We found when we grew nerve cells in the presence of this protein, axons would not grow.
In a region of the brain called the basal ganglia, known in people to be involved in language, the humanized mice grew nerve cells that had a more complex structure.
In a region of the brain called the basal ganglia, known in people to be involved in language, the humanized mice grew nerve cells that had a more complex structure and produced less dopamine, a chemical that transmits signals from one neuron to another.
One of serotonin's jobs is to show growing nerve cells how they should connect from the frontal cortex, where reasoning takes place, to the limbic system, the seat of many emotional responses.
As for Dr. Bishop's invention of an automated way to grow nerve cells in the laboratory, Dr. R. Douglas Fields of the National Institute of Child Health and Human Development, said, "There is not a great need for it that I'm aware of".
Even here, though, stem-cell therapists talk openly of treating brain diseases such as Parkinson's with specially grown nerve cells, so some form of partial immortalisation might be on the cards.
In people, eventually, a way to achieve this may be to take cells from within a blind person's eye and treat them to turn them into progenitor cells that will grow nerve fibers and reconnect to cells in the brain, allowing the person to see again.
The researchers suggest that this grid-like organization may be advantageous during brain development, providing the equivalent of highway lane markers to help growing nerve fibers find their way to the appropriate destination.
The preliminary trial that has just been approved is to ensure the safety of the procedure, and the ultimate goal is to use the stem cells to re-grow nerve tissue in individuals with acute spinal cord injury.
Animal studies have suggested that during brain development, netrin tells growing nerve fibers to cross over to the other side of the brain, and Rouleau speculates that the message might not always get through in people with only one working copy of the DCC receptor.
Growing nerve sprouts migrate along specific matrix components, including laminins [34].
