Thinking with your gonads: testosterone and cognition.

Sex hormones play a crucial role during brain development, but do they modulate or maintain cognition throughout life? Despite several million prescriptions annually for testosterone supplementation, we do not really know the answer. Here I review recent evidence that testosterone alters neural activity essential for learning and memory, and plays an important role as a neuroprotective agent in aging. In particular, testosterone deprivation is associated with poor memory in men and replacement can enhance memory and spatial cognition. However, there is little evidence that testosterone selectively affects only those cognitive domains where sex differences in performance have been found. There are also gaps in our knowledge surrounding the individual cognitive processes altered by testosterone, their neural basis, and the degree to which testosterone affects cognitive performance in women.