Signatures of detection in FA trials and high-amplitude miss trials. (A, Left) In high-amplitude miss trials DA neurons responded transiently to the vibrotactile stimulus. (A, Right) The activity of neurons after the SO, standardized with respect to a prestimulus window (SI Materials and Methods), showed a significant phasic activation (P < 0.05, two-sample t test) in high-amplitude miss trials compared with low-amplitude ones. (B, Left) The mean activity in FA trials (SI Materials and Methods) exhibited a significant positive modulation with respect to that in CR trials during the PSW (P < 0.05, two-sample one-tailed t test) but not outside it (P = 0.80, two-sample one-tailed t test). (B, Right) On the contrary, the activity in low-amplitude miss trials was indistinguishable from that in CR ones both outside (P = 0.28) and within (P = 0.11) the PSW.