The Frontal Cortex

Identity Delusions

Benedict Carey at the Times has an interesting article documenting the harrowing story of Adam Lepak, who has struggled with identity delusions since 2007, when he was involved in a serious motorcycle accident:

The diagnosis [given to Adam] was diffuse axonal injury. “The textbook definition is essentially a blow that shuts down the bundle of wires responsible for keeping us conscious,” said Dr. Jonathan Fellus, a neurologist at Kessler Institute for Rehabilitation in West Orange, N.J., who has overseen Adam’s gradual recovery. “It’s as if the major highways have taken a hit, and now the brain has to use back roads to function. But every brain responds differently. I have given up making predictions.”

Researchers who have taken images of the brain as it processes information related to personal identity have noticed that several areas are particularly active. Called cortical midline structures, they run like an apple core from the frontal lobes near the forehead through the center of the brain.

These frontal and midline areas communicate with regions of the brain that process memory and emotion, in the medial temporal lobe, buried deep beneath each ear. And studies strongly suggest that in delusions of identity, these emotion centers are either not well connected to frontal midline areas or not providing good information. Mom looks and sounds exactly like Mom, but the sensation of her presence is lost. She seems somehow unreal.

The classic delusion of identification is called Capgras syndrome, after the French psychiatrist Dr. Jean Marie Joseph Capgras, who with Dr. Jean Reboul-Lachaux described in 1923 the case of a 53-year-old patient “who transformed everyone in her entourage, even those closest to her, such as her husband and daughter, into various and numerous doubles.”

In an analysis of such cases published in January in the journal Neurology, Dr. Orrin Devinsky, a neurologist at New York University, documented that people with the delusion typically have more damage to their right hemisphere than their left. Linear reasoning and language tend to be predominantly left-hemisphere functions, while holistic judgments — of intonation, of emphasis — tend to be processed more in the right. Dr. Devinsky argues that when people lack a familiar emotional glow in the company of a parent or loved one, the left hemisphere, unchecked by a damaged right, resolves the conflict with its categorical logic. The person must be an impostor.

This reminds me of that marvelous Virginia Woolf quote, in which she described the self as our sole “theme, recurring, half remembered, half foreseen.” The quote captures the mysterious nature of identity, emerging from some alchemical concoction of memory, emotion and sensation. The self feels like a singular thing – I am me – and yet it comes from no single brain area and depends on a vast network of neurons, distributed across the brain. This means that we are not a place: we are a process. As Daniel Dennett wrote, our mind is made up “of multiple channels in which specialist circuits try, in parallel pandemoniums, to do their various things, creating Multiple Drafts as they go.”

What subjects like Adam demonstrate is the fragility of the self. It’s impossible for me to imagine reality from a perspective other than my own – I am the sole perciever of all my perceptions. And yet, and yet…All it takes is a traumatic blow to the head and that delicate ghost disappears. I am suddenly someone else, convinced that my mother is a fake. (If you’d like to learn more about the Capgras delusion, I highly recommend The Echo Maker, by Richard Powers.)

Given the fundamental role of the self in human experience, it’s sobering how little we know about it. (The fact that we call it an emergent property is a sign that nobody really understands what the self is or where it comes from.) For the most part, we’re forced to marvel at its effects via attention, as the self chooses which sensations to pay attention to. These sensory cells then show increased sensitivity and enhanced firing, making them more likely to enter the narrow stream of consciousness. (This is known as selective attention or executive attention. Here’s an excellent review of the subject.) Think, for a moment, about how profoundly strange this is: the self, a fragile figment produced by all these different mental processes, is causing very real changes in neural activity. An emergent property is altering the electrical cells from which it emerged. (Douglas Hofstadter has always been very eloquent on this paradox.) It’s as if the ghost is controlling the machine.

Comments

  1. #1 Neuro-conservative
    August 11, 2009

    Have you ever read Dostoevsky’s The Double?

