Abstract
As expressed using words such as “break down crying” or “roll with laughter” , crying or laughing is an expression of not only the face but also the feeling with the whole body. In 4 cases of forced laugher accompanied with astasia due to brain stem lesion and 5 cases of “Locked-in” syndrome, forced crying and forced laughter were clinicopathologically examined from the brain stem level.
In an autopsy case of forced laughter, there was a lesion in the pars triangularis of Guillain-Mollaret, containing an element of clonus in the laughter.
In a chronic case of “Locked-in” syndrome, tetraplegia was unchanged but head control, rotation to the gaze direction, anteflexion and retroflexion became possible. In addition, winking, swallowing and yauning were observed and a movement of mimic muscle then appeared, leading to forced crying. These events may be mediated by tectospinal tract. Three factors consisted of confrontation and antagonism existing between pyramidal tract and tectospinal tract in addition to myoclonus due to a lesion in the pars triangularis of Guillain-Mollaret may control the expressions of feeling, consequently giving such expressions as crying, laughing, break down crying, and roll with laughter.
