Lowndes M, Davies D C
Department of Anatomy, St George's Hospital Medical School, Tooting, London, UK.
Eur J Neurosci. 1994 Apr 1;6(4):525-30. doi: 10.1111/j.1460-9568.1994.tb00296.x.
The avian archistriatum, part of which may be homologous with the mammalian amygdala, has been implicated in fear and avoidance behaviour. There is also evidence to suggest its involvement in learning. One-trial passive avoidance learning (PAL) has been used extensively to study memory formation in the chick. Young chicks will peck spontaneously at a small, visually conspicuous bead. If the bead has been coated with an aversive substance, the chicks show a disgust response and learn in a single trial not to peck a similar bead on subsequent presentation. Successful acquisition of this one-trial PAL task involves the formation of a learned association between the bead and a noxious taste, followed by the expression of an avoidance response. In view of the possible involvement of the archistriatum in avoidance and learning behaviour, its role in one-trial PAL was investigated by ablation. Bilateral electrolytic lesions of the entire archistriatum prevented the acquisition of the one-trial PAL task. Neither bilateral lesions of the lateral cerebral area nor sham operation affected learning. The impairment of one-trial PAL caused by archistriatal lesions was not due to effects on the visual or motor components of pecking behaviour. The archistriatum could therefore be directly involved in memory formation. It could also be involved in the organization of avoidance behaviour associated with the task, or it could form part of a circuit linking two other forebrain regions previously implicated in one-trial PAL, the intermediate part of the medial hyperstriatum ventrale and the lobus parolfactorius.
鸟类的古纹状体，其部分结构可能与哺乳动物的杏仁核同源，已被认为与恐惧和回避行为有关。也有证据表明它参与学习过程。单次被动回避学习（PAL）已被广泛用于研究雏鸡的记忆形成。幼雏会自发地啄一个小的、视觉上显眼的珠子。如果珠子涂有厌恶物质，雏鸡会表现出厌恶反应，并在单次试验中学会在后续呈现时不再啄类似的珠子。成功完成这项单次PAL任务涉及在珠子和有害味道之间形成学习关联，随后表现出回避反应。鉴于古纹状体可能参与回避和学习行为，通过损毁来研究其在单次PAL中的作用。双侧电解损毁整个古纹状体可阻止单次PAL任务的习得。双侧大脑外侧区域的损毁以及假手术均不影响学习。古纹状体损毁导致的单次PAL损伤并非由于对啄食行为的视觉或运动成分产生影响。因此，古纹状体可能直接参与记忆形成。它也可能参与与该任务相关的回避行为的组织，或者它可能构成连接先前在单次PAL中涉及的其他两个前脑区域——腹侧内侧新纹状体中间部分和嗅觉叶——的神经回路的一部分。
