Memory in humans is a complex process and is divided into several components. Different areas of the brain are responsible for different memory-related functions such as short-term memory and long-term memory, which can be further divided into subcategories such as emotional and semantic memory. Using fMRI, it is possible to pinpoint brain regions that participate in memory and detect changes in memory resulting from aging or other neurological diseases and the pathology of underlying brain structures. An example of a memory study was performed by Todd and Marois, with the aim of observing the role of the posterior parietal cortex in short-term visual memory. To achieve this, seventeen subjects were given a delayed visual matching to sample task during which subjects were first shown a display of one to eight colored discs and after a timed delay had to indicate whether a disc probe corresponded to one of the disks of the initial sample. Furthermore, to reduce any effects resulting from subjects' use of verbal strategies, subjects were required to simultaneously maintain a two-digit number during the delay period. The results showed that the accuracy of the responses decreased as the number of discs presented at the beginning of the study increased. Furthermore, it was established that the average short-term visual memory capacity was limited to three or four objects. fMRI data were collected and analyzed from three brain regions: the intraparietal sulcus/inferior occipital sulcus (IPS/IOS), the ventral-occipital cortex (VO), and the anterior cingulate cortex (AC). Activity in the IPS/IOS appeared to increase with increasing task load, and this region was shown to be active during maintenance and encoding. On the other side of the paper......Alzheimer's you can observe the roles of cognitive reserve and compensatory recruitment. For example, education level and overall intelligence could alleviate some of the cognitive and memory deficits found with age- and disease-related brain changes. Compensatory recruitment, such as bilateral activation of frontal regions in a verbal memory task compared to the left lateralized activation observed in younger adults during the same task, is also observed in older adults. These articles illustrate the fact that there are multiple memory systems with different functions. Taken together, these findings help explain why patients with brain damage in different regions do not always exhibit the same neurological deficits associated with memory. The use of fMRI has been extremely successful in identifying which regions of the brain are necessary for multiple types of memory.