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Working memory (WM) updating is a controlled process through which relevant information in the environment is selected to enter the gate to WM and substitute its contents. We suggest that there is also an automatic form of updating, which influences performance in many tasks and is primarily manifested in reaction time sequential effects. The goal of the present study was to dissociate WM updating and automatic updating, characterize the nature of these operations and identify the memory system responsible for each. In addition, we investigated the relationship between WM updating and the P3 event-related potential component. In Experiment 1, we compared the sequential processes in 1-back and 2-alternative forced choice tasks. These results indicated differential sources of sequential processes in the 2 tasks. We proposed that automatic updating operates in long-term memory on representations separate from WM representations. In addition, the event-related potential results of Experiment 1 are inconsistent with the idea that P3 is triggered through WM updating. Subsequently, in Experiments 2-3, we decomposed the 1-back task to major subprocesses. To this end, a new paradigm is introduced: the reference-back task. This paradigm facilitated the empirical distinction between automatic updating, comparison processes, gating and WM updating, within the same task. The results replicated the separate effects of WM updating and automatic updating on performance, and they provided behavioral evidence for a gating mechanism that separates WM from long-term memory. (PsycINFO Database Record

Effective working memory (WM) functioning depends on the gating process that regulates the balance between maintenance and updating of WM. The present study used the event-based eye-blink rate (ebEBR), which presumably reflects phasic striatal dopamine activity, to examine how the cognitive processes of gating and updating separately facilitate flexible updating of WM contents and the potential involvement of dopamine in these processes. Real-time changes in eye blinks were tracked during performance on the reference-back task, in which demands on these two processes were independently manipulated. In all three experiments, trials that required WM updating and trials that required gate switching were both associated with increased ebEBR. These results may support the prefrontal cortex basal ganglia WM model (PBWM) by linking updating and gating to striatal dopaminergic activity. In Experiment 3, the ebEBR was used to determine what triggers gate switching. We found that switching to an updating mode (gate opening) was more stimulus driven and retroactive than switching to a maintenance mode, which was more context driven. Together, these findings show that the ebEBR – an inexpensive, non-invasive, easy-to-use measure – can be used to track changes in WM demands during task performance and, hence, possibly striatal dopamine activity.

Optimal working memory (WM) functioning depends on a control mechanism that balances between maintenance and updating by closing or opening the gate to WM, respectively. Here, we examined the neural oscillation correlates of WM updating and of the control processes involved in gating. The reference-back paradigm was employed to manipulate gate opening, gate closing, and updating independently and examine how the control functions involved in these processes are mapped to oscillatory EEG activity. The results established that different oscillatory patterns were associated with the control process related to gate opening than in gate closing. During the time of gate closing, a relative increase in theta power was observed over midfrontal electrodes. This theta response is a known EEG signature of cognitive control that is proposed here to reflect reactive conflict resolution, achieved by closing the gate when facing irrelevant information. On the other hand, proactive gate opening in preparation for relevant information was associated with an increase in relative delta power over parietal-occipital electrodes. Finally, WM updating was associated with relative increase in delta power over midfrontal electrodes, suggesting a functional role of delta oscillations in WM updating.

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