  2. #2 M Blacklock
    August 12, 2009

    Yet when this fluidity of identity happens in dreams we don’t find it disturbing.

  3. #3 gregorylent
    August 12, 2009

    you really do need to talk to yogis …

    how long can this institutionalized inbred ignorance of western “mind scientists” go on? too damn long …

    go to india, learn about meditation, practice meditation … so many centuries of wisdom around these questions and you simply ignore it in your hubris …

    great blog, but your intellect and your western pov will never tell you what you want to know … too effing limited, from basic models to the “scientific” method, which cuts off all subjectivity …

    i mean, what is the self after all? pure subject …

    enjoy,

    gregory lent

  4. #4 ncoffee
    August 12, 2009

    “the self, a fragile figment produced by all these different mental processes, is causing very real changes in neural activity.”

    Is it though? It certainly feels like it is, that’s for sure.

    But would it not make more sense to say that the different mental processes are themselves the very real changes in neural activity? I suspect our experience of self is much like our experience of red — that is, a subjective experience, not an actual source of “willpower” or real decision-making.

    As per this blog entry, we can’t point to where the self originates in the brain because it’s not any one single thing or process. We recognize the self when we’re aware of a tiny piece of our decision-making process in action, but the self doesn’t do that work; that work is done unconsciously and is mostly unavailable to the self.

    What we call the self is only our awareness of the tip of the iceberg — and it certainly doesn’t control the iceberg. It just gets to see the final steps in the iceberg’s plan, and then (wrongly) assumes it was responsible.

  5. #5 Rhodora Online
    August 12, 2009

    Hofstadter’s I Am a Strange Loop must be read who very neatly explains how “the tip of the iceberg” does indeed come to control (or let us say ‘lead’) the iceberg itself… Otherwise, I agree with the point Gregory Lent is trying to make. The method we have chosen to study such a ‘metaphysical’ ‘subject’ is not equipped to lead to the profound truths that underlie it all. I am reminded of Bernard d’Espagnat…

  6. #6 jb
    August 12, 2009

    How do these midline brain structures mentioned above relate to the default mode network?

  7. #7 dgoodman
    August 12, 2009

    Is the self really such a “delicate ghost”? Identity delusions are fairly uncommon occurrences … even in persons with massive brain injuries. It seems as if the brain, with it’s complex networked systems and potential for plasticity (and repair), can maintain a surprisingly consistent sense of self, even in the face of dramatic challenges. (And aren’t similar design principles employed by engineers at google and elsewhere who use them to build remarkably robust and cost efficient servers etc?)

  8. #8 LRA
    August 12, 2009

    Richard Power’s “The Echo Maker” comes to mind.

  9. #9 e
    August 12, 2009

    Fascinating article. “An emergent property is altering the electrical cells from which it emerged”. This makes me think of a feedback loop, and I’m not entirely sure why, but here goes.
    In a simple, single cell organism, input sensory stimuli are just mapped directly to behavioural responses, and there is no real consciousnes, or sense of self. As the organism increases in complexity, some mechanism is required to handle the increasing amount of sensory data, which could be the beginning of animal consiousness. This is necessary to selectively process the data and decide what action (or reaction) to take in response to external stimuli, and perhaps memory to store all the additional data. There has been some studies which suggest that the development of memory (particularly emotional memory) is a necessary precursor to a sense of self. It has been suggested that this is why we dont remember our infancy, because our emotional memory, and hence our sense of self (in effect, the person who is me) has not yet developed.

    As the system evolves and drastically increases in complexity, perhaps some form of feedback loop develops whereby input sensory stimuli and memory produce an immensely complex emergent process which in turn alters the memory (I believe it has been said that everytime we recall a memory, we alter it) and selectively ignores and focuses on specfic sensory information. In addition, we can ignore the sensory information and just wander through the staggeringly complex inner world of our consciousness which allows us to develop scientific theories and mathematics and literally project ourselves in time and space, back to the beginning of the universe and out amongst the stars. Perhaps Buddhist teachings do have something to tell us about how to perhaps direct the iceberg in a good direction, It also worth remembering that although our awareness is only the tip of the iceberg, it is still part of the iceberg. There is only one iceberg, it just so happens that one part is above the water.

