Age-related reduction of hemispheric asymmetry by pigeons: A behavioral and FDG-PET imaging investigation of visual discrimination.
Bibliographic record
Abstract
Pigeons are long-lived and slowly aging animals that present a distinct opportunity to further our understanding of age-related brain changes. Generally, for pigeons, the left hemisphere contributes to discrimination of local information, whereas the right contributes to processing of global information. The function of each hemisphere may be examined by covering one eye, as the optic nerves decussate almost completely in birds, directing the majority of visual information to the contralateral hemisphere. Using this eye-capping technique, we investigated pigeons' ability to select grains from among grit while under binocular and monocular viewing conditions, across three different age groups. Prior to the grit-grain discrimination task, pigeons were injected with a radioactive tracer, which was taken up by the brain as the pigeons performed the task. Upon completion of the discrimination task, the pigeons' brains were imaged via [18F] fluorodeoxyglucose positron emission tomography (FDG-PET) scans. This process allowed us to compare hemispheric activity during the discrimination task for each individual within each age group. The Very Old subjects showed significantly worse discrimination performance compared to the Adult and Old subjects, particularly when needing to search primarily with their right hemisphere. Furthermore, the Very Old subjects did not show differences in hemispheric activation when performing the task, whereas the left hemisphere was most active for the Adult and Old groups. To our knowledge, this is the first study to use FDG-PET imaging to evaluate whether the pigeon brain shows evidence of age-related reduction in hemispheric asymmetry during a visual discrimination task.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| 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".