Saturday, May 30, 2015

Mesmeric Maleness in The Bostonians

What was Henry James thinking in his novel about women's suffrage?

Henry James lived in the closet, a Victorian "bachelor" transplanted from the US to Britain. I don't know much about either him or his work, but was somewhat mystified by his novel, The Bostonians. This review is spoilers all the way down, so quit now if you don't want to know the plot.

It is a triangle at heart, with one vertex named Olive Chancellor, a rich, young Boston woman dedicated heart and soul to the liberation of all women. James's prose is wonderfully evocative in the first half of the book, describing her joyless, earnest, spinster life, and particularly her hatred of men- individually, corporately, comprehensively. Her long-lost cousin Basil Ransom forms another vertex. He is not from Boston, but rather from a South that is still prostrate after being crushed by the Civil War, and setting up shop in New York as a lawyer, to very little success. He is apparently handsome and well-spoken, indeed well-mannered, but given to the most retrograde opinions, especially when it comes to women. When he comes to Boston for the first meeting of their lives, he meets the last vertex of the plot, the lovely Verena Terrant.

Verena is slightly younger than Olive, pretty, and the daughter of relatively low-class parents of whom the father is a mesmeric healer. He has passed his gift in some degree to his daughter, who is a captivating public speaker and is introduced to both Olive and Basil at a public meeting of the local women's movement sponsored by a friend of Olive's, and speaks briefly about women's rights and oppression. Verena is instantly recognized as a sensation, and Olive spends the first half of the book taking her under her wing as a protoge, to speak all the things she herself is not talented enough to say, at least in public.

The second half of the book describes an excruciating compaign by Basil, who has been equally captivated, though in an entirely different way, to win Verena's heart and shut her mouth. He jokes and mocks in a light-hearted way, but when they finally have a serious discussion, Verena is shocked and repulsed by his antediluvian attitudes. Verena is consistently portrayed as exceedingly bright and quick-witted, ready with sharp, though never bad-tempered, repartee.

So it is mystifying in the extreme that James engineers the plot to have Verena fall hopelessly in love with Basil, especially when there was another suitor much better suited, so to speak- rich, handsome, sympatico, supportive, and a wonderful pianist to boot! Olive had previously extracted a promise from Verena that she would never marry, so as to keep the sisterhood unsullied, but this is a promise that one knows immediately is as doomed as it is inappropriate, since Verena is cut from far more colorful cloth than Olive.

Nevertheless, James requires that Verena's brain falls out of her head to have us believe the ending, where Basil scoops her up from the spectacular proscenium where Olive has arranged to have Verena give the feminist manifesto to the assembled throngs of Boston's high society. Basil whisks her away to a married life- full, as James promises at the end, of tears. James makes out Basil as some kind of enchanting reptile:

Verena writes to Basil from her Cape Cod cottage, where he had invited himself in unannounced and proceeded to court Verena for several weeks:
"In the course of the day Ransom received a note of five lines from Verena, the purport of which was to tell him that he must not expect to see her again for the present; she wished to be very quiet and think things over. She added the recommendation that he should leave the neighborhood for three or four days; there were plenty of strange old places to see in that part of the country. Ransom meditated deeply on this missive, and perceived that he should be guilty of very bad taste in not immediately absenting himself. He knew that to Olive Chancellor's vision his conduct already wore that stain, and it was useless, therefore, for him to consider how he could displease her either less or more. But he wished to convey to Verena the impression that he would do anything in the wide world to gratify her except give her up, and as he packed his valise he had in idea that he was both behaving beautifully and showing the finest diplomatic sense. To go away proved to himself how secure he felt, what a conviction he had that however she might turn and twist in his grasp he held her fast. the emotion she had expressed as he stood there before poor Miss Birdseye was only one of her instinctive contortions; he had taken due note of that- said to himself that a good many more would probably occur before she would be quiet. A woman that listens is lost, as the old proverb says ..."

The Bostonians was not well-received in its day, nor since, I think, and no wonder. Here is the novelist, however skilled in his language, making marionettes of his characters instead of following their development based on their given, or even plausible, natures. George Eliot and Leo Tolstoy come to mind as authors who were far more organic in their creations and their willingness to properly mould their characters and then follow them, come hell or high water, to more believeable, as well as artistically deep and edifying, conclusions.

