Featured Research

from universities, journals, and other organizations

Cerebral Neurons Assist Adjacent Neurons

May 19, 2009
After retinal lesions, the affected cerebral neurons suddenly no longer receive input signals. However, they do remain inactive: they receive signals from neighboring cells, strengthen these and then transmit them. For this purpose, they form new networks during the first few weeks after the lesion - initially on a trial basis and later as permanent connections.

Cortical neurons are tightly linked over long distances. It is estimated that the entire length of the linkages between the neurons within a single cubic millimetre of grey matter would cover about three kilometres. Every cell thus receives numerous thousands of input signals and transmits just as many output signals to, in part, distant neurons. This leads to a rapid wave-like distribution of excitations.

Related Articles

What, however, happens if some of the normal input signals are suddenly no longer present due to the lesion of a sensory organ? Dr. Dirk Jancke (Institute for Neuroinformatics) explained that the neuronal networks are formed and stabilized during the early phases of development.

For many years, it had thus been assumed that the adult brain is not capable of compensating such lesions. During the past decades, scientists have however been able to demonstrate that the adult brain is also capable of changes in plasticity, even if only to a limited degree. Old, no-longer used contacts between cells are weakened or become detached, and new contacts are formed. Dr. Jancke explained that cortical neurons suddenly no longer have a direct entrance after a retinal lesion, but that their connection to still functional distant neighbours at least enables them to look around the corner again. This process is already experimentally discernible within only a few weeks after the lesion, the activity waves from the intact surroundings into the affected areas being strengthened.

Optical measurement with voltage-sensitive dyes

Older measuring procedures that evaluate the electric activity on the neurons can only present total signals. The new method is more sensitive, latent input signals also lighting up. Dr, Jancke explained that, for the first time, the scientists have now been able to demonstrate the long assumed continuous dispersion and strengthening of initially subthreshold waves of activity within the affected area using this newly developed imaging process. Gradual changes in the synaptic potential that develop during neuronal activity are registered as changes in the intensity of the fluorescent light. To this end, a dye is incorporated in the cell membrane and releases photons proportional to the voltage via the cell membranes.

A high-resolution camera system detects these light signals, which can be visualized by subsequent computing. The dyes and the basic measuring technology were developed in the laboratory of Prof. Amiram Grinvald, Weizmann Institute of Science, Israel. During his two years of work in Israel, Dr. Jancke managed to present activity waves in the optic cortex and to supply the first description of their significance for visual perception processes. Dr. Jancke has established this newly developed imaging method at RUB within the frameworks of his Assistant Professorship “Cognitive Neurobiology, Faculty for Biology and Biotechnology.”

Interfaculty cooperation at RUB

The current study is a continuation of work performed by RUB’s Medical Professor, Dr. Ulf Eysel, one of the pioneers and leading scientists in the field of neuronal plasticity, who has worked in close cooperation with the Max-Planck Institute for Neurobiology in Munich. The results showed that three times as many nerve fibres (so-called “spines”) develop in the cerebral cortex of mice after small spot lesions in the retina. The newly established cell contacts often broke before stable networks were finally established. It thus seemed appropriate to investigate the relationship between this extensive reorganization of the neuronal structure and the changes in the activity dynamics in large cell aggregates.

Ganna Palagina, scholarship holder of the International Graduate School (IGSN) at the Ruhr University, selected this subject for her doctoral thesis. During the two years in which she carried out the current study on mice, she commuted between the laboratory in the Dept. of Neurophysiology (Prof. Eysel), where the retinal lesions could be accurately made, and the Optical Imaging Laboratory in the Dept. of Biology (Dr. Jancke) for optical measurement using voltage-sensitive dyes.

Story Source:

The above story is based on materials provided by Ruhr-Universitaet-Bochum. Note: Materials may be edited for content and length.

Cite This Page:

Ruhr-Universitaet-Bochum. "Cerebral Neurons Assist Adjacent Neurons." ScienceDaily. ScienceDaily, 19 May 2009. <www.sciencedaily.com/releases/2009/05/090512093545.htm>.
Ruhr-Universitaet-Bochum. (2009, May 19). Cerebral Neurons Assist Adjacent Neurons. ScienceDaily. Retrieved December 21, 2014 from www.sciencedaily.com/releases/2009/05/090512093545.htm
Ruhr-Universitaet-Bochum. "Cerebral Neurons Assist Adjacent Neurons." ScienceDaily. www.sciencedaily.com/releases/2009/05/090512093545.htm (accessed December 21, 2014).

Share This

More From ScienceDaily

More Health & Medicine News

Sunday, December 21, 2014

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

The Best Tips to Curb Holiday Carbs

The Best Tips to Curb Holiday Carbs

Buzz60 (Dec. 19, 2014) It's hard to resist those delicious but fattening carbs we all crave during the winter months, but there are some ways to stay satisfied without consuming the extra calories. Vanessa Freeman (@VanessaFreeTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Sierra Leone Bikers Spread the Message to Fight Ebola

Sierra Leone Bikers Spread the Message to Fight Ebola

AFP (Dec. 19, 2014) More than 100 motorcyclists hit the road to spread awareness messages about Ebola. Nearly 7,000 people have now died from the virus, almost all of them in west Africa, according to the World Health Organization. Video provided by AFP
Powered by NewsLook.com
Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
The Best Protein-Filled Foods to Energize You for the New Year

The Best Protein-Filled Foods to Energize You for the New Year

Buzz60 (Dec. 19, 2014) The new year is coming and nothing will energize you more for 2015 than protein-filled foods. Fitness and nutrition expert John Basedow (@JohnBasedow) gives his favorite high protein foods that will help you build muscle, lose fat and have endless energy. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.


Breaking News:

Strange & Offbeat Stories

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News


Free Subscriptions

Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile

Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?

Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins