Department of Medicine, Neurology Research Group, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
Eur J Neurosci. 2012 Jan;35(2):323-31. doi: 10.1111/j.1460-9568.2011.07938.x. Epub 2011 Dec 15.
Motor imagery (MI) increases corticomotor excitability and modulates intracortical inhibition. This study aimed to relate these neurophysiological mechanisms to imagery quality. Twenty-three healthy adults participated. First, the ability to vividly and accurately imagine performing a finger-to-thumb opposition task was evaluated by calculating a MI index (MII) based on psychological, behavioural and psychophysiological measurements. These scores were used to distinguish good from poor imagers. Transcranial magnetic stimulation was then used to assess modulation of corticomotor excitability, short-interval intracortical inhibition (sICI) and short-interval intracortical facilitation (sICF). Participants imagined abduction of their right thumb paced by a 1-Hz metronome. Single and paired magnetic stimuli were delivered at rest, while listening to the metronome, and during or between imagined movements. Corticomotor excitability was facilitated in the right opponens pollicis for good and poor imagers during MI, and this was positively correlated to the MII score. Poor imagers also facilitated corticomotor excitability of the right abductor digiti minimi, which was not involved in the movement. No interactions were found with sICI and sICF for good imagers, whereas poor imagers recruited intracortical facilitation while imagining. Accurate MI performance was characterised by muscle-specific temporal modulation of corticomotor excitability.
运动想象（MI）会增加皮质运动兴奋性并调节皮质内抑制。本研究旨在将这些神经生理机制与想象质量联系起来。23 名健康成年人参与了研究。首先，通过基于心理、行为和心理生理学测量来计算 MI 指数（MII），评估了进行手指对拇指对指任务的生动准确想象的能力。这些分数用于区分优秀和较差的想象者。然后使用经颅磁刺激评估皮质运动兴奋性、短间隔内皮质抑制（sICI）和短间隔内皮质易化（sICF）的调节。参与者在听节拍器的同时想象右手拇指外展，节拍器频率为 1Hz。在休息、听节拍器、进行或在想象运动期间或之间，给予单刺激和双刺激。在 MI 期间，优秀和较差的想象者的右侧对掌肌的皮质运动兴奋性都得到了促进，这与 MII 评分呈正相关。较差的想象者还促进了不参与运动的右手小指展肌的皮质运动兴奋性。优秀的想象者在 sICI 和 sICF 方面没有发现交互作用，而较差的想象者在想象时则募集了皮质易化。准确的 MI 表现的特征是皮质运动兴奋性的肌肉特异性时间调制。
