Signal-, set- and movement-related activity in the human brain: an event-related fMRI study.
Signal-, set- and movement-related activity in the human brain: an event-related fMRI study.
复制标题
人脑中与信号、设定和运动相关的活动：一项与事件相关的功能磁共振成像研究。
作者：
I. Toni;N. Schluter;O. Josephs;K. Friston;R. Passingham
对猴子进行的电生理学研究已经能够通过伪随机延迟指示运动的线索和触发运动的刺激来区分时间接近的感觉和运动信号。我们在功能性磁共振成像（fMRI）中使用了类似的实验设计，在受试者按照指示延迟执行视觉运动条件任务时对他们进行扫描。简要介绍了四种形状之一。两个图形指示受试者弯曲食指;另外两个图形编码中指的弯曲。受试者被告知在一个音调后进行运动。我们开发了一种事件相关功能磁共振成像的新用途。通过系统地改变视觉和听觉刺激之间的间隔，已经可以估计对每个刺激的诱发血液动力学反应（EHR）的意义，尽管它们相对于EHR的时间常数在时间上接近。此外，通过改变事件和图像采集之间的相位，我们已经能够在扫描整个大脑的同时实现高时间分辨率。我们分离的感觉和运动组件的感觉运动的转换引起的任务，并评估持续的活动在指示延迟。在距状核和枕颞叶皮层，反应只与视觉指令线索。在颞叶听觉皮层和初级运动皮层，它们只与听觉触发刺激有关。在腹侧前额叶皮层有运动相关的反应之前的准备活动和信号相关的活动。最后，在背侧运动前皮层和背侧后顶叶皮层中观察到与指令线索和延迟期间持续活动相关的反应。在视觉线索和适当的运动之间的关联是任意的情况下，潜在的视觉转换并不完全通过额顶相互作用来实现。相反，这些过程似乎依赖于腹侧视觉流、腹侧前额叶皮层和背侧前运动皮层的前部。
Electrophysiological studies on monkeys have been able to distinguish sensory and motor signals close in time by pseudorandomly delaying the cue that instructs the movement from the stimulus that triggers the movement. We have used a similar experimental design in functional magnetic resonance imaging (fMRI), scanning subjects while they performed a visuomotor conditional task with instructed delays. One of four shapes was presented briefly. Two shapes instructed the subjects to flex the index finger; the other two shapes coded the flexion of the middle finger. The subjects were told to perform the movement after a tone. We have exploited a novel use of event-related fMRI. By systematically varying the interval between the visual and acoustic stimuli, it has been possible to estimate the significance of the evoked haemodynamic response (EHR) to each of the stimuli, despite their temporal proximity in relation to the time constant of the EHR. Furthermore, by varying the phase between events and image acquisition, we have been able to achieve high temporal resolution while scanning the whole brain. We dissociated sensory and motor components of the sensorimotor transformations elicited by the task, and assessed sustained activity during the instructed delays. In calcarine and occipitotemporal cortex, the responses were exclusively associated with the visual instruction cues. In temporal auditory cortex and in primary motor cortex, they were exclusively associated with the auditory trigger stimulus. In ventral prefrontal cortex there were movement-related responses preceded by preparatory activity and by signal-related activity. Finally, responses associated with the instruction cue and with sustained activity during the delay period were observed in the dorsal premotor cortex and in the dorsal posterior parietal cortex. Where the association between a visual cue and the appropriate movement is arbitrary, the underlying visuomotor transformations are not achieved exclusively through frontoparietal interactions. Rather, these processes seem to rely on the ventral visual stream, the ventral prefrontal cortex and the anterior part of the dorsal premotor cortex.
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影响因子：
2.5
作者：
Scott T. Grafton;A. Fagg;M. Arbib
通讯作者：
Scott T. Grafton;A. Fagg;M. Arbib
影响因子：
3.7
作者：
Penhune, VB;Zatorre, RJ;Evans, AC
通讯作者：
Evans, AC
影响因子：
2.5
作者：
Shen, LM;Alexander, GE
通讯作者：
Alexander, GE
DOI：
10.1073/pnas.92.18.8135
发表时间：
1995-08-29
影响因子：
11.1
作者：
MALACH, R;REPPAS, JB;TOOTELL, RBH
通讯作者：
TOOTELL, RBH
影响因子：
2.5
作者：
ALEXANDER, GE;CRUTCHER, MD
通讯作者：
CRUTCHER, MD