New Approaches for Investigating Brain-Body Scaling and the Evolution of Mammalian Brains

脑大小在行为和智力方面的重要性一直是神经科学研究的一个基础领域。一个多世纪以来，生物学家一直对大脑大小如何随着体型的增加而变化，以及这对不同物种行为复杂性的影响感兴趣。尤其是人类和其他灵长类动物，它们的大脑比我们的体型要大得多，这被认为是我们独特智力的基础。在这个项目中，卡塔尼亚博士将验证一个假设，即拥有更多感官输入或更复杂运动行为的动物，它们的大脑比它们的体型所能预测的要大，以处理更多的输入或输出。具体来说，他将研究鼹鼠（鼩鼱科）和鼩鼱（鼩鼱科）的身体大小和大脑大小之间的比例关系以及感觉或运动特殊化程度。这些物种非常适合进行这样的研究，因为这些哺乳动物与其他哺乳动物和人类有许多共同的大脑特征，但在高级处理和新皮层区域有特别明确的细分。这些清晰的脑细分在较大的脑哺乳动物中是看不到的。研究鼩鼱和鼹鼠可以精确地量化大脑中与每个物种的视觉、体感或听觉发育程度相关的区域。收集的具体数据包括大脑输入（传入）的计数和大脑输出（传出）的计数。此外，这些数量将与每个物种个体的大脑大小和体型进行比较。这些研究的主要目的是揭示大脑大小、身体大小和感觉能力之间以前未确定的关系。最终，这项研究可能会告诉我们哺乳动物大脑的一般缩放原则，这将有助于我们理解智力的进化。

New Approaches for Investigating Brain-Body Scaling and the Evolution of Mammalian Brains The significance of brain size in behavior and intelligence remains a fundamental area of study in the neurosciences. For well over a century biologists have been interested in how brain size scales with increasing body size and what this suggests about behavioral complexity in different species. Humans and other primates in particular have a much larger brain than would be predicted for our body size and this is thought to underlie our unique intellectual abilities. In this project, Dr. Catania will test the hypothesis that animals with more sensory input or more complex motor behavior have larger brains than would be predicted from their body size to process the greater input or output. Specifically he will investigate the scaling relationship between body size and brain size and the degree of sensory or motor specializations in moles (Family Talpidae) and shrews (Family Soricidae). These species are well-suited for such studies because these mammals share many brain features in common with other mammals and humans, but have particularly clear subdivisions in the higher processing, neocortical areas. These clear brain subdivisions are not visible in larger brained mammals. Studying shrews and moles will allow precise quantification of areas in the brain that can be related to the degree of development of the visual, somatosensory, or auditory senses in each species. The specific data that will be collected include counts of inputs (afferents) to the brain and counts of output (efferents) from the brain. In addition, the quantities will be compared with brain size and body size in individuals from each species. The primary goal of these studies is to reveal previously unidentified relationships between brain size, body size, and sensory abilities. Ultimately the research may inform us about scaling principles general to mammalian brains that will help us to understand the evolution of intelligence.