Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Nat Ecol Evol. 2020 Apr;4(4):639-651. doi: 10.1038/s41559-020-1137-2. Epub 2020 Mar 16.
Amniotes, such as mammals and reptiles, have vision and other senses represented in the pallium, whereas anamniotes, such as amphibians, fish and cyclostomes (including lampreys), which diverged much earlier, were historically thought to process olfactory information predominantly or even exclusively in the pallium. Here, we show that there is a separate visual area with retinotopic representation, and that somatosensory information from the head and trunk is represented in an adjacent area in the lamprey pallial cortex (lateral pallium). These cortical sensory areas flank a non-primary-sensory motor area. Both vision and somatosensation are relayed via the thalamus. These findings suggest that the basic sensorimotor representation of the mammalian neocortex, as well as the sensory thalamocortical relay, had already evolved in the last common ancestor of cyclostomes and gnathostomes around 560 million years ago.
羊膜动物，如哺乳动物和爬行动物，其视觉和其他感觉在大脑皮层中得到体现，而无羊膜动物，如两栖动物、鱼类和圆口动物（包括七鳃鳗），它们在更早的时候就已经分化，历史上被认为主要甚至完全在大脑皮层中处理嗅觉信息。在这里，我们表明，在七鳃鳗大脑皮层（外侧大脑皮层）中有一个具有视网膜代表的单独视觉区域，并且来自头部和躯干的躯体感觉信息在相邻区域得到体现。这些皮质感觉区域位于非主要感觉运动区域的两侧。视觉和躯体感觉都是通过丘脑进行传递的。这些发现表明，在大约 5.6 亿年前的圆口动物和有颌类的最后共同祖先中，哺乳动物新皮层的基本感觉运动代表以及感觉丘脑皮质传递已经进化。
