Spills of War

It’s good to see NASA hasn’t completely abandoned its mandate to look after the home planet. As its Earth Observatory notes:

Among the casualties of the conflict between Lebanon and Israel in the summer of 2006 was the Mediterranean. Israeli raids in mid-July on the Jiyyeh Power Station released thousands of tons of oil along the Lebanese coast, perhaps rivaling the Exxon Valdex accident in 1989. By August 8, the spill covered approximately 120 kilometers (75 miles). The Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard NASA’s Terra satellite took this picture on August 15, 2006. The United Nations, the European Union, and the International Maritime Organization planned a meeting for August 17 to discuss cleanup operations, which had been delayed by the fighting between the neighboring countries.


The spill put some 15,000 tons of oil into the Mediterranean. These images show the spill as it moves north from the Jiyyeh Power Station to the coasts of Lebanaon and Syria. The upper photo was taken August 15, a month after the power station was damaged; the lower photo,

Continue reading →

Fast Plasticity

Among the many wonders of neuroscience — and central to the discipline — is the brain’s plasticity, its ability to rework synapses and networks to respond to new challenges and experiences. In this dynamic lies the physical explanation of the fluid nature of experience, thought, and consciousness. This is why I find so fascinating the work of those who proposed and discovered the mechanisms underlying this plasticity, such as Ramon y Cajal, Donald Hebb, and Eric Kandel. These and other researchers showed the fundamentals of how changing synapses allow our brains to learn new lessons and behaviors or change old ones.

Some of the most fascinating current research is adding detail to the basic picture of plasticity painted by Kandel and others. The latest to catch my eye is excting indeed, as the research team at the Brain Mind Institute of the Ecole Polytechnique Federale de Lausanne, led by Pierre Magistrietti, has shown the brain can accomplish significant rewiring in just hours — “suggesting,” as the press release puts it, “that the brain is evolving considerably even during the course of a single day.”

Markran and Le Bé came to these findings by studying neuron clusters from the neocortex of neonatal rats. As the EPFL release put it,

Continue reading →

Neurologist Helen Mayberg in SciAm Mind

My profile of Emory neurologist Helen Mayberg is out now in Scientific American Mind. You can read either a text-only version at my website, or get the full published version, with photos and such, at the Scientific American Mind site (free to subscribers, $5 for the article for non-subscribers).

Mayberg made headlines last year when she, psychiatrist Sidney Kennedy, and neurosurgeon Andres Lozano, as the story put it,

cured eight of 12 spectacularly depressed individuals … by inserting pacemaker-like electrodes into a spot deep in the cortext known as Area 25.

Continue reading →

Breastfed Babies Bounce Back Better (or: Of Mice & Moms Redux)

No sooner had I noted that mouse pups seem to handle stress better when near their mothers than I found a study of some 9000 British kids showing that breastfeeding seems to make kids more resilient to stress even well after they’ve stopped breastfeeding. As the press release puts it,

Breastfed babies cope better with stress in later life than bottle fed babies, suggests research published ahead of print in the Archives of Disease in Childhood

The findings are based on almost 9000 children, who were part of the 1970 British Cohort Study, which regularly monitors a sample of the British population from birth onwards.

Relevant information was obtained at the children’s birth, and at the ages of 5 and 10 years, from midwives and health visitors, parents, and teachers. This included how much the child weighed at birth and whether s/he was breastfed.

It also included factors that might influence or be linked with a child’s reactions to stress and coping mechanisms, including maternal depression, parental education levels, their social class, and smoking.

When the children were 10 years old, their teachers were also asked to rate the anxiety of their pupils on a scale of zero to 50, while parents were interviewed about major family disruption, including divorce or separation, which had occurred when their child was between 5 and 10 years of age.

Unsurprisingly, when all the data were analysed, the findings pointed to a greater likelihood of high anxiety among children whose parents had divorced or separated. But children who had been breastfed were significantly less anxious than their peers who had not been breastfed. Breastfed children [of divorced parents] were almost twice as likely to be highly anxious, while children who had been bottle fed were over 9 times as likely to be highly anxious about parental divorce/separation.

A ninefold increase instead of a twofold increase; that’s a remarkable jump in vulnerability among the non-breastfed. The breastfed kids, in short, were about 1/4 as vulnerable as the nonbreastfed.

What about breastfeeding might explain such resilience? The researchers didn’t want to guess. Possibly breastfeeding gives some direct physiological benefit — the milk itself contributes physiologically, say, in roughly the way that the antibodies in mother’s milk make kids more resistant to infection. Goodness knows, breastfeeding gives so many other benefits, this wouldn’t surprise me. On the other hand, the protective effect might simply come from because breastfeeding creates tighter bonds with the mothers, inspiring higher levels of maternal care.

