Drugs and Mental Exercises Enhance Recovery of Lost Memories in Mice

A team from MIT developed a transgenic mouse in which the gene encoding a protein important in various neurodegenerative diseases could be turned on at will. Turning on the gene for 6 weeks in adult mice led to neuronal and synaptic loss in the forebrain, resulting in impaired spatial learning.

Exposing the mice to a program of environmental enrichment — exposure to new experiences that required learning — improved spatial learning. Interestingly, the number of neurons was not increased, but the number of dendrites sprouting from each neuron (and, hence, the number of synaptic connections to other neurons) was greatly increased. Moreover, the increased number of synapses correlated with increased histone acetylation — an event that activates…