Inverse p-zombies: the other direction in the Hard Problem of Consciousness

post by gwern · 2011-12-18T21:32:26.850Z · score: 21 (35 votes) · LW · GW · Legacy · 31 comments

Contents

  3. Inverse zombies
  4. Anesthesia awareness and anesthetic depth
  5. Philosophical implications of i-zombies
  6. The hard problem of unconsciousness
  Further reading
  References
None
31 comments

402. "Nothing is so certain as that I possess consciousness." In that case, why shouldn't I let the matter rest? This certainty is like a mighty force whose point of application does not move, and so no work is accomplished by it.

403. Remember: most people say one feels nothing under anaesthetic. But some say: It could be that one feels, and simply forgets it completely.

--Wittgenstein, Zettel (1929-1948)

I offer for LW's consideration the interesting 2008 paper "Inverse zombies, anesthesia awareness, and the hard problem of unconsciousness" (Mashour & LaRock; NCBI); the abstract:

Philosophical (p-) zombies are constructs that possess all of the behavioral features and responses of a sentient human being, yet are not conscious. P-zombies are intimately linked to the hard problem of consciousness and have been invoked as arguments against physicalist approaches. But what if we were to invert the characteristics of p-zombies? Such an inverse (i-) zombie would possess all of the behavioral features and responses of an insensate being, yet would nonetheless be conscious. While p-zombies are logically possible but naturally improbable, an approximation of i-zombies actually exists: individuals experiencing what is referred to as "anesthesia awareness." Patients under general anesthesia may be intubated (preventing speech), paralyzed (preventing movement), and narcotized (minimizing response to nociceptive stimuli). Thus, they appear--and typically are--unconscious. In 1-2 cases/1000, however, patients may be aware of intraoperative events, sometimes without any objective indices. Furthermore, a much higher percentage of patients (22% in a recent study) may have the subjective experience of dreaming during general anesthesia. P-zombies confront us with the hard problem of consciousness--how do we explain the presence of qualia? I-zombies present a more practical problem--how do we detect the presence of qualia? The current investigation compares p-zombies to i-zombies and explores the "hard problem" of unconsciousness with a focus on anesthesia awareness.

3. Inverse zombies

What would an inverse (i-) zombie look like? Since the p-zombie is a creature that behaves and responds as if it were conscious when in fact it is unconscious, we posit an i-zombie to be a creature that appears to be unconscious when in fact it is conscious. Any query of a p-zombie elicits a response to indicate consciousness; thus, any query of an i-zombie should thus elicit a response (or lack thereof) to indicate the absence of consciousness. Characteristics of the unconscious appearance of an i-zombie could be unresponsiveness to verbal commands, absence of spontaneous or evoked vocalization or speech, absence of spontaneous or evoked movement, and unresponsiveness to noxious stimulus. Like the p-zombie, the concept of the i-zombie entails no logical contradiction and hence can be considered both conceivable and possible. Unlike the p-zombie, however, i-zombies are naturally probable. We argue that a subset of patients experiencing awareness during general anesthesia, or ‘‘anesthesia awareness,” may fall into the category of i-zombie.
Having looked at some differences, we might also consider some similarities between p-zombies and i-zombies. It would seem that whatever solution we find for the problem of detecting consciousness in the case of i-zombies would be equally applicable to p-zombies in some important sense. What sense do we have in mind? In i-zombie cases, some type of consciousness detector could be used to confirm or disconfirm the hypothesis that anesthetized (or possibly even comatose) patients are conscious. In p-zombie cases, we could also use some type of consciousness detector to confirm or reject the same hypothesis with respect to infants, humans, animals, or aliens, which behave and function as if they are conscious. A consciousness detector of some sort would have to be able to distinguish between the presence and absence of consciousness in any possible creature and would therefore apply in detecting both p-zombies and i-zombies. Below we explore potential solutions to this consciousness detection problem (see Section 5).

4. Anesthesia awareness and anesthetic depth

Although the terms 'awareness' and 'explicit recall'are distinct and dissociable cognitive processes, in the clinical practice of anesthesiology 'anesthesia awareness' denotes both awareness and subsequent explicit recall of intraoperative events. Anesthesia awareness is a problem receiving increased attention by clinicians, patients, and the general public. A multi-center American study estimated incidence of awareness with explicit recall of approximately 0.13% (Sebel et al., 2004), a rate consistent with large European studies demonstrating awareness in 1-2/1000 cases (Sandin, Enlund, Samuelsson, & Lennmarken, 2000). A proportion of patients experiencing awareness may subsequently develop serious psychological sequelae, including post-traumatic stress disorder (Osterman, Hopper, Heran, Keane, & van der Kolk, 2001).
There are a number of subjective states that are associated with general anesthesia. In a recent study, dreaming has been reported in 22% of patients undergoing elective surgery (Leslie, Skrzypek, Paech, Kurowski, & Whybrow, 2007). Awareness itself can vary from the transient perception of conversations in the operating room to the sensation of being awake, paralyzed, and in pain (Sebel et al., 2004). The condition of anesthesia awareness is truly a clinical ‘‘problem of consciousness.” This can also occur in patients with neurologic injury leading to vegetative states or locked-in syndromes (Laureys, Perrin, & Bredart, 2007).
...These shortcomings led to the development of EEG techniques to assess anesthetic depth and detect consciousness. In the 1930s, it was demonstrated that the EEG was sensitive to the effects of anesthetics (Gibbs, Gibbs, & Lennox, 1937). There is not, however, a unique electrical signature that is common to all agents. Furthermore, the apparatus is bulky, labor intensive, and requires a dedicated observer in the operating room. Due to these limitations, processed EEG modules that often rely on Fourier transformation have been developed. Such 'awareness monitors' include the Bispectral Index, Narcotrend, Patient State Index, A-line, and others (Mashour, 2006). In general, these modules collect raw EEG and/or electromyographic data, subject them to Fourier transform, and then analyze parameters that are thought to best represent a state of hypnosis. The output is often a dimensionless number, usually on a scale of 100 (wide awake) to 0 (isoelectric EEG). One such monitor has been shown to reduce the incidence of awareness in a high-risk population (Myles, Leslie, McNeil, Forbes, & Chan, 2004), although the results of this study have recently come into question (Avidan et al., 2008).
...Such EEG-based monitors, although promising, also have limitations (Dahaba, 2005). Many of these modules are insensitive to well-known anesthetics such as nitrous oxide, ketamine, and xenon. These agents may be pharmacologically similar in their effect on the N-methyl-D-aspartate glutamate receptor. Conversely, EEG monitors can be sensitive to agents that do not suppress consciousness, such as B-adrenergic blockers or neuromuscular blockers. There are other ways by which such 'awareness monitors' can be confounded, such as individuals who have a congenitally low-voltage EEG, as well as patients who are hypothermic or hypoglycemic. Finally, such monitors are subject to artifact from other electrical equipment in the operating room.
The current limitations of assessing anesthetic depth entail that we have no completely reliable way to ensure the absence of consciousness in a patient undergoing anesthesia and thus there is a class of individuals who may appear completely unconscious and yet who are nonetheless conscious. Furthermore, despite advances in demonstrating intentionality in patients with persistent vegetative states (Owen et al., 2006), neuroimaging techniques are not practical or even possible for real-time intraoperative monitoring. In short, for all practical purposes, i-zombies are not simply possible or probable—they are known to exist.

