Eyeblink conditioning in the developing rabbit.

Eyeblink classical conditioning in pre-weanling rabbits was examined in the present study. Using a custom lightweight headpiece and restrainer, New Zealand white littermates were trained once daily in 400 ms delay eyeblink classical conditioning from postnatal days (PD) 17-21 or PD 24-28. These ages were chosen because eyeblink conditioning emerges gradually over PD 17-24 in rats [Stanton et al., (1992) Behavioral Neuroscience, 106(4):657-665], another altricial species with neurodevelopmental features similar to those of rabbits. Consistent with well-established findings in rats, rabbits trained from PD 24-28 showed greater conditioning relative to littermates trained from PD 17-21. Both age groups displayed poor retention of eyeblink conditioning at retraining 1 month after acquisition. These findings are the first to demonstrate eyeblink conditioning in the developing rabbit. With further characterization of optimal conditioning parameters, this preparation may have applications to neurodevelopmental disease models as well as research exploring the ontogeny of memory.