Monday, June 20, 2005

Orgasm in the Brain, or Porn for Neuroscientists

Sometimes I really think I went into the wrong area of cognitive science. I mean, I'm not really a big fan of cognitive neuroscience; I tend to think it's a faddish discipline that tells us little more than that cognition happens in the brain (a joke that I stole, but since none of you are likely to know the person from whom I stole it, and since he probably isn't reading this, I'm going to pretend it's my own). But when I read about studies like the one I'm about to describe, my opinion of imaging research changes dramatically, not so much because I think it's more scientifically sound, but because I would really like to run the experiments.

The research, which I discovered through John Hawks (my new source for all things cool and neuroscientific), involves looking at the brain regions that are active during sexual arousal and orgasm. The article that John links in his post is mostly about a study on female orgasms, and more specifically on the differences between the brain areas that are active during faked and real female orgasms. That research is so new that I can't find it on any of the article databases that I usually use. The research on male orgasm, however, was published a couple years ago, so I can talk about that*.

Here is the background: several studies of brain activation, or dysfunction as a result of brain lesions, during ejaculation have been conducted using rats, along with at least one study using nonhuman primates. These studies have been inconclusive with regard to the specific functions of different brain regions during ejaculation, and there are differences between the activation in rat and primate brains. These two facts limit our ability to draw conclusions about brain activation in human males during ejaculation from the animal literature. Now that we have some fairly good imaging techniques (in particular, fMRI and positron emission tomography, or PET), though, we can look at brain activation in humans during ejaculation directly, and bypass the animal literature altogether.

How, you might ask, do we get people to ejaculate while in a PET scan machine? Well, that's where this research gets interesting (for me, at least), and what makes me think I should have gone into the neuroscience of sex. Here is the description of the experiment, from the methods section of the above-linked paper:
The volunteers were asked to perform the following tasks twice: rest, erection, sexual stimulation, and ejaculation induced by sexual stimulation. To minimize motor activity by the volunteer during the scan, sexual stimulation was provided by his female partner by means of manual penile stimulation in the tasks stimulation and ejaculation. Manual stimulation was continued throughout ejaculation. The volunteer's head was maintained in position with a head-restraining adhesive band, and, to minimize visual input, volunteers were asked to keep their eyes closed.
Seriously, does this not sound like neuroscientist porn (complete with bondage)? If sessions were taped, how much do you want to bet that the videos are currently being sold on some neuroscience email group? Anyway, in order to make sure that the volunteers could perform the task, it was suggested that for a few weeks prior to the experimental session, they practice at home, "especially regarding minimizing head and limb movements." So the experiments were probably fun for the participants as well.

Once they had them in the machines, they took scans during stimulation and during orgasm, and later analyzed the data by comparing the stimulation scans to orgasm scans in 11 volunteers (only 8 of the 11 could be used for some analyses, for reasons discussed in the paper that are simply too uninteresting to mention in a blog post).

Most of the results are unsurprising. They found the strongest activation during ejaculation in the mesodiencephalic transition zone (MTZ), which is comprised of several regions involved in the brain's rewards system, and its dopamanergic reward system in particular. Specifically, the ventral tegmental area is part of the MTZ, and is associated with the pleasurable sensation people get from drugs like heroin and cocaine. Thus, orgasm and heroin highs appear to use the same brain structures in males. Activation was also found in the right thalamus and neighboring regions, which are associated with arousal and "visceral sensory responses." The right parietal lobe, which is also associated with sensation, was also active during ejaculation. All of this sounds about right. The same goes for the activation found in certain parts of the visual system, including the precuneus (visual memory) and the secondary visual cortex, because as the authors note, most of the volunteers reported using visual imagery during the session.

Finally, and perhaps this is a bit surprising, they found a lot of activation in the cerebellum. Traditionally, the cerebellum has been thought to be primarily involved in movement, but the volunteers' movements were restricted, and their female partners were doing all of the work. Recently (over the last decade or so), researchers have begun to realize that the cerebellum is involved in a lot more than just movement, though. In particular, it appears to be heavily involved in emotion, and the authors of the article explain its activation by arguing that cerebellum activity during ejaculation produces a "rush" similar to that experienced during other rewarding activities, such as heroin use and listening to pleasant music.

The researchers did find deactivation in two areas, the amygdala and entorhinal cortex. These areas, especially the amygdala, are also associated with emotion. The amygdala is particularly associated with fear responses, and decreased activation in this area has been shown to cause euphoric states associated with drug use and intense love. So, the corresponding activation of the cerebellum and deactivation of the amygdala appear to cause the intense euphoric emotional state associated with orgasm.