5. Philosophical implications of i-zombies

Standard philosophical criticisms of behaviorism are built around conceptual considerations alone and sometimes appeal to intuitions that behaviorists would find question-begging. By contrast, the existence of an i-zombie implies a compelling, empirically based counterexample to behaviorism. An i-zombie is not only real, but has feelings without the possibility of behaviorally responding to stimuli. Therefore, feeling is not simply responding to stimuli.
...A plausible alternative to behaviorism is functionalism. Functionalism arose on the philosophical scene in response to the shortcomings of behaviorism and type-type identity theory. Functionalism holds that mental states are interdefined in terms of causal relations: the defining characteristic of any mental state P is the set of causal relations that P has with respect to inputs, internal mental processes, and behavioral outputs (Fodor, 2000; see also Churchland, 1996). Instead of characterizing the mind simply in behavorial terms, functionalists argue for the causal efficacy of mental states. For example, my belief that a tidal wave is about to form is caused in me by my perception of wave patterns characteristic of tidal waves; and in relation to my desire to preserve my life, the fear of a potential tidal wave will cause me to seek shelter. In contrast to type-type identity theory, functionalists do not hold that mental states can be identified exclusively with a single type of matter (e.g., the neural stuff that composes our brains), but instead maintain that mental states can be realized in any suitably organized system.
An explanatory advantage of functionalism is that it affirms the mental as the source of behavior causation by insisting that mind is defined in terms of function, or by what it does—an interdefined web of causal relations between inputs, inner processes and outputs. An explanatory weakness, however, is that by defining mind in terms of causal relations, functionalism is logically compatible with the absence of experience itself (Armstrong, 2000, p. 142; see also Chalmers, 1996; Churchland, 1996; LaRock, 2007)...In order to motivate functionalism within this practical context, we need to answer a basic question, such as: Where is consciousness caused in the brain?
Answering the 'where' question of consciousness in functionalist terms returns us to our discussion of anesthetic depth. In order to localize the neurophysiologic endpoints of anesthesia such as loss of consciousness, we should not use structural space but rather functional or phase space. Phase space, fractal geometry, and strange attractors are now being employed to characterize states of consciousness and anesthesia. In the late 1980s, Watt & Hameroff, (1988) demonstrated that phase space analysis of EEG reveals distinct attractors and dimensions for the waking state, anesthesia, and burst suppression. More recent work from van den Broek, van Rijn, van Egmond, Coenen, & Booij, (2006) confirms fractal dimensionality as a measure of anesthetic depth.
...Taken together, one answer to the 'where' question of consciousness and anesthesia is 'phase space'. This form of explanation is consistent with functionalism as it does not attach itself to a specific neural process or location, but rather considers the overall dynamic or 'functional' properties of the system. Furthermore, because it can be applied to EEG analysis of the anesthetized patient, it also holds promise in the detection of i-zombies in the clinical realm.

6. The hard problem of unconsciousness

It should be clear immediately that the hard problem of unconsciousness is fundamentally practical or clinical. The fact that there is no uniformly reliable method to identify or predict intraoperative awareness leaves us with a situation in which consciousness is truly a problem. Assuming 30,000,000 general anesthetics delivered every year in the U.S. alone, with an incidence of anesthesia awareness of approximately 0.15%, we are left with 45,000 patients each year who have not had the adequate suppression of qualia. If we include patients who dream during general anesthesia, the number of potential i-zombies increases dramatically.
This problem is not limited to the operating room: it is becoming clear that patients who carry a clinical diagnosis of persistent vegetative state are capable of 'responding' (as assessed by functional imaging) in a way that indicates both comprehension and conscious intentionality (Owen et al., 2006). This hard problem of unconsciousness—detecting the presence of qualia—is again relevant. Decisions of continued life support, as in the highly publicized case of Terry Schiavo, are often made on the assumption of an absence of qualia.
...The foregoing examples highlight the ethical dimension of the hard problem of unconsciousness. The demonstrated natural possibility of i-zombies has implications for our treatment of individuals presumed unconscious. How should clinicians behave in the operating room given the demonstrated incidence of 1–2 individuals/1000 that may still experience qualia during a surgery? Should we comport ourselves acknowledging that the patient has the capacity for suffering? Should we at least ensure that if qualia cannot be extinguished that suffering is minimized with adequate analgesia? Should we restrict our speech to that which is respectful to all patients, conscious or ‘‘unconscious”? These ethical implications seem to readily fall out of the possibility of i-zombies.
...A more controversial ethical question relates to life support for patients with a diagnosis of persistent vegetative state. Given recent data suggesting that these patients may somehow covertly experience undetected qualia, what are the implications? Do we need to further consider the possibility that patients with even more dire diagnoses such as coma or brain death could potentially be i-zombies? The ethical exploration of this question is beyond the scope of this essay and would have important implications for end-of-life decision processes in critical care medicine, as well as organ donation.
...Furthermore, there can still be brain activation during general anesthesia. For example, primary and feed-forward visual processing persists during general anesthesia, while higher order processing is interrupted (Imas, Ropella, Ward, et al., 2005a, 2005b). A study of auditory processing under propofol anesthesia has reached a similar conclusion (Plourde, Belin, Chartrand, et al., 2006). These findings further emphasize the need to assess which brain states are associated with qualia. Mere activation or arousal of the brain does not necessitate consciousness and may still be a feature of an unconscious being. Indeed, this question touches not simply on the detection but on the very definition of i-zombies.

