Mechanisms and optimal parameters for induction of cortical plasticity using transcranial focused ultrasound stimulation
Bibliographic record
Abstract
Abstract Our previous study showed that theta burst transcranial ultrasound stimulation (tbTUS) increased motor cortical (M1) excitability for at least 30 minutes in human subjects. This talk will describe studies that examined different stimulation parameters, mechanisms, and changes in brain oscillations with tbTUS. Different tbTUS parameters were tested in 14 subjects. Acoustic intensity of 10W showed no effect while 20W increased M1 excitability. Pulse repetition frequency (PRF) of 5Hz produced greater effects than 2Hz or 10Hz. Duty cycle of 15% led to longer increase in M1 excitability than 10% or 5%. Sonication duration of 120s caused greater increase in M1 excitability than 80 or 40s. In a pharmacological study, we showed that carbamazepine (Na+ channel blocker), nimodipine (Ca2+ channel blocker), lorazepam (enhance GABA transmission) and dextromethorphan (NMDA receptor blocker) all reduced the effects of tbTUS on M1 excitability compared to placebo, suggesting that tbTUS induced plasticity could be mediated by long-term potentiation which requires activation of NMDA receptors, Ca2+ influx and is blocked by increased GABAergic input, and involves activation of mechanosensitive Na+ and Ca2+ channels. A magnetoencephalography study showed that tbTUS of the left M1 lead to widespread changes in cortical oscillations, particularly increase in movement-related alpha and beta oscillations, and increased functional connectivity in the delta, theta and alpha bands. tbTUS was applied to the M1 in 14 Parkinson’s disease (PD) patients and age-matched controls. Older normal subjects also showed tbTUS induced increase in cortical excitability. PD patients off medications showed no increase in M1 excitability which was restored in the on medication state. tbTUS appears to be a reliable method to increase M1 excitability. These studies provide data to optimize the tbTUS protocol and provides insights into its mechanisms of action. It could be further tested as a novel non-invasive treatment for PD and other neurological disorders. Research Category and Technology and Methods Translational Research: 6. Pulsed Ultrasound (pUS) Keywords: Ultrasound neuromodulation, Pharmacology, Magnetoencephalography, Parkinson’s disease
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".