Which part of brain is responsible for advance or unseen imagination For example:ones brain can make a situation in mind which is impossible to happen ...which part of brain is hyper active?
Edit: Added two studies to better show how different types of imagination tasks use different parts of the brain.
Imagination is a complex process that can use many regions of the brain. Insights into how our brain imagines have been gained through a number of studies. There is not an "imagination" area of the brain. Instead, different areas, and often several at a time, may be used depending on the type of imagination. I'll highlight a few examples here.
Ogino et al. (2007) asked 10 male participants to imagine feeling pain while watching pictures suggesting either pain or fear. Both pain and fear tended to activate an area of the brain called the anterior cingulate cortex (ACC), which helps to regulate blood pressure and heart rate among other basic nervous functions. Imagining pain activated not only the ACC but also another four areas of the brain were especially active. In comparison, fear tended to activate the ACC and the hypothalamus, which regulates the "flight or fight" response. Both sides of the brain were activated at the same time.
Boly et al. (2007) studied 12 brain-injured patients who where not capable of communicating. They were not in a coma. They were asked to imaging tasks involving spatial skills or motor skills. The two most common areas of the brain that were activated were the supplementary motor area, which helps to control movement, and the dorsal premotor cortex, which may contribute to movement and spatial coordination. (Wikipedia information so interpret cautiously.)
A detailed study was recently provided in a study by Schlegel et al. 2013. (An alternate version is here; both versions are open access.) Summaries of their work written for the general public can be found in Popular Science and Science Daily.
The scientists identified what they called the "mental workspace" which is not a particular region of the brain but instead is several different regions of the brain (from both sides of the brain) interacting together.
The researchers asked the study participants (9 males and 6 females) to select from a set of abstract shapes to assemble a particular target shape. The target shape (the one the participants had to create) was a 2x2 grid. Each abstract shape that to be selected would fit one of the grids. So, four abstract shapes had to be selected to assemble the target shape. They also tested the reverse: Given a target shape, could the participants identify the four abstract shapes needed to make the target shape.
During the task, the researchers used functional magnetic resonance imaging (fMRI) to monitor brain activity. After the analysis of the fMRI results, they identified 11 distinct regions of the brain were active during the task. In nearly all cases, the regions were active in both sides of the brain. However, I noticed that one region, the medial frontal cortex, only appeared to be active in the left side of the brain. This region was identified as one important component of the mental workspace for certain tasks.
The researchers concluded that four of the 11 regions were most important. You can see the regions of the brain in any four of the links above (and the abstract shapes in all but the Science Daily article). They argue that the interaction among the four major and seven minor regions contribute to our process of imagination.
Each of the three studies I highlighted requires the participants to perform different types of imgination tasks. Each type of task showed that different regions of the brain were used. Each type of task also required that several areas of the brain were used simultaneously during the imagination process. Together, these results show that no single part of the brain is used for imagination. Instead, many different areas are used, depending on what the person is imagining.
Boly, M. et al. 2007. When thoughts become action: An fMRI paradigm to study volitional brain activity in non-communicative brain injured patients. NeuroImage 36: 979-992.
Ogino, Y. et al. 207. Inner experience of pain: Imagination of pain while viewing images showing painful events forms subjective pain representation in human brain. Cerebral Cortex 17: 1139-1146.
Schlegel et al. 2013. Network structure and dynamics of the mental workspace. Proceedings of the National Academy of Sciences USA 110: 16277-16282.