Life and Cognition without Cortex
Published in In Prep, 2025
Recommended citation: **Zheng, J.**, Turan, Z., Sadorf, K., and Meister, M. (In Prep). Life without Cortex
Talks and presentations
SfN 2025 Cognition Without Cortex: Rapid Learning, Generalization, and Long-Term Memory in Acortical Mice
I’ll present the latest progress about the acortical mice at the SfN 2025 meeting. This is funded by the Trainee Professional Development Award (TPDA) and the Chen Institute Travel Aaward.
Presentation time: (1) Sat. Nov. 15 Early-career presentation (2) Wed. Nov. 19 Session Animal Navigation
Abstract
In humans, the neocortex and hippocampus are central to memory, learning, and cognitive flexibility. To test whether these structures are similarly essential for rodent cognition, we studied an “acortical” mouse mutant born without the dorsal forebrain, lacking hippocampus and most of the neocortex. We tested these mice in two maze tasks: a complex binary-choice labyrinth and a massively reconfigurable arena called the Manhattan Maze. We probed four phases of learning across increasing timescales: exploration leading to reward discovery, rapid learning of anoptimal route, long-term memory of the same environment, and generalization to novel mazes.
Surprisingly, acortical mice were impaired only during the early training and exploration phase but retained other learning capacities. Despite delayed discovery of the reward location in the maze (~3× slower than controls), they exhibited one-shot learning of a short route to the reward, comparable to normal mice. They also rapidly obtained rewards when revisiting the same maze configurations after weeks-long and even months-long gaps. After learning the first maze, they solved new configurations more efficiently, generalizing across both acyclic and cyclic graph structures.
Together, these results show that the absence of cortex and hippocampus in the acortical mice slows the initial phase of exploration leading to a solution, but does not interfere with rapid exploitation of that solution, long-term memory, or generalization across similar tasks in the long run. We highlight the potential of subcortical circuits to support complex spatial cognition in mice, and suggest a more limited and specific role for the mouse hippocampus in the process of learning.
Poster and talk info will be posted closer to the meeting.