Dupont P, Vogels R, Vandenberghe R, Rosier A, Cornette L, Bormans G, Mortelmans L, Orban G A
Departement Nucleaire Geneeskunde, Universitair Ziekenhuis Gasthuisberg, Leuven, Belgium.
Eur J Neurosci. 1998 Dec;10(12):3689-99. doi: 10.1046/j.1460-9568.1998.00376.x.
In order to compare regional cerebral activity involved in simultaneous as opposed to successive orientation discrimination, we used positron emission tomography to measure regional cerebral blood flow, in two threefold sets of conditions, in a large number of subjects. The first such triad involved simultaneous orientation discrimination, orientation identification and detection, with all tasks using the same pair of gratings. The second triad consisted of successive orientation discrimination with its corresponding identification and detection tasks. Comparisons between tasks within each triad isolate attention to orientation and, respectively, spatial or temporal comparison. The subtraction of detection from simultaneous discrimination revealed activation of right fusiform, right lingual, left precentral, left cingulate and left temporal cortex, in addition to right insula, cerebellum and left thalamus. Only the fusiform, insular and precentral activations remained when the corresponding identification was subtracted from simultaneous discrimination. In contrast, most of the non-visual activation sites remained when simultaneous discrimination was compared with successive discrimination, which also revealed a left lingual activation. These experiments provide further evidence for task-dependent processing in the human visual system and suggest that the right fusiform cortex is involved in spatial as much as temporal comparisons.
为了比较同时性与相继性方向辨别过程中涉及的局部脑活动，我们使用正电子发射断层扫描技术，在大量受试者中，于两组三种条件下测量局部脑血流量。第一组三联任务包括同时性方向辨别、方向识别和检测，所有任务均使用同一对光栅。第二组三联任务由相继性方向辨别及其相应的识别和检测任务组成。每组三联任务中各任务之间的比较分别分离出对方向的注意以及空间或时间比较。从同时性辨别中减去检测任务后发现，除右侧脑岛、小脑和左侧丘脑外，右侧梭状回、右侧舌回、左侧中央前回、左侧扣带回和左侧颞叶皮质也被激活。从同时性辨别中减去相应的识别任务后，仅梭状回、脑岛和中央前回的激活仍然存在。相比之下，将同时性辨别与相继性辨别进行比较时，大多数非视觉激活部位仍然存在，同时还发现左侧舌回有激活。这些实验为人类视觉系统中任务依赖的加工提供了进一步证据，并表明右侧梭状回皮质在空间和时间比较中均有参与。
