Figure 7.
Ultrasound Stimulation of the ACC and BF Modulates Time to Act
(A) Probability map of the combined neural impact of sonications targeted at the BF. This is calculated as the average stimulation intensity (Isppa) map across the two consecutive stimulations delivered over the left and right hemisphere, respectively (Figure S5). The combined impact probability map is overlaid on a standard F99 brain. The low impact probability level corresponds to 10 W/cm2, in correspondence with previous work (Verhagen et al., 2019) and Figure S5. As the color changes from red to bright yellow, the probability of neuromodulation from bilateral BF TUS increases.
(B) The result of a regression analysis comparing, for each point in the brain, its whole-brain coupling map (“connectome”) in the no-stimulation state against its coupling map observed after TUS targeted at the BF. The hot colors indicate points in the brain with enhanced whole-brain coupling strength after BF TUS compared with no TUS, whereas the cool colors indicate reduced whole-brain coupling strength after BF TUS compared with no TUS. Compared with no TUS, BF TUS showed a clear enhancement in activity coupling within the BF and between the BF and ACC and superior temporal area (Ts2).
(C) Sites where TUS was applied for each animal (S1, S2, S3, and S4) to assess its effect on actTime. The TUS transducer was set at a resonance frequency of 250 kHz and concentrated ultrasound in a cigar-shaped focal spot in the ACC, BF, and POp. For the sham control, the transducer was positioned on the skull but without sonication.
(D) Animals acted more quickly after ACC than after BF, POp, or sham TUS when offered medium or large compared with small rewards. actTime is indexed as the number of dots at response (Di) and the corresponding reward probability (Dii).
(E) BF TUS reduced the bias between observed and deterministic actTime compared with POp and sham TUS.
Error bars show SEM across observations. Multilevel ANOVA followed by pairwise t test. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001.
See also Figures S5–S7.