We have talked about problems with multitasking, sensory overload, etc. And while we have been taught to think in terms of a chemical shortage, a lot of us have vague suspicions.

If we think for a minute of dopamine as the shuttle bus carrying information from one cell to the next, then we are envisioning a shortage of shuttle buses and we try to increase their number. But, what if we think in terms of the problem being a lack of enough good roads for the buses instead? After all, a hundred buses will do you little good if your system saturates at ten.

This was triggered by a report this morning in Science Daily -
"In human and mouse brains, kalirin is the brain protein needed to build the dense network of highways, called dendritic spines, which allow information to flow from one neuron to another. Northwestern scientists have found that without adequate kalirin, the frontal cortex of the brain of a person with schizophrenia only has a few narrow roads. The information from neurons gets jammed up like rush hour traffic on an interstate highway squeezed to a single lane.

"Without enough pathways, the information takes much longer to travel between neurons and much of it will never arrive," said Peter Penzes, assistant professor of physiology at the Feinberg School. He is senior author of a paper reporting the findings published in a recent issue of the Proceedings of the National Academy of Science. Michael Cahill, a Feinberg doctoral student in neuroscience, is the lead author."

Finally, what makes this doubly interesting to me are reports like this one:

1: Jpn J Pharmacol. 2002 Nov;90(3):254-62.

Axonal and dendritic extension by protopanaxadiol-type saponins from ginseng
drugs in SK-N-SH cells.

Tohda C, Matsumoto N, Zou K, Meselhy MR, Komatsu K.

Research Center for Ethnomedicines, Institute of Natural Medicine, Toyama
Medical and Pharmaceutical University, Toyama, Japan.

Extension of axons and dendrites in neurons may compensate for and repair
damaged neuronal networks in the dementia brain. To find out drugs capable of
regenerating the neuronal network, we focused on several herbal drugs belonging
to the genus Panax, kinds of Ginseng, and investigated neurite outgrowth
activity of their extracts and compounds. We found that the methanol extracts of
Ginseng (root of P. ginseng), Notoginseng (root of P. notoginseng) and Ye-Sanchi
in Chinese (rhizome of a relative to P. vietnamensis) increased neurite
outgrowth in SK-N-SH cells. The protopanaxadiol-type saponins, ginsenosides
Rb(1) and Rb(3), and notoginsenosides R(4) and Fa isolated from Ye-Sanchi
extract extended neurites, while protopanaxatriol-, ocotillol- and oleanane-type
saponins had no effect on the neurite outgrowth. The percentage of cells with
multipolar neurites and number of varicosities were intensely high in cells
treated with the methanol extract of Ye-Sanchi as well as ginsenosides Rb(1) and
Rb(3), and notoginsenosides R(4) and Fa. Both phosphorylated NF-H-expressing
neurites and MAP2-expressing ones were extended by treatment with those saponins
and the extract. Especially, longer neurites were mainly positive for
phosphorylated NF-H. These results suggest that protopanaxadiol-type saponins
enhance axonal and dendritic formation activity.

PMID: 12499580 [PubMed - indexed for MEDLINE]