Mice in the Manhattan Maze

Overview

What is intelligence, and how does the brain create it? The neural basis of intelligent behaviors remains one of the biggest mysteries in science. Evolution leaves clues in model organisms. This project seeks to uncover in laboratory mice conserved principles underlying complex cognition. The Manhattan Maze is a reconfigurable arena that allows systematic task designs in a vast space of 2¹²¹ possible maps. Completely naive wildtype mice quickly learned to navigate their first map in about 10 round trips, retained overnight memory of the same map, and accelerated learning in new configurations. I also tested acortical mice, a structural mutant born without both the hippocampus and neocortex. Surprisingly, despite delayed discovery of the reward location in the maze, about 3 times slower than controls, the acortical mice shortened their routes in one shot. They remembered the same configurations after even months-long gaps. Together, these results show that the absence of cortex and hippocampus slows the initial phase of exploration leading to a solution, but does not interfere with exploitation of that solution, long-term memory, or generalization across similar tasks in the long run.