Fig. 1: Anatomical recording planes and behavioral tasks.

a, Coronal fUS imaging planes used for monkeys P and L. The approximate fUS field of view superimposed on a coronal MRI slice. The recording chambers were placed surface normal to the skull above a craniectomy (black square). The ultrasound transducer was positioned to acquire a consistent coronal plane across different sessions (red line). The vascular maps show the mean power Doppler image from a single imaging session. Different brain regions are labeled in white text, and the labeled arrows point to brain sulci. D, dorsal; V, ventral; L, left; R, right; A, anterior; P, posterior; ls, lateral sulcus; ips, intraparietal sulcus; cis, cingulate sulcus. Anatomical labels are based upon ref. ⁶³. b, Memory-guided saccade task. * ±1,000 ms of jitter for fixation and memory periods; ±500 ms of jitter for hold period. The peripheral cue was chosen from two or eight possible target locations depending on the specific experiment. Red square, monkey’s eye position (not visible to the monkey). NHP, nonhuman primate, that is, monkey. c, fUS-BMI algorithm. Real-time 2-Hz functional images were streamed to a linear decoder that controlled the behavioral task. The decoder used the last three fUS images of the memory period to make its prediction. If the prediction was correct, the data from that prediction were added to the training set. The decoder was retrained after every successful trial. The training set consisted of trials from the current session and/or from a previous fUS-BMI session. d, Multicoder algorithm. For predicting eight movement directions, the vertical component (blue) and the horizontal component (red) were separately predicted and then combined to form each fUS-BMI prediction (purple). e, Memory-guided BMI task. The BMI task is the same as in b except that the movement period is controlled by the brain activity (via fUS-BMI) rather than eye movements. After 100 successful eye movement trials, the fUS-BMI controlled the movement prediction (closed-loop control). During the closed-loop mode, the monkey had to maintain fixation on the center fixation cue until reward delivery. Red square, monkey’s eye position (not visible to the monkey); green square, BMI-controlled cursor (visible to the monkey).