I am interested in biological 'death programs': specifically
programmed cell death called apoptosis, and also -- it might be the
same process, for all I know, I am not a biologist -- in the
developmental sequence in human infants and young children, where, as
I understand it, there is a pre- and postnatal period of explosive
growth in neurological connections, resulting in a tremendous
redundancy, and then, at age three ?? (or so, I am not sure), there is
a pretty massive death or severing of connections, in order to
strengthen the most useful (i.e. adaptively necessary) connections,
and then that the brain (more or less) is set in what it will be. Can
you explain this to me in succinct and laymman' s terms, and/or point
me to readable source material? Thank you in advance

<Apoptosis or programmed cell death is the mechanism that the body
uses to eliminate cells that it no longer needs.
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/Apoptosis.html
For example when toes and finger are formed in the fetus, apoptosis is
used to remove the tissue between the fingers and toes. Without
apoptosis we would be born with webbed fingers and toes. Apoptosis is
also used to destroy cells that could harm the body like cells
infected with a virus, cells of the immune system, cells with DNA
damage and cancer cells.

Apoptosis is also necessary for normal development of the brain.
Apoptosis is used to remove unnecessary connections and make the
wiring of the brain more efficient.  By the age of three a baby has
formed approximately 1000 trillion connections in it’s brain. By the
age of 11 connections that are not used start to be eliminated via the
process of apoptosis.
http://www.kaiserpermanente.org/newsroom/releases/firstyears/busleaderforum/brain.html>


<Additional links :>

<Brain development>
<http://www.preventingharm.org/pdf/IHW_Ch_2.pdf>

<Early brain development>
<http://nccic.org/hcca/nl/jan99/earlybra.html>

<Search strategy:>

<apopotosis>
<://www.google.com/search?hl=en&lr=&ie=ISO-8859-1&q=apoptosis+>

<apoptosis  development infants neurons>
<://www.google.com/search?hl=en&lr=&ie=ISO-8859-1&q=apoptosis++development+infants&as_q=neurons>


<Hope this helps.>

Thank you so much. Especially the links were very helpful as I am a
psychoanalyst writing a paper on the theoretical concept of the 'death
instinct'.

I'll give you a bit to get you started - I'll chime in with more if no
real researchers pick it up.

You are right.  PCD, or apoptosis, is indeed the process that causes
the selective die-off of superfluous neurons.  It is an entirely
normal process, and indeed, I doubt if any multicellular organism with
differentiated tissues could exist without it.

Many things can induce apoptosis.  It's normal advent in embryogenesis
and early development is one, but it is also an important mechanism by
which cells that sustain irreparable genomic damage remove themselves
from the population, thereby reducing the chances of tumour formation.

Normal tissue homeostasis is a balance between proliferation and
apoptosis (and other types of cell death).  While the proliferation
side has usually been suspected in cancers, there is strong evidence
that flawed apoptosis may also be involved.  Note that the gene most
commonly mutated in all human cancers, TP53, encodes a protein crucial
to the instigation of apoptosis after DNA damage.

Sorry - I've wandered a bit.  I hope someone can shed a bit more light
on the developmental role for you.  If not - I'll be back.