# Functional Ultrasound **Collection:** [[collections/Neurotech|Neurotech]] **Domain:** Neuroimaging / Hemodynamic Measurement **Doc Type:** Modality Node **Maturity:** Research and intraoperative translation **Primary Source:** [[articles/The Organic-Synthetic Brain Atlas|The Organic-Synthetic Brain Atlas]] ## Definition **Functional ultrasound** (fUS) is a neuroimaging modality that infers neural activity indirectly by measuring changes in cerebral blood flow or blood volume with ultrasound. It occupies a middle region between optical techniques with limited depth and field of view and room-scale [[wiki/Functional Magnetic Resonance Imaging|fMRI]]. ## Measurement profile The source atlas characterizes fUS as offering broad or whole-brain coverage in small-animal settings, sub-millimeter spatial resolution, and temporal resolution on the order of hundreds of milliseconds. It has been used in awake animals and investigated in human intraoperative contexts. ## Interface role fUS is relevant to [[wiki/Non-Invasive BCI|non-invasive BCI]] research because it may support portable hemodynamic measurement at higher spatial resolution than [[wiki/Functional Near-Infrared Spectroscopy|fNIRS]]. It may also participate in ultrasound-based neuromodulation systems, but imaging and stimulation are different functions and should not be conflated. ## Constraints Hemodynamic signals are indirect proxies for neural activity. Skull transmission, probe coupling, motion, field of view, hardware form factor, and subject-specific calibration constrain deployment. Research demonstrations do not establish a consumer wearable or a validated semantic decoder. ## Relationships **Related cluster nodes:** [[wiki/Neural Signal Acquisition|Neural Signal Acquisition]] · [[wiki/Functional Magnetic Resonance Imaging|Functional Magnetic Resonance Imaging]] · [[wiki/Functional Near-Infrared Spectroscopy|Functional Near-Infrared Spectroscopy]] · [[wiki/Non-Invasive BCI|Non-Invasive BCI]] <!-- BEGIN NEUROTECH RELATIONSHIP GRAPH 2026-09-10 --> ### Master relationship graph patch — 2026-09-10 **Collection:** [[collections/Neurotech|Neurotech]] **Relationship source:** [[research/Neurotechnology Ecosystem Relationship Graph - 2026-09-10|Neurotechnology Ecosystem Relationship Graph — 2026-09-10]] **Related source articles:** [[articles/The Architecture of Continuity and Emerging Neuroinformatics Standards|The Architecture of Continuity and Emerging Neuroinformatics Standards]] · [[articles/2026 Annual Report on Brain-Computer Interfaces|2026 Annual Report on Brain-Computer Interfaces]] · [[articles/The Organic-Synthetic Brain Atlas|The Organic-Synthetic Brain Atlas]] #### Incoming typed edges - **Edge 256 — [[wiki/Forest 1|Forest 1]] `uses` → this entry** — **VERIFIED**; evidence `ARBOR_TECH`. Hemodynamic neural-activity readout. #### Epistemic boundary `VERIFIED`, `VERIFIED_SECONDARY`, `CORPUS`, `STRONG_TECHNICAL_LINEAGE`, `STRONG_TECHNICAL_CONVERGENCE`, `ANALYTIC`, and `UNRESOLVED` are retained as distinct relation states. An edge does not imply ownership, control, funding, licensing, technology transfer, or organizational identity unless its predicate and evidence state that relationship explicitly. <!-- END NEUROTECH RELATIONSHIP GRAPH 2026-09-10 -->