Sailer Uta, Eggert Thomas, Strassnig Martin, Riedel Michael, Straube Andreas
Klinikum Grosshadern, Dept. of Neurology, Ludwig-Maximilians University, Marchioninistr. 23, 81377 Munich, Germany.
Eur Arch Psychiatry Clin Neurosci. 2007 Oct;257(7):413-22. doi: 10.1007/s00406-007-0749-8.
Schizophrenic patients are known to have problems suppressing reflexive eye movements. This is considered to indicate a dysfunction in prefrontal cortex. As the eye and hand motor systems are tightly coupled, we investigated whether predictive hand movements and eye-hand coordination are unimpaired in schizophrenic patients.
Saccades and hand movements of 19 patients during an acute schizophrenic episode and 19 controls were measured in a task in which the predictability of target timing was varied.
Schizophrenic patients generated more anticipatory and less visually triggered saccades than controls with both non-predictable and predictable target timing. Anticipatory saccades in the wrong direction were clearly directed towards previous target positions, indicating that they are indicators of erroneous prediction rather than of fixation instability. In contrast to saccades, the number of anticipatory and visually triggered hand movements was the same in patients as in controls. As a consequence, patients took longer to initiate a hand movement after a saccade than controls.
Schizophrenic patients show increased predictive saccadic activity, but no qualitative changes in predictive saccades. Since prediction itself was not disturbed, the patients' deficit rather lies in the suppression or gating of anticipatory saccades than in their generation. This may be explained by a selective dysfunction of the basal ganglia oculomotor loop. As predictive hand movements were unimpaired, the problems in eye-hand coordination as expressed by a longer initiation time of hand movements relative to saccades are a direct consequence of impaired predictive saccadic behaviour.
已知精神分裂症患者在抑制反射性眼球运动方面存在问题。这被认为表明前额叶皮质功能障碍。由于眼睛和手部运动系统紧密耦合，我们研究了精神分裂症患者的预测性手部运动和眼手协调是否未受损害。
在一项目标时间可预测性不同的任务中，测量了19名急性精神分裂症发作期患者和19名对照者的扫视运动和手部运动。
在目标时间不可预测和可预测的情况下，精神分裂症患者比对照者产生更多的预期性扫视运动，而视觉触发的扫视运动更少。错误方向的预期性扫视运动明显指向先前的目标位置，表明它们是错误预测的指标，而非注视不稳定的指标。与扫视运动不同，患者预期性和视觉触发的手部运动数量与对照者相同。因此，患者在扫视运动后启动手部运动的时间比对照者更长。
精神分裂症患者表现出预测性扫视活动增加，但预测性扫视运动没有质的变化。由于预测本身未受干扰，患者的缺陷在于抑制或控制预期性扫视运动，而非产生这些运动。这可能由基底神经节动眼神经环路的选择性功能障碍来解释。由于预测性手部运动未受损害，相对于扫视运动，手部运动启动时间延长所表现出的眼手协调问题是预测性扫视行为受损的直接后果。
