Decoding the Brain (Breakthrough S01E03)

  • cloustrum is the on off switch for human consciousness
  • It in now possible to change memories and even implant false memories in mice using opto genetics
  • In a seisure, the consciousness goes missing and it’s like all the neurons, instead of doing their own thing, suddenly become synchronized and do just one thing.
    conscious mind is simply the tip of the iceberg of our mental state
  • MRI studies show that the unconscious mind make most of our decisions upto 7 sec. before conscious mind becomes aware of these decisions and takes credit for it.
    Most of the time we’re running on auto pilot
  • Note that the conscious and unconscious mind work together and are continuously influeced by each other. In fact, the conscious mind can easily negate the decision made by the unconscious mind till the last stage when the actions is actually performed. This is proved by dual activity experiment where volunteers are asked to press food pedal before light switches from green to red.

Documentary: The Brain

  • For the dark and deaf brain and it’s 100 Billion Neurons, electrochemical signals are the only way to perceive the world and drive the 40 trillion cells in the body
  • The brain takes longer to process sight than sound. But the reason we don’t feel this difference is coz the brain synchronizes it all leading to half a sec overall delay in our perception of the external world.
  • A blind man given sight at mid life cannot perceive depth or recognize faces or read. This is coz, all these actions need certain areas of the brain, which his brain has long back rewired for sound and other perception.
  • The brain is like a city. Different areas specialize in different functions and yet constantly interact with and rely upon each other just like in a city. Reality in this analogy is like the Economy of the city. It emerges out of the interactions of different brain areas and like the economy, it’s not a real tangible thing.
  • Though reality is a byproduct of external input, it doesn’t depend on it. This is proved by experiments where prisoners who were secluded for days on end in solitary confinement, actually saw real things like flying kites and leaves. This goes beyond dreaming or daydreaming.
  • This is backed by science coz when we actually see with our eyes, then too, the amout of information flowing from the thalamus(connected directly to eyes) to the visual cortex is six times less than the info flowing the other way, proving that what we perceive depends much more on what’s inside us than on what info we take in through out eyes
  • The reality hence is what’s already in our brain. The brain’s reality is constantly being updated by info coming in from outside (this is proved by experiment where people were asked to wear prism glasses that switch their leu and right, and within a week, the brain adjusted), but from moment to moment, what  we experience isn’t what’s out there, but a beautifully rendered simulation. This is called the internal/mental model, made subconsciously from years of experience.
  • The reason brain makes this internal model is coz it’s primary aim is survival and so it needs to quickly classify external things so as to identify threats.
  • So to preserve energy, instead of creating a new model of reality every moment, the brain simply compares the sensory input with the preexisting model it already has, updating, refining and correcting it all the time. This work of the brain can be experienced easily when u encounter optical illusions. They prove that the brain can’t help but perceive what it knows (the internal model) even when you consciously know that what the brain is perceiving is wrong.
  • The cortex sends the thalamus what it expects to see (internal model) and the thalamus compares it with the external input (from eyes) and sends the difference to the visual cortex to update it’s model. This is why the downstream info is 6 times less than upstream( thalamus to cortex) coz it’s only the difference.
  • The internal model is also the reason the world is perceived as stable even though our eyes move 4 times a sec. The eyes make this motion to perceive bits of data, to update the city’s model that’s already in my head, so that I have a more accurate model and hence navigate the world better, which is the sole purpose of eyes.
  • Brain doesn’t pick every little detail, just enough to get us through, but it plays the trick of making us feel like we’ve seen it all. The brain works on a need to know basis, so just seeing an object doesn’t ensure that we’ve seen it. Unless we are asked questions about the object, the brain will not look for answers in the photons coming from the object and hence will never perceive those aspects of the object.
  • Similarly, there is no Color in external world, but it’s our brain that’s evolved to perceive different wavelengths of external EM (electromagnetic) waves input and represent it as different colors in our head.
