Glutamatergic synaptic transmission participates in generating the hippocampal EEG
Bibliographic record
Abstract
The participation of ionotropic glutamatergic synapses in the generation of hippocampal electroencephalography (EEG) of behaving rats has not been systematically studied. In this study, field potentials in hippocampal CA1 were recorded following injection of N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonists, or vehicle control, either into the lateral ventricles or directly into the hippocampus or the medial septum. Intraventricular (i.c.v.) AMPA receptor antagonist 6,7-dinitroquinoxaline-2,3-dione (DNQX, 5-10 microg) decreased the commissural evoked potential and the amplitude of the hippocampal EEG, including the theta rhythm. Theta frequency was decreased by 10 microg, but not 5 microg DNQX i.c.v. Unilateral intrahippocampal injection of DNQX (5 microg) only decreased the amplitude, but not the frequency, of the theta rhythm near the site of injection, without affecting theta amplitude or frequency at the opposite hippocampus. Other than theta, the large irregular activity (with a delta frequency peak at 1-2 Hz) and gamma EEG (30-100 Hz) were also decreased by i.c.v. and intrahippocampal injections of DNQX. Intrahippocampal injection of NMDA receptor antagonist D-2-amino-5-phosphonovaleric acid (D-APV, 2.5 microg) decreased the amplitude of the theta rhythm and, less consistently, the gamma EEG. The frequency of the theta rhythm and the peak of the commissural evoked potential were not significantly affected by intrahippocampal D-APV injection. Medial septal injections of D-APV or D,L-APV (2.24 microg in 0.4 microl), but not DNQX (10 microg in 0.4 microl), decreased the amplitude of the hippocampal theta significantly, but theta frequency was not significantly affected. It is concluded that both NMDA and AMPA receptors in the hippocampus are involved in generating the amplitude of the hippocampal EEG of theta and gamma frequencies, while NMDA receptors in the medial septum are involved in controlling the amplitude of theta and gamma EEG in the hippocampus. Excitatory glutamatergic synaptic currents, activated by afferents from the entorhinal cortex and CA3, are suggested to participate in hippocampal EEG activities.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".