The awareness rate is chilling. One wonders whether surgery rates would be significantly affected in everyone was aware of this; it's like that utilitarian puzzler 'how much would I have to pay you to torture you with amnesia afterwards?' but in real life.

Further reading

References

31 comments

Comments sorted by top scores.

comment by gwern · 2012-04-09T15:05:15.858Z · score: 20 (20 votes) · LW · GW

'...I know that everyone who comes back from a colonoscopy says it was fine and they slept through it and it didn't hurt at all. And about three quarters of people did sleep through it.

But about a quarter of the time, the anaesthetic didn't work too well, and the patient was awake and in horrible, horrible pain. Outside of movies and TV, I've never seen someone in such pain before. And watching someone literally writhing in agony is a terrible, terrible experience.

What did the doctor say? He told me that they couldn't up the anaesthetic because an overdose could cause respiratory arrest, and that it wouldn't matter because the anaesthetic on any dose caused severe short term memory loss and whatever happened the patient would forget all about it. The second point, at least, was right on. One patient spent the entire procedure writhing in agony and screaming something incoherent to God. The doctor finished the procedure, took out the endoscope, and cut off the anaesthetic, and the patient turned his head, looked the doctor right in the eye, smiled, and said, laughing "Wow, that wasn't bad at all! Guess I slept right through it!"'

--Yvain

comment by Manfred · 2011-12-18T23:30:43.190Z · score: 12 (12 votes) · LW · GW

Meh. Being conscious for surgery is significantly less horrifying to me than dying of a burst appendix. I'd probably be pretty saturated with analgesics anyhow.

This isn't particularly related to p-zombies, though. An inverse p-zombie is a thing that responds exactly as if it weren't conscious, but is conscious. The authors talk about the problem of "detecting qualia" - but if you could, if you could follow every atom and had perfect decision-making, detect the consciousness, it wouldn't be an i-zombie. An i-zombie isn't a sleeping person who forgets that they dreamt, it's a conscious rock.

comment by torekp · 2011-12-20T10:54:00.958Z · score: 2 (2 votes) · LW · GW

This is an i-zombie at the behavioral level, so it isn't entirely unrelated. You're right about the complete-physical-description level, which is the philosophers' favorite. The authors do point out that the poorly anesthetized are not i-zombies at the functional level, which also implies that they're not, at the complete physical description level.

What puzzles me is why they appear to favor functionalism for (e.g.) pain, over type-identity theory. None of their main points depend on it. And the supposed "advantage" of functionalism, that it affirms the mental as the source of behavior causation, applies equally to type-identity.

comment by gwern · 2011-12-19T01:50:02.790Z · score: 1 (3 votes) · LW · GW

Being conscious for surgery is significantly less horrifying to me than dying of a burst appendix.

Is it less horrifying than not being conscious during the surgery?

comment by J_Taylor · 2011-12-19T02:40:04.471Z · score: 1 (1 votes) · LW · GW

Is not being conscious during surgery particularly horrifying?

comment by gwern · 2011-12-19T04:52:53.779Z · score: 7 (9 votes) · LW · GW

I was, perhaps opaquely, pointing out Manfred's false dichotomy - the choice is not between surgery with faulty anesthesia and dying; the choice is between surgery with faulty anesthesia, dying, and a myriad of other options (such as the authors' own suggestion: intensified investigation into neural correlates of consciousness, so failed anesthesia can be detected and the surgery aborted or the anesthesia improved).

comment by Manfred · 2011-12-19T14:13:55.406Z · score: 1 (1 votes) · LW · GW

That's reasonable, and I'd agree there are some good third options (though if the pain is managed to less than getting my teeth drilled into under local anesthesia, I wouldn't really care). We're pretty much faced with my dichotomy now, though. So my statement was the sort of boring one that the current cost/benefit of going into surgery for anything worth even a few weeks of life remains very similar.

comment by gwern · 2011-12-19T14:56:14.647Z · score: 4 (4 votes) · LW · GW

We're pretty much faced with my dichotomy now, though.

I'm not an anesthesiologist though, so I can't agree with that. Maybe there are alternatives. I can imagine there being workarounds or trade-offs which make more sense in light of these thoughts about i-zombies, such as greater use of local anesthetics (where it's very easy to test whether it works, as opposed to blanket general anesthetics).

comment by Oligopsony · 2011-12-18T23:19:38.642Z · score: 12 (16 votes) · LW · GW

While p-zombies are logically possible but naturally improbable, ... Like the p-zombie, the concept of the i-zombie entails no logical contradiction and hence can be considered both conceivable and possible ... the existence of an i-zombie implies a compelling, empirically based counterexample to...

These are not at all uncontentious claims.

comment by jhuffman · 2011-12-19T16:38:47.059Z · score: 5 (5 votes) · LW · GW

Maybe this whole article is a stealthy way to assert that p-zombies are a meaningful idea.

comment by gwern · 2019-03-13T01:55:26.805Z · score: 11 (2 votes) · LW · GW

"This is what it’s like waking up during surgery: General anaesthetic is supposed to make surgery painless. But now there’s evidence that one person in 20 may be awake when doctors think they’re under", Robson:

One day, for instance, she was waiting in the car as her daughter ran an errand, and realised that she was trapped inside. What might once have been a frustrating inconvenience sent her into a panic attack. “I started screaming. I was flailing my arms, I was crying,” she says. “It just left me so shaken.” Even the wrong clothing can make her anxiety worse. “Anything that’s tight around my neck is out of the question because it makes me feel like I’m suffocating,” says Donna, a 55-year-old from Altona in Manitoba, Canada.

...The lingering trauma can resurface with the slightest trigger, and still causes her to have “two or three nightmares each night”. Having been put on medical leave from her job, she has lost her independence. She suspects that she will never fully escape the effects of that day more than a decade ago. “It’s a life sentence.”

...When she woke up, she could hear the nurses buzzing around the table, and she felt someone scrubbing at her abdomen – but she assumed that the operation was over and they were just clearing up. “I was thinking, ‘Oh boy, you were anxious for no reason.’” It was only once she heard the surgeon asking the nurse for a scalpel that the truth suddenly dawned on her: the operation wasn’t over. It hadn’t even begun. The next thing she knew, she felt the blade of his knife against her belly as he made his first incision, leading to excruciating pain. She tried to sit up and to speak – but thanks to a neuromuscular blocker, her body was paralysed. “I felt so… so powerless. There was just nothing I could do. I couldn’t move, couldn’t scream, couldn’t open my eyes,” she says. “I tried to cry just to get tears rolling down my cheeks, thinking that they would notice that and notice that something was going on. But I couldn’t make tears.”

