La Torre, J. C. 1968. Effect of differential environmental enrichment on brain weight and on acetylcholinesterase and cholinesterase activities in mice. Experimental Neurology 22, 493-503.

Two inbred strains of mice were used in a replication of the Berkeley rat studies on the cerebral effects of differential environmental enrichment. Those raised in a complex environment and given extensive maze training showed significantly heavier brain weights and higher total AChE and ChE activities than mice raised in isolation. The enriched animals also showed a greater ratio of cortical to subcortical weight. These results corroborated the rat experiments. Significant strain differences were also found.Full-size image (<1 K)mice showed heavier weights and higher total enzyme activities in the subcortex and ventral cortex than didFull-size image (<1 K)mice, while the opposite was true in some other regions of the cortex. Specific AChE and ChE activities were greater for theFull-size image (<1 K)mice throughout the brain.