Experimental studies on the relationship between brain pathology and abnormal motor behavior

通过严格的心理学实验，客观地描述了异常运动行为的临床表现。以下是根据这些临床表现与MRI.1病变分析结果之间的关系而得出的发现。后关联区运动行为异常后关联区被认为是视觉、躯体感觉和听觉相互交叉并进一步整合以完成复杂功能的场所。结果发现：(1)后上联结区病变引起单纯失写和躯体感觉障碍，提示该区域可能存在体觉表象；(2)后下联结区病变引起运动性失用和/或概念性失用；(3)后内侧联结区病变引起轴性感觉障碍(两侧楔前周围的病变)或地形性定向障碍(从右侧楔前到扣带回后部的病变)。前额叶病变引起的异常运动行为可导致模仿行为、利用行为、强迫操作工具、异样手征、多写和抓握现象。所有这些都与患者的意图或意愿有关。由于前额叶区域与基底节和边缘系统相连，因此，额叶前部病变有可能产生意向和意志障碍。考虑到前额叶和皮质下结构之间的关系，提出了一个解释实践及其障碍的神经学模型。

Clinical pictures of abnormal motor behavior were described objectively through rigorous psychological experiments. The fo1lowings are the findings based on the relationship between those clinical pictures and results of lesion analysis by MRI.1. Abnormal motor behaviors due to 1esions in posterior association areaPosterior association area is considered as a site where visual, somesthetic, and auditory sensations cross over each other and are further integrated to fulfilll complicated functions. It was found that : (1) Lesion in upper posterior association area causes pure agraphia and somesthetic dyslexia, which suggests that literal somesthetic image may be represented in this area ; (2) Lesion in lower posterior association area causes ideomotor apraxia and/or ideational apraxia ; (3) Lesion in medial posterior association area causes axial sensory disorder (pathology around precuneus on each side) or topographical disorientaton (pathology from right precuneus to posterior region of cingulate gyrus).2. Abnormal motor behaviors due to prefrontal lesionsPrefrontal lesions can cause imitation behavior, utilization behavior, compulsive manipulation of tools, alien hand sign, hypergraphia, and grasping phenomenon. All of these are related to the patient's intention or will. As the prefrontal area is connected to basal ganglia and 1imbic system, it is possible that prefrontal lesions produce disorder of intention and will. Considering the relation between the prefrontal area and the subcortical structures, a neurological model was proposed for explaining praxis and its disorders.