Glutamate levels in the cingulate cortex are associated with objective markers of pain sensitivity by way of pre-stimulus alpha band oscillations
Bibliographic record
Abstract
• Glutamate signaling across the cingulate cortex is related to laser evoked potential amplitudes. • The effect of the ACC/PCC glutamate ratio on LEP amplitudes is mediated by pre-stimulus alpha band oscillations. • Brain metabolites and spontaneous brain fluctuations shape subsequent individual brain responses to noxious input. Pain varies substantially from one individual to the next. Understanding the role of brain function in variations to pain, both in health and disease, represents an important steppingstone towards individualized pain management. This study aimed to investigate the association between glutamate levels and pain sensitivity, and whether this is mediated by alpha band oscillations. Fifty-one healthy individuals were recruited for this study. Laser evoked potentials (LEPs) and pain ratings were recorded in response to 20 stimuli applied at 4 different intensities (2.75, 3, 3.25, 3.5 J) to the right volar forearm. Brain alpha band oscillations (7–13 Hz) were extracted from the pre-stimulus timeframe (−1000 ms to −100 ms). Single-voxel magnetic resonance spectroscopy data were collected to estimate regional differences in glutamate levels across the anterior (ACC) and posterior cingulate cortex (PCC) using a 3 T scanner. Cluster analysis of LEPs revealed two clusters (high vs. low N2P2 amplitudes). Glutamate levels were reduced in the PCC versus ACC in the ‘low LEP’ (t = 3.6, p < 0.001), but not ‘high LEP’ cluster (t = 1.08, p = 0.285). Causal mediation analysis revealed that the effect of ACC:PCC glutamate ratio on LEP peak-to-peak amplitudes was mediated via pre-stimulus alpha band oscillations (β indirect = −25.6(−63.9, −2.4), p = 0.034]. This study indicates that glutamate levels across the cingulate cortexshape subsequent brain responses to noxious input, and that this is mediated by pre-stimulus alpha band oscillations. Both brain metabolites and oscillations thus likely play a vital role in individual variabilities in experimental pain.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.001 |
| 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) | 0.002 | 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".