There are so-called pressure points located throughout the body, on lines, which are refered to as meridians. Rubbing your temples when you have a
headache in opposite directions are good to relieve a headache
Most of these pressure points are actually nerve clusters. There is also a
"headache relief" never cluster located in the webbing between the thumb and index finger. Pinching it is a good way to relieve a headache.
I've seen demonstartions of dim mak being used (pressure point martial art) to basically sap the energy out of someone, and render them unable to
continue in a fight.
Two easy examples of this, that most everyone is aware of, but probabaly do not consider the martial arts implications of such areas are:
When you hit your funny bone, sometimes you experience a HOT rush of energy travel down your arm and into your palm, causing you to be unable to move
your arm for a time.
Bumping into a table with the side part of your knee in the right spot and your energy will be drained and you will feel like passing out.
Having parts of your body "fall asleep" with "Pins-and-needles"
Just like when the doctor checks the reflexes on your knee, there are other points such as that around your body that can be depressed to control your
bodily actions, such as opening your hand, or the involuntary bending your arm, and certain points that cause muscles to contract or relax.
I'd say the very most basic form of attacks composed of the above are simple nerve strikes that can be performed with a kick or with a forearm/fist.
They teach some simple nerve strikes in the USMC MCMAP program, which may be a good starting point if you wish to persue more advanced techniques
(individual fingers or knuckles, and perhaps, needles, although I mention needles with a bit of skepticism)
Keep in mind, there are other, less known points that can have the same effect of depleting your energy. This includes individual points, and
combinations of points. I'm not sure if sequential combinations of points would produce myriad effects as I have never persued the study that far.
This is where the study and practice come into play. You will either take it seriously, or lean towards ignorance and mainstream so as to pass it off
as a joke.
What you see in movies is a glorified version of the possibilities, however, it would not be too far off assuming you have god-like hand eye
coordination and reflexes, but this would be pretty rare, unless you are, maybe of morihei ueshiba experience and talent (I would mention Bruce Lee,
but he died young and did not appear to use too many pressure points). I personally am up in the air as to whether this type of technique is shown in
hollywood movies to promote a disbelief in the subject and it's reality. It could be very well that it is embellished a bit in order to make it
appear as if it could "just never be true." Or it could just be "good entertainment," whatever that means
As far as the delayed death, and putting someone to sleep, I don't know. You can knock someone out pretty fast with a hard pressure point hit, and
even kill them, you can disable someones leg with a few well placed kicks, etc... but as far as placing needles in certain areas to accomplish this, I
don't know. Needles are usually used for accupuncture and produce beneficial effects rather than detrimental ones. I would not imagine many martial
artists would carry accupuncture needles around with them
Do some searches for it, there are plently of good resources out there.