Bombardiei R A, Johnson J I, Campos G B
J Comp Neurol. 1975 Sep;163(1):41-63. doi: 10.1002/cne.901630104.
To determine whether the largely ipsilateral, inverted representation of mouth parts in the ventrobasal thalamus of sheep was unique to that species or an expansion of a general mammalian pattern, the corresponding thalamic projections were mapped electrophysiologically in a selected series of mammals (oppossums, agoutis, squirrel monkeys, cats, raccoons, and sheep) representing major branches of evolution among therian mammals. In mapping, tungsten microelectrodes were used to record multi-unit discharges in the thalamus in response to mechanical stimulation of oral surfaces. The pattern of projections seen in sheep is not a general mammalian pattern; there is extensive variability among mammals in the laterality and internal orgainzation of the projections from the mouth. In spite of the great variability, the results suggest an hypothesis concerning phylogenetic trends: descendants of palaeoryctoid insectivores (cats, raccoons, and sheep in our sample) have extensive ipsilateral projections from the mouth, in other therian mammals (opossums, agoutis, and squirrel monkeys in our sample) the ipsilateral component is small or absent.
为了确定绵羊腹侧基底丘脑口中各部分在很大程度上同侧、倒置的表征是该物种所特有的，还是一般哺乳动物模式的扩展，我们对一系列经过挑选的哺乳动物（负鼠、刺豚鼠、松鼠猴、猫、浣熊和绵羊）进行了电生理绘图，这些哺乳动物代表了兽亚纲哺乳动物进化的主要分支。在绘图过程中，使用钨微电极记录丘脑对口腔表面机械刺激的多单位放电情况。在绵羊身上看到的投射模式并非一般的哺乳动物模式；哺乳动物口中投射的偏侧性和内部组织存在广泛的变异性。尽管存在很大的变异性，但结果提出了一个关于系统发育趋势的假设：古食虫类动物（我们样本中的猫、浣熊和绵羊）的后代有广泛的同侧口腔投射，而在其他兽亚纲哺乳动物（我们样本中的负鼠、刺豚鼠和松鼠猴）中，同侧成分很小或不存在。