Animal studies, however, have shown that physical contact between mother and baby during the first few days of life bolsters neural and hormonal pathways important in stress responses, and that deprivation of maternal care creates hypersensitive stress systems. Moreover, as a good (if somewhat aging) research summary at NIMH describes, mere separation of rat pups from their mothers for 3 hours a day caused the mothers to give those pups less care, and the pups grew up excessively sensitive to stress all their lives; another paper finds such deprivation increases cell death in the pup’s brain. Other studies, however, have shown that some of this deprivation effect can be reversed with some TLC — or as one such paper put it, “tactile stimulation and feeding”; so it may well be that you can make up for a lack of breastfeeding with plenty of other TLC. (If you’re really into this stuff, see this paper by Fleming et alia at U Toronto, “Mothering Begets Mothering,” for how maternal care or deprivation in rats gets passed down through generations.)

I certainly don’t want to put the onus on moms, who get enough grief; the abundance of evidence about maternal deprivation exists partly because it’s easy, experimentally, to deprive baby animals of their mothers and study the results. At any rate, if there’s clearly a point here about the importance of maternal care, there’s also a broader point about how early experience can affect later vulnerability to stress. At the same time, genetic studies are showing that such vulnerability also depends on genetic make-up, as in this 2000 paper with the straightforward title, “The Long-Term Effects of Maternal Deprivation Depend on the Genetic Background.” .

We’re at an interesting time, it seems to me, as we begin to study the interlaced effects of experience and genes — the so-called gene-environmnent interactions — which toss aside the nature-nurture dichotomy and recognize life for what we naturally feel it to be: a dynamic loop in which what we are (our biology) constantly changes in response to what we experience (our environment).

Of Mice and Moms (and the Snowball Effect of Stress)

One of the pleasures of following science is seeing how researchers use old, simple tools to test new questions. In a nice piece of work published in Nature Neuroscience, University of Oklahoma researchers Stephanie Moriceau and Regina Sullivan used learned-fear association in mice to reveal how the stress of maternal abandonment raised rat pups’ sensitivity to threats. As ScientificAmerican.com describes the experiment,. Moriceau and Sullivan

tested how baby rats responded to the pairing of an unfamiliar odor–peppermint–and a weak electric shock to their tails. The charge-laced scent attracted the youngest pups without exception while repelling their older siblings of 21 days–the age when rats become fully independent. But young rats between 12 and 15 days old either learned to love the peppermint despite the shock if their mother was present or learned to fear it if she was not. When presented with the odor later in a Y-maze, the mothered pups would invariably move toward it while their motherless counterparts would move away.

The mother’s presence, it appeared, reduced the level of the most common stress hormone, corticosterone, making the pups react less fearfully to the tainted scnet — or, to put it another way, her absence elevated those stress hormones, making the pups learn a more fearful lesson from the association of shock and scent.
This doesn’t break brand new ground. But it adds a bit of detail to the model of stress and mental health that neuroscientists and endocrinologists like Bruce McEwen have been developing. One stressor or threat magnifies the impact of the next; as you string more together (particularly in the absence of more constructive learning), you gradually tip a creature away from confidence and adventurousness and toward retreat and depression.

Continue reading →

Unambiguously upside: Wellcome Trust’s Biomedical Image Award Winners

From the Department of Fairness and Balance:


Marrow stem, by Spike Walker

For an elevatory antidote to the grimness of my previous post (about global warming cracking the Eiger), see the lovely collection of images from the Wellcome Trust’s Biomedical Image Awards contest.

As the site puts it, the gallery provides “a striking display of shapes and patterns [that] show a wide variety of subjects, most invisible to the naked eye, revealing new layers of complexity…. The winners of the Awards challenge the public perspective that scientists don’t have an artistic side. “

Another example:

Some really lovely eye candy. Check out the whole gallery.

Eiger loses face

I enjoy most any mix of science and mountaineering — part of why I so like Mark Bowen’s Thin Ice, his book about climatologist Lonnie Thompson’s remarkable work documenting global warming in high-altitude glaciers. Scientific work done at rarefied altitudes. How can you not like it?


The North Face of the Eiger, 2005 — aka the Eigerwand of climbing fame. The east face, photos of which I couldn’t find, is out of sight around the corner.

Photo by Dirk Beyer via Wikipedia Commons.