  • Moreover, NO ORGANISM’S HAS ABILITY TO PERCEIVE THE TRUE OBEJCTIVE REALITY. Each organism perceives to the extent that it’s evolved to percieve. For instance humans perceive a tiny percent of the EM spectrum
  • Everyone has a personal reality (inner model) in their head, but the reason we experience that the model in the head of all humans is same is coz our brains are wired in the same way. Even a slight change in the wiring can dramatically change this model. For instance in patients of Synestesia, there is cross-talk b/w sensory areas of the brain leading them to associate colors with words, taste words or see music etc.
  • Psychotic episodes, like those in patients of Schizophrenia are due to problems in exchanging signals ie communication in brain, leading them to have a very different perception of reality than others, like seeing things or hearing voices that others don’t etc.
  • Perception of time is another thing that changes in a person from time to time. Some moments seem to take longer than normal and others shorter. The question is if, when time seems to slow down, like in instances of fear, does the perception (of sight) speed up ie is it in real time OR does the brain only store more info such that in retrospect, it seems to have taken longer?
  • This Q was answered by people thrown on bunjees with fast switching display, but none could read it in flight, proving that sight perception doesn’t speed up but instead more rich memories are formed (due to fear situation ) to have more info at hand to deal with this death situation. Hence it’s only in retrospect that we feel that the moment took longer than it actually did, just coz more memories were formed at that time.
  • The newborn has the max no. of neurons it will have in life, and it only goes down from there, but then why’s an adult more intelligent? Coz in a newborn, these neurons aren’t firing or connecting. That happens over time. By age 2 every neuron has 15K connections, twice that in an adult ie you become who you are not by what’s added, but by what’s removed. Why? In favor of focusing on a smaller no. of stronger connections. What you don’t use, you lose : Capture.PNG
  •  Age 2 is a critical turning point. If by the age of 2, the child has had experiences ie external inputs to the brain, the brain wires properly ie neural connections are made. But if the child is not stimulated in early life, the neurons don’t connect compromising brain development leading to problems in later life like stunded IQ or language skills, emotional problems, learning disabilities etc.
  • Again, in teenage years, the hormonal changes lead to both physical changes and in the brain. For instance, in teenagers, the medial frontal cortex, which is responsible for the sense of self in situations is more sensative than in adults, leading teens to be more self conscious.
  • Teens also have poor impulse control and take bigger risks as the parts of pre frontal cortex responsible for thinking about consequences of actions are still developing.
  • Even in adulthood, the brain changes to perform the task at hand and the change persists over time. Learning an instrument also changes brain dramatically.
  • Every experience changes the brain’s wiring and physical structure even.
  • This goes both ways and so change in physical structure of brain, like in case of brain tumor, can change a person’s personality.
  • Even drugs we take change our brain and hence our personality.
  • The simple process of aging also changes the brain and hence who we are
  • Memories are the core of our personality. They are actually brain states from a bygone time that we have to resurrect.
  • Our memories fade with time coz our brain only has a finite no. of neurons that over time are used for other, newer, memories. Every time we resurrect a memory, we remember less of the actual details about it, and so to reconstruct it, we fill it with new details, before tucking it away. Hence past memories are altered by the present.
  •  Hence every memory feels different depending on your state of mind when you’re resurrecting it.
  • In fact it’s proven that entirely false memories can be implanted in a person’s head, and even the vaguest false memory becomes more and more vivid over time as the person recalls it, filling in more missing details each time.
  • Why is memory so malleable? Coz memory is not only used in brain for remembering the past, but also for simulating/visualizing the future.
  • Consciousness emerges from the complex interactions of neurons just like music emerges from the interaction of beats from different instruments. But when we go to sleep, the beats of the neurons become in sync leaving no possibility of consciousness or personality to arise.
  • But WHY the Consciousness arises at all in the brain is a mystery of Science.
  • The MEANING that objects have for you is unique to you. We perceive objects not as they are, but as we are.

