Scientists at the Howard Hughes Institute have stated that individual excitation of some neurons is sufficient to cause changes in behavior or learning. So far it was thought that thousands of neurons were needed to cause a behavioral reaction. To reach this conclusion, the neurons of rodents have been analyzed.
In a study with rats, researchers have used an individual excitation technique of neurons. The aim was for rats to follow a certain behavior after stimulation. The results obtained depend on the excited neuron. Some neurons only affect 5% and some affect 50%.
In another study with mice, neurons have not been excited individually, but in small groups. Researchers have found that excitation of small groups of less than 60 neurons can influence the behavior of mice.