Feb. 11, 1999 PROVIDENCE, R.I. -- As brain development goes,
"bad" or "inappropriate" experiences are worse than no
experiences at all, according to a study in the Jan. 28, 1999,
issue of Nature. The study shows that the loss of connections
between neurons in the brain is not the result of inactivity, as
previously thought, but a consequence of activity that is
inappropriate. Experiences during early postnatal life sculpt
the connections between neurons in the brain. Some connections,
initially formed early in fetal development, are retained and
made stronger, while others are weakened and eventually lost.
This refinement of connections is responsible for the
acquisition of brain function during infancy. While the
mechanisms of experience-dependent brain modification normally
are responsible for the improvement of function during
development, in some clinical conditions they can actually lead
to a loss of function. For example, a loss of function during
infant development can result when one eye is deprived o