Continuous theta-burst stimulation of the prefrontal cortex in the macaque monkey: no behavioral evidence for within-target inhibition or neural evidence for cross-hemisphere disinhibition
Bibliographic record
Abstract
BACKGROUND: Continuous theta-burst stimulation (cTBS) can perturb neural activity and behaviour by inducing effects that persist beyond the relatively short stimulation period. Although widely used in basic research and clinical settings, there lacks an understanding of the neurophysiological and behavioral effects of cTBS. OBJECTIVES/HYPOTHESIS: Two assumptions motivating the use of cTBS are that it will i) inhibit neural activity in the targeted area, and ii) consequently disinhibit neural activity in the mirroring region in the contralateral cortex. Here, we test these assumptions in the oculomotor system of healthy rhesus macaques. METHODS: In two macaques, we delivered cTBS between blocks of trials where they performed a delayed pro-/anti-saccade task. We delivered cTBS to the right PFC (areas 8Ar and 46, which includes the frontal eye fields; 32 cTBS-PFC sessions), to the air as a SHAM control (27 cTBS-SHAM sessions), or to the nearby primary motor cortex as a brain control (21 cTBS-M1 sessions). Across these different types of sessions, we compared changes in oculomotor behaviour (reaction times, error rates, peak saccade velocity), and changes in neural activity recorded from the left, contralateral PFC. RESULTS: Despite multiple lines of evidence consistent with TMS influencing neural activity in the cTBS-PFC and cTBS-M1 sessions, we found no behavioral evidence for inhibition of the right PFC in the cTBS-PFC sessions, nor any evidence for contralateral disinhibition in the left PFC. CONCLUSIONS: Our results call into question some of the fundamental assumptions underlying the application of cTBS.
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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 | 0.001 | 0.007 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| 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".