When does life begin?

[Skye]

But what is it before you consider it alive, or human?

[YT2095]

I used the word "Human" deliberately, as the word "Alive" would be a misnomer, as it was alive from the get go.

prior to being "human" in my deffinition, it`s merely a POTENTIAL human, a mass of cells in cooperation with the "goal" or potential to become human

[BrainMan]

YT-

does anyone know at what point an unborn can respond to external stimuli, I don`t mean, will a cut heal or any other cellular based activity, I mean through 1 or more of it`s 5 senses, in a way that demonstrates clear brain activity/intervention. I would consider it alive from that point onwards. when the brainstem kicks in long before higher functions although I don`t know if there is a "non invasive" test for brain stem activity or not? but non the less maybe there will be eventualy, and I think at that point I would consider it "Human" with all the rights attatched to what being "human" demmands

 

So do I ake it that you are also against pulling people off machines after they are "brain dead"? The term applies to people that have no functioning cortex, but still have brain activity of some sorts.

 

I believe most gross aspects of brain development are done by the end of the first trimester, and I think that neural activity is presnet the whole time- necessary for guiding proper development of the brain. Im not positive though. There is evidence of memory after birth due to stimuli exposure in the womb in the third trimester. But brain development actually continues into adulthood.

 

 

You stated a point from when you consider it to be a human, but you didn't say why. Is it just an arbitrary choice? Why should anyone accept that point?

[YT2095]

if they`re brain stem dead and on a machine, I don`t consider them alive or even Human anymore from a psychological standpoint. as for taking them off the machine, I`m neither for nor against, each situation has to be assesed on it`s own merits or lack of, and not my descision to make, I wouldn`t want to be jacked into one if I was brain stem dead, and most all the people I know wouldn`t want it either.

there is also a difference between "brain dead" and brain STEM dead

[Sayonara]

Don't you need interaction to establish a psychological standpoint at all?

[YT2095]

by that I meant, that "what it means to be Human" is gone, and the Psychological part refered to me and how I perceive what being Human means

[BrainMan]

But why are you making the brain stem privileged? Isn't that just as arbitrary a distinction as conception is? Couldn't I just say "I consider it to be human when cell number 3,453,234 becomes functional" and be making just as good a statement as you?

[YT2095]

no, as that count would alter dramaticly from person to person.

when the brain stem is dead, you`re below insect status, they have a ganglia that functions in a similar way to our brain stem. when that`s fubar, you`re beyond repair and either up there playing with the angels or shoveling coal!

an animated corpse would be closer description and reliant on a machine to stop/slow the necrotising effects.

[Sayonara]

There is no evidence whatsoever that ganglia in insects support any form of consciousness (at least in the way we're describing it), so it's not the best comparison. Ganglia are more analogous to logical circuit loops.

 

A human nervous system can still respond to stimulus without the brain stem afaik.

[YT2095]

the basal ganglia is responsible for collating all these nerve impulses, sometimes known as the Primative Brain, when that`s gone, you`ll respond to nothing. although I`m sure Glider will know the exact ins and outs

[Duke]

life begins at 40

[Sayonara]

Stop using the plural in a singular context, it's bugging me

 

I think you missed the distinction I was trying to make. The fact that all nervous response to stimuli ends at point X does not mean that point X is when consciousness ends.

[YT2095]

the way I see it is like this, we have nerves (like wires) but in order to do something usefull with them, they have to be connected to something (the basal ganglia) from there at least responses can take place albeit limited, then interface that with the brain and all`s well and normal

as that component is only an interface to our cerebelum, without it, there would only be a brain floating in the skull of an animated corpse, since this is unlikely to ever occur, I reccomend that when the brain stem is dead, that you`re effectively dead too and from that point cease to be "Human" in any practical terms.

consciousness doesn`t play a part as far as I`m concerned, otherwise that would apply to Coma patients.

and besides, this entire thread is opinion based from the get go

and mine is that when you`re brain stem dead, it`s Curtains!

[Sayonara]

Being in a coma ("unconscious") does not mean you have no consciousness - we went over that in another thread a couple of weeks ago. You're also omitting the fact that the basal ganglia are useless in isolation, which could give you a false positive.

 

I don't know what point you're trying to make. "Without a brain stem you'd be dead" is not news. It certainly doesn't answer the O/P.

