Steve Engel, Psychology
"Timing of Visual Attention Measured with Functional MRI"

Reading

• Noesselt, T et al. (2002) Delayed striate cortical activation during spatial attention, Neuron, 35 575-587
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     Because fMRI has relatively poor temporal resolution, it has rarely been used to measure the timing of neural events. This talk will cover a series of studies that demonstrate that fMRI can in fact provide accurate timing information on the order of 100 msec. We make use of the observation that even though fMRI cannot distinguish between a single neural event and two events spaced closely in time, it can nevertheless provide very accurate measures of delays in the overall temporal pattern of neural activity. We use this method to measure delays in neural activity in visual cortex produced by the allocation of visual attention. In primary visual cortex, activity due to attention is quite delayed relative to activity due to a visual stimulus. Activity in later visual area V4 has reliably smaller, but still measurable delays.