MIT researcher presents new view of how the cortex forms

November 10, 2005

A leading neuroscientist at MIT and one from the University of California at San Francisco (UCSF) report in the Nov. 4 special issue of Science dedicated to the brain that the controversy is over: The "protomap" and "protocortex" theories of brain development are dead.

The cerebral cortex is a sheet of around 10 billion neurons divided into distinctly separate areas that process particular aspects of sensation, movement and cognition. To what extent are these areas predetermined by genes or shaped by the environment? The protomap and protocortex theories developed before 1990 claimed, respectively, that the task-specific regions of the cortex are spawned by a zone of "originator" cells; or that long nerve fibers from the thalamus, a large ovoid mass that relays information to the cortex from other brain regions, are activated by external stimuli to impose identity on the homogeneous blob.

New evidence indicates that the development of cortical areas involves "a rich array of signals," an interwoven cascade of developmental events, some internal and some external, according to co-authors Mriganka Sur, Sherman Fairchild Professor of Neuroscience at the Picower Institute for Learning and Memory and the MIT Department of Brain and Cognitive Sciences, and John L. R. Rubenstein of UCSF.

"Recent evidence has altered researchers' understanding of how cortical areas form, connect with other brain regions, develop unique processing networks and adapt to changes in inputs," Sur said. "Understanding basic mechanisms of cortical development is central to understanding disorders of development."

Sur, chair of the Department of Brain and Cognitive Sciences at MIT, is leading an ambitious, multifaceted approach to understanding the genetic, molecular and behavioral aspects of autism.

In the Science review article, "Patterning and Plasticity of the Cerebral Cortex," Sur and Rubenstein point out that transcription factors are key. A transcription factor is a protein that binds DNA at a specific site where it regulates transcription, or the process of copying genetic material.

In the brain's early prenatal development, transcription factors control the birth and growth of new neurons, neurons' movement and connectivity within the brain, and which ones live and which are killed off.

Later, at a critical point in development, activity in the form of outside stimulation refines the brain's topography and networks to create the specific functions and areas of the postnatal mammalian brain.
-end-
This work is supported by the National Institutes of Health, the Marcus Fund and the Simons Foundation.

Massachusetts Institute of Technology

Related Neurons Articles from Brightsurf:

Paying attention to the neurons behind our alertness
The neurons of layer 6 - the deepest layer of the cortex - were examined by researchers from the Okinawa Institute of Science and Technology Graduate University to uncover how they react to sensory stimulation in different behavioral states.

Trying to listen to the signal from neurons
Toyohashi University of Technology has developed a coaxial cable-inspired needle-electrode.

A mechanical way to stimulate neurons
Magnetic nanodiscs can be activated by an external magnetic field, providing a research tool for studying neural responses.

Extraordinary regeneration of neurons in zebrafish
Biologists from the University of Bayreuth have discovered a uniquely rapid form of regeneration in injured neurons and their function in the central nervous system of zebrafish.

Dopamine neurons mull over your options
Researchers at the University of Tsukuba have found that dopamine neurons in the brain can represent the decision-making process when making economic choices.

Neurons thrive even when malnourished
When animal, insect or human embryos grow in a malnourished environment, their developing nervous systems get first pick of any available nutrients so that new neurons can be made.

The first 3D map of the heart's neurons
An interdisciplinary research team establishes a new technological pipeline to build a 3D map of the neurons in the heart, revealing foundational insight into their role in heart attacks and other cardiac conditions.

Mapping the neurons of the rat heart in 3D
A team of researchers has developed a virtual 3D heart, digitally showcasing the heart's unique network of neurons for the first time.

How to put neurons into cages
Football-shaped microscale cages have been created using special laser technologies.

A molecule that directs neurons
A research team coordinated by the University of Trento studied a mass of brain cells, the habenula, linked to disorders like autism, schizophrenia and depression.

Read More: Neurons News and Neurons Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.