The researchers though not yet sure, one theory according to Christy Marshuetz, assistant professor in the Department of Psychology and a co-author of the study, is that the extra activity in older adults is probably compensation for age-related changes in brain volume or efficiency. The studies were conducted on a dozen people 18- to 27-years-old, and an equal number of 61- to 80-year-olds. They were asked to remember three images of houses or three images of faces and then asked to decide if another image was from the original set. Functional magnetic resonance imaging was used to track neural changes during these tasks.
Marshuetz stated that it was known that there are different regions in the inferior temporal lobes of the brain that respond to faces and to photographs of houses. It is also well established that as humans age, both neural and cognitive function become less differentiated. But he felt the data available is sparse and previous studies have examined neural activity only during passive viewing. Whereas here the researchers examined age differences in neural specialization for "faces and places" in a working memory task. They proposed that even when consciously remembering specific items, older adults would show decreased specialization in the fusiform face area of the brain and the parahippocampal place area of the brain when compared with younger adults. The researchers also found, more activity in older adults in the frontal cortex and believe this activity is compensation for less differentiation in the visual cortex at the back of the brain.
The researchers concluded that their findings were the first to demonstrate decreased neural specialization in the ventral visual cortex in older adults, along with increased activations in the prefrontal cortex. This they said underscores the importance of taking into account the connected and networked nature of the brain and its function in understanding human neural aging.