A dream is a model, which is developed, based on an invariant QER.
We shall describe several classes of dreams.
1. QER is mainly based on the external reality, but contains also some artificial elements or relations. A dream based on artificial components, tries, by development, to modify the external reality to meet the dream.
Example: we dream a situation. Such a situation doesn't meet the external reality, because some artificial elements or relations are added. The dream can activate some models to change the external reality, to meet the specifications of the dream.
2. Technological dreams (wake-up dreams) The brain generates such dreams. They solve by software, some of the design deficiencies of the brain. The most important technological dreams are wake-up dreams.
There are normal wake-up dreams, emergency wake-up dreams and nightmare dreams. They are generated to wake-up a brain, because, due to a lack of a suitable hardware, the brain must generate the wake-up function based on software.
The main design feature of the brain, which is used by these technological dreams, is to activate the PSM. As the PSM is activated, the brain wake-up, i.e. a normal ZM, is activated. Usually, the PSM is activated by some unusual changes of the external reality (powerful noises, mechanical shocks…). The wake-up dreams try to activate the PSM by software. To do this, a wake-up dream sends to PSM the information that there is a situation and no suitable model to understand it. As we already know, when there is no model to understand a specific external reality, the PSM is activated. For a wake-up model, external reality is replaced by Quasi-External-Reality (QER).
MDT does not specify which component of the brain starts the dream (this is a technological feature). The components could be associated with the internal body or to the sense organs.
The content of the dream is not important. Any dream that activates the PSM is good. So an important problem associated with the health of the being or an unimportant problem could build the same dream. Only the character of the dream is important.
In case of a wake-up dream the character has to be taken into account: