Navigation Links
Measuring the Quantity of Information Passed on From the Eye to the Brain

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. After recording electrical spikes on an array of electrodes, the researchers classified each cell into one of two broad classes: "brisk" or "sluggish," so named because of their speed.

The researchers found that the electrical spike patterns differed between cell types. For example, the larger, brisk cells fired many spikes per second and their response was highly reproducible. In contrast, the smaller, sluggish cells fired fewer spikes per second and their responses were less reproducible.

But, what's the relationship between these spikes and information being sent? "It's the combinations and patterns of spikes that are sending the information. The patterns have various meanings," says co-author Vijay Balasubramanian, PhD, Professor of Physics at Penn. "We quantify the patterns and work out how much information they convey, measured in bits per second."

Calculating the proportions of each cell type in the retina, the team estimated that about 100,000 guinea pig ganglion cells transmit about 875,000 bits of information per second. Because sluggish cells are more numerous, they account for most of the information. With about 1,000,000 ganglion cells, the human retina would transmit data at roughly the rate of an Ethernet connection, or 10 million bits per second.

"Spikes are metabolically expensive to produce," says lead author Kristin Koch, a PhD student in the lab of senior author Peter Sterling, PhD, Professor of Neuroscience. "Our findings hint that sluggish cells might be 'cheaper,' metabolically speaking, because they send more information per spike. If a message must be sent at a high rate, the brain uses the brisk channels. But if a message can afford to be sent more slowly, the brain uses the sluggish channels and pays a lower metabolic cost."

"In terms of sending visual information to the brain, these brisk cells are the Fedex of the optic system, versus the sluggish cells, which are the equivalent of the U.S. mail," notes Sterling. "Sluggish cells have not been studied that closely until now. The amazing thing is that when it's all said and done, the sluggish cells turned out to be the most important in terms of the amount of information sent."

Source : Eureka Alert


Related medicine news :

1. Measuring Death Risk in COPD Patients
2. Measuring Exercise Capacity To Predict Heart Disease
3. A Novel Method For Measuring Interstitial Fluid Pressure In Cancer Tissues
4. Measuring disseminated cancer cells in bone marrow - valuable tool for detecting early breast cancer metastasis
5. Measuring Urinary Protein Helps In Detecting Recurrent Bladder Cancer
6. New Method For Measuring Dyskinesia In Parkinsons Being Developed
7. Measuring Calcium Intake Help to Identify Osteoporosis in Prostate Cancer Patient
8. Seizure of Low Quantity of Heroin is No Ground for Bail: HC
9. Sleep Quantity Affects Morning Testosterone Levels in Older Men
10. New Information On Virus Goes Against The Age-Old Theory
11. CPHA Offers HIV Information Packages To Canadian Football League Teams
Post Your Comments:

(Date:6/26/2016)... ... June 26, 2016 , ... Pixel Film Studios Released ProSlice Levels, ... editors can give their videos a whole new perspective by using the title ... Pixel Film Studios. , ProSlice Levels contains over 30 Different presets to choose ...
(Date:6/25/2016)... D.C. (PRWEB) , ... June 25, 2016 , ... ... discuss health policy issues and applications at AcademyHealth’s Annual Research Meeting June 26-28, ... their work on several important health care topics including advance care planning, healthcare ...
(Date:6/25/2016)... ... 2016 , ... First Choice Emergency Room , the largest network of ... Medical Director of its new Mesquite-Samuell Farm facility. , “We are pleased to ... said Dr. James M. Muzzarelli, Executive Medical Director of First Choice Emergency Room. ...
(Date:6/25/2016)... ... 25, 2016 , ... Conventional wisdom preaches the benefits of moderation, whether it’s ... setting the bar too high can result in disappointment, perhaps even self-loathing. However, those ... goal. , Research from reveals that behind the tendency to ...
(Date:6/24/2016)... ... ... crisis. Her son James, eight, was out of control. Prone to extreme mood shifts and ... him, he couldn’t control his emotions,” remembers Marcy. “If there was a knife on ... say he was going to kill them. If we were driving on the freeway, ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... , June 23, 2016 Research and ... Global Market - Forecast to 2022" report to their ... treatment method for the patients with kidney failure, it replaces ... fluid from the patient,s blood and thus the treatment helps ... and chloride in balance. Increasing number of ...
(Date:6/23/2016)... 23, 2016  In a startling report released today, National ... by lacking a comprehensive, proven plan to eliminate prescription opioid overdoses. ... of how states are tackling the worst drug crisis in recorded ... – Kentucky , New Mexico ... . Of the 28 failing states, three – Michigan ...
(Date:6/23/2016)... June 23, 2016 Capricor ... ), a biotechnology company focused on the discovery, ... that patient enrollment in its ongoing randomized HOPE-Duchenne ... exceeded 50% of its 24-patient target. Capricor expects ... third quarter of 2016, and to report top ...
Breaking Medicine Technology: