated brain regions. Basically, whatever brain region communicates with each other allows for mixed matching, whatever that brain region does (synesthetic people are very concrete examples of this). What do you think? Could this be true? I find it interesting to consider but have a hard time understanding how the brainstem fits into this. -- psych. & computer science student with a strong interest in cognitive science & neuroscience
- Balgair 11y ago
  Continue your passion! Neuro is so cool and we need comp-sci people, at the least to process the data and help out with connecting VGA cables (I shudder at bio people's hard-coding). Interconnectivity in the brain is very stereotyped. Certain areas typically only talk to certain others. The 'connectome' in the brain is being mapped these days and there is a lot to learn, but I think we can say that the connectome is stereotypical. That's good, we can make a road map then! Consciousness is a tougher nut to crack, though. Many questions arise from disease studies like this one: https://www.newscientist.com/article/dn12301-man-with-tiny-brain-shocks-doctors/ https://www.newscientist.com/article/dn12301-man-with-tiny-b... . Obviously from that patient, he lives a normal life (within the IQ standard deviations) and no-one else saw deficits in him worth concern. Other patients report only balance issues and delayed speech with having half of all the body's neurons not develop: https://www.newscientist.com/article/mg22329861-900-woman-of-24-found-to-have-no-cerebellum-in-her-brain/ https://www.newscientist.com/article/mg22329861-900-woman-of.... Still other people have extreme deficits in short term memory from having comparatively small portions removed : https://en.wikipedia.org/wiki/Henry_Molaison https://en.wikipedia.org/wiki/Henry_Molaison . What I am saying is that the brain is a confounding mystery and we need the help of people in comp-sci. If you have the time, try to volunteer at your local university, we need the help.
  - stuxnet79 11y ago
    > Continue your passion! Neuro is so cool and we need comp-sci people, at the least to process the data and help out with connecting VGA cables (I shudder at bio people's hard-coding). What do you mean by the connectome is stereotypical? I was reading up on connectomes and was pleasantly surprised to find out that model organisms like C Elegans have been fully mapped but I haven't heard of any large insights being derived from this. In general what are the computational stumbling blocks in Neurosci at the moment? (I have a genomics background) I'd like to do a Phd in Cog Sci or Neurosci (computational) but I've been so stress free ever since moving to industry (from academia) 10 months ago I can't really see myself going back for the long haul.
is_this_tinder 11y ago
yeah but Joe Rogan says...

d33 11y ago

Interesting! Is there a brain region related to telling apart results of imagination and our actual perception that would work as a fail-safe mechanism?

Balgair 11y ago
The ACC. Brains are squishy and evolved from fish, especially the basal ganglia parts like the ACC. They don't have fail-safe parts. Whatever gets 'routed' is going to synapse regardless of if it is 'real' or not. You cause a neuron to fire and it fires and sends it's signal onwards, it does not care why it fired. Caution, hand-waving abounds in this comment.
- conceit 11y ago
  That's a bold claim indeed, especially with that attempt at an explanation. > You cause a neuron to fire and it fires Tautology much? > it does not care why it fired. That's not even good English grammar. I mean, it's a very informal style, that I only understand because the information is redundant. Of course there are fail-safe parts. I don't even need to study to see that redundancy is a vital feature of the nervous system. In the same way, the ACC probably isn't the only point of failure for certain perceptions of the environment.
omginternets 11y ago
The ACC is implicated in many, many, many things, but it always seems to rear its head when error-monitoring of some sort is involved. Any time you want to respond to a mis-prediction, an error of judgement, or some sort of high-level mismatch, you're pretty much guaranteed to see ACC involvement. The theory goes that beyond some differential threshold, the ACC detects the mismatch between the perception (the tiger in my example) and the sensation (the actual input into the system) and then "does something". We're not sure what that "something" is: it could -- to proceed by computational analogy -- raise an exception and signal some other process to regulate the system, or it may directly inhibit certain early visual neurons in an attempt to downplay percept. This theory could also be completely wrong.

mettamage 11y ago

I forgot where I read the idea but some neuroscientists proposed that consciousness in the brain is more a measure of interconnectivity of activated brain regions. Basically, whatever brain region communicates with each other allows for mixed matching, whatever that brain region does (synesthetic people are very concrete examples of this). What do you think? Could this be true? I find it interesting to consider but have a hard time understanding how the brainstem fits into this. -- psych. & computer science student with a strong interest in cognitive science & neuroscience

Balgair 11y ago
Continue your passion! Neuro is so cool and we need comp-sci people, at the least to process the data and help out with connecting VGA cables (I shudder at bio people's hard-coding). Interconnectivity in the brain is very stereotyped. Certain areas typically only talk to certain others. The 'connectome' in the brain is being mapped these days and there is a lot to learn, but I think we can say that the connectome is stereotypical. That's good, we can make a road map then! Consciousness is a tougher nut to crack, though. Many questions arise from disease studies like this one: https://www.newscientist.com/article/dn12301-man-with-tiny-brain-shocks-doctors/ https://www.newscientist.com/article/dn12301-man-with-tiny-b... . Obviously from that patient, he lives a normal life (within the IQ standard deviations) and no-one else saw deficits in him worth concern. Other patients report only balance issues and delayed speech with having half of all the body's neurons not develop: https://www.newscientist.com/article/mg22329861-900-woman-of-24-found-to-have-no-cerebellum-in-her-brain/ https://www.newscientist.com/article/mg22329861-900-woman-of.... Still other people have extreme deficits in short term memory from having comparatively small portions removed : https://en.wikipedia.org/wiki/Henry_Molaison https://en.wikipedia.org/wiki/Henry_Molaison . What I am saying is that the brain is a confounding mystery and we need the help of people in comp-sci. If you have the time, try to volunteer at your local university, we need the help.
- stuxnet79 11y ago
  > Continue your passion! Neuro is so cool and we need comp-sci people, at the least to process the data and help out with connecting VGA cables (I shudder at bio people's hard-coding). What do you mean by the connectome is stereotypical? I was reading up on connectomes and was pleasantly surprised to find out that model organisms like C Elegans have been fully mapped but I haven't heard of any large insights being derived from this. In general what are the computational stumbling blocks in Neurosci at the moment? (I have a genomics background) I'd like to do a Phd in Cog Sci or Neurosci (computational) but I've been so stress free ever since moving to industry (from academia) 10 months ago I can't really see myself going back for the long haul.

is_this_tinder 11y ago

yeah but Joe Rogan says...