Freund Hans-Joachim
Department of Neurology, University of Dusseldorf, Moorenstrasse 5, Dusseldorf, Germany.
Adv Neurol. 2003;93:179-93.
Lesion studies show that a wide range of integrative sensorimotor functions can be selectively disturbed in patients with parietal lobe damage. Lesions restricted to the somatosensory representations on the anterior parietal lobe produce somatosensory deficits that resemble deafferentated states, including the secondary effects on motor control. Slightly more posterior lesions often are associated with impairment of more complex synthetic somatosensory functions similar to those observed after dorsal column lesions. Damage of the posterior parietal lobe can selectively interfere with virtually every aspect of somatosensory function. These perceptive and cognitive disturbances may or may not be associated with complex motor disturbances of the apractic type. The frequent association of astereognosia and tactile apraxia illustrate the mutual interdependence of the sensorimotor processes involved in active touch and the proximity of the respective processing modules. Parietal lobe function is critical for the control of force and posture, and for the formation of the body image and its relation to external space (the guidance of movements, including the eyes, to external objects). Imaging studies underscore the prominent role of the parietal cortex as a sensorimotor interface and provide complementary information about the interrelationship between perception and action. Action observation activates premotor cortex, but parietal cortex is also recruited whenever an action involves objects, thus emphasizing the significance of parietal cortex for object-directed motor behavior. In contrast to the ventral-dorsal route processing dichotomy in the visual system, both the perceptual-cognitive and motor aspects of somatosensory processing are compromised after parietal damage, demonstrating a different functional architecture of the two sensory systems. The preservation of the comprehension of the meaning of gestures or of object use in patients with lesions restricted to the parietal lobe reveals that the semantic aspects of motor behavior are mediated in the temporal lobe.
病灶研究表明，顶叶损伤患者的多种整合性感觉运动功能可能会受到选择性干扰。局限于顶叶前部躯体感觉代表区的病灶会产生类似于去传入状态的躯体感觉缺陷，包括对运动控制的继发影响。稍微靠后的病灶通常与更复杂的综合性躯体感觉功能受损有关，类似于在背柱损伤后观察到的情况。顶叶后部的损伤可选择性地干扰躯体感觉功能的几乎每个方面。这些感知和认知障碍可能与失用型复杂运动障碍有关，也可能无关。实体觉失认和触觉失用的频繁关联说明了主动触摸中涉及的感觉运动过程的相互依存性以及各个处理模块的接近性。顶叶功能对于力量和姿势的控制、身体形象的形成及其与外部空间的关系（包括眼睛向外部物体的运动引导）至关重要。成像研究强调了顶叶皮层作为感觉运动接口的突出作用，并提供了关于感知与行动之间相互关系的补充信息。动作观察会激活运动前皮层，但每当动作涉及物体时，顶叶皮层也会被激活，从而强调了顶叶皮层对目标导向运动行为的重要性。与视觉系统中腹侧 - 背侧通路处理二分法不同，顶叶损伤后躯体感觉处理的感知 - 认知和运动方面都会受到损害，这表明两个感觉系统的功能结构不同。局限于顶叶的病灶患者对手势或物体使用意义的理解得以保留，这表明运动行为的语义方面是在颞叶中介导的。
