The provided code snippet models aspects of spatial navigation and orientation in the brain, specifically focusing on the role of landmark cells within the hippocampus. Here's the biological foundation underlying the code: ### Biological Concepts Modeled 1. **Hippocampus and Spatial Navigation:** - The hippocampus is a critical brain region involved in spatial memory and navigation. It helps animals, including humans, orient themselves in their environment using both external cues and internal representations. 2. **Landmark Cells:** - Landmark cells, like other spatially-tuned neurons such as place cells and grid cells, are thought to encode information about specific locations or features in the environment relative to an organism. - These cells are hypothesized to respond to visible or identifiable features—landmarks—in the environment, aiding in navigation and memory. 3. **Orientation and Movement:** - The model aims to simulate how organisms determine direction based on orientation and landmarks, a process that is crucial for path integration and goal-directed navigation. - The use of orientation angles suggests that directional information is encoded and processed, which is a function linked to head direction cells, helping the organism maintain a sense of direction. ### Key Code Aspects with Biological Relevance - **HexWaterMaze Environment:** - The HexWaterMaze is likely a virtual simulation of a complex environment where spatial navigation can be tested. This can be likened to experimental setups such as the Morris Water Maze used in animal studies to investigate spatial learning and memory. - **Angle to Landmark:** - The function `angle_to_landmark` likely calculates the relative angle between an organism's current orientation and a landmark. This computation is essential for tasks where navigation requires assessing the spatial relationship between the navigator and the environment. - **Response Computation:** - `LandmarkCells` and their `compute_response` function model neural activity based on spatial inputs, simulating how neurons might fire when certain environmental configurations are present. - By plotting responses across orientation angles, the model may reflect the tuning curves of landmark cells, demonstrating how these cells respond optimally to certain landmarks based on the navigator's angle of approach. In summary, the code represents a computational effort to mimic biological processes underlying spatial navigation in the brain, specifically focusing on how landmark cells in the hippocampus might contribute to this complex behavior by encoding directional information relative to environmental landmarks.