Data from rodent models of induced microgyria suggest that bilateral damage leads to more severe rapid auditory processing deficits than unilateral damage. It is unclear whether this reflects the degree, or bilateral/unilateral nature, of damage. The current study evaluates the effects of microgyric severity by assessing rats with single- vs double-pair bilateral focal microgyric lesions, using auditory discrimination and MGN measures. Behavioral data show a significant auditory processing deficit on rapid processing tasks for microgyric as compared to control subjects, and also reveal more severe deficits for double- than for single-pair bilateral microgyrics. Greater disruptions are also seen in the MGN of double-pair compared to single-pair bilateral microgyric subjects.