ELECTRICAL MEASUREMENTS OF NEUROMUSCULAR STATES DURING MENTAL ACTIVITIES

Abstract

V. Study of a total of 81 imagination tests with 19 control tests on 5 subjects indicates that imagination of activity of the right arm (or other part) is characterized by contraction of muscle fibers either in that part or in the ocular region or in both localities. This affords further evidence that mental activity is not confined to closed circuits within the brain, but that neuromuscular regions participate. VI. Tests on a subject in whom the arm had been amputated above the elbow joint at the age of 8 (presenting at the age of 40 a stump including the atrophic remnant of the biceps-brachial muscle group), showed that specific muscular imagination or recollection of movements in the amputated part no longer takes place. After repeated observations, the subject reports that his imagination is "shadowy" for movements of the lost part. During such mental activities, contractions (not characteristic in intact individuals) occur in other specific localities, evidently as substitutions. With these substitute contractions (and with visualization or verbalization such as may also occur in the intact), this crippled individual engages in mental activities involving the lost part.