It’s about time for female research subjects

In celebration of women’s history month, let’s talk about sex. More specifically, the scientist who put female sexual motivation on the (brain) map.

Dr. Mary Erskine (Oct. 8, 1946 – Dec. 12, 2007) uncovered the brain mechanisms that control female sexual behavior using the rat as a model animal. Prior to Erskine’s work, the all-male scientists characterizing sexual behavior in the rat concluded, 

the female shows no dramatic signs of orgasm and satiation comparable to those seen in the male.

Hence, how the brain controls sexual motivation was (and still is) mostly studied in male rats. 

Orgasm is a term that modern scientists would not use to describe rodent sex today (we certainly can’t ask rats if they are experiencing an orgasm). But to the extent that I’m willing to anthropomorphize, Mary Erskine found that for female rats, pleasure depends on power. That is, if female rats can control a sexual interaction, they find it rewarding. This makes sense; for us humans, knowing where your clitoris is, is power! 

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Mary changed the way sexual behavior testing was conducted to allow for the study of female sexual behavior. Since male rats are nearly twice the size of females, males dominate sexual interactions in standard laboratory tests. However, Mary created an escape space for female rats using a partition with a small, female sized escape hole. This environment better matches how rats mate in the wild. Mary found that if female rats can control the timing of a sexual interaction, they will. They chose when to exit the escape box to engage in sexual contact (or intromission) and when to retreat. Erskine’s predecessors, interpreted female attempts to time intromissions by briefly escaping from males as sexual aversion.

The presence an aversive drive in the mating situation represents, of course, a major difference between the male and female rat, since the male shows no aversion to the female at any time.

In contrast, Erskine linked female control to sexual motivation and sexual motivation to reproductive success: She identified an adaptive phenomenon. Females that control the timing of sex get pregnant twice as fast. That is, the female’s resultant timing or pacing of sexual contact causes hormonal changes that promote pregnancy. In a world where mating means exposing yourself to predation, this mechanism is highly advantageous for the female rat! 

Studying sexual behavior in rodents has been valuable for humans. We’ve learned how mammalian brains regulate complex social experiences, make decisions about what to do and when to do it, and consolidate this information over time. We’ve made massive progress in understanding how hormones produced by our reproductive organs alter the function of cells all across the body and within the brain to coordinate behavior. Ultimately, however, our science is only as good as our scientists. Scientists expend every effort to maintain objectivity in research. Yet, we operate in a larger cultural context that dictates who gets to become a scientist in the first place and which scientific questions merit answers. Add to all this the understanding that it is a scientist's unique and subjective experiences that govern how scientific data are interpreted. 

As we celebrate the impact women have had on science during #womenshistorymonth, consider here that an entire field of neuroscience research was born from Mary’s Erskine’s different perspective.