Functional Ultrasound - Bryant McGill

# Functional Ultrasound **Entity class:** Concept or analytic term **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]]  This entry is routed through [[collections/Neurotech|Neurotech]]. Its source context is developed in [[articles/Technologies for Consciousness Mapping and Transfer|Technologies for Consciousness Mapping and Transfer]], [[articles/The Architecture of Continuity and Emerging Neuroinformatics Standards|The Architecture of Continuity and Emerging Neuroinformatics Standards]], [[articles/The Next Interface Layer|The Next Interface Layer]], and [[articles/The Organic-Synthetic Brain Atlas|The Organic-Synthetic Brain Atlas]]. Status-qualified source edges are preserved in the terminal Research Edges section. ### Additional Documented Relationships - [[wiki/Forest 1|Forest 1]] uses **Functional Ultrasound**. Hemodynamic neural-activity readout.  ## Related Work in the Corpus  - In [[articles/The Organic-Synthetic Brain Atlas|The Organic-Synthetic Brain Atlas]], **Movement V — Functional Integration and Readout: Activity, Imaging, and Dynamic Coupling** provides the narrative context for **Functional Ultrasound**: Wiki route: neural signal acquisition · fMRI · fNIRS · functional ultrasound · Neuropixels · optogenetics and chemogenetics.  ## Research Edges  #### 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.  ## Research Inferences  These entries translate the forward-looking register in [[research/Research Inferences|Research Inferences]] into ordinary wiki prose. The tier labels apply to the inference, not automatically to every factual anchor inside it. The interpretive frame comes from [[articles/Technologies for Consciousness Mapping and Transfer|Technologies for Consciousness Mapping and Transfer]] and [[articles/Mind Uploading and AI — The Host is Reusable and the Person is the Delta|Mind Uploading and AI — The Host is Reusable and the Person is the Delta]]. Collection route: [[collections/Neurotech|Neurotech]]. - **INF-0033 — Analytic.** Functional ultrasound reads blood-flow dynamics, a proxy signal with seconds-scale physics, and any interface built on it inherits that time constant. The forward path is not faster hemodynamics but hybrid operation — acoustic read of slow state, molecular read of fast events.