The retinal synaptic network continues its development after birth in
mammals. Recent studies show that postnatal development of retinal
circuitry depends on visual stimulation. We sought to determine whether
there is a time period during which the retina shows evidence of
increased plasticity. We examined the effects of light deprivation on
the retinal light response of mouse retina using electroretinogram
(ERG) measurements. Our results showed that dark rearing mice from
birth to postnatal day (P) 30, 60, and 90 suppressed the amplitudes of
oscillatory potentials (OPs) and the magnitudes of suppression were age
independent. In addition, dark-rearing-produced suppression of OP
amplitudes can be completely reversed in both young and adult mice by
returning them to cyclic light/dark conditions for 1 to 2 weeks.
However, the recovery time course was age dependent with younger
animals needing a longer time to achieve a full recovery. Furthermore,
dark rearing of P60 mice raised under cyclic light/dark conditions
for 30 days resulted in a similar magnitude of suppression of OP
amplitudes as in age-matched mice dark reared from birth. These
findings demonstrate that both the normal developmental changes and the
maintenance of mature inner retinal light response in adult animals
require visual stimulation. These results indicate a degree of
activity-dependent plasticity in mouse retina that has not been
previously described.