The overall function of the brain is to maintain the physiological environment of the body e.g. breathing, digestion, urinary excretion, temperature regulation, thirst regulation etc. It is characteristic of the function that it is not under the control of the mind. Furthermore, the brain creates the inner and outer reality of the individual. The inner reality is the existential, the intentional and the emotional self. The outer reality is the environment and other people. The body perceives sensory stimuli, forwards them to the brain for processing and interpretation. Perhaps the machining and the interpretation give rise to a move to act this action is deliberate. You could say that the brain’s task is actively on choosing, make decisions and execute them through an interpretation of information. Then, it’s time to learn from its experiences.
The cerebrum fills the most of the skull and is divided into a left and right hemisphere. The outermost part of the big brain is called “cerebral cortex”.
Our intellectual functions are located in the cerebral cortex, which enables us to think and speak. The two brain halves are partially specialized, so that, for example, the left hemisphere handles the function of the language. The left hemisphere is considered more analytical, while the right half is better at assessing wholes and spatial phenomena. In general, most types of sensory impressions (e.g., vision, sensation, and hearing) will be received in the opposite hemisphere. Similarly, the areas of the brain that activate muscles will move the body in the opposite side.
The cerebral cortex can also be subdivided according to what functions each area performs. The posterior part of the brain receives visual impressions in occipital lobe. At the front of the parietal lobe lies a winding, which receives sensory impressions, while an area at the top of the temporal lobe receives sound impressions.
In other parts of these lobes, sensory impressions are processed, and impressions are compared with previous knowledge and experience to further put the impressions into a personal meaning.
It is especially the temporal lobe and the parietal lobe that are affected by Alzheimer’s disease.