The cerebellum has traditionally been associated with motor control. However, increasing evidence suggests that it also plays a critical role in cognitive processing. Despite this shift in perspective, the precise nature of the cognitive signals conveyed to the cerebellum remains poorly understood. This dissertation aims to address this gap by investigating the activity of cerebellar Purkinje cells during perceptual decision-making through a combination of approaches, including animal behavior, two-photon calcium imaging, and optogenetics. Specifically, it examines the types of information transmitted via climbing fiber inputs to Purkinje cell dendrites during an auditory cognitive task and assesses whether Purkinje cell firing itself is sufficient to drive perceptual behavior.