To understand functional neuronal circuits for emotion in the basal forebrain, patterns of neuronal activation were examined in mice by immunohistochemistry of immediate-early gene products (Zif268/Egr1 and c-Fos). In all mice examined, clusters of 30–50 neurons expressing Zif268 were found on both sides in the area between the extended amygdala (EA) and globus pallidus (GP), generally designated as sublenticular extended amygdala (SLEA). The clusters consisted of 79.9 ± 3.0% of GABAergic neurons in GAD65-mCherry mice. The expression of the cholinergic marker choline acetyltransferase and the GP markers parvalbumin, proenkephalin, and FoxP2 indicated that these neurons were different from known types of neurons in the EA and GP; therefore, we named them the sublenticular extended amygdalar Zif268/Egr1-expressing neuronal cluster (SLEA-zNC). Sublenticular extended amygdalar Zif268/Egr1-expressing neuronal clusters participated in stress processing because increasing numbers of cells were observed in SLEA-zNCs after exposure to restraint stress (RS), the induction of which was suppressed by diazepam treatment. Mapping SLEA-zNCs showed that their positions and arrangement varied individually; SLEA-zNCs were distributed asymmetrically and tended to be situated mainly in the middle region between the anterior commissure (AC) and posterior end of the GP. However, the total cell number in SLEA-zNCs was compatible between the right and left hemispheres after activation by RS. Therefore, SLEA-zNCs were distributed asymmetrically but were not lateralized. Because time courses of activation differed between the Zif268 and c-Fos, the sequential dual treatment of RSs enabled us to differentiate SLEA-zNCs activated by the first and second RS. The results supported that the same SLEA-zNCs responded to both the first and second RS, and this also applied for all SLEA-zNCs. Thus, we concluded that the cluster positions were invariable under RS in each mouse but were distributed differently between individual mice. We name these newly identified neuronal clusters as stress-related neuronal clusters, SLEA-zNCs, which are considered to be novel functional units of “islands of activation.” Moreover, SLEA-zNCs were situated at different positions in all mice examined, showing individual differences in their positions.

为了了解基底前脑中情绪的功能性神经元回路，通过立即早期基因产物（Zif268 / Egr1和c-Fos）的免疫组织化学检查了小鼠的神经元活化模式。在所有接受检查的小鼠中，在延伸杏仁核（EA）和苍白球（GP）之间的区域的两侧均发现了表达Zif268的30-50个神经元簇，通常被称为双突性扁桃体下方杏仁核（SLEA）。该簇由GAD65-mCherry小鼠中的79.9±3.0％的GABA能神经元组成。胆碱能标记胆碱乙酰基转移酶和GP标记小白蛋白，前脑啡肽和FoxP2的表达表明，这些神经元与EA和GP中已知类型的神经元不同。因此，我们将它们命名为表达亚扁桃体的延伸杏仁核Zif268 / Egr1的神经元簇（SLEA-zNC）。由于在暴露于束缚应激（RS）后SLEA-zNCs中观察到的细胞数量增加，因此表达亚扁豆状延伸的杏仁核Zif268 / Egr1的神经元簇参与了应激处理，而地西epa治疗则抑制了诱导。绘制SLEA-zNC的图谱表明它们的位置和排列各不相同；SLEA-zNCs不对称分布，并倾向于主要位于GP的前联合（AC）和后端之间的中间区域。然而，经RS激活后，SLEA-zNCs中的总细胞数在左右半球之间是兼容的。因此，SLEA-zNCs不对称分布，但没有侧向分布。由于Zif268和c-Fos的激活时间不同，RS的顺序双重处理使我们能够区分被第一个RS和第二个RS激活的SLEA-zNC。结果支持相同的SLEA-zNC对第一个RS和第二个RS都做出响应，这也适用于所有SLEA-zNC。因此，我们得出结论，在每只小鼠中，RS下的簇位置不变，但在每只小鼠之间的分布却不同。我们将这些新发现的神经元簇命名为与压力相关的神经元簇SLEA-zNC，它们被认为是“激活岛”的新型功能单元。此外，SLEA-zNCs在所有检查的小鼠中都位于不同的位置，显示出它们位置的个体差异。这也适用于所有SLEA-zNC。因此，我们得出结论，在每只小鼠中，RS下的簇位置不变，但在每只小鼠之间的分布却不同。我们将这些新发现的神经元簇命名为与压力相关的神经元簇SLEA-zNC，它们被认为是“激活岛”的新型功能单元。此外，SLEA-zNCs在所有检查的小鼠中都位于不同的位置，显示出它们位置的个体差异。这也适用于所有SLEA-zNC。因此，我们得出结论，在每只小鼠中，RS下的簇位置不变，但在每只小鼠之间的分布却不同。我们将这些新发现的神经元簇命名为与压力相关的神经元簇SLEA-zNC，它们被认为是“激活岛”的新型功能单元。此外，SLEA-zNCs在所有检查的小鼠中都位于不同的位置，显示出它们位置的个体差异。