Figure 2.

β-Bursts during stopping. A, Boxplots showing the incidence of β-bursts observed during the STOP process interval (from scheduled SSD to SSRT) during no-stop (green), non-canceled (orange), canceled (red), and during an equivalent period of time before target presentation (gray). β-Bursts are observed in ∼10–15% of trials and are slightly but significantly more commonly observed when saccades are inhibited. B, Raster plot of β-bursts aligned on a pretarget baseline interval (left), stop signal (middle), and saccade initiation (right) across all sessions. Each tick-mark shows the time of peak β-amplitudes satisfying inclusion criteria on each trial. Rasters are shown for non-canceled, no-stop, and canceled trials. The rough equivalence of β-burst frequency across types of trials is evident, as is the elevation of β-burst rate at the end of non-canceled error trials. C, β-Burst density function derived from raster plots. β-Burst peak times were convolved with a Gaussian function. During the stopping period, β-bursts were slightly but significantly more common on canceled trials (red line) than on no-stop (green) or non-canceled trials (yellow). D, Comparing time course of β-burst (top) and single neuron discharges (bottom) on canceled and latency-matched no stop signal trials for a single session. At no time did the incidence of β-bursts on single session differentiate between movement initiation and inhibition. In contrast, as demonstrated previously, the discharge rate of an example FEF movement neuron sampled in one session shows a clear separation between trial types occurring before the STOP process concludes. The neuron was recorded from another monkey in a separate study performing a choice countermanding task (Middlebrooks et al., 2020) and is provided as an example to demonstrate the mechanistic differences between the signals.