“A Cellular Basis for Mapping Behavioral Structure”, 2023-11-05 ():
[Twitter] To flexibly adapt to new situations, our brains must understand the regularities in the world, but also in our own patterns of behavior. A wealth of findings is beginning to reveal the algorithms we use to map the outside world[1-6]. In contrast, the biological algorithms that map the complex structured behaviors we compose to reach our goals remain enigmatic.
Here we reveal a neuronal implementation of an algorithm for mapping abstract behavioral structure and transferring it to new scenarios. We trained mice on many tasks which shared a common structure organizing a sequence of goals, but differed in the specific goal locations. Animals discovered the underlying task structure, enabling zero-shot inferences on the first trial of new tasks.
The activity of most neurons in the medial Frontal cortex tiled progress-to-goal, akin to how place cells map physical space. These “goal-progress cells” generalized, stretching and compressing their tiling to accommodate different goal distances. In contrast, progress along the overall sequence of goals was not encoded explicitly.
Instead, a subset of goal-progress cells was further tuned such that individual neurons fired with a fixed task-lag from a particular behavioral step. Together these cells implemented an algorithm that instantaneously encoded the entire sequence of future behavioral steps, and whose dynamics automatically retrieved the appropriate action at each step.
These dynamics mirrored the abstract task structure both on-task and during offline sleep. Our findings suggest that goal-progress cells in the medial frontal cortex may be elemental building blocks of schemata that can be sculpted to represent complex behavioral structures.