She tested her rats on 2 kinds of water mazes. The results were exactly opposite of what she predicted. She is still trying to figure out what the contribution of these additional synapses is to learning. One possibility is that the first more difficult task is more stressful and that this stress is potentiated during proestrous. Precisely what the role of these extra synapses are in the real world is unknown.
Rats have a phenomenon like menopause which is called estropause.
Unlike women, estropausal rats still have functional ovaries. However, the hypothalamus is no longer functional or responsive to hormones.