Panoptes and the Bionic Eye
Greek mythology tells us of Argus Panoptes, the "all-seeing" watchman giant and how his 100 eyes were preserved forever in the peacock's tail feathers.Copyright (left) c 1665 Hubertus Quellinus, Iconographic Database, Warburg Institute Library, UK; (right) 2009 Jebulon, Wikimedia Commons http://commons.wikimedia.org/wiki/File:Paonroue.JPG http://warburg.sas.ac.uk/vpc/VPC_search/record.php?record=29936
Vision is the primary sense of many animals and much is known about how vision is processed in the mammalian nervous system. One distinct property of the primary visual cortex is a highly organized pattern of sensitivity to location and orientation of objects in the visual field. But how did we learn this? An important tool is the ability to design experiments to map out the structure and response of a system such as vision. In this activity, students learn about the visual system and then conduct a model experiment to map the visual field response of a Panoptes robot. (In Greek mythology, Argus Panoptes was the "all-seeing" watchman giant with 100 eyes.) A simple activity modification enables a true black box experiment, in which students do not directly observe how the visual system is configured, and must match the input to the output in order to reconstruct the unseen system inside the box.
Animal vision is a remarkable system that serves as a model for engineers to design machines capable of "seeing." Engineers also apply their understanding of the visual system to design retinal prostheses that are implanted in the eyes of people with damaged photoreceptor cells in order to restore vision by directly stimulating optic nerve cells—an amazing biomedical invention.
Today, engineers are helping to restore peoples' sight by designing retinal implants.Copyright 2010 Lawrence Livermore National Laboratory https://www.llnl.gov/news/newsreleases/2010/NR-10-09-06.html
In this activity, students get a taste of the real-world methodology for a model experiment inspired from the neuroscience of vision. The concept of mapping a system's response in a black box setting, in which one indirectly observes a system via its input-output relationship, is universal in science and engineering. Additionally, this lab illustrates the value of processing experimental results in order to reduce large datasets to compact and meaningful summaries.
After this activity, students should be able to:
- Describe an overview of the visual pathway of the nervous system.
- Explain what we can learn about the visual system model through the proposed experiment (that is, the spatial concentration of light sensitivity of each sensor [the "receptive field"], and how the sensors are arranged as a group).
- Read a plot of experimental data.
- Interpret experimental data and reduce the data to a more summary graphic.