I’m less thrilled to see global warming meet alpinism on the Eiger, where last Thursday about 400,000 cubic meters of the Eiger fell off the mountain’s east face. Geologist and climatologist Hans-Rudolf Keusen, who specializes in remote detection of geological hazards and chairs a related working group at ProClim (a climate study group), had predicted this the previous week after tracking the expansion of huge rapidly widening cracks in the face. According to Keusen, the east face will lose some 2 million cubic feet altogether — a volume roughly that of the Twin Towers — will collapse this summer because global warming has melted a glacier that helped support the massive cliff, allowing it to crack apart.

The prospect of more collapses is drawing a lot of tourists. The Eiger will stand a while yet, of course. Yet as a fan of the Alps and an avid armchair mountaineer, I find distressing that we’re changing these iconic and beautiful mountains. The rockfall is probably only the most dramatic such change. Mountaineer Doug Scott (who at a lecture I was lucky enough to attend explained his assessment and retreat from a particular daunting and dangerous ascent by saying, “Anything you really want to do, you can. So why bother?”) told the Times of London that

“In the past few years the alpine climbs like the Dru and the Eiger have become more and more threatened by snowfall and massive collapses. I first climbed the Alps in 1957, but they are far more dangerous today.”

Quite dismaying.

Warming is also set to pooch the Alps’ skiing. A recent study predicted that the next 25 years will eliminate half the ski areas in the Alps. The decline has already begun, as detailed at the excellent ski site PisteHors.com and the World Wildlife Fund site. Over 20% of the Alp’s glacier cover melted between 1985 and 2000, and a Guardian story tells how some Alpine resorts are building trails higher and higher in an attempt to stay in business.

Finally, closer to home, ScienceBlog notes that a Scripps Institution study implicates global warming in Western US wildfires.

Grim stuff all around.

Tiny Stroke Ends a Druggie’s Addiction

You don’t see this every day:
Jake at Pure Pedantry draws due attention to an incredible case report in the American Journal of Psychiatry showing that a lesion in a patient’s brain cured the patient’s drug addiction, apparently by knocking out the reward circuit that made the addiction pleasurable. (It also made the man badly depressed.)

A stroke that destroyed parts of a drug addict’s globus pallidus (pale areas) left him depressed but ended his addiction. Neither drugs nor (alas) wine gave him pleasure any longer.

The article, unfortunately, is pay-per-view, but Jake’s summary is compelling on its own. To whit:

A 34-year old long-time drug-user is taken to the ER after he starts acting freaky at a party. He has a bunch of methadone (an opiate like heroin) with him that he downs on the way in to avoid detection. He proceeds to OD.

There are areas of the brain called watershed regions. These are areas in the brain where the blood supply of the major arteries is at its sparsest — at the overlapping edges of two arteries. When you overdose, you sometimes have strokes in these regions….

This gets us to the really interesting part. When the guy comes to, he has something called anhedonia. Anhedonia is one of the symptoms of depression. It is the inability to feel joy. More interestingly, he ALSO has lost his drug addiction.

After this overdose, Mr. A became acutely depressed .. [with] anhedonia, low energy, difficulties concentrating and remembering, feelings of hopelessness and guilt, poor self-esteem, social isolation, increased sleep, and a 20-lb weight gain over the ensuing year. He reported the disappearance of drug cravings and remained abstinent from all recreational drugs other than an occasional glass of wine with dinner. He reported that he no longer experienced pleasure from drinking alcohol. Four serial urine toxicology screens were negative over 6 months.

I thought I would point out this article because it is a very compelling case showing the parallels between lab science and medicine. Neurology is unfortunately often a science where you need cases like this to prove that we are not totally off base with how we think the brain works.

Quite incredible, and a delicious case study.

Cutting to the chase on climate change

My interest in global warming grows apace, both because it stands to impose some very grim effects and because it makes an interesting (if dismaying) study in culture’s attitude toward science (see my post on “Climate change as a teset of empiricism and secular democracy“) and how vested interests can affect same.


Florida at present (left) and what it will look like if seas rise 20 feet. from Al Gore’s An Inconvenient Truth

The puzzle at this point is why so many people, including intelligent people with decent scientific literacy, still doubt humans are causing the earth to warm dangerously. More people these days believe this, it seems, as they feel the summers get hotter and the weather more chaotic; seeing is believing. And Al Gore’s movie and book — the source of the image below — seem to be convincing a lot of people. Yet many otherwise literate folks still harbor doubts.

Doubters (or those who wish to sway them) might be interested in any of several good talking-point type summaries of the evidence that lately appeared:

• George Mauser’s post at the SciAm blog discusses this doubt and summarizes the reasons to dispense with it; it includes links to past discussions of the same topic.

• A Real Climate post on “Runway tipping points of no return” starts by noting the media, by attending the prospect that the climate has passed a tipping point, seems to have reached a tipping point of its own; along the way, the post summarizes some of the key evidence.

