1/28/2010

The following question was posted after my last blog. “In your book DEAD HEAD, I was fascinated by how you laid out the challenges the surgeon, Russell Lawton, faced in keeping the injured man's severed head alive and functioning. You made it seem totally plausible, even down to devising a way for the head to communicate with his fellow terrorists. Ethical issues aside, could you ever see a time where a brain could be transferred to a host body, or perhaps just the thoughts and memories, not the actual brain?”

Transplanting a brain is terrific fodder for science fiction, but it impossible at the present time. Why? Huge reasons. Let’s say Fictitious Person X has some illness that is destroying his body but leaving his brain perfectly intact and functioning at intellectual levels similar to Stephen Hawkings. So the decision is made to transplant X’s brain into a human body of a brain Dead Person Y. (Most likely, this would be a person shot through the head. Why? Because chances are they would be young, without other disease, so a healthy body.)

To actually remove the brain would be impossible. Why? Well, you would have to cut all the nerves that connect X’s brain to the eyes, nose, face, mouth, etc. Then you’d have to sever the spinal cord and blood vessels to and from the brain. You might be able to hook the blood vessels to Y’s body but then you’d be out of luck. There is no way you can reconnect all those nerves or the spinal cord. So you’re left with a living brain without any sensory input.

As described in DEAD HEAD, experiments were carried out years ago in transplanting heads from one animal to another. (For reasons I’ve never understood). These experiments failed because of tissue rejection issues that transplantation medicine has subsequently solved. But even if total head transplants could be done now, the result would be a person who was quadriplegic (because you would still not be able to hook up a functioning spinal cord).

Okay, so maybe total brain transplants are not feasible, but how about memory? Good question. And the issue of what is memory and where it is stored will be a future topic. Suffice it to say that memories considered to be “long term” (events that happened days ago) are probably stored in the brain cells chemically, perhaps even as proteins. So, theoretically it may be possible to eventually transfer memories from one person to another. But this is not something likely to happen in the near future.

The second part of the question is: “Ethical issues aside, could you ever see a time where a brain could be transferred to a host body, or perhaps just the thoughts and memories, not the actual brain?”

Here the discussion quickly changes from science to philosophy. First, defining (in physiologic terms) what a “thought” is, is in itself problematic. There is not “thought center. There are various brain regions that are essential for regulating wakefulness and sleep. If some of these areas are damaged, for example during head injury or stroke, the person may become non-responsive and stay in a coma. But do they have thoughts? Some may, others probably do not. We do, however, think during sleep. I’m sure all of us have had the phenomenon of awakening in the morning having solved a problem during sleep. But what brain areas are responsible for logic? That is something we don’t know for certain.