Davies D C, Taylor D A, Johnson M H
Department of Anatomy and Cell Biology, St. Mary's Hospital Medical School, London, United Kingdom.
J Neurosci. 1988 Dec;8(12):4662-6. doi: 10.1523/JNEUROSCI.08-12-04662.1988.
The roles of different forebrain structures in memory formation in the chick were investigated using restricted radio-frequency lesions. Young chicks will spontaneously peck at a small bright bead. If the bead has been coated with a distasteful substance, the chicks learn not to peck a similar bead on subsequent presentation. Thus, in a single trial chicks learn not to peck at an aversive stimulus. Bilateral lesions of the intermediate part of the medial hyperstriatum ventrale (IMHV) prevented the acquisition of this 1-trial passive-avoidance learning task. However, neither bilateral lesions of the lateral cerebral area (LCA) nor sham operation affected learning. IMHV has previously been shown to be critically involved in the learning process of imprinting in the chick. The present experiment demonstrates that the role of IMHV in learning is not restricted to imprinting. The function of IMHV in imprinting has been suggested to be concerned with the recognition of objects. In the present study sham-operated and LCA-lesioned chicks recognized the visual characteristics of the training bead and did not avoid a bead of a different color in the test. We propose that IMHV-lesioned chicks fail to learn the task because they are unable to recognize the visual characteristics of the training bead and consequently cannot make the association between the bead and the unpleasant taste.
利用局限性射频损伤研究了雏鸡不同前脑结构在记忆形成中的作用。幼雏会自发地啄一个小的明亮珠子。如果珠子涂有难吃的物质，雏鸡在随后再次看到类似珠子时就会学会不啄它。因此，在一次试验中，雏鸡就学会不啄厌恶刺激物。内侧腹侧上纹状体中间部分（IMHV）的双侧损伤阻止了这种单次试验被动回避学习任务的习得。然而，外侧脑区（LCA）的双侧损伤和假手术均未影响学习。此前已表明IMHV在雏鸡印记学习过程中起关键作用。本实验表明，IMHV在学习中的作用并不局限于印记。有人认为IMHV在印记中的功能与物体识别有关。在本研究中，接受假手术和LCA损伤的雏鸡识别出了训练珠子的视觉特征，并且在测试中没有避开不同颜色的珠子。我们认为，IMHV损伤的雏鸡未能学会该任务，是因为它们无法识别训练珠子的视觉特征，因此无法在珠子和不愉快味道之间建立联系。
