Shiva's Right Foot

Karma: 65

Shiva's Right Foot 11 Sep 2025 17:54 UTC
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in reply to: Seth Herd’s comment on: The Thalamus: Heart of the Brain and Seat of Consciousness

What I make of those studies is that stimulating the thalamus activates the whole corticothalemic loop.

Yes, precisely, but the inverse is not the case. It seems to make a strong argument that the loops “start” in the thalamus and that the thalamus has a primary role.

There you said the thalamus is where consciousness is happening. That is just flat wrong. It’s a system phenomenon.

Literally every empirical phenomenon is a system phenomenon at some level. Everything is the undifferentiated Brahman according to the Kharmic religions, and they’re basically right in some sense. But we make abstractions for events which are local in space and time.

US federal governance or a match of fisticuffs in an arena are complex system phenomena with many disparate influences but the language and abstractions we use place these things at a particular place and time because that is where these influences converge in time and space and resolve their conflicts.

(I think our discussion has become perfectly looped at this point.)

Shiva's Right Foot 11 Sep 2025 14:43 UTC
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in reply to: Seth Herd’s comment on: The Thalamus: Heart of the Brain and Seat of Consciousness
I do think having easy to understand language is important and advantageous. If everytime someone tried talking about the US government we got a long-winded nuancing that technically we are in a democracy and the people in Washington D. C. aren’t in control of the US government that would cause confusion.

an arena of competition

This really doesn’t seem to clash with the Washington D. C. metaphor; many people consider the power politics of the US government to be a competitive activity.

The broader issue is locality of events in time and space. Take sports competition: a common saying is that wins are made in the gym. There is a causal chain that leads back from any event to previous events not local in space which, with enough compute, have a knowable deterministic effect on the event’s outcome. We still don’t say that an MMA match takes place in the respective training gyms of the fighters, the fight happens in the octagon. That is where the disparate influences on the outcome of the fight converge in time and space to resolve conflicts to a unitary resolution.

As a more practical matter, what do you make of the studies I mentioned that produce awareness in either unresponsive human patients or anesthetized animals with only stimulation of the thalamus? That seems very powerfully indicative that the thalamus is where consciousness is happening.

Shiva's Right Foot 11 Sep 2025 3:06 UTC
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in reply to: Seth Herd’s comment on: The Thalamus: Heart of the Brain and Seat of Consciousness

So calling the thalamus the seat of consciousness is like saying the water comes from the valve because if that stuck closed no water flows.

Pardon the semantic argument, but:

Saying the thalamus is not the seat of consciousness is like saying Washington D. C. is not the seat of US government because voting constituents live all over the country or because Wall Street is a powerful lobbying group. Washington D. C. is considered the seat of US government because although disparate forces influence the decision making process in Washington, the actual process of combining these disparate influences into a coherent unitary final decision happens through the mechanisms present in Washington D. C.

Shiva's Right Foot 11 Sep 2025 2:50 UTC
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in reply to: Seth Herd’s comment on: The Thalamus: Heart of the Brain and Seat of Consciousness

More like a full second for most decisions, even in action games, and often many seconds per decision when I’m thinking about them.

I mean, I’ve done those FPS reaction time trainer things and I can feel the limit at about 200 ms, which is basically a notice decision and fire decision. I can maybe get a little lower but to do so I feel like I am potentiating actions and then canceling them until the dot pops up and I allow the action to go through. This isn’t the one I’ve used in the past (there were dots that popped on a field and you needed to mouse over to them and click on them).

https://humanbenchmark.com/tests/reactiontime

It has a nice graph that shows a peak for their users at around 200ms.

But that sort of thing “the dot has popped up over here” is a decision of a kind at least and involves the choice of that option over “the dot has not popped up over here.” Whether it is a “conscious decision” is a different matter; we are certainly aware of all the inputs to the decision, but the idea that it is itself a decision is not something we think about most of the time, unless we’re having an esoteric conversation like this.

How much of riding a bike is a decision? You could certainly lose your balance on purpose at basically any moment; you expend some mental effort in keeping yourself balanced. Are those “decisions?” At this point it is semantics.

