Relative size of the anterior thalamic nuclei differentiates anthropoids by social system.
Anthropoid primates differ in the sizes of their limbic nuclei. Morphometric analysis of the anterior principal thalamic nucleus and the medial mamillary nuclei reveal that both regions increase in size as a function of brain weight. However, after controlling for the size of the brain, anthropoids classified as having single-male societies have more anterior principal thalamic neurons than do primates that are classified as multi-male. The relative sizes of the mamillary nuclei do not show this clustering. The differences in the size of the anterior nucleus are hypothesized to be specific for this nucleus and not the result of a general limbic or of heterochronic changes.
D000818:Animals; D006127:Group Structure; D000882:Haplorhini / Q000033:anatomy & histology*; D008326:Mammillary Bodies / Q000033:anatomy & histology; D009929:Organ Size; D012930:Social Dominance; D013787:Thalamic Nuclei / Q000033:anatomy & histology*