Behavioral and Electromyographic Characterization of Mice Lacking EphA4 Receptors
Bibliographic record
Abstract
EphA4 receptors play an important role in axon guidance during development. Disrupting the expression of these receptors in mice has been shown to modify neuronal connections in the spinal cord and results in the production of a characteristic hopping gait. The EphA4-null mouse has been used in numerous investigations aimed at establishing mechanisms responsible for patterning motor activity during walking. However, there have been no detailed behavioral or electrophysiological studies on adult EphA4-null mice. We used high-speed video recordings to determine the coordination of leg movements during locomotion in adult EphA4-null mice. Our data show that the hopping movements of the hind legs are not always associated with synchronous movements of forelegs. The coupling between the forelegs is weak, resulting in changes in their phase relationship from step to step. The synchronous coordination of the hind legs can switch to an alternating pattern for a short period of time during recovery from isoflurane anesthesia. Comparison of the kinematics of hind leg movements in EphA4-null mice and wild-type animals shows that besides the synchronous coordination in EphA4-null mice, the swing durations and the swing amplitude are shorter. Electromyographic recordings from a knee extensor muscle show double bursting in the EphA4-null animals but single bursts in wild types. This double burst changes to single-burst activity during swimming and when hind legs are stepping in alternation. These observations suggest an influence of sensory feedback in shaping the pattern of muscle activity during locomotion in the mutant animals. Our data give the first detailed description of the locomotor behavior of an adult mouse with genetically manipulated spinal networks.
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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 | 0.000 |
| 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 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".