The psychiatric aspects of oculogyric crises occurring in post-encephalitic Parkinsonism are considered as dissociation phenomena. As demonstrated in three representative cases, the symptomatology follows the pattern usually seen in the neuroses and psychoses. Regression, symbolic representation and projection mechanisms in these cases are intimately bound to a motility disorder characteristically affecting the conjugate movements of the eyes. Designation of oculogyric crises as a motility disorder permits a consideration of their psychopathology as paracortical disturbances. The psychopathological configurations that are reactivated en bloc during ocular spasm are discussed as dissociated unit structures possessing definite psychomotor identity. As such, they may be termed unit reaction states. Unit reaction states are represented as physiological dissociations, delineating specific elements of ideation, emotion and motility.