Supports my view of sense, Invalidates mechanistic assumptions about eyes. The genie about the reality of sense just doesn't seem to want to stay in the bottle...
Craig http://www.newswise.com/articles/ectopic-eyes-function-without-connection-to-brain *Experiments with tadpoles show ectopic eyes that "see"* > > Newswise — MEDFORD/SOMERVILLE, Mass. (February 27, 2013) – For the first > time, scientists have shown that transplanted eyes located far outside the > head in a vertebrate animal model can confer vision without a direct neural > connection to the brain. > > Biologists at Tufts University School of Arts and Sciences used a frog > model to shed new light – literally – on one of the major questions in > regenerative medicine, bioengineering, and sensory augmentation research. > > "One of the big challenges is to understand how the brain and body adapt > to large changes in organization," says Douglas J. Blackiston, Ph.D., first > author of the paper "Ectopic Eyes Outside the Head in Xenopus Tadpoles > Provide Sensory Data For Light-Mediated Learning," in the February 27 issue > of the *Journal of Experimental Biology*. "Here, our research reveals the > brain's remarkable ability, or plasticity, to process visual data coming > from misplaced eyes, even when they are located far from the head.” > > Blackiston is a post-doctoral associate in the laboratory of co-author > Michael Levin, Ph.D., professor of biology and director of the Center for > Regenerative and Developmental Biology at Tufts University. > > Levin notes, "A primary goal in medicine is to one day be able to restore > the function of damaged or missing sensory structures through the use of > biological or artificial replacement components. There are many > implications of this study, but the primary one from a medical standpoint > is that we may not need to make specific connections to the brain when > treating sensory disorders such as blindness." > > In this experiment, the team surgically removed donor embryo eye > primordia, marked with fluorescent proteins, and grafted them into the > posterior region of recipient embryos. This induced the growth of ectopic > eyes. The recipients’ natural eyes were removed, leaving only the ectopic > eyes. > > Fluorescence microscopy revealed various innervation patterns but none of > the animals developed nerves that connected the ectopic eyes to the brain > or cranial region. > > To determine if the ectopic eyes conveyed visual information, the team > developed a computer-controlled visual training system in which quadrants > of water were illuminated by either red or blue LED lights. The system > could administer a mild electric shock to tadpoles swimming in a particular > quadrant. A motion tracking system outfitted with a camera and a computer > program allowed the scientists to monitor and record the tadpoles' motion > and speed. > > Eyes See Without Wiring to Brain > > The team made exciting discoveries: Just over 19 percent of the animals > with optic nerves that connected to the spine demonstrated learned > responses to the lights. They swam away from the red light while the blue > light stimulated natural movement. > > Their response to the lights elicited during the experiments was no > different from that of a control group of tadpoles with natural eyes > intact. Furthermore, this response was not demonstrated by eyeless tadpoles > or tadpoles that did not receive any electrical shock. > > "This has never been shown before," says Levin. "No one would have guessed > that eyes on the flank of a tadpole could see, especially when wired only > to the spinal cord and not the brain." > The findings suggest a remarkable plasticity in the brain’s ability to > incorporate signals from various body regions into behavioral programs that > had evolved with a specific and different body plan. > > "Ectopic eyes performed visual function," says Blackiston. "The brain > recognized visual data from eyes that impinged on the spinal cord. We still > need to determine if this plasticity in vertebrate brains extends to > different ectopic organs or organs appropriate in different species." > > One of the most fascinating areas for future investigation, according to > Blackiston and Levin, is the question of exactly how the brain recognizes > that the electrical signals coming from tissue near the gut is to be > interpreted as visual data. > > In computer engineering, notes Levin, who majored in computer science and > biology as a Tufts undergraduate, this problem is usually solved by a > "header"—a piece of metadata attached to a packet of information that > indicates its source and type. Whether electric signals from eyes impinging > on the spinal cord carry such an identifier of their origin remains a > hypothesis to be tested. > > Research reported in this publication was supported by grants from the > National Institute of Mental Health of the National Institutes of Health > under award number MH081842-02 and the National Eye Institute, also of the > NIH, under award number EY018168, and the Forsyth Institute, under award > number 5T32DE007327-09. > > Additional funders were the Leila Y. Mathers Charitable Foundation and the > U.S. Army Medical Research and Materiel Command (USAMRMC, award > W81XWH-10-2-0058). > > Blackiston, B. J. and Levin, M. (2013). Ectopic eyes outside the head in > Xenopus tadpoles provide sensory data for light-mediated learning.* J. > Exp. Biol.* 216, 1031-1040. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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