 Newsome and colleagues demonstrated that microstimulation of MT neurons shifted the animal’s performance in predictable ways. Assume that neural population P, by encoding information about stimulus motion, can inform the subject’s report of motion direction. This information is accessible for the control of behavior. Activation of P by microstimulation should shift behavior in a motion selective way correlated with the direction that P is tuned to (represents). Metaphorically, if a downstream control system is sensitive to the response of P when it generates behavior, then if we change P in a specific way, say amplifying its signal, we should change behavior in a way biased by P’s content. This was first demonstrated by Salzman et al. (1990). They inserted electrodes into MT and identified neurons tuned to a particular orientation. During a motion discrimination task, microstimulation of neurons with that tuning led to a shift in the psychometric curve as if that neuron was given more weight in driving behavior.