...Various projects around the world have attempted to document experiences like Donna’s, but the Anesthesia Awareness Registry at the University of Washington, Seattle, offers some of the most detailed analyses. Founded in 2007, it has now collected more than 340 reports – most from North America – and although these reports are confidential, some details have been published, and they make illuminating reading.

As you might expect, a large majority of the accounts – more than 70 per cent – also contain reports of pain. “I felt the sting and burning sensation of four incisions being made, like a sharp knife cutting a finger,” wrote one. “Then searing, unbearable pain.” “There were two parts I remember quite clearly,” wrote a patient who had had a wide hole made in his femur. “I heard the drill, felt the pain, and felt the vibration all the way up to my hip. The next part was the movement of my leg and the pounding of the ‘nail’.” The pain, he said, was “unlike anything I thought possible”. It is the paralysing effects of the muscle blockers that many find most distressing, however. For one thing, it produces the sensations that you are not breathing – which one patient described as “too horrible to endure”. Then there’s the helplessness. Another patient noted: “I was screaming in my head things like ‘don’t they know I’m awake, open your eyes to signal them’.” To make matters worse, all of this panic can be compounded by a lack of understanding of why they are awake but unable to move. “They have no reference point to say why is this happening,” says Christopher Kent at the University of Washington, who co-authored the paper about these accounts. The result, he says, is that many patients come to fear that they are dying. “Those are the worst of the anaesthesia experiences.”

...

The result is that many more people might be conscious during surgery, but they simply can’t remember it afterwards.

To investigate this phenomenon, researchers are using what they call the isolated forearm technique. During the induction of the anaesthesia, the staff place a cuff around the patient’s upper arm that delays the passage of the neuromuscular agent through the arm. This means that, for a brief period, the patient is still able to move their hand. So a member of staff could ask them to squeeze their hand in response to two questions: whether they were still aware, and, if so, whether they felt any pain. (Read more in this short on how doctors are trying to detect anaesthesia awareness.) In the largest study of this kind to date, Robert Sanders at the University of Wisconsin–Madison recently collaborated with colleagues at six hospitals in the US, Europe and New Zealand. Of the 260 patients studied, 4.6 per cent responded to the experimenters’ first question, about awareness. That is hundreds of times greater than the rate of remembered awareness events that had been noted in the National Audit Project. And around four in ten of those patients who did respond with the hand squeeze – 1.9 per cent across the whole group – also reported feeling pain in the experimenters’ second question.

These results raise some ethical quandaries. “Whenever I talk to the trainees I talk about the philosophical element to this,” says Sanders. “If the patient doesn’t remember, is it concerning?” Sanders says that there’s no evidence that the patients who respond during the isolated forearm experiments, but fail to remember the experience later, do go on to develop PTSD or other psychological issues like Donna. And without those long-term consequences, you might conclude that the momentary awareness is unfortunate, but unalarming. Yet the study does make him uneasy, and so he conducted a survey to gather the public’s views on the matter. Opinions were mixed. “Most people didn’t think that amnesia alone is sufficient – but a surprisingly large minority thought that as long as you didn’t remember the event, it’s OK,” Sanders says.

...

The survey is https://academic.oup.com/bja/article/118/4/486/3574495 (Given the described wording and the remarkably blase acceptance claimed, I'm left wondering a little if the respondents really appreciated the scenario being described - being gutted like a fish and feeling every last bit of it, so to speak.)

"Patient perspectives on intraoperative awareness with explicit recall: report from a North American anaesthesia awareness registry", Kent et al 2015:

Background: Awareness during general anaesthesia is a source of concern for patients and anaesthetists, with potential for psychological and medicolegal sequelae. We used a registry to evaluate unintended awareness from the patient’s perspective with an emphasis on their experiences and healthcare provider responses.

Methods: English-speaking subjects self-reported explicit recall of events during anaesthesia to the Anesthesia Awareness Registry of the ASA, completed a survey, and submitted copies of medical records. Anaesthesia awareness was defined as explicit recall of events during induction or maintenance of general anaesthesia. Patient experiences, satisfaction, and desired practitioner responses to explicit recall were based on survey responses.

Results: Most of the 68 respondents meeting inclusion criteria (75%) were dissatisfied with the manner in which their concerns were addressed by their healthcare providers, and many reported long-term harm. Half (51%) of respondents reported that neither the anaesthesia provider nor surgeon expressed concern about their experience. Few were offered an apology (10%) or referral for counseling (15%). Patient preferences for responses after an awareness episode included validation of their experience (37%), an explanation (28%), and discussion or follow-up to the episode (26%).

Conclusions: Data from this registry confirm the serious impact of anaesthesia awareness for some patients, and suggest that patients need more systematic responses and follow-up by healthcare providers.

"Incidence of Connected Consciousness after Tracheal Intubation: A Prospective, International, Multicenter Cohort Study of the Isolated Forearm Technique", Sanders et al 2017:

Background: The isolated forearm technique allows assessment of consciousness of the external world (connected consciousness) through a verbal command to move the hand (of a tourniquet-isolated arm) during intended general anesthesia. Previous isolated forearm technique data suggest that the incidence of connected consciousness may approach 37% after a noxious stimulus. The authors conducted an international, multicenter, pragmatic study to establish the incidence of isolated forearm technique responsiveness after intubation in routine practice.

Methods: Two hundred sixty adult patients were recruited at six sites into a prospective cohort study of the isolated forearm technique after intubation. Demographic, anesthetic, and intubation data, plus postoperative questionnaires, were collected. Univariate statistics, followed by bivariate logistic regression models for age plus variable, were conducted.

Results: The incidence of isolated forearm technique responsiveness after intubation was 4.6% (12/260); 5 of 12 responders reported pain through a second hand squeeze. Responders were younger than nonresponders (39 ± 17 vs. 51 ± 16 yr old; P = 0.01) with more frequent signs of sympathetic activation (50% vs. 2.4%; P = 0.03). No participant had explicit recall of intraoperative events when questioned after surgery (n = 253). Across groups, depth of anesthesia monitoring values showed a wide range; however, values were higher for responders before (54 ± 20 vs. 42 ± 14; P = 0.02) and after (52 ± 16 vs. 43 ± 16; P = 0.02) intubation. In patients not receiving total intravenous anesthesia, exposure to volatile anesthetics before intubation reduced the odds of responding (odds ratio, 0.2 [0.1 to 0.8]; P = 0.02) after adjustment for age.

