Measuring the Quantity of Information Passed on From the Eye to the Brain
Researchers at the University Of Pennsylvania School Of Medicine sugge...Much research on the basic science of vision asks what types of in...The retina is actually a piece of the brain that has grown into th...Investigators have known for decades that there are 10 to 15 gangl...The guinea pig retina was placed in a dish and then presented with...
Researchers at the University Of Pennsylvania School Of Medicine suggest that the human retina is capable of transmitting visual input at a rate akin to an Ethernet// connection, which is one of the known local area network systems in use. This measurement is a comparison of neural systems with artificial ones, as a means to evolve advanced artificial visual systems based on the available information. These findings have been presented in the July issue of Current Biology.
Much research on the basic science of vision asks what types of information the brain receives; this study instead asked how much. Using an intact retina from a guinea pig, the researchers recorded spikes of electrical impulses from ganglion cells using a miniature multi-electrode array. The investigators calculate that the human retina can transmit data at roughly 10 million bits per second. By comparison, an Ethernet can transmit information between computers at speeds of 10 to 100 million bits per second.
The retina is actually a piece of the brain that has grown into the eye and processes neural signals when it detects light. Ganglion cells carry information from the retina to the higher brain centers; other nerve cells within the retina perform the first stages of analysis of the visual world. The axons of the retinal ganglion cells, with the support of other types of cells, form the optic nerve and carry these signals to the brain.
Investigators have known for decades that there are 10 to 15 ganglion cell types in the retina that are adapted for picking up different movements and then work together to send a full picture to the brain. The study estimated the amount of information that is carried to the brain by seven of these ganglion cell types.
The guinea pig retina was placed in a dish and then presented with movies containing four types of biological motion, for example a salamander swimming in a tank to represent an object-motion stimulus. '"/>