Conditional motor learning in the nonspatial domain: Effects of errorless learning and the contribution of the fornix to one-trial learning

Conditional motor learning contributes importantly to behavioral flexibility. In previous work, the authors found that fornix transections impaired the ability of macaque monkeys (Macaca mulatto) to learn conditional motor associations between the nonspatial features of visual stimuli and nonspatially differentiated responses. In the present study, they found that significant 1-trial learning of such associations also depended on the fornix. Furthermore, removal of the hippocampus, subiculum, and subjacent parahippocampal cortex, added to fornix transection, had no effect, thus demonstrating that fornix transections eliminated the contribution of the hippocampal system. In addition, the authors examined the effect of errorless learning and found, in control monkeys, that errors made prior to the 1st correct response retarded 1-trial learning.