Bart - Thermosensation Flashcards
What is cold trapping, and how does it affect
Drosophila’s movement in a temperature gradient?
Cold trapping occurs when a poikilothermic animal like Drosophila becomes trapped in a cold region of a gradient because its metabolism slows down, making it difficult for the fly to move away from the cold environment.
How does Drosophila’s poikilothermic nature influence its behaviour in varying temperatures?
As a poikilothermic organism, Drosophila’s body temperature and movement are heavily influenced by the surrounding ambient temperature. Colder temperatures slow its metabolism, leading to reduced activity, while warmer temperatures increase its metabolic rate and movement speed.
Why is it important to link physiological data with behavioural outcomes in experiments?
Linking physiological data with behaviour is crucial because it shows how changes observed at the cellular or neuronal level affect the animal’s overall behaviour. This ensures that physiological findings have real-world relevance for the animal’s actions.
What is ΔF/F, and why is it used in calcium imaging?
ΔF/F (delta F over F) is a method used in calcium imaging to normalize fluorescence signals, allowing for comparison across different cells, experiments, and tissues. It tracks the relative change in fluorescence over time, reflecting neuronal activity.
How does rearing temperature influence Drosophila’s thermal tolerance and performance?
Rearing temperature significantly affects thermal tolerance. Flies reared at colder temperatures (18°C) show better cold tolerance, while those reared at 30°C are in poorer physiological condition due to the risk of desiccation and other stressors.
What does the term “null model” refer to in thermal gradient experiments with Drosophila?
A null model in thermal gradient experiments refers to the behaviour that would be expected if an animal had no temperature sensation. In this case, the animal would move randomly within the gradient, showing no preference for any particular temperature.
How do hot and cold cells in Drosophila respond to changes in temperature?
Hot cells depolarize when the temperature increases and hyperpolarize when it decreases, while cold cells show the opposite response—depolarizing when the temperature drops and hyperpolarizing when it rises.
Why is a simple thermodynamic conduction model used to estimate the fly’s body temperature during movement?
A thermodynamic conduction model is used to estimate the fly’s body temperature (TB) as it moves through different environments. This model accounts for the heat exchange between the fly and its surroundings, providing a more accurate representation of body temperature changes over time.
How does the null model help in identifying Drosophila’s temperature preferences and avoidances?
The null model helps identify temperature preferences and avoidances by serving as a baseline for random behaviour. When subtracted from the actual data, it highlights where Drosophila is actively choosing or avoiding specific temperatures.
Why is cold avoidance stronger than hot avoidance in Drosophila according to the temperature histogram analysis?
Cold avoidance is stronger than hot avoidance in Drosophila because the fly is cold trapped at the cold end, and our model might overestimate the cold avoidance through this process.
