New neurons take six months or more to mature in non-human primate brain

New neurons take more than six months to mature in adult monkeys and that time is likely even longer in humans, according to researchers at the University of Pittsburgh School of Medicine, the University of Illinois, and Pennsylvania State University. Their findings, reported this week in the online version of the Proceedings of the National Academy of Sciences, challenge the notion that the time it takes for neurogenesis is the reason anti-depressant medications are not fully effective until three to five weeks after treatment begins.

The dentate gyrus of the brain's hippocampus is known to be where new neurons still form in adult mammals, and this region is thought to play a significant role in learning and memory, cognitive change with aging, depression and schizophrenia, and other , said Judy Cameron, Ph.D., professor, Department of Psychiatry, University of Pittsburgh School of Medicine, and senior scientist, Oregon National Primate Research Center, Oregon Health and Science University.

"Expanding our knowledge beyond rodent models to understand how neurons mature in non-human primates will give us more insight into what happens in the human brain," she said. "In rodents, neuronal maturation happens in four weeks, which is considerably different than what we have found in our monkey studies."

Dr. Cameron, co-senior scientist William T. Greenough, Ph.D., of the University of Illinois, and the team gave adult monkeys injections of an agent called BrdU, which gets incorporated into replicating DNA and thus serves as an indicator of new neuron formation. At different time points after the injections, they examined the to look for markers of stages of maturation in tiny neurons called granule cells.

Six weeks after an injection, 84 percent of the new cells still bore markers of immaturity and were immature in shape; in a rodent, all of the cells would have matured by this time. Only a third of the monkey granule cells had markers of maturity up to 28 weeks after BrdU injections.

That means the majority of new will not reach maturity until more than six months have passed, Dr. Greenough and colleagues said. Also, because the human brain is larger than the monkey and takes longer to develop, maturation of adult human would likely be further lengthened.

The longer period of new granule cell maturation in primates argues against the hypothesis, based on rodent models, that the onset of effectiveness of antidepressant medications at three to five weeks is related to neurogenesis and maturation of these .

Related Stories

New brain cells listen before they talk

Oct 30, 2007

Newly created neurons in adults rely on signals from distant brain regions to regulate their maturation and survival before they can communicate with existing neighboring cells—a finding that has important implications ...

Stem cells are good for the brain

Jul 15, 2008

For some years, scientists have been speculating over why stem cells exist in the brain, as brain regeneration is limited. A German team of neuroscientists believe these stem cells help keep the brain healthy and active.

New adult brain cells may be central to lifelong learning

May 23, 2007

The steady formation of new brain cells in adults may represent more than merely a patching up of aging brains, a new study has shown. The new adult brain cells may serve to give the adult brain the same kind of learning ...

Recommended for you

Cell death proteins key to fighting disease

5 hours ago

Melbourne researchers have uncovered key steps involved in programmed cell death, offering new targets for the treatment of diseases including lupus, cancers and neurodegenerative diseases.

Unlocking the secrets of pulmonary hypertension

21 hours ago

A UAlberta team has discovered that a protein that plays a critical role in metabolism, the process by which the cell generates energy from foods, is important for the development of pulmonary hypertension, a deadly disease.

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Vendicar_Decarian
not rated yet Jun 06, 2011
And it takes a lifetime in ConservaTard Brains.

Skultch
not rated yet Jun 07, 2011
Your Tard jokes are so old, they could vote.
Skultch
not rated yet Jun 07, 2011
This seems to give insight into many fields. Muscle memory and sports performance training comes to mind. If the season is less than 6 months (most are) then you might not reap practice rewards until the following season, and you might digress during the off time.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.