Then there are the sexual issues involved. Olive is commonly understood to be a lesbian, but I would disagree. Hatred of men is not by any means confined to lesbians, or characteristic of them. Olive is consumed by her ideas, and by do-good-ism, and while I may have missed something, there is no overt note of lesbianism in the book. The closest one comes is in the final scenes when Olive loses Verena in a cataclysm of public and private humiliation. Which is all understandable enough on the terms given, without making the additional inference of sexual involvement between the two, in any form whatsoever.

On the other hand, Basil's magnetism is wholly unaccountable. He is repulsive equally to Verena, to Olive, and to the reader. The courtship is posed as a brutal contest of will, which Basil wins, apparently due to being male, confident, and conservative, with no high opinion of women. Verena, on the other hand, tends to have a submissive character, first to her parents, who are lightly sketched in the book, and then to Olive. Her fall for Basil might be taken as a sort of opposites attract kind of story, or as a defect in her character whose double edge cuts Olive so grievously. Even so, given Verena's high consciousness, her conquest seems in the end an insult to women in general, which hopefully was not James's aim.

James communicates none of his own ideas on the suffrage question directly, treating each side with cruel derision, including Basil's. He makes of another character, Olive's sister Mrs. Luna, an eye-fluttering, female wile-throwing ogre. But he also presents the feminists as dedicated and effective in a public, political sense, which belies Basil's conviction that they have no place in public. He dreams of having the public's ear for his own views, and exhults when one of his articles is accepted by a obscure crank magazine, while Verena and Olive actually do have the public's ear and are busy organizing a lengthy campaign for empowerment. One which took a century and more to come to pass, but which James of all people should have appreciated somewhat better than he shows here.

  • Fix education by making better teachers, not by flogging them.
  • Libraries remain critical institutions.
  • Attention, Pluto, we are getting closer!
  • "This gene, HLA-B, is the most variable in the entire human genome, with thousands of known forms in existence."
  • Krugman on the coming Grexit: what if Germany is the last one holding Euros?
  • Bill Mitchell on the Grexit.
  • Bernie deserves a little more love.
  • Which side is Hillary on these days?
  • Smarter presidents do smarter things.
  • One more place where "free" markets don't work- electric utilities.
  • Occupy, indecisiveness, consensus, and theology. We need more structure.
  • Bailout risk ... indicates more regulation is needed.
  • On the brazen impunity of banks. And again..
  • Economic quote of the week, by Brad DeLong"... the aggregate economic costs to America of local NIMBYism now appear to me to be much larger than I would have thought reasonable decade ago: we are no longer a country in which people can afford to move to places where they will be more productive and more highly paid because high-productivity places refuse to upgrade their residential density."

Saturday, May 23, 2015

Atheists Have No Morals

A "truth" one comes up against all the time. And what are morals, anyhow?

You hear it all the time, as an atheist. "How can you be moral if you don't believe in anything?" Or some variation, perhaps citing Nietzsche in more sophisticated versions. It is an earnest enough question, given the life-long indoctrination that religions practice, and the dependence- intellectual, social, and moral- they foster.

In large part it is a tribal badge, this conviction that we are the good ones and the others are not good. Without even looking into the particulars of a community's moral code, one can assume that they view theirs as good, and those of outsiders as deficient if not evil. Even the mob has its code of honor. Religious community membership commonly functions as a social signal of trustworthiness, of goodness, good intentions, and proper upbringing. It was not long ago that everyone had to be a member of a local church, or the national church, or was shunned. The Muslim world exemplifies this tendency, currently.

In that it does not differ much from nationalism, or membership in any other club, masonic order, Elks lodge, etc. But religions claim much more. The typical religion not only forms a social club, but to validate its existence and inflate its importance, claims to know mysteries of which the lay bumpkin is ignorant- the nature of the cosmos, the ultimate reality, and the desires of god. It offers cosmic as well as personal transcendence, and offers an objective moral order. This is the rock on which believers lay their bigotry, that they have answers to moral questions which for the atheist have no answers, leading presumably to despair at best, murder at worst.

This moral order has been under continuous renovation from time immemorial, but that doesn't keep theologians from claiming that it is objective and absolute, thus giving them the power to conflate what supposedly is (what god wants) into what you should do. God said X, therefore you must do X. Only, so much scripture has piled up in the mean time, so full of conflicts and ambiguity that there is simply no way to a clear interpretation. On the one hand, this means that all fundamentalisms are doomed to be just as subjective and self-serving as the modernist / deviationist interpreters, and on the other hand, it means that the devout need the services of some interpreter, to render fatwas out of the thicket of their so-called objective text.

