Working memory (WM) is a primary cognitive function that corresponds to the ability to update, stably maintain, and manipulate short-term memory (STM) rapidly to perform ongoing cognitive tasks. A prevalent neural substrate of WM coding is persistent neural activity, the property of neurons to remain active after having been activated by a transient sensory stimulus. This persistent activity allows for online maintenance of memory as well as its active manipulation necessary for task performance. WM is tightly capacity limited. Therefore, selective gating of sensory and internally generated information is crucial for WM function. While the exact neural substrate of selective gating remains unclear, increasing evidence suggests that it might be controlled by modulating ongoing oscillatory brain activity. Here, we review experiments and models that linked selective gating, persistent activity, and brain oscillations, putting them in the more general mechanistic context of WM. We do so by defining several operations necessary for successful WM function and then discussing how such operations may be carried out by mechanisms suggested by computational models. We specifically show how oscillatory mechanisms may provide a rapid and flexible active gating mechanism for WM operations.
The paper looks at the role of working memory in the effect of "misses in continued search". The effect consists in missing the second target stimulus after a successful detection of the first in a visual search task. One of the theories links the effect to the fact that the detected first stimulus exhausts the resource of the working memory and thus blocks the search. In our study we used a standard working memory task which consisted in memorizing one digit (low working memory load) or six digits (high working memory load) with a subsequent report. A visual search task consisted in looking for the letters T among letters L. There might have been one or two Ts or none at all. The subjects' task in each trial was to identify the Ts while retaining the information about the digital task in the working memory. The experiment revealed meaningful significance of the number of stimuli, but the factors of the working memory load and interference of stimuli were insignificant. Thus the degree of the effect of "misses in continued search" (the difference between percentage of correct answers in the task with two target stimuli and in the task with one target stimulus) turns out to be the same in all trials irrespective of high or low loading of the working memory. Comparison of the findings of the study with other research data allows a conclusion that the effect of misses is either not linked to working memory or is linked to another memory sub-system. The study also revealed a link between the effect of misses and the number of search stimuli, i.e. the perceptive load of the system of information processing.