 

ps - nobody got my 'bugging me' joke

[YT2095]

sorry, I didn`t actualy get it, I thought it was something to do with the "life begins at 40" comment (I like that guy)

 

anyway, back to it, the point is, with the basal ganglia intact and the limibc system working, I say from that point you`re human (just) anything beyond this towards the development of the neo-cortex just gets better

[-Demosthenes-]

there is also a difference between "brain dead" and brain STEM dead

There is? What is it?

[Glider]

The brainstem, particularly the medulla, contains nuclei necessary for the maintenance of physical life. Brain-stem death means physical death. The body can no longer sustain life. Brain death is more tricky. The absence of cortical activity (brain death) is often termed persistant vegetative state. The body can sustain life, but the 'person' has gone.

 

I suppose a way to look at it would be: Brain stem death = physical death. Brain death = death of the person (the body can persist).

[PerpetualYnquisitive]

...it is a continuation of life that came before.

[Radical Edward]

The brainstem' date=' particularly the medulla, contains nuclei necessary for the maintenance of physical life. Brain-stem death means physical death. The body can no longer sustain life. Brain death is more tricky. The absence of cortical activity (brain death) is often termed persistant vegetative state. The body can sustain life, but the 'person' has gone.

 

I suppose a way to look at it would be: Brain stem death = physical death. Brain death = death of the person (the body can persist).[/quote']

 

would it be possible to kill the brain stem, but keep all the cortical activity going by putting the body on life support? or is the cortex so intertwined with the brain stem, that killing the stem means killing the cortex?

[J'Dona]

I don't know if anyone else has seen this, or how much of an affect it wold have on definition of when life starts (though I imagine they would), but here's something that might be interesting:

 

http://news.bbc.co.uk/2/hi/health/3846525.stm

http://news.bbc.co.uk/2/hi/health/3105580.stm (both same topic)

[Glider]

would it be possible to kill the brain stem, but keep all the cortical activity going by putting the body on life support? or is the cortex so intertwined with the brain stem, that killing the stem means killing the cortex?

 

Not for any useful period of time, no. You could keep the blood oxygenated and circulating for a time, but all you're doing is preventing (delaying) decomposition.

 

This is done sometimes to maintain organs that are to be removed for transplant, but it cannot be maintained for long. For example, you could use heart-lung bypass and so on, but the mechanisms for controlling BP are gone, as are the vaso-vagal systems. The body would leak fluid through congested and uncontrolled capillary beds from the central system to the periphery.

 

The tissues would become oedematus and overloaded and the lungs would fill. You could haemodyalyse to try to control that problem, but as the chemoreceptors are also non-functional, the body could not compensate for the concentration of dialysate that would be needed and the higher brain would be poisoned and/or starved (dialysis is traumatic enough on a relatively healthy system).

 

There would be no homeostatic mechanisms to maintain the physiological balances required to support the higher brain, which is extremely sensitive to chemical imbalance.

 

Further, the brainstem is where incoming (afferent and proprioceptive) information enters higher CNS areas. If that's gone, the rest of the brain becomes pretty redundant.

[Pleiades]

Human life is obviously special, but loosing a bit of skin doesn’t mean you have ended life of any significance. I think that a new human life begins when the two haploid reproductive cells combine chromosomes to become a new, unique cell. Where this puts clones, I’m not sure; perhaps the point is when the donor DNA starts making new, undifferentiated cells.

 

On a side note, I don’t know if the new unique cell has a soul directly after conception, but I think it is given a chance to have one, either some point later in the life of the baby, or sometime after the death of the aborted cell…….Although I’m not sure what would be left after the cell has died to be given a soul, but oh well. It’s a religious point anyway, so I wont try and reason it out. I still think conception is an important point.

[Sayonara]

The problem with getting souls involved is that you end up having to invent rules, such as "when the soul enters a new body" and "why it is a bad thing that a soul gets bumped on to the next place", which is a poor position to argue from.

[Pleiades]

Well, it was just a side note, it’s just my opinion, and as I said, I’m not going to try arguing my stance on the soul issue. My first paragraph on when ‘human life’ begins seems logical enough and based on science. Feel free to ignore the one about souls.

[Sayonara]

It was more a general comment on that approach than it was a rebuttal against you.