Sunday, February 19, 2006

Brain Scanning and Depression: Strange Days.

What is the current situation for understanding depression with brain scanning? The issue is cloudy, and with the paradox that certain treatments by means of brain scanning technology have preceeded the understanding of brain structure and processing -- which, of course, is just what brain scanning was supposed to accomplish before methods of treatment were ever determined. Things are not going as planned.

Consider, for example, Transcranial Magnetic Stimulation. This is a newly discovered, though experimental method of treatment for people diagnosed with manic depressive disorder. The effects appeared to be short term, at least when this method was applied on a frequency of about one to two times per week ("Magnetic Therapy", 2006)

The treatment technique was earlier and accidently noted when researchers observed a correlation between patients self-reporting diminished feelings of depression after their receiving regularly scheduled MRI scanning. The the original MRI technique yeilding this phenomena of improvement for depression symptoms was ecoplanar magnetic resonance spectralscopic imaging , or EP-MRSI ("MRI Scans", 2005).

Later follow-up studies had confirmed similar responses in laboratory rats. These gave additional support to the observations made in human treatment contexts. The animal study was a follow-up to check that that electromagnetic fields could indeed affect brain biology. William Carlcon, the director of Harvard's Mclean's behavioral genetics laboratory, notes that, "we found that when we administered the magnetic stimulation to the rats, we saw an anti-depressant like effect, the same effect as seen after administration of standard anti-depressant drugs" ("MRI Scans", 2005).

There is a certain irony in that MRI imaging has had a positive correlation with treating depression in human beings, when the high hopes for brain imaging systems have not returned the hard science that researchers suspected it would during the rise of such technologies in the 1990s. Published imaging studies appear of a rate of around 500 a year, but have not been effective for understanding the root causes of depression in the brain (Carey, 2005).

I argue that this because brain scanning presents both correlation and causation challenges. It is not clear, for example, whether depression brings about a change in brain structure, or whether particular brain structures cause depression. Moreover, there are significant variations in gross brain structure among people, and also in the processing areas where particular types (or groupings of types) of mental states occur. However, the technology curve is promising, with MRI scanning technology roughly following well-tracked computational power increases, which double around every 20 or so months.


Carey, Benedict "Can Brain Scans see depression" October 18, 2005

"MRI scans may have antidepressant effect: Study suggests electromagnetic fields can affect brain biology" March 10, 2005

"Magnetic Therapy May Help Control Depression: Brain Stimulation Can Improve Symptoms Small Study Finds" January 30, 2006.

Saturday, February 18, 2006

The Moon Race is Wrongheaded.

I am still not sure why there is a sudden interest to go back to the moon. Let me give three reasons why a renewed race to revisit the moon is a bad idea.

The first complaint I have is this: it's really expensive. I'm all for going to space and doing exploration, but the kind of money it takes to land people, or even just craft on the moon seems better spent on robotic exploration to other places. I think the current use of technology to build rovers and satellites to visit other planets is the right way to go. (Obviously, I'm happy with the Mars uses of NASA's money.)

The second complaint is that the moon is not that interesting. Contrast that with Europa, a moon of Jupiter. It has an icy crust, and practically no cratering. Ronald Greeley, a Galileo imaging team scientist and a geologist at Arizona State University, Tempe, AZ. recently said, "We're seeing evidence of a lot of geological activity on Europa." Try finding a statement like that for the Moon! Geologically speaking, it's just a really boring place. Thus, our efforts at exploration should be refocused on what's most likely to give interesting science.

The third complaint I have regards the possibility for finding life. The moon is a dead place. But there are other, accessible places where there might be life. Take yet another of Jupiter's moons: Callisto. Callisto is about the size of the planet Mercury, so as moons go it's big (third biggest, actually, in the solar system). It has a very stable icy surface -- as in it has WATER -- and though that surface is billions of years old, lacks any sign of volcanic activity, and is populated with rifts and craters, the Galileo spacecraft pass seemed to indicate that its surface overlies a salty liquid ocean. Now what other life-yeilding place has a salty ocean? Hint: you're Mom was born there. Does not Callisto seem a lot better investment of time, labor, and technology than the moon? Of course it does.

Expense, scientific interest, and the importance of the search for life are the three reasons why I think the whole new moon race is just plain wrongheaded.