Transcript: Christof Koch Do you hear me? Do you hear me? Yes. Do you see me? Yes. The fact that you hear, not that you respond to my sound by moving your hand, the fact that you see, not the fact that you can navigate around this room, but you actually have a picture in Your head. The fact that you love, the fact that you hate, the fact that you dream, that you imagine, that you dread, those are all conscious experience. It’s the stuff of life, literally. (Time 0:03:32)
Transcript: Christof Koch The study of consciousness is really a modern phenomenon. It’s really René Descartes. So, you know, Aristotle and Plato, much as they are foundational fathers of philosophy, didn’t really have a position on the mind or on consciousness. That’s a modern thing. Where we have struggled is trying to put it in objective form. So you don’t access my consciousness and I don’t access your consciousness. And this makes it different from anything else that we study, different from a black hole, from a virus, from a brain. Because all those I can study with what philosophers call third-person properties, right? You can stick them in a magnet. You can point a telescope at it. We can agree on, you know, what’s the wavelength, what’s the waves, what’s the mass, what’s the molecular constituency. We can’t do that with consciousness. I believe you’re conscious. In fact, I ask you, how are you feeling today? You tell me, well, I’m a little bit depressed because what happened. Well, so I’m trying to get at your state of consciousness. But ultimately, it’s always an inference, whether it’s you or whether it’s a baby or whether it’s an animal that can’t directly talk because the language is another way to infer. So that makes it more difficult. (Time 0:05:37)
Transcript: Christof Koch Consciousness is not primary doing. Of course, we can do things, right? We do it all the time. That’s how we make a living. But consciousness is really more about being. It’s a state of being. And by the way, that’s also why computers, they can do everything we can do, but they can’t be what we are conscious. Please elaborate on that. We confound consciousness and behavior because we talk, we’re speaking apes, right? But if you take that away, you’re still highly conscious. If you don’t move, if you meditate or sleep, or you have a mystical experience, you’re sitting or a psychedelic experience, you’re sitting or lying, you’re not moving anybody, hardly Any overt movement, yet you’re highly conscious, right? So behavior is not required for consciousness, and consciousness, of course, is not required for behavior. (Time 0:11:53)
Transcript: Christof Koch We always live in the gravitational field of planet ego. It is always about me. It is always about me, me, me. And even if I don’t think explicitly, there’s things that I’m, you know, there are processes monitoring my consciousness to make sure that it’s always, it’s important for me. And it’s very rare, but of course, the self can also be highly dysfunctional. You can catastrophize, you can be highly anxious, you can think people insult you or they say bad things about you, while in fact they don’t at all. And so there are rare conditions of selflessness when just like an astronaut that can become weightless, you can become selfless. So during episodes when you are experiencing a state of flow, I used to have this when I wrote computer code when I was way younger, you can totally get absorbed by it, right? Or you read a book or you read an engaging movie or you play some sports or something or you’re Alex Holov and Klein, right? And partly these states are so addictive because it’s such you’ve just realized you spent the last 20 minutes in this heavenly state doing something, but again, the critic is gone. And of course, during high, during sometimes heroic dose of psychedelics, you can also totally lose a self, the sense of self, and you realize how profound, beautiful the world is without You, you know, the self being there and constantly interfering and relating it to what does it mean for me? What does it give me? It’s incredible. (Time 0:18:19)
Transcript: Christof Koch Bayesian is a view of uncertainty in the world. There’s this famous vicar, British vicar, Thomas Bayes in the 17th century that started this, this is called Bayesian, whereby I look at something and I try to infer, well, what’s the Underlying reason for it? And I update my, based on certain observations that I make, I continuously have this running estimate what I think is really going on. And this also includes my base assumption about the world, including political assumption, including assumption, how will people react or what’s the true motive of people? So the point that she’s trying to make with this perception box, it includes everything. So a benign, funny example is, do you remember, what was it called? Hashtag the dress? Oh, yeah. Okay. So remember, so this was the dress that went viral in 2015. It was a wedding dress where if you looked at it, roughly, I can’t remember the exact percentages, half the people saw it unambiguously as gold and white. That’s how I see it. There’s no question. Same. Yeah. Okay. Same. But half of other people see it as blue and black. And again, it’s not something guessing. Is it maybe one or the other? They just see it blue and black or, okay, so then people ask, well, is there anything real? What is the real color? Often people go, no, there is no real color. What there is are photons that are, you know, from the sun that strike the two-dimensional surface of the dress that get absorbed by my photoreceptors that then get processed, and they Get evaluated in one way in our brain, so we see it as white and gold and get evaluated differently in a different brain because we all have different priors. (Time 0:23:46)
