What Matters? Week 4

Gray and white matter,

Matter connecting to world;

Nutrition matters

That Brainy Feeling or I’m Feeling All Sparkly Upstairs - Week 4

Relax and brreeeeathhhe; no big long crammed-too-full posting this week. But there were a couple of things in the instructor’s notes concerning brain development and cognitive change.

First: a LOT of myelination occurs postpartum; Babinski’s reflex (an upside ‘J’ stroke on the plantar surface of the foot) is normally elucidated in infants up to about a year of age. The reason is myelination of the spinal cord not complete at birth, resulting in a spinal cord reflex action rather than being suppressed by the cerebral cortex (http://bit.ly/UFnyKY). If Babinski’s reflex is noted in adults, it is a sign of spinal cord damage, lesions, tumors, etc. and signals pathology. Also, recall from the text that the human brain is not fully mature until about 30 years of age, especially the executive functions. That’s the stuff Leah mentioned in her notes about frontal/prefrontal lobe development. 

My interest here focuses on nutrition; myelination requires lipids (fatty acids) to occur properly. If the mother’s contains insufficient fatty acids, myelination will slow, placing constraints on developmental milestones. In a rat study, researchers found that dietary fat regulated how well myelination proceeded (abstract here: http://1.usa.gov/ZSicfE). A separate study found that maternal diets (both pre/postpartum) high in these fatty acids, actually accelerated myelination. (They used the term “precocious appearance”; in other words, the reflexes of the baby rats matured earlier and stronger than the control group.) I like words/phrases like that; they are so rich in depth and meaning – like up or down regulation of gene expression. It is clear that proper nutrition pre/postpartum is essential in both mother and baby to achieve proper neural system development. The transfats of French fries, potato chips and snack foods are not the kind of fatty acids that promote myelination.

Here’s a great little synopsis of myelination both in the peripheral/central  nervous systems: http://bit.ly/ZSjZkT.

Gee, the words are starting to pile up :-}

Ok here’s the second: on the pruning part in the notes, I think most of us get the concept: use it or lose it. So, if a neural circuit is busy all day long doing its little job of polarizing/depolarizing it gets to stay. Sort of like a quiet but regularly used side street, say the ‘road’ to your tongue. At first there’s not a lot of traffic, but as time goes by a lot of road construction is underway connecting distant towns like Wernickeville, Brocaville and Middleearville (road map: http://bit.ly/ZSkSKc). 

Pretty soon that first little neuron can’t handle all the traffic, so those glial cells I wrote about last week commence turning the single lane road into a multilane complex to make all the connections. The oligodendrocytes are chatting with the neurons which advise things could go a lot faster with a little blacktop (myelin), and so the oligos punch the clock and get to work. And the more the circuits to various organs/functions are used, the more complex and multilayered the system becomes. And when they’re all done (well, they’re never done), you are able to go talking and walking and looking and turning and listening (no texting pls) to nature’s wonderful world – all at the same time and without hardly a thought about all the processes involved. Well, except if bite your tongue while chewing gum!

And putting that whole complex system together is the result of synaptogenesis, the capacity and efficiency mentioned in Leah’s notes. 

To Reflect Upon.

Nurture - Week 3 Haiku

Love falling softly
Through mother's touch on soft new skin;
Shines back through bright eyes.

Fast Tracking or Let's Get Exponential + Some Gender Identity Tidbits - Week 3

¹fast–track

 adjective \ˈfas(t)-ˌtrak\

Definition of FAST-TRACK

1 : of, relating to, or moving along a fast track <fast–trackexecutives>

2 : of, relating to, or being a construction procedure in which work on a building begins before designs are completed.

In the brain development PBS linked article (http://www.pbs.org/wnet/brain/episode1/index.html), they mention that neural tube development occurs at about the rate of 250,000 neurons/minute. That translates to 360,000,000/day. Recalling last weeks material, that neural tube is completed in 11 days. Hmmm, that's 15,000,000/hr; or 360,000,000/day; which translates to a staggering 11 day total of 3,960,000,000 cells or 3.96x10⁸.  That's fast tracking. Certainly reinforces prenatal nutritional requirements and the complications that may result if deficient.