What is clear is that the thalamus provides the unitary consensus of the mind so that you don’t do things like believe an object is two things at once (unless you’re on some heavy drugs).

Shiva's Right Foot 10 Sep 2025 16:54 UTC
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in reply to: Richard_Kennaway’s comment on: The Thalamus: Heart of the Brain and Seat of Consciousness
It is difficult to say fully conclusively, but I would speculate there is not an effect.

The absence of the massa intermedia when it is associated with a noticable disorder is usually part of a larger midline deformation which impacts a wide array of extremely important structures, so attributing causation to the absence of the massa intermedia is difficult.

So absence of the massa intermedia may be more of a symptom of other disorders rather than a cause of any particular mental effect.

Anyway, horse’s mouth:

Massa intermedia (MI), also known as interthalamic adhesion is an inconsistent bridge connecting the two thalami. Recent studies suggest MI contains functional neuronal tissue and is responsible for interhemispheric communication. Absence of MI has been linked to cognitive differences and psychiatric disorders. However, MI is naturally absent in up to 35 percent of cases but its true prevalence during life in humans is unknown. High resolution anatomical MR studies of 1410 subjects aged 2 months to 93 years were reviewed and those with MI were identified. Prevalence and characteristics of MI were identified and grouped by gender and decade of life. MI was present in 87.3% of the studied subjects. Absence of MI was noted in as early as first decade of life as well as all decades of life, but its absence increased with age, suggesting additional factors during life as mediators. Females had 2.75 times higher likelihood of MI presence than males. Size of MI decreased with increasing age up to age 70. Size of MI was best predicted by third ventricular width and age mediating a larger MI with smaller third ventricular size and younger age. MI is present in 87.3% of the population as determined in this MRI study. Absence of MI is identifiable in very early years of life, suggesting a congenital cause. MI’s prevalence, however, was also found to decrease with advancing age, suggesting a dynamic process of MI disappearance during life.

Borghei A, Piracha A, Sani S. Prevalence and anatomical characteristics of the human massa intermedia. Brain Struct Funct. 2021 Mar;226(2):471-480.

Shiva's Right Foot 10 Sep 2025 16:39 UTC
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in reply to: TAG’s comment on: The Thalamus: Heart of the Brain and Seat of Consciousness
One area of “decision” that the thalamus is involved in is attentional filtering of external sensory information. I mention that here:

I would speculate that an evolutionary story is that the thalamus moved from a role of filtering incoming sensory information for attentional purposes to filtering internal thoughts for similar attentional and reinforcement purposes. The thalamus extended from the task of deciding to which sensory patterns the mind attends to more general decision making. This evolutionary story is a strong argument to conceive of decision making as happening in the thalamus despite being influenced by the cortex and the decision-making process being inherently looped; the thalamus or thalamus-like structures have been making decisions since before there was a neocortex.

This sort of happens before conscious thought in adult human systems, although embryonically and evolutionarily it happens before the neocortex and consciousness exist.

Conscious decision making is a subset of overall decision making, perhaps, but it is the highest function of consciousness. Elements of consciousness like sensory and emotive qualia are there to push information into this particular function of consciousness: decision making.

Shiva's Right Foot 10 Sep 2025 13:57 UTC
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in reply to: TAG’s comment on: The Thalamus: Heart of the Brain and Seat of Consciousness
From the conclusion:

the thalamus has a distinctive central role in what may be the highest function of consciousness: making decisions.

Decision making is arguably the highest conscious function since it requires marshalling all of the information of the senses and cortex to contribute to the decision. Discrimination and deciding are the constant tasks of consciousness, happening dozens of times per second.

Edit: I think I may have been somewhat hasty and neglected subjective awareness. The discussion in the first part of the post really centers around subjective awareness, as mentioned by Ned Block in the clip I link as well as being the positive clinical result of Chudy et al. (2023, the study that had unresponsive patients return to full awareness after thalamus deep brain stimulation). This is very directly what that opening line is referring to as this research is very recent.

