Precentral sulcal complex of the human brain: Morphology and statistical probability maps
Bibliographic record
Abstract
The morphology of the precentral sulcus was examined via 3D visualization in 40 structural magnetic resonance images of the human brain to define its common features and their variability. The precentral sulcus is composed of two distinct sulcal configurations: 1) the inferior precentral sulcus (IP), situated caudal to the inferior frontal sulcus, and 2) the superior precentral sulcus (SP), caudal to the superior frontal sulcus. The SP was usually a single connected structure, and only in 24% of cases studied did it consist of two separate folds. The caudal end of the superior frontal sulcus and the SP merge on the surface of the brain. However, a clear separation can be established in 72% of cases by analyzing the morphology of the depth of this region in serial sections. Two or three small sulci can be identified in the area between the SP and the midline: the medial precentral sulcus, the marginal precentral sulcus, and a paramidline sulcus. The IP is composed of three different parts: a dorsal and a ventral branch, both oriented vertically, and a short horizontal extension. The ventral branch forms the caudal border of the inferior frontal gyrus, the dorsal branch forms the caudal border of the ventral portion of the middle frontal gyrus, and the horizontal extension runs in a rostrodorsal direction into the middle frontal gyrus. These three structures are closely related to each other but can, in most cases, be separated in the depth of the inferior precentral sulcal complex.
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 | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.004 | 0.003 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| 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".