The organisation of invertebrate brains: cells, synapses and circuits
Bibliographic record
Abstract
Abstract Meinertzhagen, I.A. 2010. The organisation of invertebrate brains: cells, synapses and circuits. — Acta Zoologica (Stockholm) 91 : 64–71 Invertebrate brains are structurally diverse. Neuron numbers range from ∼10 2 to 10 8 in different groups, compared with larger numbers in vertebrate brains, ∼10 7 to 10 14 . The underpopulated brains of invertebrates are noted in their extreme cases for having few cells, and neurons that can be identified from animal to animal, many known in great detail. Although few in number, invertebrate neurons nevertheless comprise many classes. Correlated with the paucity of their number they are sparsely connected, many having ∼50 synapses or fewer. Synaptic densities, roughly 1 per μm 3 of neuropile, differ little from those for much larger vertebrate neurons. Invertebrate neurons differ from their vertebrate counterparts in the position of their soma, generally in a cortex surrounding the neuropile that consequently occupies a relatively small volume. Their axons typically lack myelin and, supporting a range of conduction velocities, have diameters that differ over a wide range, from 10 3 to 10 −1 μm. Nerves with thousands of axons differ from neuropile fascicles, which typically have 20 or less. Unlike most vertebrate synapses, but like those of the vertebrate retina, synapses in many invertebrate groups – probably all ecdysozoans and possibly some lophotrochozoans – have synaptic contacts with multiple postsynaptic elements, dyads, triads and so on.
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 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 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".