Figure 4. Firing Fields Span the Entire Time on Treadmill.
(A) Histogram showing the distribution of the normalized peak firing times. A normalized time value of 1 indicates the moment the stop signal was sent to the treadmill. In this figure, and the corresponding analysis, time was normalized by dividing time by the duration of each individual lap, such that data from “distance-fixed” session was normalized based on distance traveled, while data from “time-fixed” sessions was normalized based on time elapsed.
(B) Histogram showing the distribution of normalized field widths (defined as the extent of firing at least 20% of the peak rate). A field width of 1 indicates the field extended across the entire treadmill run.
(C) The normalized field widths plotted against the normalized peak firing time. The neurons are subdivided based on whether their firing fields ended before the treadmill stopped (black dots) or whether the edge of the field reached the end of the treadmill runs (gray circles). Peak time and field width were correlated among the fields that did not reach the end of the treadmill run (Pearson’s linear correlation coefficient: 0.50; p = 2 × 10−17). The distinct pattern seen among the fields observed at the end of the treadmill run is a result of many of those fields being truncated when the treadmill abruptly stopped, such as in the bottom two examples in Figure 2.