Visual spatial attention and visual short-term memory: Electro-magnetic explorations of the mind

In this chapter we review recent work from our laboratories that explores how early and late attentional mechanisms interact to select and store information of interest to the observer. The studies are based on the analysis of electrophysiological and magnetoencephalographic recordings using paradigms that allowed us to track the moment to moment deployment of visual spatial attention and the participation of visual short-term memory in ongoing cognitive processing. These studies showed that visual spatial attention modulates early cortical responses to attended stimuli, whether attention was deployed voluntarily or involuntarily, that the deployment of spatial attention is impaired by concurrent processing in the attentional blink and psychological refractory period paradigms, and that transfer to visual short term memory is impaired and/or delayed by concurrent central processing. Finally, converging evidence from functional magnetic resonance imaging, event-related potentials, event-related magnetic fields, and time-frequency analysis of magnetoencephalography data, showed that activity of neurons in parietal cortex play an important role in the representations of objects in visual short-term memory.