Doc Bushwell's Chimpanzee Refuge

Tuesday, August 09, 2005

Pink and blue matter




So my elder kid is off in Boston for summer school at the World's Greatest University. Don't be impressed. If a high school student has a B average, seems motivated, and the parents are willing to fork over tuition, the W.G.U, more appropriately known as the World's Greediest University, is quite happy to take him or her in like Flint.

Over the Fourth of July weekend, my son traveled by train to visit dear old Mumsy and Pops. On the day of his return trip, I knew we were cutting it close when I decided to offer a lunchtime sacrifice of animal flesh to the patriotic altar of the Weber grill. I figured if my kid and spouse left a half hour before the departure time, all would be well since the Amtrak site said the train was running 6 minutes late. They took off. Not long after his father delivered him at the station, I received a call from my son, who said he didn't have much time to talk since the battery was low on his cell phone. He was unable to find the notice for his train on either the monitor or the board. I advised him to go talk to the ticket agent, and then...the connection cut out. I hoped for the best, and over the course of the evening, I tracked the train which he allegedly boarded. The arrival time for the train on which he might, or might not, have traveled, came and went, followed shortly by a call from a concerned adult in Cambridge who was awaiting his return. I assumed he caught the next train, which was running an hour late. In spite of this rational assumption, I nonetheless was freaking out with motherly worry: "Why didn't he use a pay phone and call me!!??" Finally, a good three hours after he was supposed to arrive in Boston, he called and all was well. Nonetheless, winding down from worried mother mode was slow, so I didn't go to sleep until the wee hours of the morning, and was thus semi-wiped out for the duration of the next day.

Lesson learned by the kid: make sure the cell phone is charged before a trip and have some spare change in the old pocket.

Now my otherwise intelligent son's lack of attention to contigency plans or other means of ordered thinking simply may be due to adolescence, but his thought process also hints of the differential functioning of the male and female mind. Although my friend, Pete, may be better known in the Boston region for his athletic prowess (placed 23rd in the U.S. Men's Olympic Marathon Trials five years ago), he is an accomplished fellow in other areas, including his vocation which is scientifically oriented. He also has a propensity for wry observations of people and life. When comparing the ways in which men and women organize their memories, Pete said something to this effect: women's minds are like Rolodexes with everything in their place which can be quickly accessed, whereas men's minds are like an Etch-a-Sketch: capable of holding a great deal of detail but prone to erasure.

I have often quoted Pete's droll observation because I think it is true in that men and women process information differently. What I find fascinating is that although men and women take divergent paths at problem solving, they arrive at the same conclusions whether by Rolodex or Etch-a-Sketch. Having survived the past couple of decades or so, I recall the rampant feminist-inspired orthodoxy which held that most male and female human behaviors, aside from those directed toward mating, were culturally ingrained. However, as a budding scientist in the 70's, I had my doubts as to the politically correct sociological canon. This was solidified when I became a card-carrying scientist (I keep the card in my wallet) and became involved in the study of steroid biochemistry. I knew that the gonads and adrenals contained the requisite steroidogenic enzymes to produce hormones like our old friends, the progestins, estrogens, androgens, and corticoids, but I learned that the brain also has a set of of steroidogenic enzymes which synthesize steroids in situ. These steroids exert either non-genomic effects or genomic effects in the brain.

Neuroactive steroids, also called neurosteroids, act at the non-genomic level, meaning that they do not influence gene transcription. Their roles in the CNS are not completely elucidated but a signficant amount of research has ensued since their discovery in 1981. A good, albeit fairly technical, review article entitled "Neurosteroids and Psychiatric Disorders" by C.E. Marx describes the various neurosteroids, their interactions with receptors in the brain, and how they may modulate neurotransmitter function. Neurosteroids distinguish themselves from their gonadal and adrenal brethren by interaction with a different class of receptors called ligand-gated ion channels. Here's a neat little animation representing such a receptor: Ion channel at work! In this movie, the grey blob which attaches itself to the receptor (from the right) is the ligand. When it binds, the channel opens up and lets ions pass through to the other side of the cell. This causes a response, namely altering the excitability of the nerve cells. Thus neurosteroids which bind to these channels can exert effects in a timeframe of seconds.

