Both of these studies suggest that older adults may recruit brain tissue beyond the ventral storage areas at lower working memory loads than young adults do, thus making demands on the dorsolateral prefrontal cortex (where executive processes reside) earlier
than young adults do. The Rypma and D’Esposito61 Inhibitors,research,lifescience,medical study is also important in suggesting that the locus of the effect they observed is at the response (retrieval) stage, rather than at the encoding stage. Inhibition and task-ABT-263 nmr switching and dedifferentiation. The data on inhibition and task switching are relatively sparse. In one study on the imaging of interference effects, Jonides et al62 demonstrated larger interference Inhibitors,research,lifescience,medical effects behaviorally for older adults compared with younger adults by creating response conflict in a verbal working memory task. Young adults showed more activation than older adults in the left lateral prefrontal cortex, and this appears to be an important site for mediating response conflicts in the young, since they showed smaller interference effects than the old. There were no other differences in activations between Inhibitors,research,lifescience,medical young and old, and so the study primarily provides information about how the young deal with response interference. In a study on task -switching in
working memory, Smith et al59 found age and performance to be important variables related to activation patterns. Both old adults and poorly performing young adults recruited left prefrontal cortex during a dual-task condition involving Inhibitors,research,lifescience,medical simple computations and storage, whereas young adults who performed well did not
show these frontal activations. In both of these studies, patterns of unique recruitment were observed. For inhibition, young adults showed Inhibitors,research,lifescience,medical unique recruitment compared with older adults, whereas for a switching task, older adults and poor young adults showed unique recruitment of frontal regions. Binding and dedifferentiation. Mitchell et al63 investigated the ability of young and older adults to bind object with feature information (color, spatial) in a working memory task. They found evidence for a disturbed prefrontal/hippocampal circuit in older adults for performance of the binding operation. Older adults showed less activation Levetiracetam than the young of anterior hippocampal structures in a binding condition compared with an object-only or feature-only condition, and also showed evidence of less activation in right prefrontal Brodmann area 10 for the binding condition. This important work provides an excellent bridge to understanding the relationship of working memory to long-term memory function, as it is primarily in long-term memory that source and binding operations have been demonstrated to be deficient. Long-term memory and dedifferentiation.