Wednesday, August 26, 2020

Secret Science Club Zoom Lecture Recap: The Livewired Brain

 Last night, the Secret Science Club presented a Zoom lecture by Stanford University neurologist Dr David Eagleman, who was lecturing about brain plasticity, the subject of his book Livewired: The Inside Story of the Ever-Changing Brain.  

Dr Eagleman indicated that the brain cannot be typified as either hardware or software, and coined the term 'liveware' to describe the brain, which is malleable enough to create new connections if it is damaged.  A dramatic example of the ability of the brain to reconfigure its connections can be found in hemispherectomy patients, who have an entire hemisphere of the brain removed, typically to treat individuals who suffer from extreme seizure disorders.  Even with half of the brain removed, many patients receiving the surgery in childhood can rewire the brain to the extent where they exhibit no symptoms more noticeable than a slight limp.  Dr Eagleman coined the term 'livewired' to describe the brain's plasticity, the ability to mold into a new shape which can be held, because 'plasticity', coined by William James in the 19th Century, implies that the brain molding reaches a fixed state, while in reality the brain continually reconfigures connections, though plasticity diminishes over age.  

Certain parts of the brain are more malleable than others, the visual cortex is less malleable than the somatosensory cortex- visual data is relatively stable, while data from our changing bodies is unstable.  Brains match their input... the cortex is relatively uniform (Dr Eagleman joked that it was a 'one trick pony'), but the different sensory organs input different data.  The brain wraps itself around new data streams.  Dr Eagleman founded a company which developed a vest which can allow deaf people to use vibrations on the skin to simulate hearing.

Unlike, for example, zebras which can run shortly after birth, humans are helpless at birth.  Dr Eagleman described humans as having 'half baked' brains at birth, and the malleability of human brains have allowed us to overrun the planet.  The goal of the brain is to model the world.

The brain figures out how to control the body it finds itself in.  Dr Eagleman presented us with the example of an armless archer, who holds the world's record for the longest accurate bowshot.  A robotics team has developed a starfish robot which uses machine learning to figure out how to locomotor.

Brain circuitry comes to reflect what an individual does.  New neural pathways develop in the cortex to accommodate juggling or playing a musical instrument.  The modeling, regulated largely by acetylcholine, is based on relevance... for instance, a piano player who uses two hands equally, should show different pathways than a guitar player, who uses two hands in different manners.

In the case of brain damage resulting from a stroke, constraint induced therapies which bind the non-impaired limb can force patients to recover functionality more rapidly.

The takeover of territory in the cortex occurs rapidly, subjects who are blindfolded exhibit activity in the visual cortex triggered by touch within an hour.  It is probable that dreaming provides stimulation to the visual areas of the occipital cortex to prevent takeover from other senses during sleep.

Dr Eagleman noted that memory involves changing the structure of neural connections while keeping function.  

To get an idea of how this lecture went, here is an interview of Dr Eagleman conducted by MIT researcher Lex Fridman in which the good doctor defines the concept of livewiring:


If you want in on the actual Zoom lectures, drop a line to my great and good friends at the Secret Science Club.  You don't have to be in Brooklyn to let Margaret and Dorian introduce you to fantastic lectures by brilliant intellects such as Dr Eagleman.

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