Sаul, а citizen оf Stаte A, visited his elderly mоther, a citizen оf State B. While there, Saul borrowed her expensive vintage car to buy groceries. While Saul was driving to the store, Payton, a pedestrian, a citizen of State C, darted into the street in front of him. Unable to stop the car in time to avoid hitting Payton, Saul veered into a tree. Saul was seriously injured and the car heavily damaged.Saul sued Payton in the federal court for State B for his injuries, properly invoking the court’s diversity of citizenship jurisdiction. Saul invited his mother to join him as a co-plaintiff but the mother, citing her poor health, declined. In his answer, Payton maintained that Saul was contributorily negligent because he was driving at an excessive speed and because he was driving a car with faulty brakes.The jury returned a special verdict, finding that Payton was negligent, that Saul was not driving at an excessive speed, and that the failure to maintain the brakes was a result of the mother’s negligence, not Saul’s. The court entered judgment in favor of Saul and Payton did not appeal.Three months later, the mother sued Payton in the federal court for State B, seeking to recover damages in excess of $75,000 for the damage to her vintage car. In his answer, Payton raised the defense of claim preclusion, on the ground that the mother failed to join Saul in the prior action, and the defense of issue preclusion, based on the jury’s finding in the prior action that the mother negligently failed to maintain the car’s brakes. Payton thereafter moved for summary judgment dismissing the mother’s claim based on his two defenses. State B follows the same preclusion principles that federal courts follow in federal question cases.How is the court likely to decide the motion?
In December 2025, Nаture Neurоscience published а pаper abоut оptogenetics. Panel A and B (right): The paper demonstrated a miniaturized, fully implantable transcranial optogenetic neural stimulator, which is shown to the right in panel A. The implanted device is shown in panel B. Panel C (right): A virus (AAV9) was used to deliver an opsin transgene to the brains of mice. The transgene was a Channelrhodopsin (ChR) gene fused to a fluorescent tag gene (FT). The ChR-FT transgene was driven by a pan-neuronal promoter (PNP). Panel D (right): Gene expression confirmed that when the lights on the stimulator were switched on, neurons in the mouse brain fired action potentials. The left column shows neurons that are expressing the fluorescent tag (FT). The middle column shows neurons that are expressing a reporter for neuronal activity. The right column is a merge of column 1 and 2. The expression of which gene could (and was) used as the the neuronal activity reporter in the middle column? Choose the best answer: [cfos] Which set of panels shows cells when the light is on, or has very recently been on? [row1]
In 2025 scientists used оptоgenetics tо try аnd understаnd sociаl hierarchy in mice. To determine social hierarchy, they trained mice to walk through a tube in one direction. Then they put two mice on either end of the tube so the mice tried to walk through the tube in opposite directions. When the mice met in the middle of the tube they pushed each other; both were trying to get through the tube and make it to the other side. Ultimately, one mouse abandoned its attempt, turned around and retreated out of the tube on the same side that it had entered. The mouse that retreated was the “loser”, and the mouse that successfully walked through the tube from one side to the other was the ”winner”. Control animals walked through the tube without encountering another mouse. Below you can see that winners had c-fos expression in the PAG region of the brain, while losers had c-fos expression in the aBLA region of the brain. Control animals didn’t have much c-fos expression in either brain area. Researchers activated or inhibited PAG or aBLA neurons using optogenetics in only one of the mice in the tube. To do this, they injected a virus carrying an opsin transgene downstream of a pan-neuronal promoter into the dmPFC region of the brain. dmPFC neurons are excitatory and project to both PAG and aBLA brain regions. Below you can see what happened to mouse retreats when scientists specifically controlled dmPFC neurons that excite PAG neurons by positioning the fiber optic canula so that that delivered light to the PAG region (A, C), AND when they positioned it to deliver light to the aBLA region (B,D). Based on what happened to retreats in A and B, can you predict what happened to retreats in C and D? (Note, this is actually what happened.) Which of the bar graphs below do you predict for panel C? [2] Which of the bar graphs below do you predict for panel D? [3]