中国现生六种非人灵长类和树鼩大脑两半球不对称性的比较研究

THE COMPARATIVE STUDY OF BRAIN ASYMMETRY IN SIXSPECIES OF LIVING NONHUMAN PRIMATES AND TREESHREWS DISTRIBUTED IN CHINA

对中国现生六种灵长类动物:懒猴、猕猴、灰叶猴、川金丝猴、滇金丝猴、长臂猿以及与灵长类关系密切的树鼩的大脑两半球形态,功能的不对称性以及由此引起的行为不对称性进行了研究。结果表明:大脑两半球不对称现象均存在于上述几种动物中。因而,这种不对称性可能经历了一个长期演化历程。

The brain asymmetries of tree shrews (Tupaia belangeri chinensis), the slow loris (Ny-cticebus coucang), rhesus monkeys (Macaco mulatta), leaf-eating monkeys (Presbytis ntellus), golden hair monkeys (Rhinopithecus roxellanae). (Rhino pithecus bieti), and gibbons (Hylo-bates hoolock) have been observed with anatomical, electrophysiological, and behavioural methods. The results are shown below (N = the numbers of animals): Anatomy: The brain sulci of six species of primates were measured, the length of Sylvian sulcus of right cortex in slow loris was' longer than that of left side. In the leaf-eating monkeys, the shape of arcuate sulcus was different between two sides of the brain. Most sulci of the parietal, occipital and temporal lobes were located more posteriorly in the right cortices compared to the left for rhesus monkeys, golden hair monkeys and gibbons. And in six of nine rhesus monkeys, the left fronral poles were more posteriorly than that of right sides. In golden hair monkeys and gibbons, the shape of some sulci in left cortices were more complex than that of right cortex and some sulci in right sides were longer than that of left sides. In tree shrews, the weights of left cortices were greater than the right, while the volume did not differ. This may reflect cell density. Electrophysiology: The amplitule of visualevoked potentials (VEP) were higher in left cortices than right in 70% of tree shrews. Using VEP method to measure the areas of visual cortex, no difference was found between the areas of left and right visual cortex. During atten-live tasks in rhesus monkeys the right prefrontal cortices showed EEG of higher frequency and lower amplitude compared to the left. After lesion left sides of dorsal hippocampus, in tree shrews, the heart rate became lower than before, but were not, if lesions were done in the right sides. Behaviour: The hand preference of rhesus monkeys, leaf-eating monkeys, golden hair monkeys, and gibbons in picking up food was observed. With the exception of the rhesus, there was right handed perference in males but not in females. Conclusion: The results suggest that there are brain asymmetries in nonhuman primates even in tree shrews; these asymmetries are more clear for species that are higher on the evolutionary ladder. There is also a difference in male and female animals in hand preference.