Certain language functions such as word retrieval and production were found to be located to more anterior language cortices, and deteriorate as a function of age. Sowell et al., also reported that these anterior language cortices were found to mature and decline earlier than the more posterior language cortices. It has also been found that the width of sulcus not only increases with age, but also with cognitive decline in the elderly. Age-related neuronal morphology
There is converging evidence from cognitive neuroscientists around the world that age-induced cognitive deficits may not be due to neuronal loss or cell death, but rather may be the result of small region-specific changes to the morphology of neurons. Studies by Duan et al., have shown that dendritic arbors and dendritic spines of cortical pyramidal neurons decrease in size and/or number in specific regions and layers of human and non-human primate cortex as a result of age (Duan et al., 2003; morph). A 46% decrease in spine number and spine density has been reported in humans older than 50 compared with younger individuals. An electron microscopy study in monkeys reported a 50% loss in spines on the apical dendritic tufts of pyramidal cells in prefrontal cortex of old animals (27–32 years old) compared with young ones (6–9 years old). Neurofibrillary tangles
Age-related neuro-pathologies such as Alzheimers disease, Parkinsons disease, diabetes, hypertension and arteriosclerosis make it difficult to distinguish the normal patterns of aging. One of the important differences between normal aging and pathological aging is the location of neurofibrillary tangles.
Although these levels were studied in the normal human brain, the parietal and basal ganglia regions are often affected in degenerative brain diseases associated with aging and it has therefore been suggested that brain glutamate may be useful as a marker of brain diseases that are affected by aging. Neuropsychological changes
Changes in orientation
Orientation is defined as the awareness of self in relation to ones surroundings Often orientation is examined by distinguishing whether a person has a sense of time, place, and person. Deficits in orientation are one of the most common symptoms of brain disease, hence tests of orientation are included in almost all medical and neuropsychological evaluations. While research has primarily focused on levels of orientation among clinical populations, a small number of studies have examined whether there is a normal decline in orientation among healthy aging adults. Results have been somewhat inconclusive. Some studies suggest that orientation does not decline over the lifespan. For example, in one study 92% of normal elderly adults (65–84 years) presented with perfect or near perfect orientation. However some data suggest that mild changes in orientation may be a normal part of aging. For example, Sweet and colleagues concluded that "older persons with normal, healthy memory may have mild orientation difficulties. In contrast, younger people with normal memory have virtually no orientation problems" (p. 505). So although current research suggests that normal aging is not usually associated with significant declines in orientation, mild difficulties may be a part of normal aging and not necessarily a sign of pathology.