Domain: Healthcare — Pathophysiology
Target concept: Morphological changes of neurons under ischemia and hypoxia

Video generation prompt: Incubate the cultured neurons in an oxygen- and glucose-deprived environment for 30 minutes, and observe cell morphology, changes in neurites, and nuclear status under an optical microscope.

Evaluation guide:
(i) Target concept: Acute neuronal injury due to combined oxygen and glucose deprivation.
Minimum mechanism: ATP depletion → Na⁺/K⁺-ATPase failure → loss of membrane potential → Ca²⁺ influx → calpain activation → spectrin cleavage → cytoskeletal disintegration → neurite beading/fragmentation AND caspase-independent chromatin condensation → nuclear pyknosis.
(ii)Storyline: Frame 1–3: Dish with confluent neuron monolayer placed into labeled OGD chamber (sealed, gas inlet visible). Frame 4–6: Chamber remains static; no time-lapse overlay, but environmental cues (e.g., gas flow indicator, label fade-in) imply incubation progress. Frame 7–10: Seamless cut to microscope eyepiece view of *same neuronal field*: initial frame shows healthy morphology (intact neurites, round nuclei); final frames show progressive, synchronous appearance of shrunken somata, beaded/fragmented neurites, and pyknotic nuclei, all within fixed field, same magnification, no perspective shift. Visibility constraint: Only brightfield-compatible features visible (no fluorescence, no stains); all pathology must be resolvable at 20× objective.

Manual:
Experimental Procedure
1. Place the neuron culture dish inside an oxygen-glucose-deprived (OGD) chamber.
2. Seal the chamber and begin the 30-minute OGD incubation.
3. Transfer the dish to an optical microscope for immediate brightfield imaging.
Observation of Experimental Phenomena
- Neuronal somata shrink in size.
- Neurites become beaded and fragmented.
- Nuclei condense into small, dark, pyknotic bodies.
Summary of Experimental Principles
Oxygen-glucose deprivation halts ATP production, so the Na⁺/K⁺-ATPase pump fails and the neuron loses its membrane potential; the resulting Ca²⁺ influx activates calpain, which cleaves the spectrin cytoskeleton and drives neurite beading and fragmentation, while the accompanying K⁺ efflux and cytoskeletal collapse produce the loss of cell volume seen as somal shrinkage, alongside caspase-independent chromatin condensation into pyknotic nuclei.

Prompt Grounding rubric:
level_1: No cultured neuron dish is visible; no OGD setup appears; no optical microscope view is shown; none of the three required elements (the incubation environment, neurite morphology, nuclear status) appear.
level_2: At least one object is present (e.g., a petri dish or a microscope), but the OGD setup itself is missing (no sealed hypoxia chamber, no gas line, no indication the medium is glucose-free); neurites and nuclei are never both visible in the same frame; the sequence of steps is missing or reversed.
level_3: All three core elements appear: a dish with a neuron monolayer, an OGD setup (e.g., a sealed chamber with a labeled gas inlet, or a visible glucose-free/hypoxic-gas indicator), and a microscope view of the cell layer; the incubation is implied by the static sealed-chamber shot; neurites and nuclei are both visible, though the contrast between healthy and injured morphology is not yet distinct.
level_4: Everything required at the 3-point level holds, and additionally the OGD cues are unambiguous (a sealed chamber with a visible gas line and a glucose/oxygen-free label together); the microscope view shows the same field of cells at two points (before and after the incubation is implied to have elapsed, via a cut or split-frame), with neurites and nuclei both visible and co-located within that same field in both views.
level_5: Everything required at the 4-point level holds, and additionally the two microscope views of the same field share identical framing, scale, and focal plane: the first shows intact neurites and round nuclei, the second (after the implied 30-minute OGD incubation) shows shrunken somata, beaded or fragmented neurites, and pyknotic nuclei; no unrelated objects or extra procedural steps appear anywhere in the clip.

Scientific and Causal Correctness rubric:
level_1: The neurons look healthy throughout the clip: no shrinkage, no neurite beading, no nuclear condensation, and no state change of any kind, directly contradicting what ischemic/hypoxic injury should produce.
level_2: Some morphological change happens, but it runs the wrong direction for OGD injury: e.g., the nuclei swell rather than condense, the neurites thicken or extend rather than bead or fragment, or cells detach from the dish en masse without the somata first shrinking; or the changes appear without the OGD setup ever being shown.
level_3: At least one genuine ischemic change is visible: beaded or discontinuous neurites, OR small hyperchromatic (pyknotic) nuclei, OR visibly shrunken somata, but not all three together, and the microscope view never draws any visual link between the change and the preceding OGD incubation.
level_4: All three hallmark changes co-occur in the same field of neurons after the OGD setup has been shown: neurites are beaded or fragmented, nuclei are small and pyknotic, and somata are visibly shrunken; these only appear following the incubation step, and nothing else in the field (e.g., debris or an air bubble) is mistaken for pathology.
level_5: All three changes appear together throughout the post-incubation field, with no unaffected neurons left in view: neurites show both beading and outright fragmentation, nuclei are pyknotic with chromatin visibly clumped toward the nuclear edge, and somata are shrunken and appear phase-bright against the background, a morphology fully consistent with 30 minutes of combined oxygen-glucose deprivation.

Spatiotemporal Consistency rubric:
level_1: Severe break in continuity: the neuron field jumps to a different location between frames; the culture dish changes position abruptly; the microscope view suddenly swings from the cell layer to an unrelated area (e.g., the ceiling or an empty background); the lighting flips discontinuously from dark to fully lit within a single frame; a neurite vanishes mid-segment and then reappears unchanged.
level_2: Several moderate breaks appear together: the cut from the chamber setup to the microscope view lands on a visibly different dish, cell density, or field than what was shown being placed in the chamber; the same neuron or nucleus appears twice in the same frame; the lighting flickers repeatedly or casts a shadow inconsistent with any visible light source; neurites move in a jerky, physically implausible way inconsistent with static cells under a microscope.
level_3: Small flaws are present but continuity holds overall: a slight drift of the camera during the otherwise static chamber shot; brief refocusing (blurring in and out) during the microscope view; the neuron field, dish, and chamber keep the same relative arrangement to one another throughout; neurites and nuclei stay traceable and coherent from frame to frame.
level_4: No breaks in continuity are detectable: the microscope's field of view stays fixed on the same group of neurons throughout; the lighting stays even and physically plausible with no unexplained flicker; no neuron, nucleus, or neurite duplicates, teleports, or vanishes; every neurite that starts a frame intact stays traceable as it beads or fragments, with no segment disappearing outright; nuclei stay inside their somata at all times.
level_5: No continuity flaws of any kind: the same neuronal field stays framed, focused, and evenly lit from the first frame to the last with no detectable jitter or drift of the dish, chamber, or cells; magnification and depth of focus never noticeably change; there is no motion blur, since the cells and dish are not supposed to be moving; the dish, chamber, and microscope components never shift relative to one another.