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The Tell Tale Brain

Aug 15, 202415 min read

Author: Ramachandran V.S.

0. Intro and Anatomy Basics

Mirror neurons ⭐

  1. Neurons that mimic what another person is doing/feeling and can replicate same sensations in you. Springs compassion and empathy.
  2. A patient with electrodes in brain
  3. Are we hardwired to gel the gap between self and other (like Buddha says?)
  4. Mirror neurons are inhibited by frontal lobe in the brain to avoid your sense of self getting distorted. Also sensory receptors send reverse signals saying you are going through this experience it is somebody else to maintain balance.
  5. More effects in privacy, sense of self, projection issues and autism

Cerebellum - Servo-control loop

  1. Controls coordination of voluntary movement. Motor cortex issues commands, sends to muscles via spinal cord, cerebellum is sent a copy of the signals.
  2. Cerebellum also gets sensory feedback from muscle and joint receptors. It checks if the movement matches the signal, if not sends corrections to achieve the intended movements.
  3. Cerebellum damage - intention tremor

1. Phantom limbs and Plastic brains

  • Patient with amputated leg feels his leg constantly. But when touched on his face also feels it. Pour water feels it.
  • The body maps in brain, face is next to hands - Penfield map of skin surface on brain.
  • Possibly the nerves leak signals into limbs area from the face area or there is a movement of maps from limbs to face region. This may be due to the limbs region hungry to want signals so it steals them almost. Or the maps were already merged that you feel the sensations only after amputation.
  • In either case this means maps can be modified in a person’s life as usual understanding is that the brain once formed or damaged can’t be fixed.
  • Interesting case - a guy whose leg was amputated, started feeling his orgasms in his leg as the regions were mapped close by in the brain XD
  • After amputation, the brain does not know that the arm is gone. It keeps cc-ing motor commands to parietal lobe and this whole thing is misinterpreted as an arm being there.
  • The brain thus learning or becoming accustomed to previous states. For example - people whose arms were paralysed before they were amputated, have the same sense of phantom paralyses even after the amputation, basically a phantom paralysed limb.

Mirror box (Mirror visual feedback - MVF)

  • Move one limb normally in front of box and make the eyes see them like both limbs are moving in a normal manner. The visual feedback, confuses the brain and fixes the paralysed limb, phantom pain etc. Motor commands say limb is there, no sensory feeback, visual feedback says arm is there, so finally brain gives up and amputates the phantom limb.
  • Also, if a magnifying/minifying glass were put before to shrink the fake image on mirror, then the phantom limb or pain shrinks for the patient too.
  • Fixes functional or learned pain - Complex regional pain syndrome type 2 (CRPS-2).
  • Possible use-cases - optical mediated anaesthesia

Brains are plastic

  • How humor evolved - when the brain is expecting something but something of no consequence or rather ridiculous consequence happens. Same theory applies to tickling.

2. Seeing and Knowing

  • How humans evolved to see color by the need to pick colorful fruits. Same way the thumb evolved to oppose the forefinger to be able to pick things.

    1. is an ironic thought that our enjoyment of a Monet or a Van Gogh or of Romeo’s savoring Juliet’s kiss may ultimately trace back to an ancient attraction to ripe fruits and rumps. (This is what makes evolutionary psychology so much fun: You can come up with an outlandishly satirical theory and get away with it.) In addition to the extreme agility of our fingers, the human thumb developed a unique saddle joint allowing it to oppose the forefinger. This feature, which enables the so-called precision grip, may seem trivial, but it is useful for picking small fruits, nuts, and insects. It also turns out to be quite useful for threading needles, hafting hand axes, counting, or conveying Buddha’s peace gesture.

  • Perception and action

    1. Canonical neurons. These neurons are similar in some respects to the mirror neurons I introduced in the last chapter. Like mirror neurons, each canonical neuron fires during the performance of a specific action such as reaching for a vertical twig or an apple. But the same neuron will also fire at the mere sight of a twig or an apple. In other words, it is as though the abstract property of graspability were being encoded as an intrinsic aspect of the object’s visual shape. The distinction between perception and action exists in our ordinary language, but it is one that the brain evidently doesn’t always respect.

  • Case of John, who gets a stroke after appendix removal due to something like DVT

    1. His vision works as he can see but he can't associate it with objects from his memory.
    2. He walked out of his house and much to his wife’s surprise picked up a pair of shears and proceeded to trim the hedge effortlessly. However, when he tried to tidy up the garden, he often plucked the flowers from the ground because he couldn’t tell them from the weeds. Trimming the hedge, on the other hand, required only that John see where the unevenness was. No identification of objects was required. The distinction between seeing and knowing is illustrated well by John’s predicament.

  • Homunculus fallacy

    1. If the image on the retina is transmitted to the brain and ‘projected’ on some internal mental screen, then you would need some sort of ‘little man’—a homunculus—inside your head looking at the image and interpreting or understanding it for you. Then for him to understand, tere must be another man sitting inside him. Hence the fallacy.
    2. The brain creates symbolic descriptions. It does not recreate the original image, but represents the various features and aspects of the image in totally new terms—not with squiggles of ink, of course, but in its own alphabet of nerve impulses.

