 Quote:
Originally Posted by foundit66  | I'd add the following to this discussion: “One claim that is often made in the abortion debate (by those arguing both sides of the issue) is that the fetal brain exhibits “electrical activity” at some astonishingly early age. We have seen claims in which this age ranges from nine to twelve weeks. For example, the following quotation is taken from an article about the philosophical aspects of the abortion controversy by Goldenring in the scholarly Journal Medical Ethics: “If the fetus has reached the age of 8 weeks, a wealth of evidence indicates that its brain has begun functioning electrically.” Given what we know about the way the brain is formed, this sort of claim just didn’t make sense to us, regardless of the fact that it seems to be widely accepted. We decided to try to track down the original data from which the claim comes. The result of this bit of detective work constitutes, we think, a cautionary tale about how experimental results can be distorted as they move from scientific journals into general discourse. … For what were termed therapeutic reasons, Bergstrom and Bergstrom, the authors of the article…had performed a series of Cesarean abortions at quite early ages of pregnancies, from 59 days (8-1/2 weeks) to 158 days (22-1/2 weeks). In this procedure, they removed the fetus from the uterus surgically. After they had carried out the procedure, and while the fetus was still alive, they inserted electrodes into three different regions of the brain and measured the voltage. These regions were the brain stem, the hypothalamus, and the top of the cortex. When the authors made their measurements, they found that there was, indeed, a time-varying electrical potential of a few microvolts (about one-thousandth of the voltage across an individual axon membrane) from the electrode in the brain stem. In the older fetuses (from 84 days on), they occasionally saw electrical activity in the brain stem in response to touching the fetus in the region of the mouth. A few signals were recorded from the hypothalamus in the oldest fetuses, and no signals whatsoever were recorded from the cortex. These measurements, as far as we can tell, are the sole source of the claim that there is electrical activity in the brain of nine- to twelve-week-old fetuses. If you think about this experiment for a moment, you will realize that the mere presence of an electrical signal has nothing to do with normal brain activity. As we pointed out earlier, every cell exhibits some sort of electrical activity. If you placed electrodes on two sides of the cell membrane of a paramecium (as biologists often do these days), you’d also get a time-varying electrical signal. The fact that you get an electrical signal from cells just tells you they’re alive. Indeed, the Finnish surgeons saw similar electrical activity when they stimulated the fetus’ leg muscles. The brain stem, you will recall, governs the most fundamental body functions: heartbeat, respiration, and automatic muscle responses. Every vertebrate, from a codfish to a Nobel laureate, has a functioning brain stem. The fact that electrical signals can be evoked in the brain stem by external stimulation just means that the circuits that carry signals to the cerebellum have been completed. It is much more significant that no activity whatsoever was seen in the cortex, and almost none in the hypothalamus, even in fetuses well into the fifth month of development. What this means is that the Finnish experiment, far from disproving our argument about the development of the cortex, provides strong evidence for it. Finally, we have to point out that none of the readings taken on the fetuses showed any trace of the kind of organized activity we associate with the EEG. In fact, most of the readings from the brain stem look very much like those taken from the muscle. They in no way indicate the presence of a being capable of sentient thought or even of sensation. This simple fact has not, of course, prevented this particular canard from being repeated over and over in the abortion debate. This situation does, however, illustrate the importance of scientific honesty in the discussion of social issues.” "The Facts of Life" Harold J. Morowitz and James S. Trefil
Last edited by baloney_detector; 06-11-2007 at 11:16 AM.
Reason: Corrected some typos
|