Two dissociable updating processes in working memory
Frontal lobe patients showed major difficulties in inhibiting interfering information, an ability requiring an involvement of the CE component.In contrast, Alzheimer’s dementia patients evidenced a relative impairment in maintaining relevant information, requiring the intervention of the PL.It is suggested that maintaining active verbal information mostly relates to an intact PL, while the inhibition of interfering information preponderantly involves the CE.To distinguish these effects, two groups of brain damaged patients were administered with an updating task.This network becomes active during updating of different types of visual stimuli (Roth et al., 2006), updating from a sensory stimulus or an item from long term memory (Roth and Courtney, 2007), and when the rule operating on a stimulus is updated (Montojo and Courtney, 2008).is the process of attending to information that is not perceptually present but is momentarily active from either recent perception or thought (e.g., thinking back to a just-seen stimulus no longer on the screen; Raye et al., 2002; Johnson et al., 2002, 2005).
Bilateral areas of frontal cortex, supplementary motor area, and parietal cortex were similarly active for both updating and refreshing, suggesting a common network of areas are recruited to bring information to the current focus of attention.
Update and refresh may involve different areas of cortex. Assuming that there is a distinction between the cognitive operations and neural activity involved in perceptual vs.
For example, Updating should show relatively greater activity in posterior visual processing regions as a new target is perceptually attended, and Refreshing should show relatively greater activity in frontal regions (e.g., left DLPFC) associated with modulating representations of no longer present perceptual stimuli (M. reflective attention (e.g., Dobbins & Han, 2006; Gilbert, Frith and Burgess, 2005; Johnson, Raye, Mitchell et al., 2005; Johnson & M. Johnson, in press), directly comparing the neural correlates of an active representation of a stimulus that is no longer perceptually present should help clarify similarities and differences in neural activity observed in more complex cognitive tasks that recruit these processes.
Bilateral areas of frontal cortex, supplementary motor area, and parietal cortex were similarly active for both updating and refreshing, suggesting that a common network of areas is recruited to bring information to the current focus of attention.
In a direct comparison of update and refresh, regions more active for update than refresh included regions primarily in right frontal cortex, as well as bilateral posterior visual processing regions.