Quantitative studies of cell size in the cat's dorsal lateral geniculate nucleus following visual deprivation

Abstract

The effects of visual deprivation upon dorsal lateral geniculate (DLG) cell size were compared for seven kittens reared with monocular lid-suture (MD), seven with binocular lid-suture (BD), and six with one eye lid-sutured and the other eye enucleated soon after birth (MD-E). Six additional kittens were reared normally for comparison. For each kitten the cross-sectional areas of 300 cells were measured in one or both nuclei. Measurements were taken from the binocular segment of laminae A and A1 and the monocular segment of lamina A. In agreement with previous studies, cells in the binocular segment of the deprived laminae of MD cats were smaller (33-34%) than those in the non-deprived laminae. Comparisons with normal animals indicated that this difference was due to an increase (10-15%) in size of cells in the non-deprived laminae as well as a decrease (23-25%) in size of cells in the deprived laminae. Cells in the monocular segment also were affected by deprivation in MD cats, and this effect increased with the age (and duration of the deprivation) of the animal. However, it was always smaller than the decrease in cell size in the binocular portion of the DLG. In BD kittens, DLG cells were smaller (7-12%) than normal in all portions of the nucleus, including both the binocular and monocular segments. Direct comparisons between the deprived laminae of MD and BD kittens indicated that the decrease in cell size was greater for MD kittens in the binocular segment, but tended to be greater for BD kittens in the monocular segment. In MD-E kittens, DLG cells in the deprived laminae were smaller (11-17%) than normal in all portions of the nucleus, including both the binocular and monocular segments. Thus, the effects of deprivation were similar to those in BD kittens, even though inputs from the deprived eye had been placed at a competitive advantage in MD-E kittens. These results indicate that two factors may affect cell size in the DLG of visually deprived cats: deprivation per se and abnormal binocular competition. Finally, separate analyses for the ten largest and the ten smallest cells in each lamina of each cat were carried out in an attempt to determine if the changes in cell size were limited to the largest cells. In every case, differences observed for the total sample of cells were paralleled by differences from normal of both the largest cells present and the smallest cells present in the deprived laminae. Since at least two alternative interpretations can account for this finding, the question of whether the large cells are selectively affected by visual deprivation remains unanswered in the cat.

Effects of monocular deprivation in the nucleus rotundus of zebra finches: a Nissl and deoxyglucose study

“…Using cells in the corresponding non-deprived nucleus rotundus of the same animal as a control, our results show that after 40 or 100 days of monocular deprivation neurons in the deprived nucleus rotundus are 15% smaller than those in the non-deprived hemisphere. Analysing our data this way, our results are in close agreement with findings in the visual system of mammalian species with large binocular fields (Guillery and Stelzner 1970;Sherman and Wilson 1975;Hickey et al 1977;Vital-Durand et al 1978;Casagrande and Joseph 1980;Tigges et al 1984), although the size differences expressed as percentage between deprived and undeprived cells in cats, monkeys, squirrels and dogs are about twice as high as those observed in zebra finches. After a shorter deprivation time of 20 days, however, there are no differences in cell size between the two hemispheres.…”

“…As mentioned above, there is now extensive support for the existence of competitive mechanisms underlying cell size changes after monocular closure (for review see Sherman and Spear 1982), as neurons in the monocular and "critical" part of the LGN are less affected than somata in the binocular LGN laminae (Guillery and Stelzner 1970;Garey et al 1973;Sherman and Wilson 1975;Hickey et al 1977;Casagrande and Joseph 1980). According to a hypothesis put forward by Guillery (1972, Guillery andStelzner 1972) the soma size of a neuron is a reflection of its axonal arborization and the number of synapses (Tiernan 1984).…”

“…This interpretation is supported by three findings: first, binocular deprivation causes milder e!ectrophysiological (Wiesel and Hubel 1965) and anatomical effects (Guillery 1973;Hickey et al 1977;Kalil 1980; but see Vital-Durand et al 1978;Mower et al 1985). Second, cell sizes in the monocular or artificially induced "critical" segment are less affected by monocular closure than neurons in the binocular LGN segments (Guillery and Stelzner 1970;Guillery 1972;Von Norden et al 1974).…”

Axonal conduction velocity changes following muscle tenotomy or deafferentation during development in the rat.

“…There is substantial evidence in the literature which suggests that this hypothesis is equally applicable to other regions of the nervous system. For example, cells in the lateral geniculate nucleus were smaller when deprived of activity during development (Wiesel & Hubel, 1963;Hubel & Wiesel, 1970;Hickey, Spear & Kratz, 1977), and in the kitten spinal cord, Smith (1974) has shown that neurones of Clarke's nucleus, deafferentated by dorsal root section at 3 days after birth, were markedly smaller than controls. The results of Lewis, Bagust, Webb, Westerman & Finol (1977) apparently demonstrate a change in conduction velocity of axons brought about by changes of activity in adult animals.…”

The visual system of the cat

“…Subsequent work (Guillery & Stelzner, 1970) has shown that this morphological effect of monocular deprivation is largely confined to the binocular portion of the lateral geniculate nucleus; cell size in the monocular crescent of the deprived lamina is more nearly normal. Other recent work (Oursteler, Garey, & Movshon, 1976;Hickey, Spear, & Kratz, 1977;Movshon & Oursteler, 1976;Wan & Cragg, 1976) has confirmed and extended these findings concerning the effects of monocular deprivation on LGN cell size. In contrast, binocular deprivation (via either bilateral lid suture or dark rearing) produces only a transitory retardation in LGN cell growth, with neurons eventually achieving almost normal size (Guillery, 1973;Hickey et al, 1977;Kalil, 1978).…”