  • Most actions we make, even though we think are intentional, are really automatic
  • As we learn and practice new skills, they transform from software to hardware ie physical changes in the brain. They carve themselves into the structure of our neurons ie become muscle memory and so we are able to do those tasks without expending any brain power, rapidly and efficiently. These skills include typing, cycling, climbing stairs, tying laces etc. When we do these tasks we don’t use our conscious mind, and if through intense practice, we can let go of our conscious mind while performing some task directly through the unconscious, we’re said to be in a flow state or the zone. It’s when the conscious mind moves out of the way and instead of thinking about what we’re doing, we just do it.
  • So if unconscious mind governs most of our lives, what role does consciousness play?
  • Conscious mind is called into action when we come across something we weren’t expecting. The job of consciousness then is to figure out if this new thing is a threat or opportunity, to access what’s going on, to make sense of the situation
  • Consciousness is like the CEO of a company. It makes the executive decision. It’s the arbitrator of conflicting motivations in the brain. It has a unique vantage point that none of the billions of neurons have. It’s a way for the neurons to see themselves as a unified whole, for them to hold a mirror up to themselves. It allows the brain to see itself.
  • Why is the unconscious of every person different? It’s all in the GENES. For instance, half the population contains a set of genes that increase a person’s chances to commit violent crime by 882%. This gene is the Y Chromosome, and if you have it, we call you a male. Hence, we see that everyone comes on the table with different drives and behaviors based on their genes.
  • Still genetics is just a part of your story, coz which genes get a chance to express and when depends on your environment.
  • Do you have free will of any kind?  NO. All current neurological experiments have shown that decisions aren’t made by any kind of will, but instead, the conscious mind tricks itself into thinking that the decision was conscious and free. Free Will is an Illusion.
  •  Also, hoping for any kind of predictability in our actions is naive, coz billions of neurons fire every sec. and it’s their interactions that lead us to feel stuff and have thoughts, and there is no way to predict the interactions of these neurons. Moreover every other brain/person we interact with affects our neurons/cranial activity, making the whole system impossibly complex.


  • Every decision in the brain is a result of fight between conflicting neural networks in your brain.
  • When faced with Chocolate vs Vanilla, you don’t know why you chose one over the other and you classify it as “I felt like Vanilla, so  I chose it”. But that feeling arose from the Vanilla network having won against the Chocolate one.
  • In general we classify our options as Reason vs Emotion. Generally they work with one another helping us make decisions all day long without stress or conflict, but sometimes the conflict can be seen, for instance, in the classic “Trolley Dilemma”, where we’re faced with 2 scenarios, one where we have to pull lever to choose 4 lives over 1 and in other we’ve to decide to throw a man on track with same result. The consequences are the same, but in former decision you are detached and so rational n/w wins but in latter decision, the emotional n/w comes into play and wins.
  • Even with simple decisions, like choosing what to purchase, we feel that our decisions are purely rational, but  the emotional system is key to each of our decisions making us care about making the choice. To make a decision, you need to value one option over the other, and that can only be done with Emotions.
  •  Moreover, emotional system’s affect affects the whole physiology of the body like tense muscles, sweaty palms, dilated pupils etc. This is also classified as “Gut feeling” or a “Hunch”
  • “Ego Depletion” is when body is running low on energy. It affects our ability to make rational decisions. Hence make imp decisions on a full stomach
  •  Even decisions like staying with your partner over another is made by the brain and not you. Oxytocin, aka love hormone, drives us to choose our partner over others as 2 parents is better for the offspring so brain is evolved to driving us towards monogamy .
  •  Even things like one’s political affiliation are unconscious. One research shows that a person’s neural response of disgust, when presented with a gory image is a clear indicator of their affiliation. High disgust response predicts with 95% accuracy that you will vote conservative.
  • How do we make decisions about the future? Our brain continuously runs simulations about the future possibilities and rates them as per their worth to us, based on past experience. The dopamine system keeps updating our assessment of the world. If something turns out better than expected, the dopamine release increase in burst telling other brain systems to provide more of that stimulus. This reward and motivation scheme continually tells the brain what’s worth how much to us.
  • Will power, and resisting temptation uses up energy and so it’s not something we exercise, but something we use up. So don’t rely on will power to get things done, coz you might be running on empty fuel some day.
  • Instead enter into a “Ulysses Contract” like make a deal to meet a friend everyday at the gym. Now you don’t need will power to go to gym, coz it’s the social pressure of meeting friend that will get you there.


