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
*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
> 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
> 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.
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