Driving developing brain neurons in the right direction

Driving developing brain neurons in the right direction
Credit: Thinkstock

One of the marvels of brain development is the mass migration of nerve cells to their functional position. European research has investigated the molecules required for their successful navigation.

Formation of the cerebral cortex during requires the migration of billions of cells from their birth position to their final destination. A motile nerve cell must have internal polarity to move in the specified direction. What is more, neurons then have to extend neurites or projections from the cell body to communicate with each other.

The key to this extraordinary feat of organisation lies in cell signalling pathways. The EU-funded Neuronal Polarity project aimed to characterise these cascades important in development. At a later stage, defective cortical architecture can be responsible for brain pathologies including microcephaly, epilepsy and schizophrenia.

Project scientists showed that in vivo the guanine triphosphatase GTPase Ras-proximate-1 (Rap 1) caused an accumulation of neurons halfway to their destination. The team used time-lapse video microscopy and immunostaining to show that the problem does not lie with motility of the neurons but in a defect in their polarity. Other evidence from motility tests in vitro and the fact that some neurons do actually make it to their destination, albeit slowly, suggest Rap 1 is important for initial polarisation of the neurons.

The transmembrane receptor N-cadherin (Ncad) also has an important function in polarising cortical neurons. Experimental data confirmed that this receptor is involved downstream from Rap 1. Overall, inhibition of Rap 1 reduces Ncad presence.

Neuronal Polarity scientists suggest that Rap 1 activity is important in migrating neurons to maintain a high level of Ncad at the for to polarise correctly.

Exactly how Ncad interacts with molecular cascades for neuron is still under investigation. The Neuronal Polarity project accumulated data on which to base a concrete research path for future investigation.

add to favorites email to friend print save as pdf

Related Stories

Neuronal migration errors: Right cells, wrong place

Jan 04, 2011

Normally, cortical nerve cells or neurons reside in the brain's gray matter with only a few scattered neurons in the white matter, but some people with schizophrenia have a higher number of neurons in the white matter. Neuronal ...

New imaging studies reveal mechanics of neuron migration

Jul 23, 2009

(PhysOrg.com) -- The development of the brain proceeds a little like the European settlement of North America. The earliest pioneers settled on the east coast with subsequent waves of settlers forming communities further ...

Recommended for you

Emotional adjustment following traumatic brain injury

Oct 24, 2014

Life after a traumatic brain injury resulting from a car accident, a bad fall or a neurodegenerative disease changes a person forever. But the injury doesn't solely affect the survivor – the lives of their spouse or partner ...

New ALS associated gene identified using innovative strategy

Oct 22, 2014

Using an innovative exome sequencing strategy, a team of international scientists led by John Landers, PhD, at the University of Massachusetts Medical School has shown that TUBA4A, the gene encoding the Tubulin Alpha 4A protein, ...

User comments