I think Kappa is common ancestor of turtle and frog. Kappa is Japanese imaginary creature. Their body is green (sometimes red) and have beak and shell on their back like turtles. They have dish on their head. If the dish dry, they will die. They live in liver and like doing sumo wrestling with children. They say kappa is not exist. But I found kappa has some common feature with turtle and frog. This is my hypothesis↓ Kappa was exist before and has evolved into turtle and frog. People was living with kappa until about 200 years ago. But the number of kappa declined for some reason. So, people cannot find kappa anymore. Kappa became an imaginary creature. This notebook is not scientific :)

Is there biological sex difference in human? It is said that men have good spatial recognition ability or are good at math and women have good empathy ability. There are many papers about sex differences. Some papers say there are sex differences and some papers say not. I think there are sex differences between men and women. But it includes cultural effect. Are there "biological" sex difference in human? No one knows the right answer because we cannot remove cultural effect. But we have some ways to approach this topic. First, to use animals. We can raise animals in environment completely separated from culture. Mice has sex differences in some behavior such as coordination, anxiety-like behavior and spatial and non-spatial task performance. Second, to compare difference culture. Interestingly, difference in spatial recognition ability is more appear in countries that have big gender gap. Both methods have problems. Animal is different from human and the definition of gender gap is complicating.

Matcha Spring is matcha season. I can find many matcha sweets at convenience stores, supermarkets, and cake shops. When we drink matcha as tea, it is not sweet at all. (I'm not sure whether I can call it tea because it is suspended matcha powder...) So, we usually eat sweets with matcha. But when we use matcha for sweets such as matcha cake or matcha ice cream, they are sweet in itself. That is not the problem. I like matcha sweets. The problem is that matcha sweets sometimes have sweet bean paste in or with them. Sweet bean paste is also sweet. I cannot understand why people combine sweet one with sweet one. Too sweet!! So I always check if there is sweet bean paste in the matcha sweets. Combination of non-sweet matcha and sweet bean paste is good though :-P

Recent hot topic in neuroscience field. I will try to explain recent hot topic in neuroscience field. But I need to explain the background first. Neuron play a crucial role in various brain functions. Neuronal stem cells differentiate to neurons and other type of cells in brain. Neurons can not self-reproduce but neuronal stem cell can. Embryos and infants have many neuronal stem cells in their brain and neurogenesis actively occurs. Until recently, it is said that neurogenesis does not occur in adult brain. But in 1998, first neurogenesis in adult brain was observed. After that some experiments indicate neurogenesis in adult brain. So, neurogenesis in adult brain became common sense among neuroscientists. Last month, Mexican scientist released the paper about neurogenesis in adult brain.They analyzed more number of human brain than previous report and concluded they could not observe neurogenesis in adult brain. This report gave a big impact to neuroscientists. But in this month (so quick！), a report that contradicts to the report was released. They insist that neurogenesis persists throughout human life. This topic is very interesting. I will keep watching :)