The conference has been astounding, but today, day four, I'm officially getting brain fatigue. (Notice how these posts are getting shorter?) Nevertheless, researchers continue to present fascinating work. Today's noteworthy event was a session on neurogenesis. A number of researchers presented interesting twists on the phenomenon, including:
Intermittent fasting significantly increases neurogenesis in mice—even more than calorie restriction does. The finding is particularly interesting because the calorie-restricted mice and the fasting rats were eating the same number of calories. All that differed was the timing. Mice who fasted every other day had much more neurogenesis than rats who were on a constant calorie-restricted diet.
Another researcher, Tarique Perera of Columbia, presented compelling new data about antidepressant and neurogenesis. Other scientists have previously noted associations between antidepressant use and elevated rates of neurogenesis—Perera's work strengthened this association considerably. Working with a macaque model of depression, Perera showed, unsurprisingly, that administering Prozac reversed the symptoms of depression. But when he gave the monkeys Prozac and then prevented neurogenesis by administering low doses of radiation to the temporal lobe, the anti-depressant was no longer effective. A simple and cool demonstration. There's definitely more to be found there.
Finally, Sebastien Couillard-Despres discussed his interesting work on neurogenesis and aging. We know that the rate of neurogenesis gradually decreases as animals age. Couillard-Despres gave Prozac to 100, 200, and 400-day old mice (roughly corresponding to humans 15, 30, and 60 years old). She found that the mice of all ages had similar rates of proliferation of new neurons, but in these neurons had much higher rates of maturation and survival in the youngest mice. It's a big step toward helping untangle the relationship between aging and neurogenesis.