The brain also contains another class of proteins to which steroids bind called nuclear hormone receptors (NHR). When steroids bind to their NHR partners, they act at the genomic level, meaning that they can "turn on" gene expression. In a simple model, a steroid, like testosterone or estrone, diffuses into the cell, then binds to the NHR. The activated NHR then relocates, or translocates as cell biologists like to say, to the cell's nucleus where it, along with other protein partners, sits down on a segment of DNA and turns on a gene which then goes on to express a particular protein. Here's a cartoon of the androgen receptor and its protein partners which illustrates how this funcitons. Note that it's quite different than the ion channel example above. In contrast to the rapid effects of the ligand-gated ion channels, NHR-induced changes at the genomic level take place over a much longer period of time, e.g. hours to days.

With the knowledge that steroids bind to these two major receptor classes in the brain, and exert a wide range of effects, it comes as no surprise that men's and women's brains appear to have different neural architecture and processing. These observations have been greatly aided by the advent of more precise imaging techniques. PET scans and MRI have allowed neuroscientists to gaze into the living human brain. Jill Goldstein, a principal investigator at the WGU's Medical School, used imaging technology to study brain function in schizophrenics and healthy patients. Her pioneering work revealed sex-based differences in the etiology of the disease as well as differences in control male and female subjects. Among Goldstein et al.'s findings for healthy male and female brains were the following:

  • The frontal cortex, where many higher cognitive functions occur, is bulkier in women than in men.

  • The limbic cortex, involved with emotional response, is bigger in women's brains.

  • The parietal cortex, which is associated with spatial perception, is larger in men's brains.

  • The amygdala, that part of the brain which is associated with heightened emotional arousal, is larger in the male brain.


  • The larger versus smaller comparisons are proportional, i.e., the size of a sub-structure is considered in comparison to overall volume of each brain. Typically, the proportionate size of a part of the brain is thought to correspond to its importance to the organism. Primates are visual animals, so the brain sub-structures associated with vision tend to be larger. Olfactory-oriented animals, like dogs or rats for example, have larger sub-structures associated with the sense of smell. Thus, the differences in the sizes of human male and female brain sub-structures suggests that hormones may play a role in shaping these areas. It is believed that hormones in the pre-natal environment assist in differentiation of the fetal brain. In laboratory animals, those areas with high densities of steroid NHR's during brain development correspond to the same regions which diverge in men's and women's brains. It is likely that the differences in the male and female brain are intrinsic, and present from birth.

    This is only the tip of the neural iceberg with regard to the complexity of research directed at the human male and female brain function. Since this is a blog, and I tend to be too wordy as it is, I'm not going to attempt to write a scholarly review. I have a copy of an accessible-to-the-layman article from the May 2005 issue of Scientific American entitled "His Brain, Her Brain" by Larry Cahill. If you're interested in obtaining this for further reading, please let me know.

    As with any research directed toward human biology and behavior, misinterpretation abounds. Enter Lawrence Summers, the current president of the W.G.U.

    Summers is a controversial president. He caused a ruckus in those hallowed ivy halls by his notion that the undergrad curriculum should be overhauled to reflect modern times, supporting the expansion of the Harvard campus across the Charles into Boston, and twitting Cornel West so much that West was driven to join the faculty in Einsteinville. The first two of these are commendable; the latter one, well, I have yet to see West "keepin' it real," as a putative intellectual role model for the minority students in the Einsteinville regional public school system. That's no surprise since he surely didn't hang out in the 'hood in the far more diverse Cambridge Public Schools, and evidently preferred to associate with Ivory Tower types or Famous People of Color. But I digress...

