Anisotropic Spread of Cortical Activity in Human Visual Cortex
Bibliographic record
Abstract
A visual stimulus not only evokes spiking activity in neurons whose receptive fields (RFs) are overlapped with the stimulus but also promotes subthreshold activity over an extended cortical region outside the directly stimulated region, known as cortical point spread (PS). Optical imaging studies on animal visual cortex demonstrated that PS is biased to cortical sites whose orientation preferences are similar to stimulus orientation (“co-orientation anisotropy”). Anatomical studies reported also “co-axial anisotropy”, predominant horizontal connections between neurons whose RFs are positioned along the retinotopic axis collinear to their orientation preferences. By conducting fMRI experiments, we observed those two types of anisotropy in PS in early visual areas (V1, V2, V3) of human brains. By defining RFs and stimulus orientation preferences for individual voxels, we could show that PS of fMRI activity that were triggered by a small stimulus at the fovea increased with decreasing angular offset of a given voxel's RF from the axis collinear to stimulus orientation and was strong in voxels whose orientation preferences are similar to stimulus orientation. When anisotropy was probed via traveling waves of PS in a large visual field, we found that the “co-axial anisotropy” was more pronounced in the fovea than in the periphery.
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 | 0.001 | 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) | 0.001 | 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".