Conclusions: Intraoperative connected consciousness occurred frequently, although the rate is up to 10-times lower than anticipated. This should be considered a conservative estimate of intraoperative connected consciousness.

comment by printing-spoon · 2011-12-19T00:47:33.014Z · score: 7 (7 votes) · LW · GW

The dual of this approximated i-zombie is just a sleepwalker, not a literal, atom-for-atom-identical p-zombie.

comment by gwern · 2013-01-06T03:32:01.139Z · score: 6 (6 votes) · LW · GW

The operation was successful, but not long after Campbell returned home, her mother sensed that something was wrong. The calm, precocious girl who went into the surgery was not the same one who emerged. Campbell began flinging food from her high chair. She suffered random episodes of uncontrollable vomiting. She threw violent temper tantrums during the day and had disturbing dreams at night. “They were about people being cut open, lots of blood, lots of violence,” Campbell remembers. She refused to be alone, but avoided anyone outside her immediate circle. Her parents took her to physicians and therapists. None could determine the cause of her distress. When she was in eighth grade, her parents pulled her from school for rehabilitation.

...Many of these cases are benign: vague, hazy flashbacks. But up to 70 percent of patients who experience awareness suffer long-term psychological distress, including PTSD—a rate five times higher than that of soldiers returning from Iraq and Afghanistan. Campbell now understands that this is what happened to her, although she didn’t believe it at first....The lawsuit claimed that Sizemore was tormented by doubt, wondering whether he had imagined the horrific pain. No one advised Sizemore to seek psychiatric help, his family alleged, and no one mentioned the fact that many patients who experience awareness suffer from PTSD. On February 2, 2006, two weeks after his surgery, Sizemore shot himself. He had no history of psychiatric illness.

...Doctors began investigating how anesthesia affects consciousness during the 1960s, shortly after the first reports of awareness. One South African researcher was especially curious about whether and how one might recall memories from a surgery. Perhaps a near-death experience? Pushing well beyond the limits of what would today be considered ethical, he collected 10 volunteers undergoing dental surgery. The procedures went along as normal until, midway through, the room went silent and the medical staff reached for scripts....Of the 10 volunteers, four remembered the words accurately; four retained vague memories; and two had no recollection of the surgery. The eight patients who did remember it displayed anxiety during the interview, many of them bursting from hypnosis, unable to continue. But when out of hypnosis, it was as though nothing had happened. They had no memory of the incident. The terror and anxiety seemed permanently buried in their subconscious.

"Awakening", Atlantic

comment by gwern · 2012-06-15T19:48:47.512Z · score: 6 (6 votes) · LW · GW

http://www.nature.com/news/neuroscience-the-mind-reader-1.10816

Months after her infection cleared, Bainbridge was diagnosed as being in a vegetative state. Owen had been using positron-emission tomography in healthy people to show that a part of the brain called the fusiform face area (FFA) is activated when people see a familiar face. When the team showed Bainbridge familiar faces and scanned her brain, “it lit up like a Christmas tree, especially the FFA”, says Owen. “That was the beginning of everything.” Bainbridge was found to have significant brain function and responded well to rehabilitation3. In 2010, still in a wheelchair but otherwise active, she wrote to thank Owen for the brain scan. “It scares me to think of what might have happened to me if I had not had mine,” she wrote. “It was like magic, it found me.”

Owen moved from visual to auditory tests — “up the cognition ladder, from basic sound perception, to speech perception and then to speech comprehension”. For example, he presented people in a vegetative state with phrases containing words that sound the same but have two meanings, such as “The dates and pears are in the bowl”. The ambiguity forces the brain to work harder and shows up in characteristic fMRI patterns in healthy people — if, that is, they are comprehending the words. One of Owen's patients, a 30-year-old man who had been incapacitated by a stroke, showed the same pattern4. But not everyone was convinced that these signs pointed to comprehension. “Every time I would go to a neurologist or anaesthesiologist and say, 'he's perceiving speech', they'd ask 'but is he conscious?'.”

...Owen hopes one day to ask patients that most difficult of questions, but says that new ethical and legal frameworks will be needed. And it will be many years, he says, “before one could be sure that the patient retained the necessary cognitive and emotional capacity to make such a complex decision”. So far, he has stayed away from the issue. “It might be a little reassuring if the answer was 'no' but you can't presuppose that.” A 'yes' would be upsetting, confusing and controversial.

comment by gwern · 2019-03-12T01:13:36.572Z · score: 5 (2 votes) · LW · GW

Daniel Dennett turns out to discuss precisely this problem in the context of curare/analgesics/anesthetics/amnestics in Dennett 1978, "Why You Can't Make A Computer That Feels Pain".

He also discusses an interesting detail of pain, "reactive dissociation". In my pain taxonomy, I split the various kinds of pain disorders into useful/motivating/qualia; the only combination I was missing was a kind of pain which is experienced as painful and yet was not motivating/aversive/unpleasant. "reactive dissociation" turns out to be just that - if morphine is administered after pain starts happening, people apparently frequently will report that the pain is excruciatingly painful, and yet they don't mind it.

Aspirin by antagonizing bradykinin thus prevents pain at the earliest opportunity. This is interesting because aspirin is also unique among analgesics in lacking the 'reactive disassociation' effect. All other analgesics (e.g., the morphine group and nitrous oxide in sub-anesthetic doses) have a common 'phenomenology.' After receiving the analgesic subjects commonly report not that the pain has disappeared or diminished (as with aspirin) but that the pain is as intense as ever though they no longer mind it. To many philosophers this may sound like some sort of conceptual incoherency or contradiction, or at least indicate a failure on the part of the subjects to draw enough distinctions, but such philosophical suspicions, which we will examine more closely later, must be voiced in the face of the normality of such first-person reports and the fact that they are expressed in the widest variety of language by subjects of every degree of sophistication. A further curiosity about morphine is that if it is administered before the onset of pain (for instance, as a pre-surgical medication) the subjects claim not to feel any pain subsequently (though they are not numb or anesthetized - they have sensation in the relevant parts of their bodies); while if the morphine is administered after the pain has commenced, the subjects report that the pain continues (and continues to be pain), though they no longer mind it.