    Larry Summers truly stirred the pot early this year at a conference on women and minorities in science and engineering. When contemplating the small number of women at the elite levels of the field, he speculated that perhaps the reason women are underrepresented is that their innate ability in math and science is less than that of men. As one might imagine, the shit hit the fan upon those remarks, which Summers flailingly noted were supposed to be controversial. Here is the transcript of Larry Summer's fateful speech. As predictable as the screams of outrage were, so were the "Oh, this is an overreaction" responses. Interestingly, none of the "overreaction" responses came from women scientists and engineers.

    The chilly atmosphere for women scientists, particularly at the senior level, is well recognized within the W.G.U. Although I am not a liberty to name them, I personally know two women scientists on the faculty who have attested this to me, and they were among a significant group to protest Summer's remarks. So, it wasn't just the women's studies humanities types who were outraged. It hit much closer to home.

    The much beleaguered Larry Summers was correct in his observation that there are differences in men's and women's brains, but he really needed to do his homework on this complex research area before that speech. Women's and men's scores for tests of general intelligence are equivalent. Now test scores in math suggest that guys have a bit of an edge, and with men's ability to tap into spatial reasoning, something that really boosts mathematical understanding, maybe there's something to this. However, there are women and girls who possess this enhanced spatial reasoning component. Me , for example. I can mentally twirl three dimensional objects around in my little noggin, which has certainly helped me envision molecules in three dimensions. Who knows? Maybe my parietal lobe was slightly "androgenized" when pre-I was in utero. Also, there's evidence that women and men arrive at equivalent mathematical solutions using different neural networks.

    Even if men have a slight edge in mathematics, which might barely register as statistically significant, environment acts as a huge multiplier of very small differences, i.e., boys are encouraged to excel at math whereas girls are not, or were not. I say "were" because the younger generation of women increasingly embraces math, and consequently, any gap between boys and girls in standardized math scores is rapidly closing. Anecdotally, my son's AP calculus class was divided almost equally between young men and women, something one did not see when I was a teenager.

    As different as men and women are morphologically and behaviorally, it's little wonder that our respective brain structures show variation. Heck, I regard men as a separate species. I have worked in a predominantly male field for years now (there are more young women in the discipline these days, but as one rises throught the ranks, you see fewer old broads), and by and large, I truly appreciate the male mind although at times I find you guys baffling. Rolodex or Etch-a-Sketch...viva la difference!

    4 Comments:

    At 11:32 PM, Blogger Suesquatch said...

    I remember being told, in algebra, that the girls didn't really have to worry about it except to pass the Regents exam, since we'd be getting married and wouldn't be using it.

     
    At 3:40 PM, Blogger wilson said...

    Holy catsnjammer's Doc, that was one hell of a treatise on the brain-behavior question. But it all makes good logical sense. My wife and I had a minor coniption the other day when she was preparing directions to our house to a female friend who will visit us. Gawd, I thought, why spend an hour or so writing up all this detail (which she sees) when you can sketch it out in 3 minutes or look it up on MapQuest in a few more.

    Mmm, your son's odessy reminds me of when at about the same age I was supposed to take the bus from Salt Lake to Colorado, and I hitched instead. Didn't tell anyone, and know one knew where I was for about 2-3 days.

     
    At 12:22 PM, Blogger Suesquatch said...

    Wilson, my husband and I have the same fight every time he gives me directions. "Don't tell me go three miles then turn northeast! Tell me where to make the left, and what's there so I know!"

    I need, "Make a right at the Red Lobster, and then you'll be on Munsey Street. Follow that until you get to Crabtree - there's a Target on the left, just before the intersection."

    Three miles north and then east north east my ass.

     
    At 11:39 PM, Blogger wilson said...

    I hear you Sue. I basically have a GIS reference map in my head and that's how I get around. None of this flower pot by the big green sign stuff!

    And what's with this long monologue at the end of the day--all those details that just have to be conveyed...

    Me, "yup, work was fine"

     

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