[Gamma rigidity in parkinsonism].

The paper presents the results of the study on a muscle tension in patients with parkinsonism. The great role in the maintenance of the motor tonic activity in parkinsonism is played by an increased excitability (of a static type) of the receptors of the muscle length. The assumption is made that an increased sensitivity in these receptors is the result of the increased fusiomotor activity. The author discusses a possibility of changes in the structure of intrafusal fibres in spindles of the muscle due to which these receptors can preserve an excited state for a long time.