...Lobotomized subjects similarly report feeling intense pain but not minding it, and in other ways the manifestations of lobotomy and morphine are similar enough to lead some researchers to describe the action of morphine (and some barbiturates) as "reversible pharmacological leucotomy [lobotomy]".^23^

23: A. S. Keats and H. K. Beecher, "Pain Relief with Hypnotic Doses of Barbiturates, and a Hypothesis", J. Pharmacol, 1950. Lobotomy, though discredited as a behavior-improving psychosurgical procedure, is still a last resort tactic in cases of utterly intractable central pain, where the only other alternative to unrelenting agony is escalating morphine dosages, with inevitable addiction, habituation and early death. Lobotomy does not excise any of the old low path (as one might expect from its effect on pain perception), but it does cut off the old low path from a rich input source in the frontal lobes of the cortex.

Dennett throws in this disturbing anecdote in footnote 27:

Scopolamine and other amnestics are often prescribed by anesthesiologists for the purpose of creating amnesia. "Sometimes", I was told by a prominent anesthesiologist, "when we think a patient may have been awake during surgery, we give scopolamine to get us off the hook. Sometimes it works and sometimes not."

comment by gwern · 2013-10-27T17:29:50.935Z · score: 5 (5 votes) · LW · GW

"IamA Anaesthesia Awareness survivor! AMA!", by ohnozombees:

...Unfortunately, the anaesthetic didn't work, and I was left completely conscious and paralyzed during the two and a half hour procedure. Worst of all, I could feel everything.

...what was the most painful part?

...The first incision was the worst pain-wise, but the horror of hearing a bone saw coming for you and being unable to move/cry out/scream was pretty bad.

...Have you reached the statute of limitations for legal action?

I have passed the statute. It's two years, and it's been longer. The problem there, though, is that noone at the time anticipated how badly the PTSD would go, and even training a service dog alone is anywhere from $3500-$20,000. And then there's the psych bills for therapy and the rest... It's expensive being crazy

...Do you harbor any ill will toward the medical team?

A little, but only for the anaesthesiologist. I really wish he'd been more thorough with the checks-- I don't know quite what went wrong, but damn did he ever phone it in that day.

Do you have any lasting effects from the experience, like flashbacks or anxiety? ...

I do! I developed PTSD afterwards, and do have all the classical symptoms. If there's anyone I feel bad for, it's my housemates. I occasionally wake them up with them---if I flop onto my stomach (the surgery position), for example.

During the operation could you hear the doctors I've always been curious since seeing the movie awake and what was the reaction of the doctors after you did come too? I'm sorry you endured what I imagine was a very traumatic experience thank you for doing this AMA

I could! The lead surgeon actually spent some time talking about his golf scores--and for some reason, that stuck with me. Well, when I came to I was super agitated (enough that it ended up in the medical notes, as you can see). And I started screaming "I can feel it! I could feel it I was AWAKE!", so they called the doctor. The nurses tried to tell me it was just a bad trip from the morphine, and in my anger and panic, I looked at the doctor and snarled, "You suck at golf!"

He'd talked about that about halfway through, so it wasn't anything I could have known otherwise. I have never seen someone go the colour of concrete before or since.

And yeah, it was pretty shitty and I'm still dealing with the PTSD from it, but hopefully this'll be therapeutic! You're very welcome.

How was the intubation? The breathing tube?

The absolute goddamn worst. It felt like I was choking and gagging and it hurt. I have a new respect for sword swallowers.

Would you say this is the worst pain you've felt?

Yes. Both physically and psychologically. I seen some shit, but that by far took the cake.

I am so glad to have never experienced this, though I did wake up during a retroparitaneal lymphadectomy. Standard procedure is to tape the eyes shut so they don't dry out, and you're on a respirator of course, but the tape wasn't on tight enough so I was able to get one eye open. Kind of a mindfuck to look down and see your intestines unspooled onto the gurney next to you. Thankfully I was numbed up quite well, so as soon as one of the nurses saw me wink at her I was knocked back out. Anesthesia is a weird thing. ...

Exactly! It's actually fairly common for people to have some degree of awareness, but most of the time it's something like Egon's experiences, where the sleeper wears off, but the analgesic keeps working. It's especially common in cases where low doses of anaesthetic are required to avoid putting the patient into a coma or something. Cesarians and, horrifically, after bodily trauma, I think I read somewhere.

But figures I'd be the like, 0.001 dude that gets the worst case scenario. And what's worse is, I remember having that exact thought.

"Oh, come onnnnn"

...Can you describe what pain on that level is like? Why didn't you pass out?

... The pain... I can't put it into words, without getting flowery.

So remember, I can hear them, right? I just can't see them (eyes taped closed, I can remember the tickle of my eyelash against the tape), on my stomach. Everything is black.

Ive had three surgeries prior, so this is no big deal for me. I'm thinking Im in the recovery room. Okay---but... why cant I breathe?!!? Panic, flail, manage to figure out how to manage and relax enough to let the machine breathe for me. Okay, I can handle this.

So I'm just awake a little early--that explains why I'm on my stomach. And then I hear, "Nurse, scalpel please."

And then I realized very quickly that things were about to get really ugly if I didn't do anything. So I talk myself through it. "Move your toes." they dont move. "Next muscle." Nothing. Oh god. "Fingers! Don't panic, just wiggle your fingers." I try, so hard, but nothing happens. That pounding is the sound of your heart in your ears. "Okay. Scream. Scream, please let them hear me" And nothing came out. And then I remember thinking, "Okay. Panic."

and then I felt a tickle along the back of my ankle. It felt like when your leg goes numb and you drag a nail over if, or a sharp needle over skin, that sort of focused itchy feeling. And I thought, "Oh thank god". I thought I couldn't feel it---and then I felt it as cold. This intense, horrific dead-of-february-with-wet-hair cold... and then just the worst white heat ever.

I did. And always, the pain was enough to keep me awake.

You should write a book about this. I like your style and it's very interesting

Thanks! I've considered it, if for no other reason than the fact that a service dog is expensive, and a psychologist even more so. ...

... OP should have been knocked out.

I was supposed to be--- someone sorta screwed the pooch with mine.

But still--the concept of it happening twice... fuck that, I'd rather die. Literally, no hyperbole. I've got it written into my general med file; if there's a chance that giving me anaesthetic will kill me, but the alternative is pain of that level?

Dope me up and I'll take it up with the devil.

