The neural correlates of the emergence of sleep and waking in chickens
Bibliographic record
Abstract
In adult rodents, wakefulness is sustained by activation in an interconnected set of neuronal populations (the "arousal system"), which includes the orexin, noradrenergic Locus Coeruleus (NA-LC), serotonergic dorsal raphe (5HT-DR) and pontine cholinergic (ChAT-LDT/PPT) neurons. Sleep is supported by activation in various GABAergic neuronal populations, and a lack of activation in the arousal systems. Rapid eye movement (REM) sleep is supported by activation of ChAT-LDT/PPT and melanin-concentrating hormone (MCH) neurons.Birds and mammals show similar sleep and waking states (Lesku and Rattenborg 2014). Chickens are precocial; they develop sleep-like electroencephalographic (EEG) patterns before hatching, and a stable waking state within a few hours after hatching (Mellor and Diesch 2007; Martinez-Gonzalez et al 2012). In order to understand when activation in neuronal populations that regulate sleep and waking becomes coordinated and able to support stable states, I investigated activation of the 5HT-DR and ChAT-LDT/PPT systems in undisturbed chick embryos. The orexin, NA-LC, and MCH systems were previously investigated in the lab. I extended this work into neonatal, posthatched day (P) 1 chicks separated into natural sleep, sleep deprivation, and sleep recovery conditions. cFos was used as a marker of neuronal activation in double-labelling immunofluorescent studies. Activation of 5HT-DR and ChAT-LDT/PPT neurons followed the pattern seen for the other arousal systems and previously studied in the lab: it was low at embryonic day (E) 12 and slowly increased at E16 and E20. Activity of all arousal systems reached their highest activation levels in awake P1 chicks, and were low in both natural and sleep recovery conditions. In the sleep-promoting system, previous work done in the lab had shown that activation of MCH neurons also progressively increased in embryos and reached its highest values at E20. Here, low activation of the MCH system was seen in all P1 conditions. Among neuronal populations, significantly correlated activation was seen only between NA-LC and 5HT-DR cFos expression in embryos, and among most arousal systems at P1.I conclude that the arousal systems become progressively recruited in embryos and become coordinated only after hatching. MCH neurons may be involved in the emergence of REM sleep-like in chick embryos. Absence of activation of the ChAT-LDT/PPT and MCH systems in the sleeping postnatal chicks may be due to the relatively short duration of the sleep episodes studied here.
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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 | 0.000 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 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".