The Mind Chip From: New Scientist - 02/03/2007 Vol. 193, No. 2589, P. 28 By: Douglas Fox A notable achievement in computer vision has been made by researcher Kwabena Boahen and colleagues at the University of Pennsylvania in Philadelphia, who constructed a device that can see via chips that physically imitate the electrical activity of neurons in the primary visual cortex. "I want to figure out how the brain works in a very nuts-and-bolts way," explains Boahen. "I want to figure it out such that I can build it." Boahen aims to top his accomplishment of building an artificial retina with the creation of an artificial cerebral cortex through the generalization of the chip's function; such a breakthrough may be an important step in helping restore neural function to people impaired by disease or injury. The concept of the artificial neuron as a technology for enabling brain-like computing in real time was first suggested in the late 1980s by California Institute of Technology scientist Carver Mead, who discovered he could build such circuits by having digital processors use transistors in their analog amplifier phase instead of their on/off switching phase. Mounted on the surface of Boahen's artificial retina are photosensitive transistors that translate incoming light into analog voltages with a value determined by the light's intensity and which last for as long as the light is beamed onto the transistors; these transmissions are routed to the artificial retina neurons where motion and regions of contrast are recognized, signaling the edges of objects in the image. Processing information about edges and movement in the visual scene is carried out by the low-power visual cortex chips, which build object outlines out of the signals. A successful cortical implant will have to be able to mimic the plasticity of the brain's neural network, in which connections between neurons are created and adapted on the fly. Read the preview of this article at: http://www.newscientisttech.com/channel/tech/mg19325891.500-the-mind-chip.html Links: Neuroengineering Research Laboratory of the University of Pennsylvania http://www.neuroengineering.upenn.edu/ Kwabena Boahen, PhD http://bioengineering.stanford.edu/faculty/boahen.html Brains in Silicon http://www.stanford.edu/group/brainsinsilicon/ Bioengineering professor hopes to mimic the brain on a chip http://news-service.stanford.edu/news/2006/march22/boahensr-032206.html A studied eye on the human brain http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/04/03/BUGOTI0US51.DTL