Castiello Umberto, Ansuini Caterina, Bulgheroni Maria, Scaravilli Tomaso, Nicoletti Roberto
Dipartimento di Psicologia Generale, Università di Padova, Via Venezia 8, 35131 Padova, Italy.
Neuropsychologia. 2009 Feb;47(3):835-42. doi: 10.1016/j.neuropsychologia.2008.12.016. Epub 2008 Dec 24.
Evidence exists that action observation activates the same cortical motor areas that are involved in the performance of the observed actions. An untested idea is whether subcortical structures such as the basal ganglia play a role in the coding of other people's actions. This study used kinematics to examine how Parkinson's disease patients react to the observation of an action which they were subsequently requested to perform. In each trial a model and an observer, which could be either a Parkinsonian patient or a neurologically healthy participant, were seated facing each other. The model was requested to grasp a stimulus (action condition), to perform a kicking action towards the stimulus (control-action condition), and to not perform any action (control condition). The task for the observer was always to grasp the stimulus after having watched the model performing her task. Results show that Parkinson's disease patients did show facilitation effects only when the model was a Parkinsonian patient. Whereas, neurologically healthy participants' movements were facilitated following the observation of either the Parkinsonian and the healthy model grasping the object. No facilitation effects were found for both the control and the control-action conditions. The fact that normal visuomotor priming takes place in PD patients when the observed action matches with what they can perform suggests that basal ganglia might not be necessary for it. However, damage to the basal ganglia might become relevant when such a match does not occur. In such circumstances, a damage to these structures might prevent the deployment of additional activity which might be necessary to influence cortical functions related to the representations of observed actions.
有证据表明，动作观察会激活与执行所观察动作相关的相同皮质运动区域。一个未经检验的想法是，诸如基底神经节等皮质下结构是否在对他人动作的编码中发挥作用。本研究运用运动学来考察帕金森病患者对随后要求他们执行的动作观察的反应。在每次试验中，一名示范者和一名观察者（观察者可以是帕金森病患者或神经功能正常的参与者）面对面就座。要求示范者抓取一个刺激物（动作条件），对刺激物执行踢腿动作（对照动作条件），以及不执行任何动作（对照条件）。观察者的任务始终是在观看示范者执行任务后抓取刺激物。结果表明，仅当示范者是帕金森病患者时，帕金森病患者才表现出促进效应。而神经功能正常的参与者在观察帕金森病患者和健康示范者抓取物体后，其动作均得到促进。在对照条件和对照动作条件下均未发现促进效应。当观察到的动作与帕金森病患者能够执行的动作相匹配时，正常的视觉运动启动在帕金森病患者中发生，这一事实表明基底神经节对此可能并非必要。然而，当这种匹配未发生时，基底神经节的损伤可能就变得重要了。在这种情况下，这些结构的损伤可能会阻止额外活动的展开，而这些额外活动可能是影响与所观察动作表征相关的皮质功能所必需的。