Transcript: Christof Koch In psychedelics. This is called the integration period. So I would submit you had a transformative experience. You had what philosophers call direct acquaintance now with some form of racism, right? Subtle racism, right? In this VR. And now you’re doing the explicit work of reformulating everything. You’re changing literally your Bayesian priors. So I imagine you’re top down, you know, from let’s say prefrontal cortex back into whatever, you know, theory of mind, for instance, areas, right? You are changing priors. (Time 0:27:25)
Transcript: Christof Koch So for most of us, we grew up with a normal brain, and I think there the relevant circuits are the corticothalamo circuits. And we can, in fact, we can exploit this knowledge now to test whether someone is conscious. Because in principle, so what you can do, you can knock the brain using a technique called transcranial magnetic stimulation, right? And then you listen to its echo using a high-density EG net, okay? And you can see if you knock here or here, depending where exactly you knock, you get these up and down states. And if they last for, let’s see, two, three, 400 milliseconds, and they occur different places, you can formally compute what’s called brain complexity using Lempel-Ziv complexity. And you can show when everyone who’s either awake like us, or we asleep in a dream state, or we on ketamine, where we dissociate it. In all those cases, the brain complexity is high, it’s above a threshold. However, when you’re in a non-REM state, when you’re in a state of deep sleep, or you’re anesthetized, or you’re, of course, in the most extreme case, you’re brain dead, then the brain Complexity is very low. And in animals, we’ve even done at the Allen Institute, we’ve done this experiment where we can systematically manipulate the corticothalamocortical circuits to really show it Is this circuit that is really, that is the one that’s critically involved in consciousness. In fact, what we discovered over the last 10 years is this very abrupt threshold in brain complexity defined using this technique. There’s a thing called perturbation complex index. It’s a single number, PCI, between zero and one. Zero means there’s no complexity. It’s flat, like in a dead brain, flat line. One, it means every EG is totally, electrode is totally independent from anyone else. Never happens in a real brain. In real brain, typically, wake brain, you get things between 0.65 and 0.8, let’s see. There’s a sharp threshold, 0.31. Anyone that we’ve had now, there are 300 people that have both patient and normal people that have been measured. If you’re above the threshold of 0.31, you’re conscious. If you’re below the threshold, you’re unconscious. That probably means there’s this nonlinear, just like Hodgkin-Huxley, there’s probably a nonlinear circuit mechanism that once the circuit is intact, it’s sufficient to support Consciousness. (Time 0:43:48)
Transcript: Christof Koch Now, you can ask, well, this is all very nice. Why is this relevant? Well, it is relevant in the following case, something that could happen to any of us. I step out here onto the Pacific Coastal Highway. I get hit by a car, okay? I’m now unconscious. I get to the ICU, whether that’s a traumatic brain injury or cardiac arrest or hemorrhage. I’m unconscious. I’m like this. I might be aroused, so my eyes are open. I’m now what used to be called vegetative state, what’s now more often called behavioral unresponsive state, okay? And there are thousands of these people worldwide because with proper care, with proper nursing care, you can stay in this state for weeks or months or in the case of Terry Schiavo, 14 Years. Furthermore, what happens after typically in most cases, after four to five days, the doctors will talk with their loved ones. Is this what he would have wanted? And 70 to 90 percent of the time they decide, no, this is not what you wanted, and you withdraw life-sustaining therapy. But we now know that 25% of these patients have what’s called covert consciousness. They’re there. We know this because, for example, some of these patients, there was a big study last year in New England Journal of Medicine made a front page of the New York Times where you can show 25% Of these patients can still voluntarily up and down regulate their motor cortex in response to a command, clench your fist for 30 seconds, relax it. Clench your fist for 30 seconds, relax it. So these people that otherwise, when you ask them, sir, can you hear me? Can you track my finger? Can you pinch them very hard to see, do they do a withdrawal of limb reflex? They don’t do any of that. So they have what’s called a Glasgow Coma scale, very low Glasgow Coma scale or Coma and recovery GSC-R scale, very low, but they still seem to be conscious. They either have high brain complexity or they can modulate their brain. So this is now the first time ever that we have a practical way in people that cannot respond, that clinically, behaviorally are considered unresponsive, first to convince the family That although their loved one doesn’t respond doesn’t mean that they’re unconscious. And then try to see, well, okay, so this person is conscious. (Time 0:46:17)