Comparison of hippocampal neuron spine densities in acute and perfusion‐fixed slices using the lipophilic dye DiI
Bibliographic record
Abstract
The hippocampus is a key brain structure involved in learning and memory. Hippocampal acute slices are widely used in ex vivo electrophysiological experiments to study cellular mechanisms of synaptic transmission and plasticity. Many approaches have been used to optimize slice viability and to maintain accurate in vivo physiological conditions during experimental procedures. Several different variables such as the age of the animal, the composition of the artificial cerebrospinal fluid (aCSF), the maintenance conditions in recording chambers, temperature and slice cutting methodology, among others, can affect hippocampal slices features. Specifically, by using electron microscopy and two‐photon microscopy it has been previously reported that dendritic spines, crucial neuronal structures that receive most of the excitatory synaptic inputs in the brain, show increased numbers in acute hippocampal slices compared to perfusion‐fixed sections. These alterations in dendritic spines could be one of the underlying mechanism explaining differences in ex vivo and in vivo electrophysiological experiments, as for instance success rates in long‐term depression (LTD) induction protocols. In our experiments, we have compared dendritic spine density in the cornu ammonis 1 (CA1) and dentate gyrus (DG) between hippocampal acute slices and aldehyde perfusion‐fixed hippocampi of Sprague‐Dawley (both males and females) using the lipophilic carbocyanine dye 1,1′‐Dioctadecyl‐3,3,3′,3′‐Tetramethylindocarbocyanine Perchlorate (DiI). We observed an increase in a range of 37–68% in dendritic spine density in the acute hippocampal slices when compared to aldehyde perfusion‐fixed sections independent of sex. These data suggest that spine plasticity in ex vivo electrophysiological experiments may not be reflective of the in vivo situation and interpretation of data should take this into account. Support or Funding Information Canadian Institutes of Health Research Natural Sciences and Engineering Research Council This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 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) | 0.001 | 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".