The article this week on "Babies, Bonds and Brains" has parallel considerations. First, the above numbers reflect 11 days of neural development; from there, brain development continues and the final numbers must be staggering. This week's article suggests the number of connections (synapses) between these nerve cells increases by about 20x during an infant’s first several months are 2x that in a 2 year old. That's a lot of neurons and their supporting glial mates, without whom neurons just barely function. As mentioned, as we develop, the neural landscapers (glial cells) are always at hand "pruning" away the circuits and synapses that are in disuse and create new neural pathways in response to new or increased stimuli. 

Sort of like the living bridges of the Meghalaya (http://youtu.be/5jrmm7gjZGE) - except one can appreciate how fast the human brain can build its "new bridges". Experiences (stress, lovelessness, affection, love, nurturing,) are the dynamic forces changing both the neuronal circuitry and the "living bridges". The far reaching effects of lack of nurture and attachment I find are amazing. From depressed immune systems to what seems like PTSD in the extreme abuse/neglect situations, leave me shaking my head in wondering how it all works. It seems we’re clearly built to love and be loved, with all the breadth and depth that word encompasses.

In another lifetime, I was a DEA agent. During one undercover investigation, I walked up to the street entrance apt and met my connection, a young couple. They were sitting on the front steps, just finishing shooting up with heroin (it was a very hot Chicago summer evening).  I went inside and found their 9 month old lying in a bassinette; feces were coming out both leg openings of the diaper in such large quantities, I guessed the baby hadn't been changed for two day. A bottle of formula was propped up on the edge at the baby’s mouth. The scale of neglect was so huge and so extensive; it was difficult for me to maintain focus on what I was there for. It has been the only time in my life I became so enraged, I wanted to shoot someone. I've never forgotten that little tyke and wondered if it ever had any chance at all at a life. The case was handed over to someone else and I have no recollection of the outcomes. Perhaps child protective services were finally notified, as I detailed the conditions of the baby in my report.

To close this section, I’d like any reader to reflect on a couple of aspects of the neuroanatomist Santiago Ramón y Cajal, 1852 – 1934. (http://bit.ly/11fsULe). Using just simple microscopes he painstakingly hand – mapped neurons and their circuits of the brain.  Below, I've provided two examples of his work; one of a single neuron and one showing the synaptic and branching of active neural circuits.  Note the complex routing, connections and networks. Imagine the glial cells nudging more connections in really active neurons, even calling for new neurons to keep up with the traffic. In a small way, perhaps it will foster an appreciation for the complexity and wonder of our brains. Not to mention, how a guy with a microscope and a pen, started figuring out for us how these things work.

A single neuron

Neuronal Networks


Here's the Promised Tidbits
Well, they're sorta big ones! More satisfying :-}

After reading the materials concerning gender, it seemed that at times, the concepts of gender identity and the conformation of gender roles were somewhat/sometimes conflated. I want to make it crystal clear that gender identity is the gender that one perceives her/his self and is not something that is shaped through the early developmental years. Gender identity is established in utero and complete at birth. But it is also clear that once gender identity is established, the expression of that identity is shaped by culture, parenting, etc. I'm reminded of the transwoman in Saudia Arabia who walked through a shopping mall in a full burka. She was arrested because her gait was not consistent with a cis-gendered female. She was not well treated.

A group of Dutch researchers studied the brains of transgendered male → females and found a certain critical area of the brain (BST_c) that controls gender identity was the same as in cis-gendered females. This part of the brain is formed in response to prenatal hormone secretion as up/downregulated by gene expression. There are two particular times in prenatal development that these hormones play a crucial role in gender identity. One is occurs about at the 4 – 6 week period and the last closer to the end of the third trimester (sorry cites not available). The result is that gender identity is formed in utero and is nothing the individual “decides”. I found it interesting that the one female → male transgender (does there have to be a label?) had the BST_c of a normal male.