So it is not really objective after all, and one empathetic judge or practitioner can do more for her flock than gaggle of rule-divining theologians. But wait, isn't the mere proposition of an objective moral order worth something, and better than the utter nihilism of atheism? Isn't the dedication to seeking moral truths, however far we are from discerning or attaining them, one key point of religious engagement and a noble quest that separates us from the brutish, thoughtless, care-less atheists? And even if the moral order is ambiguous, isn't the promise of a deity who sees all and judges all a prod to good behavior?

Well, those are fascinating questions. If one doesn't really know what is good in a reliable, clear way, however, it hardly seems helpful to have an eye of Sauron watching our every move, or the promise of eternal suffering if we take a wrong step. Theologians themselves are all over the map on the reality of hell and the nature of posthumous justice. The Catholic church recently excused babies from their stay in purgatory, after centuries of selling indulgences and demanding pennance of endless varieties from its adherents to get their loved ones out of it. The fact of the matter is that we behave as if our conscience is our final judge, whatever our theological commitments. It is our conscience that is the field of moral battle, whether it is cultivated by a program of guilt and self-hatred, one of compassion and calm introspection, or one of empathy with other living beings of all kinds including humans.

More interesting is the question of the quest for moral laws. Our legal systems are always straining to make their apparatus and judgements seem as objective as possible. Guilty! Innocent! The lure of certainty seems to be a strong feature of human nature, and this illusion is surely of practical benefit to our systems of communal judgement. A cautionary example can be seen in the sorry state of our Supreme Court, which has, though its nakedly ideological bickering and party-line decisions, ceded any claim, even illusory, to objective, above-the-fray judgement.

So each religious tradition toils on, seeking that final, absolute moral object that will tell its children to go to bed on time and to turn off their cell phones. And the kicker is that they phrase this as finding out "what god wants", as if unloading all the ethical work to someone else elevates our moral nature. As you can probably tell, I regard this as quixotic at best, for our morals are very much ours, and are fundamentally subjective and biological. Had we no empathy for our fellow creatures, all would be lost, whatever the absolute moral code. Conversely, the person who cares for others and expands her sympathies to the largest possible extent has no need of theological commandments.

So seeking for objective morals is a fool's errand. But that doesn't mean that there is no room for serious moral inquiry, particularly that premised on things that are real, like the existence, needs, and desires of others and our many levels of individual and communal interest. It is complicated enough without invoking unseen phantasms.

Which brings us back to the atheist. Once one understands that there is no moral high ground for those who pound on bibles or cart about granite slabs inscribed with the ten commandments, and that communities will typically grant themselves moral superiority whatever the content of their codes and practices, (one is reminded of the extensive forgiveness the Catholic church lavished on its wayward priests), one is left on a much more even playing field.

Religious people are often perplexed by the apparent uprightness of atheists. They seem to be smart, well-behaved, oddly capable of putting up a good front and not getting into trouble. What could be going on? Statistics of course reinforce that impression. Atheists are indeed better-behaved than religious people, staying married longer, murdering less, having fewer abortions, committing less crime, etc. Truly, a conundrum.

It almost seems as though attentiveness to reality, not only in the form of science, evolution, and similar nerd-ish fixations which lead many atheists to their philosophy, but in the forms of civic affairs, politics, history, and psychology- attentiveness in short, to other people- might form a sounder moral education than indoctrination in some crazy story about master beings, resurrections, perfect scriptures, and eternal life. The humanist viewpoint (which is the general atheist position) may not have the plotline and passion of dramatic religions, but that may be a point in its favor. While religions often foster the best in humanity, they frequently seem to go astray, whether due to inattention in the face of the distracting, even overwhelming, story they carry, or directly from some part or interpretation of that story that gives official license to violate the most basic elements of human morality. The Israel-Palestine conundrum comes to mind.

When pressed, a religious person may offer that, sure, given the culture we have inherited, most atheists still manage to do alright, but this comes from the solid grounding that Christianity has given the West (insert culture and religion of choice here). At some point, if religion continues to decline and our cultures lose this moral anchor, there is no telling what might happen. Even those idyllic quasi-socialist countries of Scandinavia that are the most secular in the world still have state churches and their rich moral patrimony.

