Age-related changes in word retrieval: Role of bilateral frontal and subcortical networks C Wierenga et al. Neurobiology of aging-6681 (2006).

Is there a deterioration of the lexical-semantic information in older adults, or is it a question of difficulty finding words or accessing the lexical-semantic information? In this study, BIRC scientists looked at 20 younger adults (aged 20-34 years) and 20 older adults (aged 68-84 years) and their brain activity with functional magnetic resonance imaging (fMRI) during word retrieval (picture naming) sessions. The purpose of the study was to examine changes in neural substrates underlying word retrieval. The two groups had similar accuracy rates in the picture naming task. Nonetheless, the older group had more activity than the younger group in the following areas: right Broca’s area homologue, the anterior region of the right inferior frontal gyrus, the left and right anterior cingulate areas, and the superior temporal gyrus, bilaterally. The older group showed less laterialization of activity as a result of the increase in right frontal activity. There were no regions in which younger adults showed greater activity than the older adults. Findings suggest that there was no gross compromise in lexical-semantic substrates or, in other words, that healthy older adults do not experience a deterioration of lexical-semantic stores. However, the deterioration of the frontal neural substrates hinders the ability to access appropriate lexcial word forms. Simply put: the actual retrieval process, not the storage of words, is hindered with age.