The effects of subdural haematoma on spatial learning in the rat.

Although memory deficits are one of the most persistent consequences of human subdural haematoma, cognitive functioning has hardly been investigated in the rat subdural haematoma model. In the present study, the effects on spatial learning of right- and left-sided unilateral subdural haematoma and of bilateral subdural haematoma induced above the sensorimotor cortical areas were evaluated. Spatial learning was assessed by standard acquisition in the Morris water escape task (five sessions). Additional issues addressed were sensorimotor functioning (footprint analysis), recovery of cognitive functioning (tested by an overtraining and a reversal training) and replicability of induced cognitive deficits. Following unilateral subdural haematoma surgery, hardly any impairments in the Morris water escape task were observed: rats with a unilateral right-sided subdural haematoma showed very mild, transient deficits, whereas rats with left-sided subdural haematoma were indistinguishable from controls. Bilateral subdural haematoma surgery led to a clear, although transient, performance deficit. We conclude that animals with bilateral subdural haematoma may provide a promising cognitive deficit model for investigating recovery of function.