Jp. Shaffery et al., REM sleep deprivation in monocularly occluded kittens reduces the size of cells in LGN monocular segment, SLEEP, 21(8), 1998, pp. 837-845
Study Objectives: In this study, we test the hypothesis that when REM-state
activation (which impinges upon all lateral geniculate nucleus laminae irr
espective of stimulating eye) is deprived, the monocular segment (MS) that
is cut off from visual input and also deprived of REM-state activation will
exhibit smaller cells, owing to the loss of extrinsic as well as intrinsic
activation.
Design: We carried out a study comparing soma sizes in the MSs of kittens s
ubjected to monocular deprivation (MD) + REM deprivation (RD) to two age-ma
tched nonRD groups, MD ONLYs and MD MOMS (MD kittens living in their home c
ages).
Measurements and Results: Perikaryal outlines of 100 cells in each of the b
ilateral MSs were measured. As predicted, mean cell size in the MS connecte
d to the patched eye of MD+RD kittens, but in neither of the control groups
, was significantly smaller than in the MS afferented by the nonpatched eye
. One-way ANOVAs comparing MS cell-size means from the same sides across gr
oups were also significant, but the two MSs showed different results on pos
t hoc tests. The ordering of MS cell-size means correlated significantly wi
th a measure that aggregates the sources of activation reaching a particula
r MS and their durations.
Conclusions: These results reveal that removal of REM-state activation duri
ng CNS development amplifies the plasticity processes generated when normal
Visual afferentation to central visual areas is interrupted. Our findings
in the MS of the LGN indicate that during the usual operation of REM sleep,
central visual-sensory sites receive intrinsic activation that, in the vis
ual system, is additive and complementary to the stimulation obtained from
extrinsic sources. In the course of early development, normative symmetrica
l activation of central visual areas during REM sleep may counterbalance pl
asticity changes caused either by absent or aberrant sensory stimulation.