Here’s the research results:

Volume 1, Number 1, July - September 1997 Reprinted with permission by the authors from NATURE, 378: 68-70 (1995) A Sex Difference in the Human Brain and its Relation to Transsexuality By J.-N. Zhou, M.A. Hofman, L.J. Gooren and D.F. Swaab Citation: Zhou J.-N, Hofman M.A, Gooren L.J, Swaab D.F (1997) A Sex Difference in the Human Brain and its Relation to Transsexuality. IJT 1,1, http://www.symposion.com/ijt/ijtc0106.htm Acknowledgements References Transsexuals have the strong feeling, often from childhood onwards, of having been born the wrong sex. The possible psychogenic or biological etiology of transsexuality has been the subject of debate for many years [1,2]. Here we show that the volume of the central subdivision of the bed nucleus of the stria terminalis (BSTc), a brain area that is essential for sexual behavior [3,4], is larger in men than in women. A female-sized BSTc was found in male-to-female transsexuals. The size of the BSTc was not influenced by sex hormones in adulthood and was independent of sexual orientation. Our study is the first to show a female brain structure in genetically male transsexuals and supports the hypothesis that gender identity develops as a result of an interaction between the developing brain and sex hormones [5,6]. Investigation of genetics, gonads, genitalia or hormone level of transsexuals has not, so far, produced any results that explain their status [1,2]. In experimental animals, however, the same gonadal hormones that prenatally determine the morphology of the genitalia also influence the morphology and function of the brain in experimental animals in a sexually dimorphic fashion [6,7]. This led to the hypothesis that sexual differentiation of the brain in transsexuals might not have followed the line of sexual differentiation of the body as a whole. In the past few years, several anatomical differences in relation to sex and sexual orientation have been observed in the human hypothalamus (see [6] for a review), but so far no neuroanatomical investigations have been made in relation to the expression of cross-gender identity (transsexuality).