  • Our brains crave and depend on interactions with other humans
  • We are born with instincts about judging who’s trustworthy and what’s good vs bad, and choose the good over bad by instinct. This is shown in babies when asked to choose b/w good and bad bears
  • The brain relies on feedback from facial muscles to figure out how it’s feeling. Hence when we are trying to study the expressions of someone else, the brain tries out their expression on itself ie on our own face, to come to a decision about what feeling, the other person is expressing. This is proved by experiment where people injected with botox are worse at judging other’s feelings via their expressions.
  • When we experience other’s pain, the same neural n/w are in play, which are active when we ourselves are in pain. This is the basis for empathy.
  • Groups use propaganda and fear to dehumanize other groups hence leading to everyone in the group now acting as if the other group are not human and so are ok to kill or torture. This was replicated in blue eyed people are better than brown eyed people. Switching of the groups on top the next day allows the students to see that the rules of this world are arbitrary or have an agenda, but aren’t necessarily true.

PBS.The.Brain.with.David.Eagleman.6of6 Who.will.we Be


  • The way the brain works is by interpreting external signals. As long as the signals mirror, however crudely it maps to the real world. The brain will interpret the patterns from the input and in consort with input from other senses, will make sense of it. This is proved by Cochlear Implants. A cochlear implant (CI) is a surgically implanted electronic device that provides a sense of sound to a person who is profoundly deaf or severely hard of hearing in both ears. It does this by generating EM signals (that are the currency of the brain) from audio and feeding them directly to the brain.
  • This proves that in theory, there is no limit to the sensory expansion that we can create by just supplying EM signals to the brain that it’ll over time, learn to interpret and make sense of.
  • Though technique exist that could map the entire human brain with every neural connection, the amount of disc space needed to store this is 1 zeta-byte () for single person. 1 ZB is the sum of all info in the world today.
  • Another way to preserve the brain is to physically store it in liquid nitrogen and there are facilities around the world that provide this service.
  • Yet another theory is that of Computational Hypothesis, which argues that there is nothing special about the biological stuff (neurons etc) and that it’s the connections that make us who we are. If that’s true then it’s possible to simulate the entire brain digitally without bothering about mapping the neurons themselves or the structure of brain. per this theory, the mind is not what the brain is but what the brain does.So it proposed to sway cells with circuits and oxygen with electricity. This is what the “Blue Brain Project” is doing today. It’s goal is to deliver, by 2023, the software and hardware, capable of running the simulation of whole brain.
  • Yet another effort is in AI where machine learning is allowing us to make systems that learn from experience. Neural Networks do just that.
  • The concept of “Emergent Properties” explains that just as in a ant colony, the individual ants don’t have any idea of the big picture, and just do their job, similarly the individual neurons are like these ants. What emerges from the interactions and actions of ants is a super organism, a colony, with new properties that no individual ant has. Same is with the brain. All a ant and a neuron does is react to local signals while being a part of the network, but all these interaction leads to emergence of the mind.
  • TMS (Trans magnetic stimulation) in sleeping and awake patients clearly shows that the difference is that in sleeping patients the external signals don’t spread while when awake, they propagate throughout the brain, leading to idea that consciousness is what causes these interactions b/w different local regions of brain.

Why don’t we remember everything we see, and how to do so?


The brain doesn’t pick every little detail of the external world, but just what’s enough to answer the immediate question (like when we’re walking from point A to B, the immediate question is how to navigate our way etc.), but it plays the trick of making us feel like we’ve seen it all.

The brain works on a need to know basis, so just seeing an object doesn’t ensure that we’ve seen it. Unless we are asked questions about the object, the brain will not look for answers in the photons coming from the object and hence will never perceive those aspects of the object

So how do we ensure that we perceive the maximum out of any moment? Simply be asking the maximum questions at any moment.