Fig. 9

Deteriorated spatial working memory and impaired associative learning ability in monkeys with hTau overexpression. A A schematic drawing illustrates the experimental design of the WGTA-based monkey spatial working memory test. B Quantification of the memory retention interval before and after hTau overexpression. The working memory capacity of the monkeys declined significantly after hTau overexpression. Each dot represents an individual animal. **P < 0.01. Student’s t test. N = 5. C Quantification of the memory retention interval of the control virus- and hTau-expressing virus-injected monkeys. The working memory capacity of the hTau-expressing virus-injected monkeys was significantly lower than that of the control virus-injected monkeys. Each dot represents an individual animal. *P < 0.05. Student’s t test. N = 5. D A schematic drawing illustrates the experimental design of the WGTA-based monkey delayed match-to-sample test. E, G Quantification of the associative learning period before and after hTau overexpression in two associative learning tests (E, using katakana characters as visual cues; G, using LEGO® blocks as visual cues). Learning ability was noticeably impaired in monkeys after hTau overexpression. Each dot represents an individual animal. *P < 0.05; **P < 0.01. Student’s t test. N = 5. F, H Quantification of the associative learning period of the control virus- and hTau-expressing virus-injected monkeys in two associative learning tests (F, using katakana characters as visual cues; H, using LEGO.® blocks as visual cues). The learning ability of the hTau-expressing virus-injected monkeys was noticeably weaker than that of the control virus-injected monkeys. Each dot represents an individual animal. **P < 0.01. Student’s t test. N = 5