We have studied the hypothalamus of six male-to-female transsexuals (T1-T6); this material that was collected over the last eleven years. We searched for a brain structure that was sexually dimorphic, but not influenced by sexual orientation, as male-to-female transsexuals may be "oriented" to either sex with respect to sexual behavior. Our earlier observations showed that the paraventricular nucleus (PVN), sexually dimorphic nucleus (SDN) and suprachiasmatic nucleus (SCN) did not meet these criteria ([6] and unpublished data). Although there is no accepted animal model for gender identity alterations, the bed nucleus of the stria terminalis (BST) turned out to be an appropriate candidate to study for the following reasons. First, it is known that the BST plays an essential part in rodent sexual behavior [3,4]. Not only have estrogen and androgen receptors been found in the BST [8,9], it is also a major aromatization centre in the developing rat brain [10]. The BST in the rat receives projections mainly from the amygdala and provides a strong input in the preoptic-hypothalamic region [11,12]. Reciprocal connections between hypothalamus, BST and amygdala are also well documented in experimental animals [13-15]. In addition, sex differences in the size and cell number of the BST have been described in rodents which are influenced by gonadal steroids in development [16-18]. Also in humans a particular caudal part of the BST (BNST-dspm) has been reported to be 2.5 times larger in men than in women [19]. The localization of the BST is shown in figure 1. The central part of the BST (BSTc) is characterized by its somatostatin cells and vasoactive intestinal polypeptide (VIP) innervation [20]. We measured the volume of the BSTc on the basis of its VIP innervation (Fig. 2). The BSTc volume in heterosexual men (2.49±0.16 mm3) was 44% larger than in heterosexual women (1.73±0.13 mm3) (P<0.005) (Fig. 3). The volume of the BSTc of heterosexual and homosexual men was found not to differ in any statistically significant way (2.81±0.20 mm3) (P=0.26). The BSTc was 62% larger in homosexual men than in heterosexual women (P<0.005). AIDS did not seem to influence the size of the BSTc: the BSTc size of two heterosexual AIDS-infected women and three heterosexual AIDS-infected men remained well within the range of the corresponding reference group (Fig. 3). The AIDS-infected heterosexuals were therefore included in the corresponding reference group for statistical purposes. A small volume of the BSTc (1.30±0.23 mm3) was found in the male-to-female transsexuals (Fig. 3). Its size was only 52% of that found in the reference males (P<0.005) and 46% of the BSTc of homosexual males (P<0.005). Although the mean BSTc volume in the transsexuals was even smaller than that in the female group, the difference did not reach statistical significance (P=0.13). The volume of the BSTc was not related to age in any of the reference groups studied (P>0.15), indicating that the observed small size of the BSTc in transsexuals was not due to the fact that they were, on average, 10 to 13 years older than the hetero- and homosexual men. The BST plays an essential role in masculine sexual behavior and in the regulation of gonadotrophin release, as shown by studies in the rat [3,4,21]. There has been no direct evidence that the BST has such a role in human sexual behavior but our demonstration of a sexually dimorphic pattern in the size of the human BSTc, which is in agreement with the previously described sex difference in a more caudal part of the BST (BNST-dspm) [19], indicates that this nucleus may also be involved in human sexual or reproductive functions. It has been proposed that neurochemical sex differences in the rat BST may be due to effects of sex hormones on the brain during development and in adulthood [22,23]. Our data from humans however, indicate that BSTc volume is not affected by varying sex hormone levels in adulthood. The BSTc volume of a 46-year-old woman who had suffered for at least 1 year from a tumour of the adrenal cortex that produced very high blood levels of androstenedione and testosterone, was within the range of that of other women (Fig. 3: S1). Furthermore, two postmenopausal women (aged over 70 years) showed a completely normal female-sized BSTc (Fig. 3: M1, M2). As all the transsexuals had been treated with estrogens, the reduced size of the BSTc could possibly have been due to the presence of high levels of estrogen in the blood. Evidence against this comes from the fact that transsexual T2 and T3 both showed a small, female-like BSTc (Fig. 3), although T2 stopped taking estrogen about 15 months before death, since her prolactin levels were too high and T3 stopped hormone treatment since a sarcoma was found about three months before death; also a 31-year-old man who suffered from a feminizing adrenal tumour which induced high blood levels of estrogen, nevertheless had a very large BSTc (Fig. 3: S2). Our results might also be explained if the female-sized BSTc in the transsexual group was due to the lack of androgens, because they had all been orchidectomized except for T4. We therefore studied two other men who had been orchidectomized because of cancer of the prostate (one and three months before death: S4 and S3, respectively), and