Four macaque runs show pulse-locked VPL LFP responses to VPL- and insula-targeted focused ultrasound

We tested whether 0.5 s transcranial focused ultrasound (FUS) pulses produce pulse-locked local field potential (LFP) responses in macaque ventral posterolateral thalamus (VPL), and whether the response is specific to the FUS target. We analyzed four OpenNeuro ds008610 v1.0.0 runs from two animals: three VPL-target runs and one insula-target run, with a 32-channel probe in VPL in every run. A pre-analysis plan specified channel-median RMS of the baseline-corrected trial-average LFP from 0 to 0.6 s, compared with 2,000 random pseudo-onset sets and Holm correction across runs. All four runs exceeded the random-onset null (Holm p = 0.002–0.008). The insula-target run had the largest standardized response (z = 9.17; VPL-target runs: 5.25, 3.40, and 3.63). In sub-02, peak latencies were 87 ms for VPL-target FUS and 101 ms for insula-target FUS. The 70–250 Hz power ratio showed no consistent increase; the insula-target run had a small decrease (Holm p = 0.048). These results do not establish direct, target-specific neuromodulation in VPL. Auditory or somatosensory side effects, or electrical or mechanical artifact, could explain the response, and these data cannot distinguish among them. The sample is limited to four runs from two animals, including one insula-target run; target is confounded with session. All opened NWB files, including files described as the “Spikes dataset,” contained 32-channel LFP sampled at 1 kHz, with no 30 kHz data or spike times found. The findings are descriptive for these runs.

focused ultrasound · local field potential · macaque · ventral posterolateral thalamus · insula · neuromodulation · electrophysiology