Ashley Havlicak and Joanna Beachy, University of Utah
Health
Background:
The white matter in chronically ventilated preterm lambs exhibits diffuse damage with increased apoptosis and decreased proliferation of neurons and glia compared to term control lambs. The hippocampus, the source of learning and memory, is affected by chronic ventilation. Currently, there are no established neurodevelopmental tests to investigate outcomes in lambs.
Objective:
Establish a series of developmental tests to assess learning and memory in lamb model.
Methods:
Six control lambs (5 group raised and 1 individually raised) were evaluated with the following developmental tests (all trials were 10 minutes): 1) Habituation to the testing area occurred over 2 days with 2 trials/day. 2) Novel object – The lamb was placed in the room with two dissimilar objects for 2 trials. The next trial, one object was replaced with a novel object. The last trial, a ball was added. 3) A mirror and a dull object were placed on the walls for 2 trials. 4) Maze – A maze was constructed in the same room. The time to locate the reward was recorded. For all tests the number of vocalizations, time spent by the entrance, in exploration, and standing were recorded. The time to first notice an object, number of times the object was approached, and total time spent with object was analyzed.
Results:
During all tests, the individually raised lamb vocalized significantly less than group raised lambs (p<0.0001), had markedly different responses to the tests, and was excluded from further analysis. Lambs approached the novel object faster than familiar objects. Lambs spent more time looking at the mirror compared to the dull object (p<0.001). Lambs approached the mirror faster on the second trial compared to the first trial (p=0.02). Lambs completed the last maze trial significantly faster compared to the first maze trial (p<0.04). Conclusion:
We are able to demonstrate that lambs are capable of memory and learning.