The provided code snippet appears to be part of a computational neuroscience model concerning spatial representation and navigation, which are crucial aspects of understanding how animals, particularly mammals, navigate their environments. Here are the key biological concepts that the code likely relates to: ### Biological Basis 1. **Spatial Navigation and Representation:** - The code involves calculating the displacement of a trajectory's center, which suggests it's part of modeling an organism's navigation within a defined space or arena. This type of modeling is common in studies of spatial memory and cognitive maps, which are often represented through neural circuits in the brain, particularly the hippocampus and associated structures. 2. **Hippocampal Function:** - The hippocampus is heavily involved in spatial memory and navigation. It is known to contain 'place cells,' which become active when an animal is in a particular location in space. This model might attempt to mimic or analyze the behavior of these cells by assessing trajectories, possibly representing paths taken by an animal or gaze patterns. 3. **Normalized Displacement:** - The concept of "trajectory_centre_displacement" likely relates to measuring how far an animal's traversed path is from a central reference point. This measurement's normalization by dividing it by a constant (`g_config.ARENA_R`) suggests that the model is examining the trajectory within a bounded area, akin to experimental setups in animal navigation studies, such as the Morris water maze or open field tests. 4. **Arena and Experiment Design:** - In biological experiments, especially those involving rodents, a circular or otherwise defined arena is often used to study navigational behavior. The code's use of parameters like `CENTRE_X`, `CENTRE_Y`, and `ARENA_R` indicates that this computational model simulates such an experimental environment. This involves a setup where an animal's path is tracked, and deviations from the center can indicate aspects of exploratory behavior or spatial learning effectiveness. ### Conclusion Overall, the function is working to quantify how effectively an animal (or a model representing an animal) explores or navigates a given environment by calculating its trajectory in terms of displacement from a center point. This aligns with the biological study of how spatial information is encoded and processed within the brain, particularly regarding the roles of hippocampal and related neural structures involved in spatial cognition.