The Neural Basis of the Attentional Blink

ABSTRACT

A fundamental characteristic of visual attention is its severely limited processing capacity: We have great difficulty in attending to more than one visual event at a time. This limitation is clearly illustrated by the attentional blink (AB) paradigm: When subjects search for two targets in a rapid serial visual presentation (RSVP) of distracter items, they are severely impaired at detecting the second of the two targets when it is presented within 500 ms of the first target. Imaging and electro-physiological studies of the attentional blink suggest that the bottleneck of information processing revealed by the AB is not located in visual cortex, but instead primarily resides in a network of fronto-parietal regions previously implicated in visuo-spatial attention. Brain lesions studies are consistent with these findings, but also suggest that additional cortical and subcortical regions may be involved as well. Overall, these findings are consistent with a late, post-perceptual locus for the bottleneck of information processing for the attentional blink, and further suggest that the AB may be a multicomponent deficit arising from the contribution of a multitude of brain regions.

The human brain is heralded for its complexity and enormous processing capacity: Its billions of neurons and trillions of synaptic connections can process and exchange massive amounts of information over distant extents of brain tissue in the matter of milliseconds. Correspondingly, early stages of visual information processing are endowed with massive parallel processing capacities. Yet, for all their neuro-computational sophistication, humans show severe capacity limits in the number of objects they can attend to or hold in mind, or in the number of tasks they can perform at once. Thus, from early sensory stages with seemingly unlimited capacities, information flow hits capacity-limited processing stages on its way to response execution.