Thus, in sum, human male brain activity during orgasm looks a lot like it does when we're doing drugs. The authors also note that it also looks more like nonhuman primate activation than rat activation, a fact which probably ruins a lot of potential jokes. Furthermore, the bulk of the activation during ejaculation was in the right hemisphere, which makes me wonder whether left-handers have stronger orgasms (a speculation that is completely unwarranted by the data, but I'm pretending to be a cognitive neuroscientist now). Mostly, though, given the terrible resolution (both spatial and temporal) of the imaging techniques that are available today (both PET and fMRI were used in this study), what we've really learned is that male orgasm causes brain activation. The authors themselves note that the resolution isn't sufficient to distinguish the activation in different parts of the MTZ, and it's hard to say exactly which of the functions of the other multi-functional brain areas are involved, because we can't tell exactly which parts, much less which neurons, are active. As is usually the case with brain imaging studies, the conclusions involve inferences to the best theoretical bias. Still, we've got to start studying the role of the brain in male orgasm somewhere, sometime, and even if I don't think this sort of research tells us a whole hell of a lot, I sure wish I could get in on it.

* Just in case you're new to the blog, or you've forgotten, it's my policy not to comment on research that I only know about through articles in the popular press, because the press generally does a horrible job of reporting about science, especially cognitive science.

24 comments:

Andrew said...

Wow, great post. "Cognition happens in a brain" - that's brilliant...

Do you have the reference for this male orgasm paper?

Chris said...

Oh crap! I meant to link to the paper in the post. My not doing so makes the "above-linked paper" reference seem a bit strange, doesn't it? Anyway, I've added the link, but I'll link it here in the comments too:
Holstege, G., and a Bunch of Other People (2003). Brain activation during human male ejaculation, The Journal of Neuroscience, 23(27), 9185-9193.

Sanketh said...

Interesting post. I've been hearing about an increased focus on the fMRI based study of the brain. Loads of imaging people are in on it.

All in all the experiments look really controlled. This may be even more signifact when it comes to studying other parts of the brain. Alternatively how do the other probe based experiments work? It must be equally difficult for a person to behave a he/she normally would with a probe sticking into their head.

I loved the way you wrote it. I did catch this research about the female orgasm on CNN. It was a funny read. Trying catching that.

Anonymous said...

Has noone noticed that this information implies that telling someone to "experiment with sexuality" is morally equivalent to passing out heroin.

Anonymous said...

Yesterday, I read the well-known article about the relationship between criminal and genius accomplishment and age. Ages 25-35 are those in which most criminals and geniuses do their groundbreaking work, after which it's just a long decline. It's interesting to compare that article with this idea. Because the motivation of these young men of accomplishment seems to be sex, and as far as I can determine from this article here, the reason for sex seems to be centered on the amygdala. Fear is the opposite of love, as they say. And so, it seems likely to me that men do their best work in their younger years, while single, in an attempt (not just to win a girl) to reduce fear, feel the comfort associated with the reduction of fear, and essentially to find peace in the world (through a girl). The world is obviously a very stressful place, filled with hostility and war (likely fought for the same reason that geniuses do their best work when young: sex, love, freedom from fear), and amidst all that male competition, the object seems clear: peace of mind through love, sex, girls, and the like...all because of the evil amygdala.

happyseaurchin said...

nice blog
humour and info mix
and the comment preceding is pretty cool too

this was linked from a vid in youtube...

Anonymous said...

ebony gay fuck
hardcore gay fucking
hardcore gay anal
horny gay sex
horny gay boys
horny black gays
horny ass black gays
big cock gay
hot black gay guys fucking and sucking cock
big gay black cocks
gay stud

WOW GOLD said...

Nice blog. I a also ardent player of WOW GOLD. I love this game. Nice posting about wow gold. Thanks

asset liability management said...

I am not really sure if best practices have emerged around things like that, but I am sure that your great job is clearly identifed. I was wondering if you offer any subscription to your RSS feeds as I would be very interested and can’t find any link to subscribe here. Please come visit my site asset management softwaresy give me any valuable feedbacks.

supply chain management software solutions said...

I can see that you are an expert at your field! I am launching a website soon, and your information will be very useful for me. Thanks for all your help and wishing you all the success in your business. Please come visit my site supply chain management courses give me any valuable feedbacks.

flis said...

Generic Levitra help mens to treat very popular problem as ED. Best regards.

Body Skin Care said...

You owe a very nice and interesting blog. Feel free to check out my site body skin care when you got time.

Belly Fat How said...

Such interesting read and information, thanks for sharing this post. I will check back to read your other new posts. Please come visit my site Causes of Tummy Fat when you got time.

lilena said...

Online guide for kitchen garden, kitchen herd gardens, vegetable kitchen gardening. From planning, soil test, composting, common vegetables and herbs growing and caring.kitchen garden

lilena said...

