Sensory deprivation affects brain's nerve c...( l of Medicine. To get a...)

To get a glimpse of living neurons in mice, the researchers employed a laborious technique for shaving the skulls of the animals. This creates an ultrathin window on the brain through which one can peer using a sophisticated optical technique called two-photon fluorescence microscopy. Dr. Gan looked at dendritic spines, which are thorny nubs found all along the branches of neurons. Spines, which are continuously formed and eliminated, are where synapses are made.

Since mice use their whiskers to explore their world, Dr. Gan altered their experience by trimming the whiskers for two weeks on one side of the mice's snouts. The spines of these mice were then compared to spines in mice of the same age with untrimmed whiskers. Young mice who kept their whiskers showed more spine loss than their whisker-trimmed litter-mates.

In the adult age group, whisker trimming for two weeks appeared to have no significant effect on spine loss. When the sensory deprivation continued for two months, however, spine loss was slightly reduced in adult animals as well. The scientists therefore found that the period of young adolescence to adulthood was particularly susceptible to sensory deprivation.

Interestingly, in adolescent mice the effects of sensory deprivation on spine loss could be largely reversed if whiskers were allowed to re-grow during a subsequent recovery period, says Dr. Gan. However, the effects of sensory deprivation in young adolescence couldn't be reversed if sensory recovery occurred after the mice reached adulthood. These findings suggest "that childhood experience has a long lasting and perhaps permanent impact on later life," he says.

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Contact: Marjorie Shaffer
Marjorie.Shaffer@nyumc.org
212-404-3555
New York University Medical Center and School of Medicine
13-Jul-2005