Burhans Lauren B, Gabriel Michael
Neurosciences Program, University of Illinois at Urbana-Champaign, USA.
Behav Neurosci. 2007 Dec;121(6):1243-57. doi: 10.1037/0735-7044.121.6.1243.
The performance of conditioned responses (CRs) is diminished when trained subjects are tested in a novel context. This study tested the hypothesis that the flow of contextual information along the disynaptic "ESA" (entorhinal cortex-ventral subiculum-nucleus accumbens) pathway is responsible for context-related modulation of CRs. Rabbits received electrolytic or sham lesions of the ventral subiculum followed by discriminative avoidance conditioning and counterbalanced extinction sessions in the original training context, a novel context, and the original training context with a novel cue. Neuronal activity was recorded simultaneously in the nucleus accumbens, cingulate cortex, and basolateral amygdala. The lesions did not affect the acquisition of avoidance behavior or prevent the reduction of CRs in response to a novel cue. However, the lesions did reduce CR incidence during extinction, and they did eliminate a further novel-context-induced CR reduction found in controls. In addition, lesions disrupted context-dependent neuronal responses in the nucleus accumbens but not in the cingulate cortex or amygdala. These findings are interpreted as supportive of the hypothesis that the ESA pathway mediates contextual modulation of CRs during extinction.
当对经过训练的实验对象在新环境中进行测试时,条件反应(CRs)的表现会减弱。本研究检验了以下假设:沿双突触“ESA”(内嗅皮层-腹侧下托-伏隔核)通路的情境信息流动负责CRs的情境相关调节。兔子接受腹侧下托的电解损伤或假损伤,随后在原始训练环境、新环境以及带有新线索的原始训练环境中进行辨别性回避条件反射和平衡消退实验。同时记录伏隔核、扣带回皮层和基底外侧杏仁核中的神经元活动。损伤并未影响回避行为的习得,也未阻止对新线索的CRs减少。然而,损伤确实降低了消退期间的CR发生率,并且消除了对照组中发现的由新环境引起的CR进一步减少。此外,损伤破坏了伏隔核中依赖情境的神经元反应,但未影响扣带回皮层或杏仁核中的反应。这些发现被解释为支持以下假设:ESA通路在消退过程中介导CRs的情境调节。