Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

From the beginning, the brain knows the difference between night and day

29.04.2011
The brain is apparently programmed from birth to develop the ability to determine sunrise and sunset, new research on circadian rhythms at the University of Chicago shows.

The research sheds new light on brain plasticity and may explain some basic human behaviors, according to Brian Prendergast, associate professor in psychology at the University of Chicago and co-author of a paper published April 27 in the journal PLoS One. The lead author is August Kampf-Lassin, an advanced graduate student at the University.

"This finding may show us why infants of many species eventually learn to discriminate daytime from nighttime," said Prendergast, a researcher on biological rhythms.

In a series of experiments, researchers were able to show that although the ability to see visual stimuli, such as movement, is lost when a developing eye is not exposed to light, the ability to determine light and dark cycles was not affected. The ability to make that distinction between night and day develops as an animal grows, they found.

Other research has found that primates as well as humans adapt naturally to a rhythm of sleeping during the night. But this research shows that the pathway in the circadian system that allows synchrony between the brain and day-night rhythms in the environment is probably an innate feature of development, he said.

"For the first time, we have established that the ability to coordinate circadian rhythms with daily changes in light exposure is not subject to very much plasticity at all — that it is not influenced by changes in the amount of light the brain receives during development," Kampf-Lassin said.

The results of the study are reported in the article "Experience-Independent Development of the Hamster Circadian Visual System," which was drawn from a series of challenging experiments with hamsters.

Shortly after the hamsters' eyes opened, but before they were exposed to light, experimenters placed a contact lens that completely blocked light over one of their eyes. Keeping one eye shut and one open, called monocular deprivation, is a standard method scientists use to study use-dependent plasticity of visual development.

The hamsters then grew up in a light-dark cycle such that only the non-deprived eye was able to send light information into the brain. In adulthood, the lenses were removed, and the function of the hamsters' previously deprived eye was assessed. The researchers found that the hamsters' brains were blind to all classical visual stimuli presented to the deprived eye, such as food or moving stimuli.

Nevertheless, the deprived eye perfectly retained the hamsters' ability to synchronize their circadian rhythms of activity with the 24-hour day. Thus, even though the hamsters could not see objects with the deprived eye, they could use input from the eye to set their internal clocks. The study also showed that long-term monocular deprivation did not affect anatomical projections from the eye to the circadian clock in the brain, and light-induced changes in gene expression in the circadian clock were also normal.

"It's interesting to see how some aspects of behavioral development are hard-wired and develop into adult-typical patterns, even in the total absence of normal environmental input to the system," Prendergast said.

Other authors on the paper were Jenny Wei and Jerome Galang, undergraduates at the University.

William Harms | EurekAlert!
Further information:
http://www.uchicago.edu

Further reports about: circadian clock circadian rhythm internal clock

More articles from Life Sciences:

nachricht Water world
20.11.2017 | Washington University in St. Louis

nachricht Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Antarctic landscape insights keep ice loss forecasts on the radar

20.11.2017 | Earth Sciences

Filling the gap: High-latitude volcanic eruptions also have global impact

20.11.2017 | Earth Sciences

Water world

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>