Lomber S G, Payne B R
Laboratory for Visual Perception and Cognition, Department of Anatomy and Neurobiology, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA.
Cereb Cortex. 2000 Nov;10(11):1066-77. doi: 10.1093/cercor/10.11.1066.
The purpose of the present study was to test the hypothesis that superficial and deep layers within a single cerebral region influence cerebral functions and behaviors in different ways. For this test, we selected posterior middle suprasylvian (pMS) sulcal cortex of the cat, a suspected homolog of the area V5 complex of primates, because the region has been implicated in several visually guided behaviors. Cats were trained on three tasks: (1) discrimination of direction of motion; (2) discrimination of static patterns partially obscured by static or moving masks; and (3) visual detection and orienting. Cooling of cryoloops in contact with pMS sulcal cortex to 8+/-1 degrees C selectively and completely impaired performance on the two motion discrimination tasks (1 and 2), while leaving the detection and orienting task (task 3) unimpaired. Further cooling to 3 degrees C resulted in an additional complete impairment of task 3. The 8 degrees C temperature resulted in silencing of neuronal activity in the supragranular layers (I-III) and the 3 degrees C temperature silenced activity throughout the thickness of pMS sulcal cortex. The variation in behavioral performance with covariation of cryoloop temperature and vertical, but not lateral, spread of deactivation shows that deactivation of superficial cerebral layers alone was sufficient to completely impair performance on the two motion discrimination tasks, whereas additional deactivation of the deep layers was essential to block performance on the detection and orienting task. Thus, these results show a functional bipartite division of labor between upper and lower cortical layers that is supported by efferent connectional anatomy. Similar bipartite division into upper and lower layers may be a general feature of cerebral cortical architecture, signal processing and guidance of behavior.
本研究的目的是验证一个假设，即单个脑区的浅层和深层以不同方式影响脑功能和行为。为了进行这个测试，我们选择了猫的后中颞上沟（pMS）沟回皮质，它被认为是灵长类动物V5复合体区域的同源物，因为该区域与多种视觉引导行为有关。猫接受了三项任务的训练：（1）运动方向辨别；（2）辨别被静态或动态掩蔽部分遮挡的静态图案；（3）视觉检测和定向。将与pMS沟回皮质接触的冷冻环冷却至8±1摄氏度，选择性且完全地损害了两项运动辨别任务（1和2）的表现，而检测和定向任务（任务3）未受影响。进一步冷却至3摄氏度导致任务3额外完全受损。8摄氏度的温度导致颗粒上层（I - III层）的神经元活动沉默，而3摄氏度的温度使pMS沟回皮质全层的活动沉默。行为表现随冷冻环温度变化以及失活的垂直（而非水平）扩展而变化，这表明仅浅层脑区失活就足以完全损害两项运动辨别任务的表现，而深层脑区的额外失活对于阻断检测和定向任务的表现至关重要。因此，这些结果表明皮质上下层之间存在功能二分的分工，这得到了传出连接解剖结构的支持。类似的上下层二分可能是大脑皮质结构、信号处理和行为引导的一个普遍特征。