Beauty Schools And Cosmetology Schools, Beauty Careers and Cosmetology training online guide. Find out how to find the best cosmetologist schools, career and job descriptions of spa therapist, hair designer, makeup artist.beauty career

Medicine Business Lookup said...

Good writing. Keep up the good work. I just added your RSS feed my Google News Reader..


Medicine Hat Business Directory, Medicine Hat Agriculture, fishing & Forestry, Medicine Hat Apparel & Accessories, business directory listings of Medicine Hat Automotive, Medicine Hat Business & Professional Services, Medicine Hat Computers, Communications & Electronics, home garden furnishing, real estate business finderMedicine Hat Construction & Renovation, Medicine Hat Education, Medicine Hat Entertainment & Media, Medicine Hat Family & Community, Lawyers Attorneys & Law Firms Directory Medicine Hat Finance & Legal,dinning restaurants Entertainment serving Medicine Hat Food & Beverages, Medicine Hat Health & Medicine Doctors Hospitals, Medicine Hat Home & Garden, Medicine Hat Industrial supplies & services , Medicine Hat Personal Care, Medicine Hat Public utilities & environment, Medicine Hat Real-Estate & Insurance, Medicine Hat Shopping & Specialty Stores, shopping, retail, department stores company guide of Medicine Hat Sports & Recreation, Medicine Hat Transportation, Medicine Hat Travel & Lodging

Red Deer Canada said...

Well Whattadya know, yet another great site to add to my reader! Google blog search has you pretty well indexed it seems! you have some brilliant contents!

Red Deer Business Directory, Red Deer Agriculture, fishing & Forestry, Red Deer Apparel & Accessories, business directory listings of Red Deer Automotive, Red Deer Business & Professional Services, Red Deer Computers, Communications & Electronics, home garden furnishing, real estate business finderRed Deer Construction & Renovation, Red Deer Education, Red Deer Entertainment & Media, Red Deer Family & Community, Lawyers Attorneys & Law Firms Directory Red Deer Finance & Legal,dinning restaurants Entertainment serving Red Deer Food & Beverages, Red Deer Health & Medicine Doctors Hospitals, Red Deer Home & Garden, Red Deer Industrial supplies & services , Red Deer Personal Care, Red Deer Public utilities & environment, Red Deer Real-Estate & Insurance, Red Deer Shopping & Specialty Stores, shopping, retail, department stores company guide of Red Deer Sports & Recreation, Red Deer Transportation, Red Deer Travel & Lodging

City of Delta said...

Good writing. Keep up the good work. I just added your RSS feed my Google News Reader..
Delta Business Directory, Delta Agriculture, fishing & Forestry, Delta Apparel & Accessories, business directory listings of Delta Automotive, Delta Business & Professional Services, Delta Computers, Communications & Electronics, home garden furnishing, real estate business finderDelta Construction & Renovation, Delta Education, Delta Entertainment & Media, Delta Family & Community, Lawyers Attorneys & Law Firms Directory Delta Finance & Legal,dinning restaurants Entertainment serving Delta Food & Beverages, Delta Health & Medicine Doctors Hospitals, Delta Home & Garden, Delta Industrial supplies & services , Delta Personal Care, Delta Public utilities & environment, Delta Real-Estate & Insurance, Delta Shopping & Specialty Stores, shopping, retail, department stores company guide of Delta Sports & Recreation, Delta Transportation, Delta Travel & Lodging

Canada Maple Ridge said...

Well Whattadya know, yet another great site to add to my reader! Google blog search has you pretty well indexed it seems! you have some brilliant contents!
Maple Ridge Business Directory, Maple Ridge Agriculture, fishing & Forestry, Maple Ridge Apparel & Accessories, business directory listings of Maple Ridge Automotive, Maple Ridge Business & Professional Services, Maple Ridge Computers, Communications & Electronics, home garden furnishing, real estate business finderMaple Ridge Construction & Renovation, Maple Ridge Education, Maple Ridge Entertainment & Media, Maple Ridge Family & Community, Lawyers Attorneys & Law Firms Directory Maple Ridge Finance & Legal,dinning restaurants Entertainment serving Maple Ridge Food & Beverages, Maple Ridge Health & Medicine Doctors Hospitals, Maple Ridge Home & Garden, Maple Ridge Industrial supplies & services , Maple Ridge Personal Care, Maple Ridge Public utilities & environment, Maple Ridge Real-Estate & Insurance, Maple Ridge Shopping & Specialty Stores, shopping, retail, department stores company guide of Maple Ridge Sports & Recreation, Maple Ridge Transportation, Maple Ridge Travel & Lodging

Surrey British Columbia Telephone Directory said...

