THE BRAIN IS... NETWORKS! (Posted 2011-02-10 15:20:24 by Ray Lopez) A great new book has been published called _Networks of the Brain_, written by Dr. Olaf Sporns. The press release [ http://newsinfo.iu.edu/news/page/normal/17284.html ] for this new book has the following quote from Dr. Sporns: -=-=-=-=-=-=-=-=-=-= _"There's a big movement all across the social and natural sciences to look at things in terms of networks. In the neurosciences, increasingly we aren't looking at only one part of the brain, but seeing how the interactions between different parts make them work together."_ -=-=-=-=-=-=-=-=-=-= I find this highly amusing, for it follows a pattern that has been around for hundreds of years: That of using the latest-greatest technology as a metaphor for how the human nervous system works. In the 17th century, Rene Descartes was once enthralled by seeing moving automatons that looked just like real people. At that time, mechanical craftsmanship was exploding, and new technologies based on steam, hydraulics, and pneumatics were being used to create all sorts of wonderful new toys and tools. These new technologies would eventually form the framework for the Industrial Revolution. The automatons that Descartes saw were machines powered by hydraulics and pneumatics, and this led Descartes to propose that animals and humans were nothing more than machines made out of meat. Our nervous systems were simply pathways that pumped our muscles up and down to create movements, and our brain was the central pump. Of course, this theory was wrong, and it was proven so by experiments in the next century. These 18th century experiments involved a new phenomenon... electricity. It was discovered early on that you could make the muscles of dead animals twitch by apply an electrical current to them via metal pins stuck in the tissue. Experimentation demonstrated that hydraulics had nothing to do with muscle movement, but electricity did, so now the brain and nervous system was viewed as a dynamo connected to a series of wires. Once again, that was wrong, and we moved on to the next century and next technology: the telegraph. Telegraph networks were pioneered and built in the 19th century and persisted well into the 20th century. People were enthralled with the ability to send information quickly and cheaply across the world. Without fail, this new technology was seized upon as the absolutely correct way in which the brain and nervous system function. Based on electricity, it was thought that the nervous system was a very large telegraph network. Different parts of the body communicated with the brain via a specific code, and the brain responded back with commands to initiate movements, thoughts, and feelings. Did they have it right? Of course not. Researching on the nervous system continued and when it became apparent that there was no way to identify anything that looked like a telegraph system, people moved on until the next great technology appeared. In the early part of the 20th century, telephone networks were constructed. Early phone networks grew rapidly and became incredibly complex. The complexity was managed by central phone offices manned by switchboard operators. The switchboard operators (usually young women) were the intelligence behind the network. They would receive phone call requests from people and route calls from point to point until the callers were connected. And so, the "telephone switchboard" model of mind and brain was born. The complexity of mental functions obviously involved some complex switching of information at some level, so people imagined the brain as a massive network of inter-communicating cells, being directed by switchboards which responded to sensations, perceptions, thoughts, feelings, what have you. This metaphor actually persisted into the second half of the 20th century, being recounted in many non-scientific publications for adults and children. A lesser known metaphor to understand brain functions came about as a result of a technology developed during World War II: the electronic servomechanism [ http://en.wikipedia.org/wiki/Servomechanism ]. A servomechanism is a mechanical or electronic device that uses negative feedback to correct and regulate its operations. For example, the furnace in your house constitutes a servomechanism. The electronic servomechanism served as the perfect theoretical construct to help understand the mysterious "intelligence" that controlled the phone switchboards in your brain. The switchboard operators could now be replaced with arrays of servomechanisms, all operating together to regulate our functions and behaviors. This metaphor worked well with the mechanistic world-view of the behaviorists of the day, such as Clark Hull and Kenneth Spence. Starting in the 1960s, it became apparent that even an extremely complex network of wires, switches, and servos was no match for the computational power of the human brain. Fortunately, technology came to the rescue with another handy metaphor for us to use in understanding brain function: the digital computer! The 1960s saw an explosion of psychological research all aimed at understanding the human mind and brain as "information processors". So it was to be expected that people started talking about our brains in terms of "CPUs", "random access memory", "disk storage", and all the other terms associated with computer technology. As computers got smaller, cheaper and faster, they fell into the hands of more and more scientists, who were more than confident that 1) the brain was in fact an information processor just like a computer, and 2) we could use computers to model human cognitive activity. No where was this expressed more confidently and hauntingly than in the fictional HAL 9000 computer from the 1968 movie classic, _2001: A Space Odyssey_. However, during the latter part of the 20th century, it became apparent that simulating human cognition was a much tougher problem than anyone had imagined, and by the mid 1980s most artificial intelligence researchers had thrown in the towel in terms of being able to do so. There were a few strategic battles won here and there, most notably by IBMs Deep Blue supercomputer, which defeated world champ Gary Kasparov in a series of chess matches. But even though the metaphor of the human mind as an information processor persists to this day, it has not helped much in figuring out the precise mechanisms by which our brains work. We need another metaphor, and thanks to the rise of the Internet, we have one: networks. So we finally arrive at the 21st century, with a long list of failed metaphors that have helped us slowly but surely understand what the brain does. The Cartesian model of hydraulics and machines helped us to understand that our nervous systems follow some laws of nature. The electrical metaphors helped us to see the electrochemical properties of our nervous systems. Telegraph and telephone metaphors introduced complexity to the mix, helping us to envision the brain as a very massive collection of interconnected parts. The servo metaphor helped us to see ways in which our brains control the functions of our bodies and our minds. Computers gave us a metaphor of information processing, the generic act of sifting through data to arrive at final solutions to problems of cognition. What will the network metaphor give us? I don't think anyone can say now. As a technology person, I am hopeful that the network metaphor will give us some insight into the "communication protocol" used by networks of neurons to render our experiences. Just as the Internet is based upon the TCP/IP protocol, I am hopeful that looking at the brain as a "network" will help us to begin to understand what the "networking protocol" of the brain really is. In the meantime, we can take books like _Networks of the Brain_ and use them to help us explore the network metaphor. I doubt that we've gotten it "right" now, in that the brain probably operates by some principles we can't even imagine yet. But let's hope that this new metaphor will enable us to scratch ahead even a little in understanding how our brains work. -------- There are no comments on this post. To submit a comment on this post, email rl@well.com or visit us on the web [ http://ratthing.com ].