Neural correlates of target choice for pursuit and saccades in the primate superior colliculus

We have examined the role of the superior colliculus (SC) in choosing targets for pursuit and saccades by comparing neuronal activity at sites representing the possible choices. After recording during a two-alternative forced-choice paradigm, we measured the difference in activity of the populations representing the two choices by computing receiver operating characteristic (ROC) curves on a millisecond timescale. A signal indicating the correct choice emerged from noise over time, forming a tradeoff between speed and accuracy. The observed performance corresponded to particular points along the predicted speed-accuracy curves-pursuit emphasizing speed and saccades emphasizing accuracy. These results show that activity from the same set of neurons in the superior colliculus can predict target choices for both pursuit and saccades.