This gets the correlation all wrong, however. It is the most religious countries that are the most backward, and the least that are socially more just, with lower crime, incarceration, etc. If religion were having all these salutary effects, why aren't the most religious countries the happiest, and the least most ridden with crime and immorality? But we see the exact opposite. It is almost as though religion is a counter-reality coping mechanism that is most attractive in countries mired in poverty and corruption, if not causing poverty and corruption. And that it seems to be unnecessary in effectively atheist countries like Luxembourg, Norway, and Denmark, either personally to help people survive adverse conditions, or communally to foster good behavior.

Additionally, one should realize that in the West, Christianity had over a millenium of free reign during the Dark and Medieval Ages. Much good was done, but I think on balance, the moral tenor of the West has increased considerably since that time, in the wake of the Enlightenment. It was the Enlightnment that generated secular concepts like fundamental human equality, human rights, democratic government, rationalism in public policy as well as scientific investigation, and much more. As ideals, they owe quite a bit to the preceeding religious conceptions, but were remade on a secular basis that made them far more effective, as it was the church itself that was a significant source of oppression, corruption, and obscurantism. We have gone to far greater moral heights in the modern age than were ever achieved previously, even while we grapple with enormous problems of scientific & political success. There were several horrible atheist movements and governments in the 20th century, which must be noted, but which have thankfully each been substantially reformed if not eliminated. Each could be seen as a religious movement of an idealistic, fanatical sort, at least in sociological, if not theological, terms.

Lastly, what of personal spirituality? Even if religions make people no more moral, empirically, than other philosophies, and even if they are factually false, and even if theology is a parody of scholarship, isn't the personal resonance with our surroundings, deep questioning, and quest for some kind of transcendence a significant feature of humanity, and of human morality?

I would actually agree with that, with some caveats, since the atheist is, in reality, just as spiritual as the religious person. The problem is whether one indulges this innate impulse with inferred pseudoscience and systems of social control based on hosts of invisible beings. The wonders of nature remain wonderous whether one chalks them up to deities or not. Religion is an *example of humans yearning for understanding and meaning, but is far from the apotheosis or sole source of meaning, let alone legibility for understanding the world. It is healthy for people to share their spiritual questions, insights, and commitments with each other, which is why not just religions, but academies, libraries and universities were invented. Here is where love- for spirituality is really the love of life and the world around us- is exercised as the freedom to be interested in and draw meaning from ... other people, phenomena of nature, arts and self-expression, and the best thinking that humanity has to offer.

This is transcendence with discipline, making of ourselves better beings, morally as well as intellectually. The idea of getting on the good side of an invisible being, or counting on another life better than this one, if such theories are not well-founded, seems a little cheap in comparison to humble dedication to slow betterment in & of this life.

  • Annals of religious BS. Being personally related to god prevents drug abuse: "We have multiple ways of knowing: we have intuition, we have rigorous logic, we have investigation. We need to use them all. They’re all important, valid forms of perception."
  • Annals of really serious religious BS.
  • Some people call it mystery, others call it BS.
  • Annals of denial: rise of the "nones" = culling of those "pretend Christians".
  • Atheism is on the rise in the Middle East.
  • Keeping tabs on Syria. And Iraq.
  • On being wrong, and being really, really wrong.
  • Virtually any existing condition is "Pareto optimal".
  • Climate action is needed immediately.
  • Happiness is an institutional, social issue.
  • Banks are too big, and we can make them smaller.
  • What is the problem with Keynes? Just imagine if government worked consistently against economic feudalism instead of for it.
  • Were the founding fathers Keynesians?
  • Finally, a church I can relate to.

Saturday, May 16, 2015

Death of a Species

Callous indifference and business-as-usual greed dooms the delta, and the delta smelt.

As ecological icons go, the delta smelt isn't much. A small silver fish, like a zillion others. But it lives in the way of dredgers, bulldozers, farmers, shippers, and a thirsty multitude. It was put on the endangered species list in 1993, and has kept right on dwindling, until in the most recent count, a single smelt was found. One.

The San Joaquin / Sacramento / San Francisco Bay delta used to be a very large estuary of marshes, reeds, rivers, and islands that gradually fed the great rivers of the Sierras into the Bay and thence through the Golden Gate the Pacific ocean. Fresh water met briny in constant tidal and rain-fed flows. Smelt were obviously not the only beneficiary of this rich ecosystem, but countless shellfish, mammals such as beavers, insects by the billion, and birds by the million. The delta was a major stop on the Pacific flyway for migrating birds. And it was the conduit for several species of now-endangered salmon.