found that their BSTc sizes were at the high end of the normal male range. The BSTc size of the single transsexual who had not been orchidectomized (T4) ranged in the middle of the transsexual scores (Fig. 3). Not only were five of the transsexuals orchidectomized, they all used the antiandrogen cyproterone acetate (CPA). A CPA effect on the BSTc does not seem likely, because T6 had not taken CPA for the past 10 years, and T3 took no CPA during the two years before death and still had a female-sized BSTc. In summary, our observations suggest that the small size of the BSTc in male-to-female transsexuals cannot be explained by differences in adult sex hormone levels, but is established during development by an organizing action of sex hormones, an idea supported by the fact that neonatal gonadectomy of male rats and androgenization of the female rats indeed induced significant changes in the number of neurons of the BST and suppressed its sexual dimorphism [17,18]. Considered together with information from animals, then our study supports the hypothesis that gender identity alterations may develop as a result of an altered interaction between the development of the brain and sex hormones [5,6]. The direct action of genetic factors should also be considered on the basis of animal experiments [24]. We found no relationship between BSTc size and the sexual orientation of transsexuals, that is, whether they were male-oriented (T1,T6), female-oriented (T3,T2,T5), or both (T4). Furthermore, the size of the BSTc of heterosexual men and homosexual men did not differ, which reinforced the idea that the reduced BSTc size is independent of sexual orientation. In addition, there was no difference in BSTc size between early-onset (T2,T5,T6) and late-onset transsexuals (T1, T3), indicating that the decreased size is related to the gender identity alteration per se rather than to the age at which it becomes apparent. Interestingly, the very small BSTc in transsexuals appears to be a very local brain difference. We failed to observe similar changes in three other hypothalamic nuclei, namely, PVN, SDN or SCN in the same individuals (unpublished data). This might be due to the fact that these nuclei do not all develop at the same time, or to a difference between these nuclei and the BST with respect to the presence of sex hormone receptors or aromatase. We are now studying the distribution of sex hormone receptors and the aromatase activity in various hypothalamic nuclei in relation to sexual orientation and gender. Acknowledgements We thank Mr. B. Fisser, Mr. H. Stoffels, Mr. G. van der Meulen, and Ms. T. Eikelboom and Ms. W.T.P. Verweij for their help, and Drs. R.M. Buijs, M.A. Corner, E. Fliers, A. Walter and F.W. van Leeuwen for their comments. Brain material was provided by the Netherlands Brain Bank (coordinator Dr. R. Ravid). This study was supported by NWO. References Money, J. and Gaskin, Int. J. Psychiatry, 9 (1970/1971) 249. Gooren, L.J.G., Psychoneuroencrinology, 15 (1990) 3-14. Kawakami, M. and Kimura, F., Endocrinol. Jap., 21 (1974) 125-130. Emery, D.E. and Sachs, B.D., Physiol. Behav., 17 (1976) 803-806. Editorials Lancet, 338 (1991) 603-604. Swaab, D.F. and Hofman, M.A., TINS, 18 (1995) 264-270. Money, J., Schwartz, M. and Lewis, V.G., Psychoneuroendocrinology, 9 (1984) 405- 414. Sheridan, P.J., Endocrinology, 104 (1979) 130-136. Commins, D. and Yahr, D., J. Comp. Neurol., 231 (1985) 473-489. Jakab, R.L., Horvath, T.L., Leranth, C., Harada, N. and Naftolin, F.J., Steroid Biochem. Molec. Biol., 44 (1993) 481-498. Eiden, E.L., Hökfelt, T, Brownstein, M.J. and Palkovits, M., Neuroscience, 15 (1985) 999-1013. De Olmos, J.S. In: Paxinos, G. (Ed.), The Human Nervous System, Academic Press, San Diego, 1990, pp. 597-710. Woodhams, P.L., Roberts, G.W., Polak, J.M. and Crow, T.J., Neuroscience, 8 (1983) 677-703. Simerly, R.B., TINS, 13 (1990) 104-110. Arluison, M., et al., Brain Res. Bull., 34 (1994) 319-337. Bleier, R., Byne, W. and Siggelkow, I., J. Comp. Neurol., 212 (1982) 118-130. Del Abril, A., Segovia, S. and Guillamón, A., Dev. Brain Res., 32 (1987) 295-300. Guillamón, A., Segovia, S. and Del Abril, A., Dev. Brain Res., 44 (1988) 281-290. Allen, L.A. and Gorski, R.A., J. Comp. Neurol., 302 (1990) 697-706. Walter, A., Mai, J.K., Lanta, L. and Görcs, T.J., Chem. Neuroanat., 4 (1991) 281-298. Claro, F., Segovia, S., Guilamón, A. and Del Abril, A., Brain Res. Bull., 36 (1995) 1-10. Simerly, R.B. and Swanson, L.W., Proc. Natl. Acad. Sci. U.S.A., 84 (1987) 2087- 2091. De Vries, G.J., J. Neuroendocrinol., 20 (1990) 1-13. Pilgrim, Ch. and Reisert, I., Horm. metab. Res., 24 (1992) 353-359. Swaab, D.F., Zhou, J.N., Ehlhart, T. and Hofman, M.A., Brain Res., 79 (1994) 249- 259. Zhou, J.N., Hofman, M.A. and Swaab, D.F., Neurobiol. Aging (1995) in press. Zhou, J.N., Hofman, M.A. and Swaab, D.F., Brain Res. 672 (1995) 285-288. Swaab D.F. and Hofman M.A., Brain Res., 537 (1990) 141-148. Correspondence and requests for materials to: J.-N. Zhou, M.A. Hofman and D.F. Swaab Graduate School Neurosciences Amsterdam Netherlands Institute for Brain Research Meibergdreef 33 1105 AZ Amsterdam ZO The Netherlands L.J.G. Gooren Department of Endocrinology Free University Hospital 1007 MB Amsterdam The Netherlands Email: lgooren@inter.nl.net

