ABSTRACT
Neurons in the lateral intraparietal area (LIP) exhibit both sensory and oculomotor preparatory responses. During perceptual decision making, the preparatory responses have been shown to track the state of the evolving evidence leading to the decision. The sensory responses are known to reflect categorical properties of visual stimuli, but it is not known if these responses also track evolving evidence. We compared sensory and oculomotor-preparatory responses in the same neurons during a direction discrimination task when either the discriminandum (random dot motion) or an eye movement choice-target was in the neuron’s response field. Both configurations elicited task related activity, but only the motor preparatory responses reflected evidence accumulation. The results are consistent with the proposal that evolving decision processes are supported by persistent neural activity in the service of actions or intentions, as opposed to high order representations of stimulus properties.