The juiciest recent summaries I’ve seen, however, are on subscription-only sites. They are

• Jim Hansen’s great piece in the New York Review of Books lays out the evidence and need for immediate action with wonderful concision. It’s one of the best, most readably concentrated summaries and appeals I’ve seen.

• The New York Times runs a long summary that’s also well done, though it’s unfortunately behind the magazine’s “TimesSelect” premium service. It’d be nice if the Times put material that’s so publicly vital a bit more up front.

All highly recommended for bringing concision to either your own or your skeptical friends’ thinking on climate change.

Flickering Lights: One-Shot Wonders versus the Network Model

Several bloggers have commented on Paul Bloom’s Seed plaint about brain imaging studies receiving too much attention and a certain false credibility. (See the posts at Cognitive Daily , Mixing Memory and — in refutation — Small Gray Matters, as well as other citing blogs via Technorati or BlogPulse.) Bloom has a point: Both popular and science media show an outsized fondness for brain imaging studies, inspiring much work more diverting than informative. The most overhyped of these studies and stories suggest that in some busy brain area lies the locus of love, the center of empathy, or the key to fear of the new — as if a trinket dropped by Caesar along some road reveals the dynamics of Rome. Some skepticism is justified.

Thus Bloom’s warning, as well as complaints from others that brain imaging amounts to a “new phrenology.” Bloom’s essay, in fact, fits into old arguments about how successfully we can localize the mind’s doings; I wrote about this controversy over imaging and its historical roots early last year in Scientific American Mind.

But overlooked in Bloom’s essay (and in much of the ongoing discussion of which it is part, including my SciAm Mind piece) is any distinction between two strains of fMRI studies that have been underway for some time. You need to recognize this distinction to really put a value on brain imaging studies, either individually or as a discipline.

One strain — the primary source of the complaints from Bloom and others — seeks simple correlations: here’s a spot that lights up when we lie, see our children’s faces, smell flowers, or confront a logical contradiction. These one-hit wonder studies can be done quickly and cheaply, so people do a lot of them, and they dominate the news releases on fMRI.

Another, more sophisticated line of inquiry gets less attention, partly because the study results appear less frequently (because the studies require more time, skill, and thought) and perhaps too because they’re harder to explain in a few hundred words and a neat caption. These studies focus not on single-site activations but on defining the more complicated networks that drive mood, thought, and behavior. In the best of them, researchers take pains to coordinate the imaging research with research into genetic dynamics or other data that can serve as a check or corroboration on the imaging results. For example:

• Joy Hirsch’s lab at Columbia is looking into areas involving vision, attention, language, and chronic pain. A sweet example is Niewuwenhauis’s and Yeung’s “Neural mechanisms of attention and control,” from Nature Neuroscience, which shows that the prefrontal cortex directs attention “by amplifying task-relevant invformation rather than inhibiting distracting stimuli”. Good stuff.

• A decade of careful imaging work defining depression networks led Emory’s Helen Mayberg to believe that a previously overlooked brain area called Area 25 (aka the subgenual cingulate) plays a key role in depression. Her hypothesis was borne out dramatically when tiny pacemakers inserted in Area 25 in a dozen depression patients seemed to cure the depression of 8 of them. That surgical trial got wide press, including stories I wrote for
Scientific American Mind
and the
New York Times Magazine
. But all but a couple of the studies she did along the way were largely ignored.

• Nikos Logothetis brings a masterly touch to his imaging studies while checking temptations to over-interpretation, overstatement, and other excesses. His review and theoretical essays on imaging have helped define the field’s possibilities, limitations, and caveats. See his “Interpreting the BOLD Signal (pdf)”; his lab web page; or, (If you have a subscription to Nature, that journal’s recent profile of Logothetis .

• Finally, Marcus Raichle’s lab at Washington University continues to do good work defining fundamental networks of attention. A typically rich paper in the Proceedings of the National Academy of Sciences describes how certain brain networks trade center stage — one dimming, as it were, as the other lights up — as the brain attends different tasks.

Studies of this caliber easily validate the promise of brain imaging. Rather than spotting trivial or questionable correlations, they identify pathways and physiological mechanisms underlying central dynamics of mood, consciousness, and cognition. Mayberg’s work, for instance, reveals something vital about both the physiology and phenomenology of depression — namely, that depression is not simply an absence or a lack but the instantiation of a network run amok. An active physiological dysfunction, a sort of neural equivalent of an overactive gland, underlies the what William James called the “active anguish” of deep depression. (For more on that, see my piece on her in the New York Times Magazine.)

Imaging may be producing some of the silliest papers these days. But it’s also producing some of the most profound work in neuroscience.