What research is revealing regarding Transgenders

Transsexuals have, often from childhood onward, the strong feeling of having been born the wrong sex. Their desire to resemble the opposite sex is so strong that they are even willing to undergo major surgery and hormone treatments to achieve this end. This gender-identity problem has been proposed to develop as a result of a disturbed interaction between the developing brain and sex hormones. The search for structures that may be directly related to gender identity, i.e., structures whose anatomy is “female” in genetically male transsexuals, has so far led to our studies of the central nucleus of the bed nucleus of the stria  terminalis (BSTc). A female-sized nucleus was found in male-to-female transsexuals. The size of the BSTc was not influenced by sex hormones in adulthood and was independent of sexual orientation. Similar results were obtained when the total number of somatostatin neurons was determined in the BSTc. In the BSTc of one female-to-male transsexual a male volume and somatostatin neuron number was found; (Zhou et al., 1995b; Kruijver et al., 2000). Although the BSTc may be one of many structures involved in the phenomenon of gender identity, these results do support the hypothesis that gender identity develops as a result of an interaction between the developing brain and sex hormones.

(Structural and Functional Sex Differences In the Human Hypothalamus

Dick F. Swaab,*, 1 Wilson C. J. Chung,*, † Frank P. M. Kruijver,* Michel A. Hofman,* and Tatjana A. Ishunina*, ‡ *Graduate School Neurosciences Amsterdam, Netherlands Institute for Brain Research, Meibergdreef 33, 1105 AZ Amsterdam, The Netherlands; †Department of Psychology, University of Massachusetts, Amherst, Massachusetts; and ‡Department of Histology And Embryology, Kursk State Medical University, Kursk, Russia Received August 9, 2000; accepted March 1, 2001)

Footnote: I just watched:

Castle 

The Fast and the Furriest

Season 5 Episode 20 (42:45)

Aired on 04/15/2013 TV-14 CC

Take the beginning and the end and wayla: Erikson's first stage trust vs mistrust taken into the adult world. Nice snapshot. :-}

Gee, I'm Nervous! Or, I'm Feelin' that Excitation! - Week 2

Merriam-Webster - Nervous

1

archaic : sinewy, strong

2

: marked by strength of thought, feeling, or style : spirited<a vibrant tight-packed nervous style of writing>

3

: of, relating to, or composed of neurons

As the text states, "...the cerebral cortex...made up of ten billion neurons...", and that's just the cerebral cortex. The cerebellum is rich with neuronal activity, featuring tall Purkinje fiber ladders and all the various parts of the brain communicate with each other either directly or indirectly.   The startling origin of all these neurons begins as the period of the zygote transitions into the period of the embryo. In the space of ten days the neural plate(how did that form?) is transformed into a tube, that is closed on both ends eleven days later, providing the rudimentary brain/spinal cord structures. All happening from day nineteen to day thirty (http://bit.ly/139xSKZ). The maternal intake of folic acid in the pre/peri natal periods is crucial for proper neural tube development. I'd sure like a journal article or two on that relationship. 

Another fascinating aspect of the brain is the ratio of neurons to the glial cells. Glial cells, sometimes referred as neuroglia, are a family of helper cells, without which neurons function only marginally. There are four distinct types of glial cells, astrocytes, oligodendrocytes,  microglia and ependymal cells. Wikipedia provides a nice summary here: http://bit.ly/139zbK9. I mention them here for two reasons:1) I wrote an anatomy/physiology paper on them several years ago; 2) they outnumber neurons five-ten to one, forming about half or more of the cranial parenchyma. The astrocytes and oligodendrocytes are crucial to neural communication and networks. They not only assist the neurons to to chat with one another, they also chat with each other and determine when a neural circuit needs to expand, new ones are needed or when a network needs to be pruned - the synaptic pruning  mentioned in the text. 

Now consider the low birth weight neonates and the study showing these kids at three years old are cognitively impaired. The complexity of the developmental processes involved requires adequate nutritional building blocks (and perhaps less environmental stressors) to provide optimal neural physiology. Consider that oligodendrocytes are especially important in myelination of cerebral cortex neurons, which enables fast transmission and are facilitators of neural networks. Associate that with the increased maternal fat intake required in the third trimester which enables completion of myelination of the entire nervous system. It is not difficult to link inadequate nutrition with poor neural network formation and myelination, leading to the impaired functioning of the study group. 

Some loose thoughts about self-identity. Let's go back to the moment just before the two gametes fuse. Were either of those me? What were they made of - just materials from nature via the origins of the universe. Are those me? Are they mine? Am I them? So, if the sum of my physiological processes/substances aren't really mine, aren't really me (always being exchanged for new stuff), and if the "me" is not the stardust (would that be twinkle, twinkle?) I think of as me, then who am I?

Interesting journal article - Neural correlates of cognitive ability: http://bit.ly/12hgYLR.

Week 2 Haiku

Neuronal vining;
Touching, chatting, then pruning.
Parenchymal change.