A multivariate statistical and data mining analysis of spatial memory-related behaviour following bilateral...

Vestibular dysfunction in animals and humans is associated with a variety of cognitive and anxiety disorders, and it has been difficult to determine how the different symptoms may be related to one another. The aim of this study was to determine the extent to which the spatial memory deficits that occur following bilateral vestibular deafferentation (BVD) in rats can be attributed to other behavioural symptoms. Spatial memory was measured using a spatial T maze alternation task (STM), while locomotor activity and anxiety were measured using open field, elevated plus and T mazes, respectively. Using multiple linear and random forest regression, we determined that the best predictors of performance in the STM were whether the animals had received a BVD or sham lesion, and the duration of rearing. Using linear discriminant analysis, random forest classification, support vector machines and cluster analysis, we found that BVD animals could be clearly distinguished from sham controls by their behavioural syndrome, in particular their decreased duration of rearing in the open field maze (suggesting reduced exploration), decreased time spent in the outer zone of the open field maze ('reduced thigmotaxis', suggesting increased risk taking), and spatial memory deficits in the STM. These results suggest that the poor performance of rats with BVD in spatial memory tasks is largely due to spatial memory deficits themselves rather than a result of other changes in locomotor activity or anxiety.