Evaluating the ability of non-rectangular electrical pulse forms to preferentially activate nociceptive fibers by comparing perception thresholds
Bibliographic record
Abstract
Abstract Aims Selective activation of nociceptive fibers is difficult using electrical stimulation as the activation threshold is higher than for non-nociceptive fibers. It remains unclear to what extent accommodation of non-nociceptive fibers during slowly rising electrical pulses can be utilized to reverse this activation order. The aim of this study was to evaluate the ability of different pulse forms to activate nociceptive fibers with minimal co-activation of non-nociceptive fibers by comparing subjective perception thresholds (PT). Methods Electrical pulses were applied on the volar forearm of 25 subjects with (1) small diameter pin electrodes providing high current density in the skin epidermis, where primarily nociceptive fibers terminate and (2) standard patch electrodes (2.63 cm 2 ). PTs were obtained for exponential current increase, linear current increase, increasing form of exponential current decay (ED), and standard rectangular current pulses. All pulse forms were tested at two relatively long durations (5 and 50 ms). The PT ratio between patch- and pin electrode was calculated as an estimate of the ability of a pulse form to preferentially activate nociceptive fibers. The short form McGill pain questionnaire (SF-MPQ) was used to assess perceived quality of pain for all pulse forms. Results For the pin electrode, PT tended to decrease with increasing pulse area. Patch electrode PT tended to increase for increasing pulse area for non-rectangular 50 ms pulses, in contrast to 5 ms pulses, indicating accommodation of non-nociceptive fibers. Largest PT ratio was obtained for the 50 ms ED. SF-MPQ scores were higher for the pin- compared to the patch electrode. Pin electrode pain qualities were mainly described as stabbing and sharp. SF-MPQ scores did not differ between pulse forms. Conclusions Long duration ED pulses seem to activate nociceptive fibers better than regular, short duration pulses; most likely reflecting accommodation of non-nociceptive fibers.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.004 | 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 source (direct Gemma or distilled Codex), 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".