The post really addresses both of these: subjective awareness/experience and decision making. They are also intimately related; as I say in my follow up the qualia of subjective experience are inputs to the decision making function.

And let me somewhat refine “decision:” we are talking about a consensus mechanism in the brain, so the “decision” of the unitary individual consciousness or mind happens in the thalamus, similar to how the decision on a bill happens in the Senate Chamber through a method of combining information from senators. “Decisions” are also made by individual senators on how to vote, possibly involving other still further removed “decisions” in the causal process from lobbying groups or individual voters. But we still view the “decision” of The Senate to happen in the Senate Chamber during a vote, similarly to how the “decision” of the mind through the consensus mechanisms of the thalamus and TRN happens in the thalamus and TRN, even if cortical areas make their own disparate “decisions” in smokey backrooms of the cortex.

Shiva's Right Foot 10 Sep 2025 13:51 UTC
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in reply to: avturchin’s comment on: The Thalamus: Heart of the Brain and Seat of Consciousness
Footnote 2.

Shiva's Right Foot 9 Sep 2025 16:05 UTC
13 points
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in reply to: Richard_Ngo’s comment on: ricraz’s Shortform
This makes no mention of the repeal of the fairness doctrine nor the shift in financial model for major newspapers. The 1987 abolishment of the Fairness Doctrine led very directly to Rush Limbaugh gaining a national political audience.

The fairness doctrine of the United States Federal Communications Commission (FCC), introduced in 1949, was a policy that required the holders of broadcast licenses both to present controversial issues of public importance and to do so in a manner that fairly reflected differing viewpoints.[1] In 1987, the FCC abolished the fairness doctrine,[2] prompting some to urge its reintroduction through either Commission policy or congressional legislation.[3] The FCC removed the rule that implemented the policy from the Federal Register in August 2011.[4]

Rush Limbaugh used to be a regular music DJ in the 1970s. His political talk show was distributed nationally in 1988, soon after the cessation of Fairness Doctrine support by the Reagan administration. Carl McIntire was the Rush Limbaugh (maybe a little more Glenn Beck) of the 1960s and had his radio talk show shut down by the Fairness Doctrine after years of litigation. The legal challenges the Fairness Doctrine presented to McIntire prevented imitators, at least until the abolishment paved the way for Limbaugh, Fox News, Glenn Beck, Alex Jones, etc.

But over the last ten years the division has accelerated largely due to left outlets adopting a similar bias after switching financial models in the aftermath of the 2008 crisis. Former editorial page editor for the NYT James Bennet explains the shift here:

It became one of Dean Baquet’s frequent mordant jokes that he missed the old advertising-based business model, because, compared with subscribers, advertisers felt so much less sense of ownership over the journalism. I recall his astonishment, fairly early in the Trump administration, after Times reporters conducted an interview with Trump. Subscribers were angry about the questions the Times had asked. It was as if they’d only be satisfied, Baquet said, if the reporters leaped across the desk and tried to wring the president’s neck. The Times was slow to break it to its readers that there was less to Trump’s ties to Russia than they were hoping, and more to Hunter Biden’s laptop, that Trump might be right that covid came from a Chinese lab, that masks were not always effective against the virus, that shutting down schools for many months was a bad idea.

This Tablet article by Zach Goldberg documents statistical evidence of a cultural shift at some point near the middle of the previous decade. Usage of terms related to racism in major newspapers increased as much as 1500% in this period.

Starting well before Donald Trump’s rise to power, while President Obama was still in office, terms like “microaggression” and “white privilege” were picked up by liberal journalists. These terms went from being obscure fragments of academic jargon to commonplace journalistic language in only a few years—a process that I document here in detail. During this same period, while exotic new phrases were entering the discourse, universally recognizable words like “racism” were being radically redefined. Along with the new language came ideas and beliefs animating a new moral-political framework to apply to public life and American society.

Consider the graph below, which displays the usage of the terms “racist(s)” and “racism” as a percentage of all words in four of the nation’s largest newspapers from (depending on the publication) 1970 through 2019.

Yes, the article has awesome graphs.