Viswanathan K's Thoughts

“Social reality” is a concept that exists only in the human brain, writes Lisa Barrett in Seven and a Half Lessons About the Brain . Social reality is anything we consider real though nothing in physics or chemistry would make it real – examples include national borders; or the idea that a specific portion of the earth’s orbit around the sun is January.   Scientists believe that the ability to construct social reality is because of a suite of capabilities of the (human) brain called the Five C’s. Creativity : Someone needs to decide to draw a line and call it the border of a “country”, then define what a country is. That needs creativity. Communication : The idea of a country can be explained to others. Via, say, language. Copying : This refers to the ability to teach and learn the practices of others. Only if newcomers and children can be taught or if one can learn the customs of a new place can social reality continue to exist for very long periods. Cooperation : We ...

  In Seven and a Half Lessons About the Brain , Lisa Barrett describes the structure of the brain. The brain is a network of neurons, around 128 billion of them in case of humans. The neurons continuously fire and communicate with other neurons they are connected to. And here’s something not everyone realizes: “Your brain network is always on.” Put differently, that means neurons are not triggered into action only when something happens inside or outside the body. Rather, they are talking with each other continuously. But the strength of the signal will change based on triggering events and also, yes, frequency of usage of those pathways.   A metaphor that Barrett uses to describe the brain is the airport network. Just as every combination of airports don’t have direct flights between them, similarly all neurons don’t communicate with all other neurons. Instead, both have “hubs” – a small number of points that connect to a huge number of other points. The rest (majori...

For what purpose has the brain evolved? As humans, we are biased when we encounter that question, writes Lisa Barrett in Seven and a Half Lessons About the Brain . We wrongly assume that the purpose of the brain is to think: “After all, thinking is the human superpower, right?”   Wrong, says Barrett. Long, long ago, unicellular life found itself in competition with others over limited resources, the importance of any capability to sense what lay where was an evolutionary advantage – Did XYZ lie to the left or right? Gradually though, raw sense organ signals weren’t enough. Choices had to be made – was it likely one could catch the prey? Make a wrong choice repeatedly and one would die of starvation. Thus: “Energy efficiency was a key to survival.”   So Barrett concludes: “Your brain’s most important job is to control your body… by predicting energy needs before they arise so you can efficiently make worthwhile movements and survive.”   But this created...

Animals have one of two kinds of symmetry – radial or bilateral, points out Max Bennett in A Brief History of Intelligence .   Animals started by having radial symmetry. Why then did so many diverge into bilateral symmetry? Simple answer: Radial symmetry works fine if the approach is to wait for food. But it is a terrible setup if you want to navigate towards food. He expands on that.   A creature with radial symmetry would detect signals from and move in all directions. Bilateral symmetry, on the other hand, is designed for movement in two directions – ahead and left/right. The former is very complicated; the latter is so much simpler. (Which is why human engineers have designed everything that moves with bilateral symmetry – cars, planes, submarines).   While simpler on one front, bilateralism creates a new need – a decision-making capability . Which direction should one move in? Thus, all bilaterals, even the tiniest ones, have brains. Two rules are the min...

In earlier blogs, we’ve seen sensory substitution and sensory addition . But, as David Eagleman writes in Livewired : “That’s only the input half of the story.” Let’s next look into the output-related reorganization of the brain.   When a limb is paralyzed, the motor system parts of the brain reorganize: “The motor areas optimize themselves to drive the available machinery.” In fact, brains are not “predefined for particular bodies”. Instead, brains “adapt themselves to move, interact, and succeed”: “(Watch a human baby and notice how she is) learning how her motor output corresponds to the sensory feedback she receives.” It doesn’t stop with babies, of course. We continue the “same learning method to attach extensions to our bodies”. That’s how we learn to ride a bicycle. Or a skateboard. Or to surf the waves: “The specifics of the devices’ weight, joints, movements and controllers – everything you can do with them – work their way into your brain circuitry.”...

In an earlier blog , we looked at sensory substitution capabilities of the brain. In Livewired , David Eagleman next looks at the brain’s capability to deal with sensory enhancement , even addition of entirely new senses.   He cites the case of a lady who lost her sense of balance (due to an inner ear problem). So a helmet that read the tilt of her head was placed on her head that would send tilt/balance signals via her tongue (her ear channel wasn’t working, remember?), and voila! Her brain learnt to “understand the strangely routed information” and her ability to balance improved tremendously.   In another instance, a color blind artist attached a device that converted color to sound signals delivered via “bone conduction behind his ear”. Now he can “see” and differentiate colors. Even better, he can see colors beyond the normal spectrum that us regular mortals can see, because the range of his color detection sensors are better than our eyes!   Impressive...

In his book on the remarkable change’ability of the brain, Livewired , David Eagleman asks: how flexible is the brain? Can it even learn to make sense of an altogether new format of data it receives? “Would a small electronic chip, speaking the dialect of Silicon Valley instead of the language of our natural biological sense organs, be understood by the rest of the brain?”   If that sounded like a question for the future, you’d be wrong. For people whose inner ear isn’t working, no amount of amplification will help. Instead, they’ve had the option of cochlear implants since 1982: “This tiny device circumvents the broken hardware of the inner ear to speak directly to the functioning nerve just beyond it… (The implanted microcomputer) receives sound from the outside world and passes the information to the auditory nerve by means of tiny electrodes.” A recipient of the implant said it took some time for the brain to be able to make sense of the new format of data, but soon h...

It is well known, as David Eagleman says in Livewired : “We drop into the world with a brain that’s largely incomplete. As a result, we have a uniquely long period of helplessness in our infancy.” So why are we human babies born that way? “That cost pays off, because our brains invite the world to shape them.” The technical term for all this is “plasticity”. As in plastic: it can be molded into any shape, and even better, it can hold that shape.   However, as we know all too well from experience, for certain topics: “(This reshaping of the brain happens) during a rapidly closing window of time. One the window is missed, it is difficult or impossible to reopen.” The good news though is that the time-window constraint doesn’t apply for all topics. Long after baby- and toddler-hood, the brain can still reshape itself: “The shape shifting of brains is not like the glacial drifting of continental plates, but can instead be remarkably swift.”   For example, re...

In his terrific book, The Brain , David Eagleman writes: “Your senses set boundaries on what you can experience… But what if the brain could understand new kinds of inputs?” New inputs would come from accessories that we attach on or implant to our bodies. Yes, like a cyborg. Whenever I’ve thought of this idea, I’ve felt the problem is that: 1)       We don’t yet understand how the brain works; 2)      And without knowing that, how would we know the “format” in which the input signals from the new sources/sensors/implants should be sent to the brain? But it looks like there’s a way around that, by using this ability of the brain: “(The brain) rewires itself to adjust to the inputs… It’s this property of the brain – its plasticity – that enables a new marriage between our technology and our biology.” Ok, how far can that ability of the brain take us? “Would the brain be able to understand crude, non-biological signals, ...