Does Human Growth Hormone have any positive effects on the brain?!

I am not taking pure HGH. I'm taking a legal supplement from Applied Nutraceuticals (www.appnut.com) called HGH-up that is supposed to naturally boost Human Growth Hormone levels. I'm not just taking it for better sleep or for anti-aging effects, as they say HGH is "the fountain of youth." I'm taking it as a supplement to my hard days in the gym to increase muscle mass and strength.

But I'm curious if HGH has any positive effects on the brain. I know HGH levels are much higher pre-30 years old, especially during puberty, etc., and besides the physiological effects on the body, I'm wondering if it has any positive mental effects on the brain.

Thanks!