I'm so sorry for you.. I had surgery a few months ago and my biggest fear was the anesthesia rather than the surgery itself. What were your thoughts during the surgery? (2.5 hours!) Have you managed the pain at the end of surgery, after having felt it so much? A kind of desensitization? After how long did you realize that you were awake? ...

Yeah, the anaesthetics are the scariest, hands down. ... My thoughts varied. Sometimes I sang. Sometimes I recited passages from books. Sometimes I remembered places I had visited-- but it was like looking at pictures, not being in the action. The pain wasn't worst at the end, it was the absolute worst when I heard the bone saw power up like the electric toothbrush from hell. That was the moment I hit rock bottom. And it only took me like, half a minute, cause I tried to move and couldn't.

comment by gwern · 2018-05-08T18:39:31.826Z · score: 4 (1 votes) · LW · GW

https://www.wired.com/story/ketamine-stirs-up-hope-controversy-as-a-depression-drug/

...It was 2013. Michael, age 43, had suffered from psychiatric problems since he was a teenager—epic procrastination, binge drinking, and depression. He'd seen psychiatrists for 20 years and tried almost every antidepressant. What had helped him, at least temporarily, was a prescription for stimulants in the wake of a diagnosis of adult attention deficit disorder in his early thirties...So one day in January 2016, Michael drove with his wife to meet Wolfson and Andries at the Pine Street Clinic in San Anselmo, where they rented space. There, water gurgled in a fountain, a bird twittered in a cage, and the smell of Chinese herbs filled the air. Wolfson, a big garrulous man with white, curly hair and a pronounced limp from several back surgeries, asked about Michael's medical history. As a teen, Michael had had a noncancerous tumor removed from his abdomen. The tumor was acting like an extra adrenal gland, secreting hormones that prevented him from growing and caused him to sweat profusely, often until his clothes were drenched. The surgery was successful, but recovery had been long and difficult, he told Wolfson. He'd been intubated in the intensive care unit for nearly a week.
As Michael recalls, Wolfson told him, "You may be depressed, but I don't think that's the root of your problem. You have every glaring symptom of PTSD." Michael wasn't a veteran. He'd never been sexually abused. Wolfson's diagnosis felt off. He also knew that, years ago, Wolfson had lost a son to leukemia; the detail was on his website. In that moment, Michael diagnosed his therapist. "He's projecting," he thought. Still, he felt comfortable enough with Wolfson to proceed.
...ABOUT SIX MONTHS after beginning with Wolfson and Andries, Michael had a breakthrough. As he was coming out of a ketamine session, his mind's eye perceived a smooth, black object that reminded him of the monolith in the movie 2001: A Space Odyssey. He remembers chuckling to himself, and thinking "What the heck?" Then the monolith morphed into a single word: anesthesia. Michael saw himself as 14 and lying on an operating table. Surgeons in white coats and masks bent over him. One turned to him and said, cheerfully, "Don't worry. You can't feel this. You're under anesthesia." During a later session at home, with lozenges, the meaning of the vision became viscerally clear. Michael felt that man cut into his belly with a scalpel. He was overcome by a searing pain so unbearable that it seemed to expel him from his body. He felt like he was floating above himself.
What Michael seemed to have remembered was that he'd woken up during surgery decades earlier—that he was conscious when doctors removed that tumor. It's impossible to know if the memory is real, although the phenomenon, called anesthesia awareness, is documented, and one of its consequences is PTSD. When I asked if Michael doubted the memory's veracity, he said that what led him to believe the memory was true were the details he wouldn't know to make up, like the oily plastic odor of the operating room and the cigarette smell on one nurse's breath. Once that memory emerged, others surfaced as well. He recalled, for instance, that during his recovery in the ICU, the morphine often wore off, leaving him in agony over the 12-inch incision in his abdomen. Just when its analgesic effects waned, therapists would guide him through a series of coughing exercises to remove fluid in his lungs, which were excruciating because his abdominal muscles had been sliced open. "It was like being tortured several times a day," he says. For Michael, these memories seemed to explain a lot. Here was the source of the PTSD that Wolfson had so confidently diagnosed that first day.
comment by Curiouskid · 2012-01-04T16:38:11.665Z · score: 3 (3 votes) · LW · GW

Why did I read this right before I was getting my wisdom teeth pulled?

comment by gwern · 2012-11-23T03:40:02.944Z · score: 2 (2 votes) · LW · GW

When I re-read the paper before making this post, I was relieved that it had not occurred to me at all before undergoing general anesthesia for my wisdom teeth a while before!

comment by Allison_Smith · 2013-08-06T05:52:30.996Z · score: 1 (1 votes) · LW · GW

I woke up while having my wisdom teeth pulled. I was not in pain, just the ordinary discomfort of all dental procedures.

comment by Curiouskid · 2012-11-23T22:17:42.230Z · score: 1 (1 votes) · LW · GW

10 month bump!

comment by gwern · 2012-11-23T22:52:54.996Z · score: 6 (6 votes) · LW · GW

One of the fun things about LW is commenting on old articles.

comment by TobyBartels · 2014-08-09T23:25:31.852Z · score: 1 (1 votes) · LW · GW

Also upvoting old comments.

comment by DanielLC · 2011-12-19T02:46:39.327Z · score: 2 (2 votes) · LW · GW

I suggest a better proof-of-concept.

Lock someone in a box that has a monitor or some other method of talking to them, but no method of them talking to the rest of the world. They are presumably still conscious, but it would be impossible for the rest of the world to tell.

One way to do this would be to drop them in a black hole. Once they pass the event horizon, they cannot communicate with you, but you can still communicate with them, at least for a little while.

Another example is the universe as a whole. It has no input or output. How could it? Where would they lead? It still has conscious beings.

comment by wedrifid · 2011-12-19T07:17:53.300Z · score: 0 (2 votes) · LW · GW

Another example is the universe as a whole. It has no input or output. How could it? Where would they lead?

