COVER STORY • 封面專題 2022 UMAGAZINE 26 • 澳大新語 21 functions of different brain regions are integrated to make cognitive abilities possible,’ says Yuan Zhen, head of CCBS and professor in the Faculty of Health Sciences. Thanks to recent advances in image scanning and analysis, scientists have created connectomes of different mapping schemes, such as gene expression, cytoarchitecture, connection, and function, and at different scales, including molecular, neuron, neural circuit, and the whole-brain network, in a variety of animals such as humans, macaques, and rats of different genders and ages. ‘Connectomes are remarkable tools that can help us gain insights into the mechanisms of brain activities,’ says Prof Yuan, who adds that scientists have created connectomes specifically for cross-species brain research. What is the purpose of cross-species brain research? ‘We study different animals, including other primates with whom we have a common ancestor, in order to explore how humans have developed high-level cognitive abilities, including the ability to speak, during evolution,’ says Prof Yuan. Nevertheless, the number of cross-species connectomes is still very limited, and the methods to create them have yet to be fully developed. One of the reasons that such connectomes are difficult to create is that it is hard to determine which brain areas of two species are homologous – that is, whether they evolved from the same structure. There are also challenges in defining the boundary between these different homologous areas based on connectional attributes. Evolution of Language Abilities Over the past few years, Prof Yuan’s team made several breakthroughs in connectome research, moving towards mapping the brain at the whole-brain level. In one of their projects, they studied the Broca area of humans and macaques to find out their similarities and differences in structural connectivity, which denotes the physical connections between neurons. The Broca area plays a key role in language production. It is located in the prefrontal cortex and consists of two parts, namely the pars triangularis and the pars opercularis. The area was named after Paul Broca, a 19th-century French physician, neurobiologist, and anatomist. Two of his patients lost their ability to speak after injuring their frontal lobe but could understand others’ conversations. 袁振教授的團隊研究人類與獼猴腦部的布羅卡區 Prof Yuan Zhen’s team studies the Broca area in human and macaque brains
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