Figure 1.

(A) An example of a pattern formed by activity in two cells recorded from two different electrodes in the same hemisphere. Details of pattern timing are shown at Left. In the Center, several action potential waveforms from each cell are overlaid (scale bars for cell # 11 apply to both). Vertical lines on the traces are superimposed markers relating to settings of the template-matching software used to discriminate the waveforms. Right, all detected examples of the pattern formed by these cells displayed in rasters. Each tick mark shows the occurrence of an action potential, and each row shows a segment of data in which a pattern was detected. The rows have been slid past one another such that the first spikes of each occurrence of the pattern are aligned (a spike of cell # 5 at time 0). The accurate timing between that spike and a subsequent spike in cell # 11 and a later spike of cell # 5 causes these later spikes to also line up in the display, forming the nearly vertical lines at 320 ± 3 and 662 ± 3 ms delay. In this example, the data shown includes trials recorded on two consecutive days, as detailed in B. (B) Relationship of occurrence of pattern shown in A to Go-vs.-NoGo task performance. The possible behavioral situations in which Go and NoGo responses could occur are illustrated schematically (Upper). Go responses resulted both from correct movements to the feeder in response to low-pitch sound at the right speaker (*L) and from incorrect movements when a high pitch was delivered to this speaker (H). Conversely, NoGo responses could be correct (high pitch to right speaker) or incorrect (failure to move in response to low pitch to right speaker). Lower shows dot rasters of the same data shown in A but on a compressed time scale and aligned to the time of stimulus onset instead of to time of the first spike of the pattern. The trials are divided into those in which Go (Left) and NoGo (Right) responses occurred. Spikes involved in generating instances of the pattern during the waiting period (time to the left of the stimulus onset) are displayed as bars instead of ticks. Three spikes constituting one instance of the pattern are denoted by open circles. Note that there are more than twice as many Go trials (n = 27) with patterns than NoGo trials (n = 12), although the total number of Go and NoGo responses was nearly the same (n = 283 and 269, respectively). In addition, in this example the reaction time for Go responses with a pattern (825 ± 60 ms) was significantly shorter than for Go responses with no pattern (985 ± 23 ms).