Event-related potential measures of visual working memory.
Visual working memory is a limited capacity system that temporarily maintains information about objects in the immediate visual environment. Psychophysical experiments have shown that most people are able to actively maintain 3 or 4 items in visual working memory at any point in time. To better understand how this process works and why our working memory capacity is so limited, a variety of neurophysiological approaches have been employed. In recent years, there has been a surge of interest in understanding how visual information is maintained in working memory at the neural level. Single-cell research with nonhuman primates has shown that neuronal firing during the retention period reflects the information that is currently held in working memory. In humans, event-related potentials (ERPs) have been used to examine the maintenance of information in working memory. An event-related potential component, known as the negative slow wave (NSW), has been used to measure the maintenance of information in working memory "online" during a given trial. More recently, another ERP component, the contralateral delay activity (CDA) has been shown to be a fairly specific correlate of the current contents of working memory. This component is sensitive to an individual's working memory capacity and may provide a window into the operations of this central cognitive construct.
Drew
Trafton W
TW
Department of Psychology, University of Oregon, Eugene 97403-1227, USA.
McCollough
Andrew W
AW
Vogel
Edward K
EK
D000818:Animals; D001288:Attention / Q000502:physiology; D002540:Cerebral Cortex / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008570:Memory, Short-Term / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology