Another process is cell death with selective
elimination of neuronal processes. This process
adjusts the size of individual neurons to their
anticipated need and is an important component of
brain plasticity. This plasticity is an advantage in
the developing brain, because neuronal processes
targeted for elimination may be saved if they are
needed because of damage to other processes, thus
preserving functional ability (Blackburn, 1993).
One factor influencing which neurons are retained
is sensory input. Thus the normal sensory input
experienced by the fetus and later the input from
the home environment are important influences.
This can also be a liability in that inappropriate
sensory input, as might occur in the NICU with the
preterm ("fetal") infant or in a deprived home
environment in an older infant, can reinforce some
pathways, which are then retained, but which are
not the most appropriate for later development.