Neural Noise- Low-intensity focused ultrasound (FUS) neuromodulation in humans can probe deep brain structures non-invasively.1
- FUS has been used to reveal a causal role for the thalamus in human conscious perception.1
- The finding informs target selection for future neuromodulation devices and potential BCI/stimulation hybrids; Nature, human data, tier-1.1 1
Weekly enrichment (2026-07-20)
- The primary study was published in Nature Communications (Jang, Fotiadis, Mashour et al., 2025; a February 2026 author correction followed) and applied transcranial low-intensity focused ultrasound (LIFU) to healthy humans during a near-threshold visual perception task analyzed with Signal Detection Theory.2 3
- Sixty participants were randomized to a high (70%) or low (5%) duty-cycle group at matched spatial-peak temporal-average intensity Ispta = 0.72 W/cm²; six were excluded for technical issues, leaving 54 (27 per group) in the final analysis.2
- LIFU was steered to four subregions of the left thalamus—ventral anterior (VA), ventral posterior (VP), dorsal anterior (DA), and dorsal posterior (DP)—in pseudo-randomized, counterbalanced order, with two LIFU-OFF baseline blocks bracketing four LIFU-ON blocks.2
- High-duty-cycle (70%) sonication of the VA thalamus selectively increased object-recognition sensitivity (d′) versus baseline (p_FDR = 0.0246; paired Cohen’s d ≈ 0.92) and outperformed all other thalamic targets, giving a significant omnibus effect F(4,90) = 4.61, p_FDR = 0.0118.2
- Enhancement magnitude tracked matrix-cell richness: the CALB1-minus-PVALB expression index (CP_T) correlated with the change in d′ at 70% DC (Spearman’s ρ = 0.35, p_FDR = 0.0135), implicating matrix-cell-rich, transmodal VA thalamus.2
- A separate target-invariant effect emerged at 70% DC—reduced object categorization accuracy across all four targets—which did not correlate with core–matrix composition, suggesting a distinct mechanism.2
- Targeting precision was high, with average lateral beam deviation ≈2 mm (beam width ≈5 mm), better than the 3–9 mm reported in prior human LIFU work, strengthening the case for sub-centimeter subcortical neuromodulation.2
- Connectivity analysis of a large-scale fMRI dataset confirmed strong functional coupling of VA thalamus with frontoparietal and default-mode networks, consistent with a thalamocortical route into conscious perception.2
- Clinical/BCI implication: non-invasive, spatially precise deep-brain modulation of the thalamus is a candidate tool for disorders of consciousness and closed-loop neuromodulation, though the correction notes FDA intensity guidelines derive from diagnostic imaging and no LIFU-specific limits exist yet (safety thresholds not established).2 4