Structural Brain Modifications in Primary Insomnia: Myth or Reality?
Bibliographic record
Abstract
965 Editorial—Dang-Vu In comparison to other disorders of sleep, the number of brain imaging studies in chronic primary insomnia remains limited.1,2 The earliest reports in this area utilized functional modalities. In a study using single photon emission computed tomography (SPECT) with 99mTc-hexamethylenepropyleneamine oxime (99mTc -HMPAO), patients displayed decreased perfusion in basal ganglia and various cortical areas during NREM sleep when compared to the same sleep stage in healthy controls.3 Nofzinger et al. then used positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG) to investigate brain glucose metabolism in primary insomnia patients, during both NREM sleep and wakefulness.4 The main finding of their study was the demonstration that relative to control subjects, patients with primary insomnia showed less reduction of glucose metabolism during the transition from wakefulness to NREM sleep in the brainstem, hypothalamus, thalamus, limbic areas, and medial prefrontal cortex. This result is commonly referred to as supporting the hyperarousal hypothesis in insomnia.5 Using functional magnetic resonance imaging (fMRI), Altena et al.6 assessed brain responses during a verbal fluency task and found that chronic primary insomniacs showed less activation in medial and inferior prefrontal cortices than controls. More recent neuroimaging studies of primary insomnia were exclusively dedicated to structural brain changes associated with this condition. In a pilot MRI study, Riemann et al. investigated volumetric differences in several brain regions of interest between chronic primary insomnia patients and control subjects.7 Only the hippocampus was reduced in volume in their small sample of 8 patients—a finding that did not survive correction for multiple comparisons. In order to reevaluate this hippocampal alteration in insomnia, two other MRI studies used a manual tracing of hippocampal volumes in 20 chronic primary insomnia patients, and both reported no significant decrease compared to controls.8,9 Data from one of these two studies were reanalyzed to focus on another region of interest: the anterior cingulate cortex. Winkelmann et al.10 observed a volume increase of this area in patients, which was confirmed by the same authors on a second independent sample of 21 primary insomniacs, and interpreted as a compensatory response to chronic sleep disruption. Another study performed MRI scans in 24 chronic primary insomniacs and analyzed differEDITORIAL
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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 | 0.001 |
| 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) | 0.001 | 0.001 |
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".