In vitro, caffeine actually encourages hippocampal dendrite growth http://news.bbc.co.uk/2/hi/science/nature/472473.stm—unless this finding (from 1999?) was wrong. That said, the studies claiming that caffeine impairs some types of learning and hippocampal neurogenesis in live rats is probably more applicable in predicting the effects of human consumption.
In vitro, caffeine actually encourages hippocampal dendrite growth http://news.bbc.co.uk/2/hi/science/nature/472473.stm—unless this finding (from 1999?) was wrong. That said, the studies claiming that caffeine impairs some types of learning and hippocampal neurogenesis in live rats is probably more applicable in predicting the effects of human consumption.