February 03, 2007
Estrogen Enhances Rewards For Women

When women win they get a bigger mental reward before ovulation than after.

Fluctuations in sex hormone levels during women's menstrual cycles affect the responsiveness of their brains' reward circuitry, an imaging study at the National Institute of Mental Health (NIMH), a component of the National Institutes of Health (NIH), has revealed. While women were winning rewards, their circuitry was more active if they were in a menstrual phase preceding ovulation and dominated by estrogen, compared to a phase when estrogen and progesterone are present.

My guess is that it is more rewarding to be around women who are in their pre-ovulatory phase.

What is the purpose of this effect of neurons on reward centers? Is it to make women get greater enjoyment from sex when they are more likely to get pregnant?

Reward system circuitry includes: the prefrontal cortex, seat of thinking and planning; the amygdala, a fear center; the hippocampus, a learning and memory hub; and the striatum, which relays signals from these areas to the cortex. Reward circuit neurons harbor receptors for estrogen and progesterone. However, how these hormones influence reward circuit activity in humans has remained unclear.

To pinpoint hormone effects on the reward circuit, Berman and colleagues scanned the brain activity of 13 women and 13 men while they performed a task involving simulated slot machines. The women were scanned before and after ovulation.

The fMRI pictures showed that when the women were anticipating a reward, they activated the amygdala and a cortex area behind the eyes that regulates emotion and reward-related planning behavior more during the pre-ovulation phase (four to eight days after their period began) than in the post-ovulatory phase.

When they hit the jackpot and actually won a reward, women in the pre-ovulatory phase activated the striatum and circuit areas linked to pleasure and reward more than when in the post-ovulatory phase.

Both reward anticipation and reward reception were enhanced by estrogen.

The researchers also confirmed that the reward-related brain activity was directly linked to levels of sex hormones. Activity in the amygdala and hippocampus was in lockstep with estrogen levels regardless of cycle phase; activity in these areas was also triggered by progesterone levels while women were anticipating rewards during the post-ovulatory phase. Activity patterns that emerged when rewards were delivered during the post-ovulatory phase suggested that estrogen's effect on the reward circuit might be altered by the presence of progesterone during that period.

So then do women enjoy life less after they've ovulated? Also, do women on birh control pills get more or less pleasure from rewards? Same question for post-menopausal women who have less estrogen in their bodies? Do they get less of a thrill from rewards?

What is going to happen with this information in the long run? Imagine drugs that cause or block the effects of estrogen on reward centers and pleasure-related neurons. Will women choose to have their minds always in the pre-ovulatory state and feel more reward from wins and gains? Or will they choose to block the effects of higher estrogen on their brains?

Share |      Randall Parker, 2007 February 03 02:51 PM  Brain Sexuality


Comments
rsilvetz said at February 3, 2007 5:46 PM:

You would have to really test women on birth control for enjoyment levels. The estradiol in the pills drives SHBG thru the roof which in turn dampens all their androgens. Women who maintain high free-testosterone levels maintain sex drive while those that don't, well -- sex drive tanks. So you have to stratify by free testo levels and then test for challenge-reward stimuli.

Randall Parker said at February 3, 2007 9:02 PM:

Robert Silvetz,

So then does the birth control pill decrease general drive? Does it make women less motivated to achieve? Testosterone gives people drive - and not just sexual drive...

rsilvetz said at February 3, 2007 10:58 PM:

Hi Randall,

The short answer is yes -- I could probably dig up the reference -- a fair fraction of women (10%?) also lose their zest for life/achievement etc, so I would in fact expect general drive to be affected.

Randall Parker said at February 4, 2007 9:08 AM:

Rohert,

Check out a recently posted sad story in the effects of oral contraceptives in the comments of a previous post I did on contraceptives and libido. The woman experienced a big enduring change. She doesn't know how to undo the change. How to bring down SHBG?

aa2 said at February 4, 2007 11:51 PM:

Birth control may be a big factor for the change of women in our western societies over the last 50 years. I personally would outlaw them in a European nation for healthy women, until the birth rate came above replacement levels. The people who want to reduce our populations don't want women to know that there is any side effects.. and try to pass off side effects the women do experience as not related to the pills.

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