Relationship Between Membrane Potential Oscillations and Rhythmic Discharges in Identified Hippocampal Theta-Related Cells
Bibliographic record
Abstract
Intracellular recordings of cells, classified according to the criteria of Colom and Bland as phasic theta-ON or phasic theta-OFF cells, were carried out in the dorsal region of the hippocampal formation in urethan-anesthetized rats. Cells were studied during two spontaneously occurring hippocampal field conditions, asynchrony, termed large-amplitude irregular activity, and synchrony, termed theta. During the spontaneous cycling between these two field states, the effect of four levels of intracellular depolarizing and hyperpolarizing constant current injections on the amplitude and phase of membrane potential oscillations (MPOs) and the rate and pattern of cell discharges was assessed. Labeled CA1 pyramidal cells and bistratified cells met the criteria for classification as phasic theta-ON cells and labeled CA1 pyramidal layer basket cells, mossy hilar cells, and granule cells met the criteria for classification as phasic theta-OFF cells. MPOs were recorded in CA1 pyramidal cells, CA1 layer basket cells, mossy interneurons, and granule cells only during theta field activity, their onset in theta-ON cells signaled by a depolarizing shift of 5-10 mV and in theta-OFF cells by a hyperpolarizing shift of 5-10 mV, in membrane potential. The effect of current injections in phasic theta-ON and theta-OFF cells during the theta field condition revealed that MPO amplitude was voltage dependent and frequency was voltage independent. There were no phase changes observed in phasic theta-ON cells during current injections; however, amplitude analysis revealed an inverted U-shaped curve asymmetrically distributed around the average value of the membrane potential occurring during the spontaneous theta (no current) control condition. The occurrence and rate of rhythmical cell discharges in CA1 pyramidal phasic theta-ON cells during the theta condition was precisely controlled within a critical range of membrane potential values from approximately -57 to -68 mV, corresponding to a range of MPO amplitudes of approximately 4-7 mV. Outside the critical range, rhythmic cell discharges were abolished. Membrane potential oscillations in CA1 pyramidal layer basket cells underwent an approximate 180 degrees phase reversal when the membrane potential was depolarized above -65 mV. The occurrence and rate of rhythmic cell discharges in CA1 pyramidal layer basket cell phasic theta-OFF cells during the theta condition was precisely controlled within a critical range of membrane potential values from approximately -62 to -60 mV, corresponding to a range of MPO amplitudes of approximately 7-7.5 mV. Outside the critical range, cell discharges were absent or occurred singly.
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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 | 0.001 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".