Department of Physiology and Neuroscience Program, Biomedicine Discovery Institute, Monash University, 26 Innovation Walk, Clayton, Melbourne, VIC 3800, Australia.
Laboratory of Neuroinformatics, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland.
Cereb Cortex. 2024 Sep 3;34(9). doi: 10.1093/cercor/bhae348.
It is known that the primate amygdala forms projections to many areas of the ipsilateral cortex, but the extent to which it forms connections with the contralateral visual cortex remains less understood. Based on retrograde tracer injections in marmoset monkeys, we report that the amygdala forms widespread projections to the ipsilateral extrastriate cortex, including V1 and areas in both the dorsal (MT, V4T, V3a, 19M, and PG/PFG) and the ventral (VLP and TEO) streams. In addition, contralateral projections were found to target each of the extrastriate areas, but not V1. In both hemispheres, the tracer-labeled neurons were exclusively located in the basolateral nuclear complex. The number of labeled neurons in the contralateral amygdala was small relative to the ipsilateral connection (1.2% to 5.8%). The percentage of contralateral connections increased progressively with hierarchical level. An injection in the corpus callosum demonstrated that at least some of the amygdalo-cortical connections cross through this fiber tract, in addition to the previously documented path through the anterior commissure. Our results expand knowledge of the amygdalofugal projections to the extrastriate cortex, while also revealing pathways through which visual stimuli conveying affective content can directly influence early stages of neural processing in the contralateral visual field.
已知灵长类动物的杏仁核向同侧大脑皮层的许多区域投射，但它与对侧视觉皮层形成连接的程度仍不太清楚。基于在绒猴中的逆行示踪剂注射，我们报告称，杏仁核向同侧的外纹状体皮层形成广泛的投射，包括 V1 和背侧（MT、V4T、V3a、19M 和 PG/PFG）和腹侧（VLP 和 TEO）流中的区域。此外，还发现对侧投射靶向每个外纹状体区域，但不包括 V1。在两个半球中，示踪剂标记的神经元仅位于基底外侧核复合体中。与同侧连接相比，对侧杏仁核中标记神经元的数量较少（1.2%至 5.8%）。与等级水平成正比，对侧连接的百分比增加。胼胝体注射表明，除了以前通过前连合记录的路径外，至少有一些杏仁核-皮质连接穿过这条纤维束。我们的结果扩展了杏仁核向外侧纹状体投射的知识，同时还揭示了传递情感内容的视觉刺激可以直接影响对侧视野中神经处理早期阶段的途径。
