The electrical signals in your brain stop, and that is when the mental 'you' ends.
Interestingly, absence or otherwise of electrical signals is not part of the criteria for diagnosing brain death. Certainly absence of electrical activity as measured by an EEG would strongly point towards brain death (although such a phenomenon can also be seen under general anesthesia - particularly if also undergoing intra-operative hypothermia as one might during cardiac bypass), but brain death can be diagnosed even in the presence of electrical activity.
Furthermore, one can experience death of the cerebral cortices, which are responsible for all higher brain functions - all sensory processing, all voluntary movements, speech and language, memory, etc. - whilst still having an intact hindbrain, which is responsible for involuntary actions - sneezing, vomiting, heart rate, blood pressure, etc. Patients such as this are particularly difficult to make decisions for regarding withdrawal of treatment; although the "person" inside is dead, the body can continue to live for several years provided it is given basic nutrition.
You can bring dead back to life if death occured within the last few minutes.
There's a saying in the medical field that "You're not dead until you're warm and dead". Severe hypothermia has a protective effect on all body tissues, and they can survive for several hours in these conditions and still be resuscitated. The longest case that I am aware of is a
patient who was "dead" for 9 hours before being successfully resuscitated.
This life is temporary and the life after death is real.
[citation needed]There is absolutely zero evidence to support the hypothesis that there is any form of life after death.