Comparison of the delta as it was, and as it is now. Virtually all its marshland and most of its complex river habitat is gone.

Despite the popular image of California as a state of nature and natural wonders, it has been pillaged in the name of greed from the beginning. The Spanish mission system started the ball rolling by enslaving and decimating the native peoples. Then the gold rush led to thorough destruction and pollution of the rivers, while working its way upwards into the hardrock mines of the Sierra. Next was agriculture, which in California became a rapacious and short-sighted industry, well-illustrated in the now-obscure novel by Frank Norris, The Octopus. Then it was onwards to a thorough re-plumbing of the state by the water lords of Southern California. The latest incarnation of this get-rich quick ethic was the dot-com bubble, by which Silicon Valley took investors all over the world to the cleaners.

The little smelt and all the natural riches it stands for had little chance, of course, when there was free, fertile land to be had by diking, draining, and dredging. A state which had some inclination to protect the spectacular, yet conveniently remote and barren, high Sierras, had no appreciation for the ecological values of wilderness in the bottomlands, even for flood control, which is increasingly difficult as so much of the "reclaimed" land is under sea level, protected by primitive, flimsy dikes. With the extended drought and the vast rerouting of fresh water, the delta has begun to flow backwards, introducing salt as well. But the state, being owned by its commercial interests, leaves public and ecological policy to die a quiet death, along with the smelt.

The planetary climate and biosphere face similar forces of corruption, greed, inertia, and neglect, which will just as soon see it die with a whimper than plan in a public and morally forward thinking spirit for future generations of all species.

  • Notes on our friends the Saudis.
  • Secularization hypothesis finds new support.
  • Further notes from the religion of peace.
  • The odd history of US fundamentalism.
  • Bruce Bartlett just can't take the corruption any more.
  • Even if corruption is quite natural.
  • Notes on real estate redlining.
  • Economics is not yet a science.
  • Silence on fiscal policy is dereliction by central banks.
  • Bill Mitchell on the Australian budget process. A cartoon.
  • Aetna raises its minimum wage: "The pay raise and benefit program for low-wage workers will cost Aetna only $26 million, while the CEO alone made $15.6 million last year, though most of it in stock options."
  • Some problems with TPP.
  • Class and money beats performance.
  • Essay on the new frontiers of brain science, and its changing nature.
  • 110 year old infrastructure for trains? We can do better.
  • Two banks find a judge with a spine, after they lied to convince Fannie and Freddie to go subprime.
  • Economic graph of the week: Stiglitz on inequality.

Saturday, May 9, 2015

The Imperialism of Universal Values

We shouldn't pretend that everyone shares our values.

Values are not universal. It is simple as that. The imputation of our values, even the most rationally derived and well-meaning, to others does not mean they are shared by them. We can claim that there is a basic human nature that intrinsically shares some values. But even then, others may have different priorities, so that even if they share many individual values, they might rank them differently, preventing us from claiming any basic set as absolute or universal. Indeed,  ideologies are notoriously powerful in re-arranging our values, to the point of valuing death over life.

The brief interlude of enthusiasm for universal rights, in the wake of World War 2, might seem to belie this philososphy. But really, it was more of an exercise in victor's justice and idealism, as well as cultural imperialism, than it was a free response of all countries around the world to the new concepts of inalienable human rights. Half the signatories to the declaration of human rights were, after all, totalitarian countries of various stripes. And it came under immediate protest from Islamic countries.

This informs the debates about Muslim responses to Charlie Hebdo, other cartoon provocations, and the West in general. Others may simply not rank free speech as highly as religious belief and cultural tradition. We in the West have a hard-won rationale to prefer our ranking, religion being a font of sensitivities and claims to power that, given precedence, tend to grow endlessly, gobbling up all other rights and ideologies. But the Muslim world has its centuries-long experience as well, which can't simply be disregarded and overrun for the sake of what we call progress. Even if we ideally could take a poll of each affected Muslim to truly, democratically, figure out what they want, as opposed to what their various mouthpieces, governments, and leaders want, that presupposes the validity of democracy, which itself is a contested value.

