Different areas of the brain have different functions. So, knowledge of location of brain damage will give the exact position of the body which has been effected.
Basically, the human brain is divided into left and right halves. The left half controls the sensations of right half of the body and vice-versa. Generally the left half of the brain is related to memory. So, if location of damage is on the left side, it means that memory has been effected.
H.M. or Henry Gustav Molaison played the key role in understanding the memory process. He was an American patient, who suffered from memory disorders. This patient was widely studied since 1957 to 2008 for various memory disorders. This patient is the sole one responsible for development of cognitive neurophysiology. Actually, he suffered from epilepsy due to a bicycle accident at age 7. The neurophysician noted damage in temporal lobes for which parts of temporal lobes including hippocampus region were surgically removed. After successful removal, the epilepsy was cured; but H.M. suffered from partial memory loss. So, the role of temporal lobes and hippocampus in memory establishment was created.
After this, a range of studies were conducted on different regions of brain to understand cognitive neurophysiology.
Brain is divided into six areas: Brain stem, cerebellum, frontal lobe, occipital lobe, parietal lobe, and temporal lobe. Out of these, frontal lobe contributes to memory for basic habits, cerebellum has memory for various reflex arcs, and temporal lobes is related to memory acquisition.