The mucopolysaccharidoses (MPS) are a family of lysosomal storage disorders, each characterized by the absence of a specific enzyme necessary for the degradation of glycosaminoglycans. We will attempt to document the decline in cognitive function seen in human MPS IIIB patients using a series of mazes that measure working memory, memory acquisition, and short and long term memory in a dog model. We are currently developing the T-maze, following the approach of Sanders et al. This maze assesses learning ability using reversal learning tasks. Each reversal phase consists of 10 trials daily, during which the dog will attempt to choose the baited maze arm. The phase ends when the dog achieves a criterion of 8/10 correct choices for two days or 9+/10 in one day. Preliminary data of two unaffected dogs as a control have shown 11.2 incorrect choices before criterion on average, with a standard deviation of 0.23. Continuation of this study will increase sample size and include MPS IIIB affected dogs. We will then continue with a radial arm maze and a foraging maze. The results of these experiments will provide insight into the cognitive abilities of MPS IIIB dogs, which may speed assessment of human directed therapies.

Sanders, D.N. 2011. A reversal learning task detects cognitive deficits in a Dachshund model of late-infantile neuronal ceroid lipofuscinosis. Genes, Brain, and Behavior. Cognitive Testing Apparatus. 10:798-804.