Posted on Thursday, May 15, 2014
Many liken the human brain to a computer, but Assistant Professor of Psychology Dan Graham doesn't think that captures the half of it. Graham says the better comparison is to the Internet, with its vast, networked system of messaging. He published a peer-reviewed article on April 10 in the online journal Frontiers in Computational Neuroscience, laying out his thoughts. The paper, "Routing in the brain," argues that neuroscientists have mostly ignored a crucial aspect of brain processing, routing-perhaps because of the personal computer metaphor.
"The idea that the brain is like a computer has dominated the field for decades, and our models of the brain largely reflect the mechanisms at work in computers," Graham says. "In shifting to the Internet metaphor, we have a new array of mechanisms to test and explore." PCs only need to communicate internally, but on the Internet, "we need to send information from many places to many other places at the same time-this requires routing," he says. "The Internet's clever schemes for accomplishing this may have counterparts in the brain."
His article examines how packet switching on the Internet is a promising model for describing routing in the brain cortex. With packet switching, messages are chopped into small packets. The packets are labeled with the recipient's address and with whatever portion of the message that packet contains. The message is reassembled once all constituent packets arrive.
"Packet switching has appealing parallels with cortical signaling," Graham says. "It can dynamically reroute traffic, as the cortex does following lesion. It has the capacity for different ‘applications'-e.g., email, http, etc.-to run concurrently on the same system, as distinct modalities and signaling systems do in the cortex. And the inherent hierarchy of the network protocol stack mirrors the hierarchical organization within and across the cortex."
Graham notes that theories of how the brain works have often reflected the high tech of the times. In the 17th century, for example, "great advancements in plumbing, culminating with the water gardens at Versailles, inspired Descartes to imagine the nervous system as an intricate waterworks in which the plumbing of the brain was controlled by a master valve, the pineal gland. His interpretations of brain function were guided by this metaphor."
His students find it intriguing. "When we discuss in class the Internet metaphor for the brain, I find it has more resonance with students than the computer analogy. Perhaps this is in part because their own social networks are so evident to them."
A casual remark by a neuroscientist that no two people have the same arrangement of neurons spurred Graham - at the time a physicist - to seek out the basic, common tenets of how brains work. His research is timely, given President Barack Obama's $100 million BRAIN initiative, which aims to study network activity in the brain in a concerted, large-scale way.
"We lack overarching theories of brain function, as we have in physics for fundamental forces," Graham says. "I am trying to use principles of evolution, in concert with network theoretic principles, to develop similarly fundamental principles."