Stimulus generalization and transfer of training in rabbits conditioned to electrical stimulation of lateral geniculate nucleus

Rabbits were classically conditioned by pairing electrical stimulation of the dorsal lateral geniculate nucleus (LGN) with peripheral electric shock as the unconditioned stimulus. In Experiment 1 generalization and transfer of training between contralateral LGN were examined. In Experiment 2 frequency generalization gradients were examined with total stimulus energy (TSE) either varied or kept constant. The chief findings of Experiment 1 were that (a) reliable eyeblink and heart rate conditioning were observed, and (b) transfer of training, but not stimulus generalization occurred between LGN. This transfer was specifically due to the previous conditioning. In Experiment 2 response frequency of unconditioned eye openings to LGN stimulation varied as a function of stimulus frequency. In contrast, the highest response frequency for conditioned eyelid closings during generalization testing occurred at the stimulus frequency used during training provided that TSE was kept constant; some generalization occurred to higher and lower stimulus frequencies. When frequency was varied without keeping TSE constant, the highest response rates occurred at stimulus frequencies higher than the training stimulus.