Featured Research

from universities, journals, and other organizations

Finding the way to memory: Receptor plays key role in regulating plasticity of brain's nerve cell connections

Date:
February 4, 2013
Source:
McGill University
Summary:
A new study reveals that DCC, the receptor for a crucial protein in the nervous system known as netrin, plays a key role in regulating the plasticity of nerve cell connections in the brain.

A new study reveals that DCC, the receptor for a crucial protein in the nervous system known as netrin, plays a key role in regulating the plasticity of nerve cell connections in the brain.
Credit: © Mopic / Fotolia

Our ability to learn and form new memories is fully dependent on the brain's ability to be plastic -- that is to change and adapt according to new experiences and environments. A new study from the Montreal Neurological Institute -- The Neuro, McGill University, reveals that DCC, the receptor for a crucial protein in the nervous system known as netrin, plays a key role in regulating the plasticity of nerve cell connections in the brain. The absence of DCC leads to the type of memory loss experienced by Dr. Brenda Milner's famous subject HM. Although HM's memory loss resulted from the removal of an entire brain structure, this study shows that just removing DCC causes the same type of memory deficit.

Related Articles


The finding published in this week's issue of Cell Reports, extends Dr. Milner's seminal finding to another level, revealing a key part of the molecular basis for learning and memory.

Although both netrin and DCC are essential for normal development (in terms of guiding nerve cell growth) until now their function in the adult brain was not known. Dr. Tim Kennedy, lead researcher and neuroscientist at The Neuro, contributed to the discovery of netrins as a young post-doctoral fellow. This new study reveals the answer to the question that drove him to first start a lab. "I remember that exact moment when I knew I could run a research lab, it was 1993 and I was studying the developing nervous system and I was amazed to spot netrins in the adult brain -- raising the important question, 'what are they doing there?' 20 years of dedicated research later the answer provides an important piece of the puzzle for understanding our nervous system and neurological disorders.

"The power of this study is that it looks at the animal on all levels, molecular, structural, and behavioural. We show that the netrin receptor DCC is a critical component of synapses between neurons in the adult brain, and is required for synapses to function properly. To demonstrate this, we selectively removed DCC from a specific subset of neurons in the adult mouse brain. This results in progressive degeneration of synapses, leading to defects in synaptic plasticity and memory. The synapses continue to function in that they still communicate but, the synapses cannot adjust or change in response to new experiences. Therefore, you can't learn anymore."

Furthermore, DCC deletion from mature neurons results in changes in the shape of specialized protrusions called dendritic spines, and alters the NMDA receptor, a critical trigger for mechanisms that make changes in synaptic strength. Therefore the study reveals that DCC is required to maintain proper synapse morphology or shape, and to regulate the ability of the NMDA receptor to switch on, which ensures activity-dependent synaptic plasticity.

Mutant mice that entirely lack DCC in all cells do not survive past birth and exhibit major defects in brain development. In order to investigate the function of netrin in the adult brain, researchers from the Netherlands Cancer Institute, collaborators on this study, engineered a new strain of floxed mice, in which the DCC gene can be selectively deleted from a specific sub-set of cells. Floxing involves putting short sequences of DNA on either side of a gene sequence. An enzyme that is activated later in life then recombines the DNA and cuts out the intervening sequence -- deleting the gene only from specific cells. The Kennedy lab activated this enzyme only in the mature mouse brain, and limited activation to only a subset of neurons, consequently deleting the DCC gene from only from these neurons. These mice live to adulthood (DCC is made normally in all other cells in the mouse) as the enzyme only turns on and deletes DCC in specific cells in the adult brain. Although the mice otherwise appear normal, testing their behavior revealed severe deficits in their ability to form certain types of new long-term memories.

This study provides important new insight into the neural mechanisms of learning and memory, processes that are fundamental to our existence, survival, and everyday life.

This research was funded by the Canadian Institutes of Health Research. Dr. Kennedy is a Chercheur national of the Fonds de recherche du Québec -- Santé and a Scholar of the Killam Trusts.


Story Source:

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


Journal Reference:

  1. Katherine E. Horn, Stephen D. Glasgow, Delphine Gobert, Sarah-Jane Bull, Tamarah Luk, Jacklyn Girgis, Marie-Eve Tremblay, Danielle McEachern, Jean-François Bouchard, Michael Haber, Edith Hamel, Paul Krimpenfort, Keith K. Murai, Anton Berns, Guy Doucet, C. Andrew Chapman, Edward S. Ruthazer, Timothy E. Kennedy. DCC Expression by Neurons Regulates Synaptic Plasticity in the Adult Brain. Cell Reports, 2013; 3 (1): 173 DOI: 10.1016/j.celrep.2012.12.005

Cite This Page:

McGill University. "Finding the way to memory: Receptor plays key role in regulating plasticity of brain's nerve cell connections." ScienceDaily. ScienceDaily, 4 February 2013. <www.sciencedaily.com/releases/2013/02/130204142644.htm>.
McGill University. (2013, February 4). Finding the way to memory: Receptor plays key role in regulating plasticity of brain's nerve cell connections. ScienceDaily. Retrieved October 31, 2014 from www.sciencedaily.com/releases/2013/02/130204142644.htm
McGill University. "Finding the way to memory: Receptor plays key role in regulating plasticity of brain's nerve cell connections." ScienceDaily. www.sciencedaily.com/releases/2013/02/130204142644.htm (accessed October 31, 2014).

Share This



More Health & Medicine News

Friday, October 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Fauci Says Ebola Risk in US "essentially Zero"

Fauci Says Ebola Risk in US "essentially Zero"

AP (Oct. 30, 2014) — NIAID Director Anthony Fauci said the risk of Ebola becoming an epidemic in the U.S. is essentially zero Thursday at the Washington Ideas Forum. He also said an Ebola vaccine will be tested in West Africa in the next few months. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Nurse Defies Ebola Quarantine With Bike Ride

Nurse Defies Ebola Quarantine With Bike Ride

AP (Oct. 30, 2014) — A nurse who vowed to defy Maine's voluntary quarantine for health care workers who treated Ebola patients followed through on her promise Thursday, leaving her home for an hour-long bike ride. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Pot-Infused Edibles Raise Concerns in Colorado

Pot-Infused Edibles Raise Concerns in Colorado

AFP (Oct. 30, 2014) — Colorado may have legalized marijuana for recreational use, but the debate around the decision still continues, with a recent - failed - attempt to ban cannabis-infused edibles. Duration: 01:53 Video provided by AFP
Powered by NewsLook.com
British Navy Ship Arrives in Sierra Leone With Ebola Aid

British Navy Ship Arrives in Sierra Leone With Ebola Aid

AFP (Oct. 30, 2014) — The British ship RFA ARGUS arrived in Sierra Leone to deliver supplies and equipment to help the fight against Ebola. Duration: 00:42 Video provided by AFP
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