The same issue extends to the treatment of women. The current Western dispensation towards liberation and equality is extremely novel, even in the West, so whatever its moral virtues in our eyes, and even those of Muslim women if that be the case, it can't claim any intrinsic universality.

This is all to say that the attacks by Muslims on offensive authors and artists can not be addressed by lecturing them or the Muslim world on the sanctity of free speech, human rights, and obvious morality. There may be an argument to make from within the Muslim tradition. The Quran expresses occasional mildness towards unbelievers, instructing to treat them fairly and ignore them otherwise. Unfortunately, such arguments stand little chance against the major themes of the Quran, which pours hatred and scorn on unbelievers and apostates on most other pages.

So perhaps the better argument is simply one of cultural self-preservation. We have a right to our values, whatever they are, and while it would be ideal to convince others of their goodness and rationality, that is far from a guaranteed course. Perhaps these defenses of free speech and rights of journalists are really directed to the choir, to buttress the values we already share, in the face of a terroristic challenge. Which is in fact straightforward cultural warfare, seeking to displace our values with others, and tactically to turn our virtues of openness against us.

The hijab is a particularly effective and notable aspect of this cultural war, being fought in Europe for the most part, the frontier between Middle East and West. While migrants are desperately seeking the safety and economic refuge of Europe, many of those already there seek to carve out cultural islands separate from the larger society, (though often perforce, being discriminated against), and sometimes, to hear what is going on in European mosques, against the larger society. The hijab is a public reminder and marker of this social segregation and power, showing a separate sub-society in the midst of the larger one, even while it relies paradoxically on the freedom the larger society makes possible. It is a message that may be read in various ways, but one way is surely as a rebuke to the dominant values, as many other religious movements have expressed through European history, incidentally.

How do these values relate? If the rebuke being offered were of a constructive nature, as nuns and monks have embodied for centuries, (at least if one takes a charitable perspective!), complete with distinctive clothing, it would not raise much ire. But the offered value system seems, at least to the West, highly distasteful, based as it is in the bigotry of the Quran and the bitter patriarchy, dysfunction, and closed-mindedness of modern Islam. For they have their imperialistic, universal values as well.

It just remains for us to reject those values, without assuming that those who are trying to displace them actually, paradoxically, believe in them. And to protect ourselves physically and socially from their proponents. What makes it tricky is that the Muslim community in this instance is not monolithic, like some army of Mongols at the gates. Many seek to assimilate, the vast majority are peaceful and appalled by their own coreligionists. So it becomes a policing issue of detecting insurgents within the gates; something that, while surely corrosive to our assumptions and traditions of openness, is hardly unprecedented in the history of the West, going back through the Cold War to the history of Venice, which in its heyday had particularly effective intelligence services.

  • Prospects for the Middle East ... look poor.
  • Afghans aren't the only corrupt ones in Afghanistan.
  • Dennett on religion & the future.
  • Religion and science are not in conflict at all. Hmmm.
  • Scientology was already a criminal organization back in 1973.
  • Ford Doolittle, on the stupidity of nature.
  • Will management be the last employees?
  • Reich on the TPP. Corporations want to run our countries ... more than they do already.
  • Krugman: Jobs, pay, and stability are the issue in Baltimore.
  • Krugman: Redistribution really works.
  • Krugman: Thinking would also work, if more people did it.
  • State's rights aren't always the top priority in Nuttistan.
  • Supreme court lays another egg. Corruption is OK for other people.
  • Economic efficiency has virtually nothing to do with today's inequality. Power and ideology are the issues.
  • Bill Mitchell on money and banks, pt 1, pt 2.
  • Economic graph of the week, from the IMF. Our finance industry is negative, not positive.

Saturday, May 2, 2015

Do Neurons Use GPS?

No, neurons and their axons use chemical guidance signs to find out where they should be going, in huge migrations though development.

The brain and nervous system don't just happen by way of cell division during development. They are products of enormous migrations from points of cellular birth, which are generally at the edges of the nascent structure, such as the ventricles of the brain. And getting the cells to the right place is only half the story, as neurons then send their axons all over the place as well, to create those amazing connections that run our bodies and minds. Neurons that enter our feet typically have their cell bodies at the base of the spinal chord and send axons along a tortuous path that of course ends up going about three feet in adults. It is astounding.

Some of our neurons are very long, and for most neurons, their axons as well as cell bodies migrate substantial distances during development.

