Featured Research

from universities, journals, and other organizations

Smell Experience During Critical Period Alters Brain

Date:
December 6, 2007
Source:
Rockefeller University
Summary:
Genes may provide the land, but experience defines the landscape. Now, researchers show that during the first few days of life, chronic exposure to carbon dioxide rather than air alters the activity of projection neurons and interneurons in the fly brain -- research that is first to show that the olfactory system is plastic.

During the first few days of life, chronic exposure to carbon dioxide (right) rather than air (left) alters the activity of projection neurons and interneurons in the fly brain -- research that is first to show that the olfactory system is plastic.
Credit: Rockefeller University

Unlike the circuitry of the visual system, that of the olfactory system was thought to be hardwired: Once the neurons had formed, no amount of sensory input could change their arrangement. Now researchers at Rockefeller University and their collaborators have upturned this scientific dogma by showing that there is a sensitive period during which the external environment can alter a circuit in the fly brain that detects carbon dioxide, a gas that alerts flies to food and mates. This research may suggest that this brain plasticity isn't limited to the carbon dioxide detection circuit. Rather, it may be a general feature of the olfactory system itself.

Related Articles


"The circuit has a genetic plan, but that genetic plan can adjust to real world conditions," says Leslie Vosshall, head of the Laboratory of Neurogenetics and Behavior. "This paper is the first compelling case that the olfactory system is plastic."

Using several imaging techniques, Vosshall and her colleagues traced the carbon dioxide circuit, a well-described pathway that consists of three different types of neurons, the axons and dendrites of which form an entangled ball called a glomerulus. The researchers exposed flies to elevated levels of carbon dioxide to see whether it would alter the shape of this circuit or how it functioned. The glomerulus's volume was already increased after two days of exposure (from birth) and kept on increasing for five days, at which point it stopped. The increase in this specific glomerulus could only be induced by elevated levels of carbon dioxide and was also reversible.

After those initial few days, however, the researchers saw a different story unfold. If they didn't expose the flies to carbon dioxide within the first five days, genetics locked in the glomerulus's size such that no matter how long the flies were exposed to the gas, the glomerulus's volume didn't increase. These findings suggest that the fly's external environment can rewire the carbon dioxide detection circuit only during a five-day window of development.

"During this critical period, the olfactory system is flexible enough to calibrate its genetic map to its local environment," says first author Silke Sachse, a former postdoc in the Vosshall lab who is now a group leader in optical imaging at the Max Planck Institute for Chemical Ecology in Jena, Germany. "But once that window closes, the circuit is no longer plastic."

To figure out the mechanism by which the glomerulus increases its volume, the Vosshall group imaged the three types of neurons that make up the glomerulus -- olfactory sensory neurons, projection neurons and interneurons -- to see whether their structure or function had changed. The olfactory sensory neurons, which report sensory information to glomeruli, did not show any sign of structural or functional changes.

However, the projection neurons, which send information from the glomeruli to the brain, and the interneurons, which communicate with the two types of neurons as well as the glomeruli, showed significant functional changes. "Usually the sensory neurons collect information and send it to the brain and it is the job of the brain to interpret what the information means," says Vosshall. "For plasticity to be useful, it probably makes sense to delegate that job to the brain rather than to the external sensory neurons."

This research is published in the December 6 issue of Neuron.


Story Source:

The above story is based on materials provided by Rockefeller University. Note: Materials may be edited for content and length.


Cite This Page:

Rockefeller University. "Smell Experience During Critical Period Alters Brain." ScienceDaily. ScienceDaily, 6 December 2007. <www.sciencedaily.com/releases/2007/12/071205122546.htm>.
Rockefeller University. (2007, December 6). Smell Experience During Critical Period Alters Brain. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2007/12/071205122546.htm
Rockefeller University. "Smell Experience During Critical Period Alters Brain." ScienceDaily. www.sciencedaily.com/releases/2007/12/071205122546.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Christmas Kissing Good for Health

Christmas Kissing Good for Health

Reuters - Innovations Video Online (Dec. 22, 2014) Scientists in Amsterdam say couples transfer tens of millions of microbes when they kiss, encouraging healthy exposure to bacteria. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Brain-Dwelling Tapeworm Reveals Genetic Secrets

Brain-Dwelling Tapeworm Reveals Genetic Secrets

Reuters - Innovations Video Online (Dec. 22, 2014) Cambridge scientists have unravelled the genetic code of a rare tapeworm that lived inside a patient's brain for at least four year. Researchers hope it will present new opportunities to diagnose and treat this invasive parasite. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Touch-Free Smart Phone Empowers Mobility-Impaired

Touch-Free Smart Phone Empowers Mobility-Impaired

Reuters - Innovations Video Online (Dec. 21, 2014) A touch-free phone developed in Israel enables the mobility-impaired to operate smart phones with just a movement of the head. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Earthworms Provide Cancer-Fighting Bacteria

Earthworms Provide Cancer-Fighting Bacteria

Reuters - Innovations Video Online (Dec. 21, 2014) Polish scientists isolate bacteria from earthworm intestines which they say may be used in antibiotics and cancer treatments. Suzannah Butcher reports. Video provided by Reuters
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.

Save/Print:
Share:

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



Save/Print:
Share:

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