a, Example PMd neuron response to free search (black) and instructed search (red). Activity is aligned to search array onset. Movement to the cell’s preferred direction. b, Example PRR neuron. c, Population average PMd spike response for cells. Activity is baseline subtracted; s.e.m. (shaded). d, Population average PRR spike response. e, Population average PRR and PMd spike responses during centre-out task to the preferred direction. f, Population response latencies for PMd and PRR during free search, instructed search and the centre-out task. Error bars, 95% confidence intervals.