INDIRECT EFFECTS OF PERINATAL AND POSTNATAL CHOLINE TREATMENT ON PLACE-LEARNING ABILITIES IN RAT

This work was aimed at analyzing the effects of perinatal choline supp lementation on the development of spatial abilities and upon adult per formance. Choline supplementation (3.5 g/L in 0.02 M saccharin solutio n in tap water) was maintained for two weeks before birth and for up t o four weeks postnatally. Additional supplementation was maintained fr om the fifth to the tenth week postnatally. Spatial-learning capacitie s were studied at the ages of 26, 65, or 80 days in a circular swimmin g pool (Morris place-navigation task) and at the age of 7 months in a homing arena. Treatment effects were found in both juvenile and adult rats, and thus persisted for several months after the cessation of the supplementation. The choline supplementation improved the performance in the water maze in a very selective manner. The most consistent eff ect was a reduction in the latency to reach a cued platform at a fixed position in space, whereas the improvement was limited when the platf orm was invisible and had to be located relative to distant cues only. However, after removal of the goal cue, the treated rats showed a bet ter retention of the training position than did the control rats. A si milar effect was observed in a dry-land task conducted in the homing a rena. The choline supplementation thus induced a significant improveme nt of spatial memory. But since this effect was only evident following training with a salient cue, it might be regarded as an indirect effe ct promoted by an optimal combination of cue guidance with a place str ategy.