Figure 2.

Differences in time course of BOLD signal between CBP patients and healthy controls. a, Group-averaged BOLD signals from mPFC (blue) and LIPS (red) for controls (top) and CBP patients (bottom) are shown superimposed on the respective group-averaged tracking time courses (gray). The main result illustrated here is that mPFC BOLD signal is more deactivated in normal subjects than in CBP patients each time the subject engages in tracking. The arrow indicates a time in which these differences can be appreciated even by simple inspection of the traces. b, Time course of average BOLD responses for mPFC (top) and LIPS (bottom) relative to transition from rest to tracking. Task-triggered BOLD signals averaged over 135 tracking events were significantly smaller in mPFC of CBP patients selectively in the deactivation phase (*p < 0.01), at times of peak tracking (10–20 s from start of tracking), whereas task performance (magnitude tracking) did not differ between the two groups (top right). The LIPS responses were similar between the groups. Middle, Cross-correlations between BOLD signal and tracking time course for each group for different time lags (−10 to 10 s) revealed that the mPFC BOLD signal was anticorrelated to the task time course in normal subjects (mean r = −0.35 ± 0.2, SEM, at lag = 2.5 s), and that this anticorrelation was significantly attenuated (mean r = −0.11 ± 0.20, SEM, at lag = −2.5 s; p < 0.001) in CBP patients. LIPS signal was positively correlated to task execution and did not differ between the groups.