The Complicity of GABAergic Neurotransmission in Ictogenesis during Acute Hyperexcitabilty
Bibliographic record
Abstract
The observations of GABAergic interneurons leading the transition into seizure events is antithetical to the current framework that seizures (“ictogenesis”) manifest from excessive excitation in the brain. This study utilized optogenetic tools to investigate the paradoxical role of interneurons in mediating ictogenesis in the in vitro cortical 4-AP seizure model. It was discovered that the brief activation of GABAergic interneurons can reliably initiate ictal events in an all-or-none fashion. It was discovered that GABA-initiated ictal events were dependent on bicarbonate, likely for efflux via GABAA receptors to mediate synaptic depolarization. It was also discovered that there are multiple mechanisms to ictogenesis, co-existing at different orders of preference, in the same brain tissue. A secondary pathway to ictogenesis was dependent on K-Cl Co-transporter 2 (KCC2) activity, likely for its role in extracellular potassium accumulation which can non-synaptically depolarize surrounding neurons. Accordingly, the partial downregulation of KCC2 and carbonic anhydrase (to reduce bicarbonate regeneration) reliably thwarted ictogenesis, and most remarkably, completely restored normal activity in the in vitro 4-AP seizure model. Collectively, these findings suggest that ictogenesis can manifest from the pathologically heightened activity of GABAergic interneurons because they activate downstream GABAA receptors in parallel and cause excessive ion fluxes that result in EGABA breakdown (loss of GABA-mediated hyperpolarization) on the post-synaptic neuron. During EGABA breakdown, the subsequent activation of GABAA receptors can mediate depolarization, synaptically and non-synaptically, via downstream carbonic anhydrase and KCC2 activity. This effectively converts intrinsic feedback inhibition circuits into feedforward excitation circuits, facilitating ictogenesis. In summary, the findings in this thesis demonstrate that GABAergic interneurons are complicit in mediating ictogenesis during acute hyperexcitable conditions, such as some cases of drug-induced seizures.
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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 | 0.001 |
| 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 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".