Binge inhalation of toluene vapor produces dissociable motor and cognitive dysfunction in water maze tasks.

Binge inhalation of toluene, a psychoactive chemical found in many household and industrial products, leads acutely to intoxication with comorbid impairments in motor function and cognitive abilities that appear to recover quickly. Recent evidence, however, indicates that the administration of toluene results in marked changes in neurons of the medial prefrontal cortex that persist for relatively longer periods compared with other brain regions. To elucidate the potential toluene-induced (∼5000 ppm) cognitive dysfunctions that continue following the recovery of locomotor abilities, rats were entered into a series of water maze tasks. Following acute toluene intoxication, rats were initially severely impaired in their swimming ability and in their ability to learn and perform a visible platform task. After about 20 min, swimming behavior mostly returned to normal, although cognitive impairments were still evident. Whereas rats with extensive toluene-free training in the maze were able to show normal spatial recall following toluene intoxication, the same acute toluene exposure severely impaired reversal learning, with the rats showing a marked perseveration for the previously learned platform location. Our results indicate that toluene inhalation results in specific cognitive dysfunctions that outlast major impairments in motor abilities, which may be related to impairments in medial prefrontal cortex activity.