Obviously, the mechanisms behind these movements are going to complex. One example is in the brain, where new neurons travel out to the various layers they are destined to inhabit via a scaffold of guide cells, the radial glia. Even when such physical structure helps out, the primary mechanism is a sort of pheromone system, like what ants use when making trails, but a good deal more involved. A recent paper describes the chemical signals that guide neural axons of the mouse through a critical crossing at the midline of the spinal chord.

These axons are called "commissural axons", since they cross the bilateral joining point, or commissure between the two sides of the body. In the brain, the corpus collosum is a large bundle of such axons.
"For example, commissural axons are initially repelled by bone morphogenic proteins (BMPs) in the dorsal half of the spinal cord. They are then attracted by gradients of Netrin-1, Sonic hedgehog (Shh) and vascular endothelial growth factor (VEGF) towards the floor plate."

The floor plate (bottom) secretes two molecules, Shh and Netrin, in wild-type mammals. If either one is mutated and absent, neurons that normally use gradients formed by those molecules to know where they are going do not find their way as reliably.
"While it is known that both Shh and Netrin-1 form gradients, it is not clear how steep the gradients are in vivo and how this steepness influences axon pathfinding in gradients formed by single or multiple guidance cues. Although theoretical chemotaxis modeling has suggested that two overlapping attractive concentration gradients could increase the probability of a cell making a correct decision about the gradient direction, this prediction has not been tested experimentally."

The "pass" from one side of the spinal chord to the other, at the early embryonic times when this axon extension process takes place, is called the floor plate of the neural tube. It is the site of expression of at least two guidance molecules, the proteins Shh and Netrin. These are secreted and form a gradient that is sensed by receptor proteins on the axons, specifically by their pseudopod-like front end called the growth cone. One trick is that once axons find their way to the floor plate, they need to reverse their response pattern so that they grow away from it instead of towards it. This repulsion from the floor place is known to be mediated by another molecule, Slit.

But that is not the topic of the current paper, which simply makes the observation that for the attraction phase of axon growth, two signals is better than one. This has been presaged by mutant studies where the mutation of each individual gradient attractant, Shh and Netrin, causes worse axon guidance, but not a complete breakdown of commissure formation as happens when both are deleted (see figure above).

Neural growth cones seen in the process of deciding where to go. Gradients are indicated by the black triangles at sides, as set up in the lab. "A" presents a schematic of a growth cone showing asymmetry of the protein signaling kinase SFK, which accumulates internally on the more highly stimulated side, reflecting part of the cell's mechanism for detecting the outside guidance molecule signaling gradient. SFK responds to both Netrin and Shh.

The researchers take this all in vitro, reproducing the gradients with microfluidic cells, and asking how their cultured neurons move in response. They find that, as expected, gradients that are shallow as they are in the embronic setting where the axons spend most of their time are not very good at guidance for each molecule individually.

Summary of experiments, showing both axon migration (the cell bodies are dots, and the axons lines) and SFK kinase orientation within growth cones, all responding to the combination of two shallow signaling gradients more reliably than to either alone.

They also show that within the guided growth cone, a key protein (kinase) that transmits the Netrin and Ssh signals from outside to inside itself adopts a biased concentration gradient, matching what is detected outside. Aside from validating the other findings, this provides some rationale for large sized of growth cones, which by spreading out physically can detect relatively shallow gradients of their signalling molecules.

It is not a momentous paper, but a small step on the way to learning how the nervous system develops ... from one cell to the most complicated machine in the universe.

  • This week in Nuttistan: "ISIS also imposed gun control immediately upon takeover of the terrain under its control.  Totalitarians fear weapons as the only threat to their supremacy.  Do not ever allow yours to be confiscated. The next step is enslavement and death."
  • Who are you calling "we"?! Just because someone discovered the Higgs doesn't mean that everyone is a smartypants.
  • A godsend for the godless.
  • A corrupt God vs the New Deal.
  • Big data needs big rules and regulation.
  • We have a lot to answer for in Cambodia.
  • Grexit is neigh, and neigh-well unavoidable.
  • Going to college? Caveat emptor.
  • The blue line isn't so thin. And is increasingly corrupt.
  • Remember the Dominican Republic?
  • Climate change talk is like religion? Just what does the GOP think is wrong with religion?
  • Oh ... ISIS deals with some more so-called apostates.