The influences of rearing environment and neonatal choline dietary supplementation on spatial learning and memory in adult rats.

The facilitative effects of early environmental enrichment and perinatal choline chloride dietary supplementation on adult rat spatial learning and memory were examined using delayed match-to-place (DMTP) and delayed spatial win-shift (DSWSh) discrimination tasks. Animals were either maintained in a standard lighted colony (LR) or were given supplementary exposure to a complex environment (CR) for 2-h daily from 20 to 90 days of age. In each case, half the animals were exposed to the choline supplementation both prenatally (through the diet of pregnant rats) and postnatally (subcutaneous injection) for 24 days. In the first experiment, all 90-day-old rats were given trials in which they first found a hidden platform in a Morris water maze (MWM) in a particular location (acquisition trial), and then were required to remember that position 10 min later (test trial). Both environmental enrichment and early diet had significant impacts on performance. CR animals, given neonatal choline pretreatment, found the platform on test trials significantly faster than any of the other groups. CR animals exposed to the control saline diet showed better retention than did the LR animals given the early choline diet, which in turn, were superior to animals given neither environmental enrichment nor choline. All animals were subsequently tested in the same paradigm immediately following atropine sulfate injections. The atropine eliminated the difference between the four groups of animals on test trials. In a second experiment, both CR, and neonatal choline treatment facilitated performance on a DSWSh radial arm maze (RAM) task previously found to be sensitive to hippocampal and/or medial prefrontal lesions. Performance differences between groups were facilitated by the anticholinesterase drug, tacrine and attenuated by the cholinergic antagonist, Atropine. The present study extends the descriptions of long-term functional enhancements produced by perinatal choline supplementation and environmental enrichment and to relate these effects to common modifications to targets of cholinergic basal forebrain systems.

The influences of sex, rearing environment, and neonatal choline dietary supplementation on spatial and nonspatial learning and memory in adult rats.

The potential facilitative effects of early environmental enrichment and perinatal choline chloride dietary supplementation on male and female adult rats' learning and memory were examined using a "stimulus-elicited investigative," and a social/observational learning-cued spatial memory paradigm. Male and female animals were either maintained in a standard lighted colony (SC) or were given supplementary exposure to a complex environment (EC) for 2 hr daily from 24-90 days of age. In each case, half of the animals were exposed to the choline supplementation both prenatally and postnatally for 24 days. In one paradigm, the 90-day-old EC rats were found to be significantly more responsive than SC rats to each change in the spatial relationships of objects contained in an open field. Neither sex nor early diet of the animals were much of a factor in the investigative behavior observed. In the second paradigm, the effects of the perinatal choline diet did interact with those of sex and postnatal environment to alter the impact of social/observational experience on the acquisition and memory of place in the water maze. The choline-treated EC males were the most influenced by their experience seeing a demonstrator swim to a platform location. The present study provides some further insight into the scope of the long-term functional enhancements produced by perinatal choline supplementation and EC in male and female animals and relates these effects to common modifications to targets of cholinergic basal forebrain systems.

The effects of neonatal choline dietary supplementation on adult spatial and configural learning and memory in rats.

The facilitative effects of pre- and early postnatal choline chloride dietary supplementation on adult rat spatial and nonspatial learning and memory were examined using a delayed match-to-place and a transverse-patterning discrimination task. Animals were exposed to the choline supplementation both prenatally (through the diet of pregnant rats) and postnatally (subcutaneous injection) for 24 days. In the first experiment, 90-day-old rats were given pairs of trials in which they first found a hidden platform in a Morris water maze in a particular location (acquisition trials), and then were required to remember that position 10 min later (test trials). Those animals given neonatal choline pretreatment found the platform on test trials significantly faster than did animals in a saline-treated control group. All animals were subsequently tested in the same paradigm following atropine sulfate injections. The atropine eliminated the difference between experimental and control animals on test trials. In a second experiment, neonatally treated choline rats performed significantly better than controls in acquiring a visual transverse patterning discrimination task previously found to be sensitive to hippocampal and/or frontal damage. The present study extends the description of long-term functional enhancement produced by perinatal choline supplementation to include the ability to use and remember visual configural associations, working spatial memory, and to relate these effects to modifications in cholinergic basal forebrain systems.