FIGURE 6:
Subthalamic nucleus (STN) deep brain stimulation (DBS) treatment resulted in gradual and sustained increases in the primary motor cortex (M1) circuit deactivation over time. (A) Group-level responses induced by STN-DBS were estimated for each postsurgical treatment visit (top 4 rows). Regions activated by STN-DBS (red/yellow) were relatively stable across the 4 follow-up visits. Activated regions at 1 month and 12 months were highly similar (Dice = 0.49). However, deactivation (blue) in the M1 circuit was gradually enhanced over time. There was no significant deactivation at 1 month postsurgery, but prominent deactivations at 12 months were observed (Dice = 0.00). Group-level comparison between blood oxygen level–dependent signal responses at 1-versus 12-month visits revealed a significant difference in deactivation but not activation levels (bottom panel). (B) Mean magnitude of activation intensity was quantified in the activated globus pallidus internus (GPi) circuit and the deactivated M1 circuit at each visit. A linear mixed model analysis revealed that the intensity of the activations was stable over time, as there was no significant main effect of time (p = 0.16). However, deactivations showed a significant time effect (F3,92 = 25.59, p < 0.001).