Medial vs lateral frontal lobe lesions and differential impairment of central-gaze fixation maintenance in man.

摘要: SUMMARY The ability to maintain central-gaze fixation was studied in 35 patients with unilateral frontal lobe lesions. The stability of tested 2 oculomotor tasks requiring the suppression reflexive saccades triggered by sudden appearance novel, peripheral visual stimuli. In first task(‘Instructed’), maintenance gaze based on verbal instruction, whereas, second task (‘Non-instructed’), it upon a foveating mechanism maintained sensory stimulation during performance categorization task. Patients lesions were classified into 3 groups: ventrolateral ( n = 18), dorsolateral 10) and medial 7) group. control group consisted 20 healthy subjects. Non-instructed task, no differences found rate saccades. Thus, did not affect reactivity extraneous stimuli per se . only exception this rule left lobe, which higher number directed contralateral hemifield observed. Instructed different patterns deficit found. First, bidirectional noted group, might be attributed an impairment either maintaining selected program behaviour ‘on-line’ or suppressing inappropriate alternatives interfering that program. Second, unidirectional voluntary from within observed It is suggested type may reflect malfunctioning supplementary motor area-anterior cingulate system involved externally programs. Finally, significant