Like this.

comment by DanielLC · 2011-12-19T18:30:46.798Z · score: 2 (2 votes) · LW · GW

I mean the entire universe, not just the part we see. If we're in a simulation, the universe would include the computer the simulation is running on, along with everything else.

comment by cousin_it · 2011-12-19T15:47:05.379Z · score: 2 (2 votes) · LW · GW

I thought the link would lead to this.

comment by gwern · 2014-11-29T22:41:15.966Z · score: 1 (1 votes) · LW · GW

Ketamine is basically the reason I will not touch drugs, including alcohol. I can’t be sure how much of my truly awful experience I should attribute to the drug itself or the context in which it was taken. I probably took ketamine in one of the worst circumstances. I was given ketamine when I was 6 years old for an operation on my arm. I was also given Valium ® so I didn’t experience anything hallucinogenic, but I definitely had the dissociation. I spent a good bit of time smacking my face into things and quoting lines from Young Frankenstein, then I was slapped down on an operating table and watched my arm get sliced open fully aware of what was happening and fully aware that I couldn’t even move my own body to try to stop it. I came out of the operating room with blood-shot eyes screaming to my mom that, “They didn’t put me out, I was awake the whole time.” I told you about that to explain the circumstances I was under when I was given the drug, which might explain a good deal. A few weeks after I had gotten out of the hospital I had a flashback in which I had intense psychosis, and paralysis. I thought I was going out of my mind, and I couldn’t pick myself off the floor to unlock the door that my sister was crying and pounding on. It also seemed to have affected my sleeping patterns, and gave me nightmares for years to follow. I know that it might have been the best thing to give me but sometimes I wish the doctors had just clubbed me with a 2” x 4” instead of giving me ketamine. While it may be some wonder drug that doesn’t jeopardize breathing and heart rate, I feel like it fucked me up for years, and sent my mom to a psychiatrist because my psychosis spread to her...

--K.U.

pg248-298 of Ketamine: Dreams and Realities, "Journeys into the Fright World"

comment by gwern · 2017-12-08T03:31:56.457Z · score: 0 (0 votes) · LW · GW

On an intermediate class of anesthetics: "Surgical Patients May Be Feeling Pain—and (Mostly) Forgetting It: Amnesic anesthetics are convenient and help patients make a faster recovery, but they don't necessarily prevent suffering during surgery", Kate Cole-Adams:

In 1993, as a little-known anesthesiologist from the recursive Hull, England, Russell published a startling study. Using a technique almost primitive in its simplicity, he monitored 32 women undergoing major gynecological surgery at the Hull Royal Infirmary to assess their levels of consciousness. The results convinced him to stop the trial halfway through.

The women were put to sleep with a low-dose anesthetic cocktail that had been recently lauded as providing protection against awareness. The main ingredients were the (then) relatively new drug midazolam, along with a painkiller and muscle relaxant to effectively paralyze her throughout the surgery. Before the women were anesthetized, however, Russell attached what was essentially a blood-pressure cuff around each woman’s forearm. The cuff was then tightened to act as a tourniquet that prevented the flow of blood, and therefore muscle relaxant, to the right hand. Russell hoped to leave open a simple but ingenious channel of communication—like a priority phone line—on the off chance that anyone was there to answer him. Once the women were unconscious Russell put headphones over their ears through which, throughout all but the final minutes of the operation, he played a prerecorded one-minute continuous-loop cassette. Each message would begin with Russell’s voice repeating the patient’s name twice. Then each woman would hear an identical message. “This is Dr. Russell speaking. If you can hear me, I would like you to open and close the fingers of your right hand, open and close the fingers of your right hand.”

Under the study design, if a patient appeared to move her hand in response to the taped command, Russell was to hold her hand, raise one of the earpieces and say her name, then deliver this instruction: “If you can hear me, squeeze my fingers.” If the woman responded, Russell would ask her to let him know, by squeezing again, if she was feeling any pain. In either of these scenarios, he would then administer a hypnotic drug to put her back to sleep. By the time he had tested 32 women, 23 had squeezed his hand when asked if they could hear. Twenty of them indicated they were in pain. At this point he stopped the study. When interviewed in the recovery room, none of the women claimed to remember anything, though three days later several showed some signs of recall. Two agreed after prompting that they had been asked to do something with their right hand. Neither of them could remember what it was, but while they were thinking about it, said Russell, both involuntarily opened and closed that hand. Fourteen of the patients in the study (including one who was later excluded) showed some signs of light anesthesia (increased heart rate, blood-pressure changes, sweating, tears), but this was true of fewer than half of the hand-squeezers.* Overall, said Russell, such physical signs “seemed of little value” in predicting intraoperative consciousness.

He concluded thus:

If the aim of general anesthesia is to ensure that a patient has no recognizable conscious recall of surgery, and views the perioperative period [during the surgery] as a “positive” experience, then ... [this regimen] may fulfill that requirement. However, the definition of general anesthesia would normally include unconsciousness and freedom from pain during surgery—factors not guaranteed by this technique.

For most of the women in his study, he continued, the state of mind produced by the anesthetic could not be viewed as general anesthesia. Rather, he said, “it should be regarded as general amnesia.”...Twenty years after that discontinued study, Russell staged similar experiments using the isolated-forearm technique alongside a bispectral-index monitor (BIS), which tracks depth of anesthesia. While the number of women who responded dropped to one-third when staff used an inhalation anesthetic, another study using the intravenous drug propofol showed that during BIS-guided surgery, nearly three-quarters of patients still responded to command—half those responses within the manufacturer’s recommended surgical range.

...(This post is adapted from Cole-Adams’s new 2017 book, Anesthesia: The Gift of Oblivion and the Mystery of Consciousness.)

comment by gwern · 2015-08-10T18:55:04.876Z · score: 0 (0 votes) · LW · GW

"Do Artificial Reinforcement-Learning Agents Matter Morally?", Tomasik 2014:

Artificial reinforcement learning (RL) is a widely used technique in artificial intelligence that provides a general method for training agents to perform a wide variety of behaviours. RL as used in computer science has striking parallels to reward and punishment learning in animal and human brains. I argue that present-day artificial RL agents have a very small but nonzero degree of ethical importance. This is particularly plausible for views according to which sentience comes in degrees based on the abilities and complexities of minds, but even binary views on consciousness should assign nonzero probability to RL programs having morally relevant experiences. While RL programs are not a top ethical priority today, they may become more significant in the coming decades as RL is increasingly applied to industry, robotics, video games, and other areas. I encourage scientists, philosophers, and citizens to begin a conversation about our ethical duties to reduce the harm that we inflict on powerless, voiceless RL agents.

Particularly germane is the discussion of the disunified nature of cognition and experimental demonstrations of learning still happening while the hippocampus is knocked out by an anesthetic-like drug like "When Memory Fails, Intuition Reigns: Midazolam Enhances Implicit Inference in Humans".