    Utter nonsense of course, but what the hell :)

    Love this blog, keep up the good work!
    e

  10. #10 Roger Bigod
    August 12, 2009

    Now I do not know whether I was then a man dreaming I was a butterfly, or whether I am now a butterfly, dreaming I am a man.

    Eastern religions have a more poetic style in these matters, but there’s plenty in the Western Civ tradition. Greek oracles under the influence of drugs being possessed by gods. The whole demonic possession schtick in general. Folk explanations of seizures. Doctrines of rebirth in Greek mystery cults, the Osiran cycle (celebrated every Easter under somewhat different management). Speaking in tongues during holy roller religious ceremonies. Cogito ergo sum.

  11. #11 ncoffee
    August 12, 2009

    Re: #9 e

    “Perhaps Buddhist teachings do have something to tell us about how to perhaps direct the iceberg in a good direction,”

    I’d go with CBT myself, but I just wanted to make a distinction here (of which e is presumably already aware): as opposed to the outlook presented in comment #3, not everyone who meditates has a problem with the supposed “western pov”.

    Many Buddhists, including the Dali Lama, have a keen interest in the scientific method and how it can be applied to and integrated into their historical/philosophical understanding of the mind. Props to ‘em!

  12. #12 Enda
    August 12, 2009

    @ ncoffee

    Yes indeed, I was trying very hard to not feed the troll. :) After all there’s a 1000 ways to skin a cat, a deeper understanding at any level can only ever be a good thing.

  13. #13 jb
    August 13, 2009

    See the book “Selfless Insight” by neurologist James H. Austin, MD who is a longtime Zen practioner as well as neuroscientist. He goes into the selfless part.

  14. #14 LRA
    August 13, 2009

    Oops! Looks like you already recommended “The Echo Maker.” (Now how did I miss that?)

  15. #15 B
    August 15, 2009

    “It’s impossible for me to imagine reality from a perspective other than my own – I am the sole perciever of all my perceptions.”

    I was going to say that I love the dialogue between the thoughts here and this article from Seed, which touches on how Markram’s plans of actually simulating the subjective experience.

    But then I realized the authors of the two are one and the same. ;)

  16. #16 elkcreek
    August 15, 2009

    The talk about Yogis, and Bhudda, are all very interesting for the very few that take the time to contemplate them. How ever these systems of thought are unprovable on a scientific scale that attempts to make such things understandable and workable. That’s what scientific investigation is all about. It is a carefully, extremely difficult search for, in this case, of the brain, for workable understanding that can be used to heal and understand normal human problems. If one prefers to sit for years at the feet of a Guru of which, not one so far, has stood up under careful scrutiny, then go for it.
    I, for one, will choose cold intellectual logic.

  17. #17 Aida Mehonic
    August 15, 2009

    Fascinating. I recently saw an entertaining talk on related issues: http://www.ted.com/talks/lang/eng/vilayanur_ramachandran_on_your_mind.html

  18. #18 joseph.odoherty
    August 15, 2009

    “Think, for a moment, about how profoundly strange this is: the self, a fragile figment produced by all these different mental processes, is causing very real changes in neural activity. An emergent property is altering the electrical cells from which it emerged.”

    Ncoffee touches on this above, but I think it bears repeating: Does the self cause neural activity to change or is it a subjective experience that emerges from changes in neural activity? The confabulations developed by those suffering from anarchic hand syndrome and other disorders and the time delays measured between a person reporting the intent to make a movement and the emergence of preparatory brain activity observed by Libet and others gives us a few clues here. For me, the simplest explanation is that the brain makes decisions and the self is “told” about these decisions post hoc. As for why there would be an evolutionary advantage to such a scheme, or how the qualila of the self emerge, of course, I have no idea.

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