  • Perception constantly changes and is like an opinion of the image seen

    1. First, what you see can’t just be the image on the retina because the retinal image can remain constant but your perception can change radically. If perception simply involves transmitting and displaying an image on an inner mental screen, how can this be true? Second, the converse is also true: The retinal image can change, yet your perception of the object remains stable. Third, despite appearances, perception takes time and happens in stages.
    2. Proved by image illusions like the trapezium rooms and some other illusions.
    3. The shaded bubbles. The brain perceives things based on some prior knowledge and does a best case choice constantly. For instance in case of a weird illusion it would assume that the sun is above your head - even if you’re looking at it upside down :P

  • While studying visual pathways of monkeys they realized that image is seen, then there are lots of back propagations in the pathways

    1. What these back projections are doing is anybody’s guess, but my hunch is that at each stage in processing, whenever the brain achieves a partial solution to a perceptual ‘problem’—such as determining an object’s identity, location, or movement—this partial solution is immediately fed back to earlier stages. Repeated cycles of such an iterative process help eliminate dead ends and false solutions when you look at ‘noisy’ visual images such as camouflaged objects

  • MT and V4 can be tested by some simulation or temporary damage. The other 30 or so visual modules cannot be tested and tried the same way because on or more of them compensate for others in case they don’t work. So it’s hard to simulate them.

    1. MT Area - Middle temporal - in charge of perceiving motion
      1. In the late 1970s a woman in Zurich, whom I’ll call Ingrid, suffered a stroke that damaged the MT areas on both sides of her brain but left the rest of her brain intact. Ingrid’s vision was normal in most respects: She could read newspapers and recognize objects and people. But she had great difficulty seeing movement.
    2. V4 area - in charge of color perception

  • Pathways

    1. Old pathway - This pathway is concerned with spatial aspects of vision: where, but not what, an object is. The old pathway enables us to orient towards objects and track them with our eyes and heads.
    2. New pathways
      1. How/where stream - concerned with relationships between objects (overlaps a but with old pathway.
      2. What stream - concerned with relationships within objects
        1. In charge of perception. Seeing vs knowing difference.
        2. The case of John that can see but not know things, this stream was damaged.
        3. In charge of associating memory to objects, and also emotions to it, which is the last stage.
        4. John’s images of flowers. He reproduces flowers from the descriptions he remembers and not images he’s seen.
        5. Emotions - Case - When a person looks at his mother and says she looks like my mother but is not my mother! Capgras Syndrome
          1. Visual information is initially sent to the fusiform gyrus, where objects, including faces, are first discriminated. The output from the fusiform is relayed via pathway 3 to the amygdala, which performs an emotional surveillance of the object or face and generates the appropriate emotional response.
          2. This is broken in Capgras and in these cases of discrepancy, the brain just resorts to delusion to fix it.
          3. With GSR patients respond to familiar faces, but John doesn’t. He responds to his mother’s voice via GSR but not her image.
        6. After the Cagras paper submission, a lawyer from London calls and says a patient sees his wife as a different person every time after an accident. They want to claim insurance for the accident with this damage. They want Ramachandran to fly and diagnose. He instead quotes Coolidge effect :P Why does the guy not like looking at a different wife everytime.
    3. Blindsight - The answer lies in the anatomical division between the old and new pathways in the brain. A patient’s new pathway, running through V1, was damaged, but his old pathway was perfectly intact. Information about the spot’s location travelled up smoothly to his parietal lobes, which in turn directed the hand to move to the correct location.

Synesthesia

  1. Newton possibly being synesthetic. Wavelength theory of color. He invented a toy that flashes different colors on screen based on different notes.
  2. Francis Galton (the eugenics guy studied S first). He studied and said 2 common types of S - auditory-visual (sounds evoke colors) and grapheme-color (where characters, numbers are tinged with colors)
  3. Types (first two are most common)
    1. auditory-visual (sounds evoke colors)
    2. grapheme-color (where characters, numbers are tinged with colors)
    3. textures-emotions (ex - touches a paper and feels disgust)
  4. Psychology BS
    1. It is usually ignored as something they might have associated with as a child and can’t forget it.
    2. Or they say the person is just quoting some sort of a metaphor
    3. Or the brain just didn’t develop properly and there is a intermingling of sensory comprehension regions.
  5. Quirks specific to S
    1. Grapheme color - a number/character is covered in a tinge of a certain color for the person, same color always for a number but different people can see different color/number combos.
    2. Roman numerals don’t show the color - not a memory association, rather sensory.
    3. Only the image of a 7 or mental image of 7 shows color. Not the thought of it.
    4. Popout tests - where an image is hidden in a mess that only S people can see the color immediately and hence the number/character as well.

