Martin T E
DERA Centre for Human Sciences, Farnborough, Hampshire, UK.
Aviat Space Environ Med. 1998 Dec;69(12):1146-57.
In order to elucidate mental functions that subserve human consciousness, brain activation was investigated in 12 normal, right-handed volunteers who performed tasks of selective attention, working memory, and sensorimotor coordination during the collection of multislice echoplanar functional magnetic resonance images.
These functions are located in (and controlled by) distinct anatomical regions that can be identified by functional magnetic resonance imaging techniques.
In each subject, 100 10-slice data sets were acquired using a 1.5-T scanner and the blood oxygenation level dependent contrast technique. Time-series regression modeling estimated power in the magnetic resonance signal during the on/off phases of task performance. Comparison between subjects was made possible by the transformation of each data set into standard Talairach space.
Activation maps were based on the median value of the fundamental power quotient at each voxel. Results showed the activation of prefrontal and parasagittal cortices in both the selective attention and working memory tasks, but they also revealed activation in both insular cortices and the posterior cingulate gyri.
The results provide evidence for structures in the anterior right hemisphere and left medial frontal lobe for attentional tasks, although there appears to be an engagement of a widespread network of anterior brain structures, possibly with the inhibition of some posterior regions, during task performance. The sensorimotor coordination task showed activation regions similar to those seen in selective attention. Once learned, this task probably demands attention rather than overt conscious motor control. Clearly, the functions of attention, working memory, and sensorimotor coordination are not located in single, discrete brain areas. However, interactions and interplay between related areas were demonstrated, giving supporting evidence that complex mental operations rely on the coordinated activity of widely distributed brain regions that contribute to neural networks.
为了阐明有助于人类意识的心理功能，对12名正常右利手志愿者进行了脑激活研究，这些志愿者在采集多层回波平面功能磁共振图像期间执行选择性注意、工作记忆和感觉运动协调任务。
这些功能位于（并由）不同的解剖区域控制，这些区域可通过功能磁共振成像技术识别。
使用1.5-T扫描仪和血氧水平依赖对比技术，在每个受试者中采集100个10层数据集。时间序列回归模型估计任务执行的开/关阶段磁共振信号中的功率。通过将每个数据集转换到标准Talairach空间，使得受试者之间的比较成为可能。
激活图基于每个体素的基本功率商的中值。结果显示，在选择性注意和工作记忆任务中前额叶和矢旁皮质均有激活，但也揭示了岛叶皮质和后扣带回均有激活。
结果为右前半球和左内侧额叶中存在执行注意任务的结构提供了证据，尽管在任务执行期间似乎有广泛的前脑结构网络参与，可能还伴有对一些后部区域的抑制。感觉运动协调任务显示出与选择性注意中所见类似的激活区域。一旦学会，这项任务可能需要注意力而非明显的有意识运动控制。显然，注意、工作记忆和感觉运动协调功能并非位于单一、离散的脑区。然而，相关区域之间的相互作用得到了证实，这为复杂心理操作依赖于广泛分布的脑区的协同活动从而形成神经网络提供了支持性证据。
