The Brain As A Complex System

A Project Encephalon & The Science Paradox Collaboration article



Out of complexities, intense simplicities emerge- Winston Churchill



Abstract


What is the brain?


A 3lb organ composed of nerves and tissue that integrates sensory and motor responses? Right, simplify that.

A mass of nervous tissue divided into lobes, that controls all behavior? Simplify that again.

A network of neurons that is connected to form trillions of synapses…


Perfect. Stripped down to its roots, the brain is simply a network. A “network algorithm” so beautifully configured that it earned itself the reputation of being the seat of intelligence itself.


Undeniably, we live in a complex world. From the cells we are made up of, to the ecosystems we make up, we form innumerable connections and interactions rendering the whole greater than the sum of its parts, and is somehow significantly different from its parts. These connections and interactions converge into a system of their own and this intricate clockwork is known as a complex system.


In essence, the complex systems theory in data science studies how the society is greater than the sum of its people or, how an online community is different from its isolated connections or even, how the brain is so much more than a network of neurons.



Walking down Memory Lane


Since time immemorial, scientists and philosophers have been trying to decipher the mystery behind how the brain does what it does. Back in 1669, Nicolaus Steno, a pioneering anatomist said “The brain, the masterpiece of creation, is almost unknown to us.” (Findlen & Bence, 2000) Unfortunately, the brain has been such a complex enigma, that the saying holds even today.


However, between the late 16th century and today, we have covered many incredible milestones, some of which have been instrumental in forging the path to where brain sciences stand today. So before we move into the story of the brain as a complex system, it would be imperative to ‘walk down memory lane’ (quite literally) and laud some brains for the progress they made in cracking the “brain-igma”!


Back in the time of the Renaissance, several ancient philosophers like Aristotle, Galen, and Leonardo da Vinci described the brain as the “seat of the Soul” and functioned to “regulate the temperature of the blood and spirit”. (Findlen & Bence, 2000)


Following the advent of the microscope in the 16th century and the proposition of the cell theory in 1853, the understanding of the brain further blossomed to bring out two opposing schools of thought - the reticular theory and the neuronal theory. The reticular theory conveniently postulated that the brain was one simple contiguous structure in which information flows freely and the neuronal theory postulated that the brain is composed of a network of functional units called cells, just like the rest of the body. The outstanding work done by Santiago Ramon y Cajal in proving this neuronal doctrine using the silver nitrate staining technique invented by Camillo Golgi was quite the proverbial birth of cellular and molecular neuroscience. It laid the foundation of modern neuroscience as we know it. (Cajal, 1906; Golgi, 1906)


Now that the presence of neuronal cells was explained through the neuronal doctrine, the next million-dollar question was, “If the brain is composed of a network of cells, how is there a continuous flow of information in it?”


Surprisingly, this question had already been answered by a prodigy Luigi Galvani. As far as neuroscience was concerned, Galvani and his wife, Lucia, worked way ahead of his time. Their discovery in the late 17th century (way before Cajal worked out his doctrine) that nerves cause muscles to contract and move through electrical signals, laid the foundation for the field of electrophysiology. This set into motion a cascade of electrophysiological experiments, whose description would require an entire book. Suffice to say that, the problem that started with Galvani discovering ‘animal electricity’ in frog legs in the 17th century, matured through the brains of experts like Emile du Bois-Reymond, Johannes Muller, Hermann von Helmholtz, Julius Bernstein, Ludimar Hermann, and several others to finally reach Alan Hodgkin and Andrew Huxley (the 1963 Nobel Prize-winning duo) for their work on measuring action potentials in squid axons. (Piccolino, 1998; Schwiening, 2012)


Around the same time, neuronal communication through synapses was discovered. Two centuries’ worth of rigorous work finally culminated in the proverbial “coming of age” of neuroscience with important insights into nerve conduction, membrane potential, and neuronal synapses.