Sensitivity to stimulus polarity in speech-evoked frequency-following responses
Bibliographic record
Abstract
It has been suggested that frequency-following responses recorded to speech sounds presented in opposite polarities can be added to emphasize responses related to the periodicity envelope (e.g., at the fundamental frequency, f0) or subtracted to emphasize responses related to the stimulus fine-structure (e.g., harmonics near formant peaks) because inverting stimulus polarity has little effect on the stimulus envelope. This hypothesis was tested by comparing frequency-following responses to several tokens of two vowels (/a/ and /i/) presented twice in one polarity and once in the opposite polarity, from nine normal-hearing listeners. At harmonics near formant peaks, most listeners displayed frequency-following responses closely related to stimulus fine-structure (i.e., responses that followed stimulus polarity). However, response amplitude and phase at f0 varied greatly across polarities for many listeners, suggesting that the f0 response does not reflect a simple encoding of the periodicity envelope or the fine-structure of the first harmonic. Most listeners had similar responses when identical stimuli were presented in the same polarity, so these varied polarity-sensitive responses were not likely related to temporal encoding difficulties or background electrophysiological noise. The summed alternating polarity frequency-following response at f0 might reflect encoding of both speech fine-structure and the periodicity envelope.
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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 | 0.009 |
| 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 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".