Pinto-Hamuy T, Olavarria J, Guic-Robles E, Morgues M, Nassal O, Petit D
Department of Physiology and Biophysics, University of Chile, Santiago.
Behav Brain Res. 1987 Sep;25(3):221-31. doi: 10.1016/0166-4328(87)90070-2.
The involvement of rat anteromedial extrastriate cortex (area AM, in the anterior portion of area 18b) in the integration of visual and somatic cues was assessed behaviorally. Following restricted bilateral lesions of selected cortical regions, rats were tested on their ability to retain or relearn a conditional visuosomatic discrimination task learned prior to surgery. Two compound, visuosomatic stimuli were used: white or black associated with either one of two degrees of roughness. The use of a guided-response procedure was essential for rats to learn this difficult conditional bimodal task. None of the 6 rats with lesions aimed at area AM retained the habit postoperatively. Four of these rats were incapable of relearning the task after 3 postoperative training series, and they had either extensive lesions of area AM or relatively small, symmetric damage of anterior portions of AM. The remaining two rats with lesions in area AM were able to relearn the task in the second postoperative training series, and their lesions either were restricted to posteromedial aspects of area AM or they involved asymmetric loci in anterior area AM. In contrast to rats with lesions of area AM, rats with lesions in visual cortex in areas 17 and 18a, or in auditory cortex in area 41, were able either to retain the task or to relearn in the first postoperative training series. These results indicate that the integrity of area AM appears necessary for rats to discriminate between pairs of compound stimuli that differ in brightness and roughness. The behavioural data point to the notion that this area might be involved in the integration of these types of visual and somatic stimuli. In addition, our finding that performance was largely unimpaired following extensive lesions of lateral extrastriate area supports previous reports indicating that medial and lateral extrastriate visual areas differ in function.
通过行为学方法评估了大鼠前内侧纹外皮层（AM区，位于18b区前部）在视觉和躯体线索整合中的作用。在对选定皮质区域进行双侧局限性损伤后，测试大鼠保留或重新学习术前习得的条件性视觉-躯体辨别任务的能力。使用了两种复合视觉-躯体刺激：白色或黑色与两种粗糙度程度之一相关联。对于大鼠学习这项困难的条件性双模式任务而言，引导反应程序的使用至关重要。6只旨在损伤AM区的大鼠术后均未保留该习惯。其中4只大鼠在术后3个训练系列后无法重新学习该任务，它们要么AM区有广泛损伤，要么AM区前部有相对较小的对称性损伤。其余2只AM区有损伤的大鼠能够在术后第二个训练系列中重新学习该任务，它们的损伤要么局限于AM区的后内侧部分，要么涉及AM区前部的不对称位点。与AM区有损伤的大鼠不同，17区和18a区视觉皮层或41区听觉皮层有损伤的大鼠，要么能够保留该任务，要么能够在术后第一个训练系列中重新学习。这些结果表明，AM区的完整性似乎是大鼠区分亮度和粗糙度不同的复合刺激对所必需的。行为学数据表明，该区域可能参与了这些类型的视觉和躯体刺激的整合。此外，我们发现外侧纹外区广泛损伤后行为表现基本未受损害，这一发现支持了先前的报告，即内侧和外侧纹外视觉区在功能上存在差异。
