The change of the free aminoacids in the cat-brains treated repeatedly by electric shocks was in vestigated. Both the systems of glutamic acid→γ-aminobutyric acid and glutamic acid→glutamine were influenced by the treatment. Especially the change in the former proved more remarkable than in the latter. In other words, glutamic acid decarboxylase has been activated and in the latter system, glutamine, has been formulated, though in a slight degree. These facts are considered to show certain rise in the brain function as results of E. C. T.