Sensory pathways in amphioxus larvae II. Dorsal tracts and translumenal cells
Bibliographic record
Abstract
Abstract Serial and interval EM series were used to examine the dorsal nerve tracts in the anterior nerve cord of a 12.5 day larva of Branchiostoma floridae . Fibres within the tracts derive from peripheral sensory cells and a class of intramedullary sensory neurones known as dorsal (Retzius) bipolar cells. Both form repeated synapses of similar type, apparently with the same targets. The synapses occur at points where, at intervals, the tracts expand to form large synaptic zones. The target dendrites, which form complex tangles, belong chiefly to dorsal translumenal cells, a class of neurone distinguished by their apical processes. The latter range from short extensions of the cell apex that contact the opposite side of the cord via junctions, but go no further, to elongate processes with slender branches that project to the contralateral dorsal tract. The morphology indicates that translumenal cells play the same role in amphioxus as internuncial neurones in vertebrate spinal cord. Their axons can be ipsilateral or contralateral; some synapse with motoneurones directly while others innervate other interneurones, including other translumenal cells. From the circuitry, the cells appear to be chiefly involved in integrating sensory input from peripheral mechanoreceptors. This could include acting as a filter that amplifies some input patterns over others, or that normalizes input, so that CNS circuits are not overloaded as new sensory cells differentiate during development. The functional importance of the translumenal system to the organism is reflected in a massive increase in size and cell numbers during the larval phase. The anterior, brain‐like integrative centres of the cerebral vesicle, in contrast, are initially small and change very little.
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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 | 0.000 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 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".