Featured Research

from universities, journals, and other organizations

Study Indicates That Brain Wiring Is Largely Inborn

Date:
November 17, 2000
Source:
Duke University
Summary:
Neurobiologists at Duke University Medical Center mapping the developing visual systems of newborn ferrets have discovered evidence challenging the long-held view that the brain's circuitry is largely wired by experience. Rather, they contend, much of the circuitry is inborn, with experience acting merely to preserve and enhance existing connections.

DURHAM, N.C. – Neurobiologists at Duke University Medical Center mapping the developing visual systems of newborn ferrets have discovered evidence challenging the long-held view that the brain's circuitry is largely wired by experience. Rather, they contend, much of the circuitry is inborn, with experience acting merely to preserve and enhance existing connections.

The finding, published in the Nov. 17 Science, calls into question a fundamental tenet of brain development – that early sensory stimulation is critical to the basic wiring of the brain.

Reporting the studies are graduate student Justin Crowley and Howard Hughes Medical Institute investigator Lawrence Katz. Besides Howard Hughes Medical Institute, their work also was supported by the National Institutes of Health.

Crowley and Katz studied newborn ferrets because the animals' visual wiring is the equivalent of that of other mammals still in the fetal stage. The researchers' objective was to detect "ocular dominance columns" in a visual area of the brain called the visual cortex. The presence of these alternating stripe-like columns of nerve fibers constitutes evidence that the visual system has established a basic component of the adult visual circuit, forming groups of nerve cells in the visual cortex that respond to input from one eye or the other.

The scientists used an innovative surgical technique that allowed them to inject tracer dye more precisely in order to reveal the neural connections from the eye within the cortex. They first reported use of the tracer technique to reveal ocular dominance columns in adult ferrets in a December 1999 article in Nature Neuroscience.

The latest studies clearly revealed the presence of columns in the newborn animals' brains earlier than ever suspected, Katz said, and the scientists' measurements showed that in size, spacing and arrangement the columns closely resembled those previously found in adult animals.

Importantly, when the researchers traced the columns in newborn ferrets that received visual information from only one eye, those animals still showed normal development of the columns. This finding confirmed that the columns did not require information from the eyes to develop normally.

"For about three decades, ocular dominance columns have served as something of a Rosetta Stone for understanding how brain circuits are wired, and in particular for understanding the role of neural activity and experience in constructing them," said Katz. "The prevailing idea has been that activity is critical for establishing brain circuits.

"Until now, the concept has been that neural connections in young animals were not specified very accurately, and that experience and environment were needed to refine initially crude connections, by a process of elimination, into the adult pattern," Katz said.

"The critical finding in our study was that this is not the case. Rather, we found that these columns were present as early as we looked for them, and they are basically as well formed as structures in an adult.

"This finding, in a way, addresses the whole question of nature versus nurture," said Katz. "It questions the notion that the young animal and its neural connections are either a ‘blank slate' or a poorly specified version of the adult's. Rather, our findings suggest that the brain of an animal or human starts life with a pretty good idea of what to expect – that it possesses an initial template of circuitry representing a ‘best-guess' of what experiences the animal will encounter. If normal experience ensues, this template is preserved and enhanced. But if the animal encounters something different during a critical period immediately after birth, there's some possibility of altering these connections."

Added Crowley, "The assumption that activity was important in initially constructing these circuits was based on good data from animals on the remodeling of circuits by visual experience during the critical period. These data led investigators to believe that the influences on wiring connections during this later period were the same ones that wired them during establishment of the circuitry. It was a good guess, but not necessarily a correct one."

According to Katz, the findings emphasize the importance of current scientific efforts to discover the intricate molecular cues that guide the initial wiring of the brain.

"While until now many scientists had searched for the mechanism by which activity drives neuronal competition to form certain brain structures, we're now offering evidence that it may not be competition at all. Rather, neurons in developing animals may initially form connections based on molecular labels. We believe that the search for these guidance molecules is critical to understanding the initial stages of brain wiring."


Story Source:

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


Cite This Page:

Duke University. "Study Indicates That Brain Wiring Is Largely Inborn." ScienceDaily. ScienceDaily, 17 November 2000. <www.sciencedaily.com/releases/2000/11/001117071126.htm>.
Duke University. (2000, November 17). Study Indicates That Brain Wiring Is Largely Inborn. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2000/11/001117071126.htm
Duke University. "Study Indicates That Brain Wiring Is Largely Inborn." ScienceDaily. www.sciencedaily.com/releases/2000/11/001117071126.htm (accessed July 28, 2014).

Share This




More Mind & Brain News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Losing Sleep Leaves You Vulnerable To 'False Memories'

Losing Sleep Leaves You Vulnerable To 'False Memories'

Newsy (July 27, 2014) A new study shows sleep deprivation can make it harder for people to remember specific details of an event. Video provided by Newsy
Powered by NewsLook.com
University Quiz Implies Atheists Are Smarter Than Christians

University Quiz Implies Atheists Are Smarter Than Christians

Newsy (July 25, 2014) An online quiz from a required course at Ohio State is making waves for suggesting atheists are inherently smarter than Christians. Video provided by Newsy
Powered by NewsLook.com
Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

AFP (July 24, 2014) A so-called drugs rehab 'clinic' is closed down in Pakistan after police find scores of ‘patients’ chained up alleging serial abuse. Duration 03:05 Video provided by AFP
Powered by NewsLook.com
New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
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:
from the past week

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