| Selective attention is the central mechanism underlying our remarkable cognitive flexibility. We can voluntarily direct attention to relevant parts of visual information among the multitude of information that our eyes encounter at any moment in time. Effects of attention are pervasive: Attended information is processed in great depth while visual information outside our focus of attention appears to be of lower contrast and is often not consciously recognized. These important consequences of attention are brought about by interactions among cortical neurons. From brain research we know that attention selectively enhances activity of those neurons processing relevant information and reduces activity of neurons processing unattended information. However, it is currently unknown how selective attention can induce such specific changes of neuronal activity that critically underlies our perceptual skills. To understand these unresolved neuronal mechanisms of attention ultimately requires knowledge of how neurons interact within and across distant regions in the brain and how attention renders behaviourally relevant neuronal interactions effective. Here, I outline a research program to directly elucidate these mechanisms of neuronal communication during selective attentional processing. I will investigate whether effective neuronal communication depends on precise synchronization of rhythmic, oscillatory activity. Oscillatory activity reflects excitability fluctuations and the time windows of peak excitability are likely windows for neuronal communication. Two groups of neurons will communicate effectively when they synchronize the time of peak excitability while desynchronization likely prevents communication. I will study the outlined mechanisms at yet unexplored spatial and temporal scales: I will record brain activity simultaneously at multiple sites within three distinct brain regions while subjects perform a selective attention task. This approach could provide unprecedented insights into how attention controls neuronal communication in the intact brain ? with the prospect to shed light on the source of attentional malfunctions evident in multiple neurological and psychiatric syndromes. |
