Department of Neurology, University Medical Center Groningen, University of Groningen, The Netherlands.
Cortex. 2011 Nov-Dec;47(10):1160-5. doi: 10.1016/j.cortex.2011.06.011. Epub 2011 Jun 22.
Free will is classically attributed to the prefrontal cortex. In clinical neurology, prefrontal lesions have consistently been shown to cause impairment of internally driven action and increased reflex-like behaviour. Recently, parietal contributions to both free selection at early stages of sensorimotor transformations and perception of specifically self-intended movements were demonstrated in the healthy brain. Such findings generated the concept that 'free will' is not a function restricted to the prefrontal cortex but is more widely embedded in the brain, indeed including the parietal cortex. In this paper, a systematic re-interpretation of parietal symptoms, such as apraxia and reduced sense of agency, is given with reference to the consequences of reduced freedom of selection at early stages of sensorimotor transformation. Failed selection between possible movement options is argued to represent an intrinsic characteristic of apraxia. Paradoxical response facilitation supports this view. Perception of self-intended movement corresponds with a sense of agency. Impaired parietal distinction between predicted and perceived movement sensations may thus equal a restricted repertoire for selection between possible movement options of which intention is attributed to either oneself, others or an alien hand. Sense of agency, and thus perception of free will, logically fits a model of the parietal cortex as a neuronal interface between the internal drive to reach a goal and a body scheme required to select possible effectors for motor preparation.
自由意志经典地归因于前额叶皮层。在临床神经病学中，前额叶损伤一直被证明会导致内部驱动动作的损伤和反射样行为的增加。最近，在健康大脑中，顶叶对感觉运动转换早期的自由选择以及对特定自我意图运动的感知都有贡献。这些发现产生了这样的概念，即“自由意志”不是仅限于前额叶皮层的功能，而是更广泛地嵌入大脑中，实际上包括顶叶皮层。在本文中，参考感觉运动转换早期选择自由度降低的后果，对顶叶症状（如失用症和自我效能感降低）进行了系统的重新解释。在可能的运动选项之间选择失败被认为是失用症的一个内在特征。矛盾反应促进支持了这一观点。对自我意图运动的感知对应于自我效能感。因此，顶叶在预测和感知运动感觉之间的区分受损可能等于对可能的运动选项进行选择的范围有限，而这些运动选项的意图归因于自己、他人或外来的手。自我效能感，因此是自由意志的感知，逻辑上符合顶叶皮层作为内部驱动达到目标与选择运动准备的可能效应器所需的身体图式之间的神经元接口的模型。