Good writing. Keep up the good work. I just added your RSS feed my Google News Reader..

Surrey British Columbia Business Directory, Surrey British Columbia Agriculture, fishing & Forestry, Surrey British Columbia Apparel & Accessories, business directory listings of Surrey British Columbia Automotive, Surrey British Columbia Business & Professional Services, Surrey British Columbia Computers, Communications & Electronics, home garden furnishing, real estate business finderSurrey British Columbia Construction & Renovation, Surrey British Columbia Education, Surrey British Columbia Entertainment & Media, Surrey British Columbia Family & Community, Lawyers Attorneys & Law Firms Directory Surrey British Columbia Finance & Legal,dinning restaurants Entertainment serving Surrey British Columbia Food & Beverages, Surrey British Columbia Health & Medicine Doctors Hospitals, Surrey British Columbia Home & Garden, Surrey British Columbia Industrial supplies & services , Surrey British Columbia Personal Care, Surrey British Columbia Public utilities & environment, Surrey British Columbia Real-Estate & Insurance, Surrey British Columbia Shopping & Specialty Stores, shopping, retail, department stores company guide of Surrey British Columbia Sports & Recreation, Surrey British Columbia Transportation, Surrey British Columbia Travel & Lodging

Victoria British Columbia Telephone Directory said...

Well Whattadya know, yet another great site to add to my reader! Google blog search has you pretty well indexed it seems! you have some brilliant contents!

Victoria Business Directory, Victoria Agriculture, fishing & Forestry, Victoria Apparel & Accessories, business directory listings of Victoria Automotive, Victoria Business & Professional Services, Victoria Computers, Communications & Electronics, home garden furnishing, real estate business finderVictoria Construction & Renovation, Victoria Education, Victoria Entertainment & Media, Victoria Family & Community, Lawyers Attorneys & Law Firms Directory Victoria Finance & Legal,dinning restaurants Entertainment serving Victoria Food & Beverages, Victoria Health & Medicine Doctors Hospitals, Victoria Home & Garden, Victoria Industrial supplies & services , Victoria Personal Care, Victoria Public utilities & environment, Victoria Real-Estate & Insurance, Victoria Shopping & Specialty Stores, shopping, retail, department stores company guide of Victoria Sports & Recreation, Victoria Transportation, Victoria Travel & Lodging

Kamloops Guides Travel Destinations Shopping said...

Good writing. Keep up the good work. I just added your RSS feed my Google News Reader..

Kamloops Business Directory, Kamloops Agriculture, fishing & Forestry, Kamloops Apparel & Accessories, business directory listings of Kamloops Automotive, Kamloops Business & Professional Services, Kamloops Computers, Communications & Electronics, home garden furnishing, real estate business finderKamloops Construction & Renovation, Kamloops Education, Kamloops Entertainment & Media, Kamloops Family & Community, Lawyers Attorneys & Law Firms Directory Kamloops Finance & Legal,dinning restaurants Entertainment serving Kamloops Food & Beverages, Kamloops Health & Medicine Doctors Hospitals, Kamloops Home & Garden, Kamloops Industrial supplies & services , Kamloops Personal Care, Kamloops Public utilities & environment, Kamloops Real-Estate & Insurance, Kamloops Shopping & Specialty Stores, shopping, retail, department stores company guide of Kamloops Sports & Recreation, Kamloops Transportation, Kamloops Travel & Lodging

Mark said...

North carolina insurance agencies and brokers. North carolina car insurance, home owner insurance, health insurance, life insurance and more.
North carolina
Accident & Health Insurance
, North carolina
Aircraft & Aviation Insurance
, North carolina
Auto Insurance
, North carolina
Bail Bonds Referral Services
, North carolina
Boat & Yacht Insurance
, North carolina
Business Insurance
, North carolina
Business Interruption Insurance
, North carolina
Casualty insurance
, North carolina
Churches Insurance
, North carolina
Contents insurance
, North carolina
Corporate Insurance Adjusters
, North carolina
Credit Insurance
, North carolina
Crime insurance
, North carolina
Dental Insurance

Mark said...

North carolina insurance companies, insurance agents brokers and insurance guide. Comprehensive information about North carolina car insurance, home owner insurance, health insurance, life insurance and more.

North carolina
Disability Insurance
, North carolina
Earthquake insurance
, North carolina
Estate Planning Insurance And Legal Services
, North carolina
Farm, Crop, & Livestock Insurance
, North carolina
Financial Guaranty & Life Insurance
, North carolina
Fire Insurance
, North carolina
Fleet Insurance
, North carolina
Flood Insurance
, North carolina
Foreign Insurance
, North carolina
Franchising
, North carolina
Government Insurance Carriers
, North carolina
Group Insurance
, North carolina
Health Insurance