9. Self

Self vs consciousness

Info

https://www.reddit.com/r/askphilosophy/s/BKEPBFtijt

Body image ⭐

Apotemnophilia

  1. Patients disown their hand/leg saying it’s not theirs. 50% of them go on to amputate the problematic limb.
  2. Historically considered a psychological disorder, turns out it’s neurological.
  3. Patients even tell the exact point from where they want to cut the limb.
  4. GSR goes of when touched below line but not above the patients defined border.
  5. Brain has a map/image of how your body looks. This image is partially innate as some people feel phantom limbs.
  6. Brain also gets signals from limbs during touch or other sensations.
  7. When signals from one module mismatch another (brain is fine with external mismatches like solving mysteries but hates internal mysteries) it derails and gets confused. Hence the dissociation.
  8. Team also mapped brain regions reaction to touch in both normal and affected patients with supporting results.
  9. Also amputees like amputees, sexually attracted. This is in a similar way that birds like birds. We like the person who is similar to the image of ourselves ib our brain. Leg amputees like only leg amputees and not hand amputees.

Somatoparaphrenia

  1. As a result of stroke and damage to multiple image forming modules in brain.
  2. Patient disowns limb and also ends up saying it is somebody else’s.

Transexual

  1. Body image having or not having sexual morphology defined or misdefined.
  2. Patients mostly don’t want the image fixed instead change their sexuality. Makes sense.

Privacy/sense-of-self

  1. Mirror neurons working up or frontal lobe failing to do a good job at inhibition causes a variety of syndromes.
  2. For example - Romantic love is a minor such syndrome where you’re able to sync with another person and share the same madness :P
  3. This can even extend to cases where the neuron activity triggers some hormonal or other body activity - like some men empathizing with women who are pregnant and their brain releasing prolactin to generate phantom pregnancy.

Autism

  1. Possibly when there isn’t enough mirror neuron activity
  2. No matter how smart an autistic person is it will be extremely hard for them to feel embarassed or empathize and so on.

Out of body experience

  • Taking ketamine causes damage to the right frontoparietal regions or anaesthesia which removes mirror neuron inhibition. As a result you start leaving your body and don’t feel pain objectively.
  • A patient had a tumor in right frontoparietal region and ended up feeling a phantom twin to his left who would mirror all his actions. This guy was told he’d only live for two years after removing the tumor and he still was pretty cool and didn’t get agonized. The author irrigated his left ear with ice water. This is known to activate the vestibular system and can provide a certain jolt to the body image and so he felt the image shrinking and moving and changing posture.
  • Dissociative states in psychology.
    • During. A threat two outputs flow from hypothalamus, one a behavioural to fight or flight and other is an emotional output like fear or agression. Then there is physical arousal like blood pressure and heart rate elevation.
    • But during extreme threats the ratio of these outputs can get messed up and person may become still. They might feel pain but no emotion or other way around.

Social Embedding

Self defines itself to it’s social environment. When that environment becomes incomprehensible the self experience distress or it feels under threat.

  1. When visual pathway for identification works but the one for evoking emotions fails, people identify but don’t feel the kind of feelings they should feel when they see that person - Capragus syndrome.
  2. The other way is when they feel emotions but can’t identify the person - prosipagnosia.

Cotard Syndrome

  1. When extreme de-personalization, both their self and the world. Usually people who are extremely clinically depressed face this.
  2. Similar to capgras but more severe possibly because all sensory pathways to the amygdala are severed. Add some mirror neuron inhibition issues then the self gets derailed.
  3. Possibly this is why people who are depressed and start antidepressants commit suicide. Because they lose their sense of self so much and when they get that sense back a little bit then they realize how miserable they are and kill themselves. This is not studied but suggestive by the author).

Continuity

Types of human memory

  1. Procedural - cycle, brush
  2. Semantic - banana is yellow, winter is cold
  3. Episodic - prom night memories, first kiss etc.

Procedural and semantic is common to all vertebrates, only episodic us unique to humans.

Some people lose episodic memories sometimes, or the ability form such new memories. When there is damage to the hippocampi, humans can’t form episodic memories. For example they can read the same story over and over again, without getting bored.

Free will

Apraxia - when motor functions and thoughts work properly, but they can’t map thoughts into actions. Can say in words what action forms waving good bye, but cannot actually wave goodbye.

My Interpretation

  • Meditation and mindfulness leads to enlightenment might still hold true. Possibly meditation activates pathways or triggers some small/large reactions in the brain and maybe gets rid of the sense of self.
  • This might result in people feeling a singular sense of consciousness and connected to the rest of the world.
  • Which is still nice, because it removes a lot of the feelings of pain/misery and rather be accepting of it. EVERYBODY is SAD and that can be fixed?
  • And if self is taken away then a lot of modern problems are taken away. But also there might not be any motivation to make money or grow the economy for example. But that again, only in the context of self, maybe humanity will do things in a different way instead of doing it for themselves?

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