This study demonstrates the use of dynamic magnetic resonance imaging (MRI) to map human brain activity during primary sensory stimulation. The researchers developed high-speed echo planar imaging techniques to detect changes in cerebral blood flow and blood oxygenation, which are indicators of neuronal activity. Using these techniques, they acquired continuous images during visual and motor tasks, showing significant increases in signal intensity in the primary visual cortex (V1) and primary motor cortex (M1) of seven normal volunteers. The changes were observed during 8-Hz patterned-flash photic stimulation, with a mean rise-time constant of 4.4 ± 2.2 seconds for gradient echo (GE) images and 8.9 ± 2.8 seconds for inversion recovery (IR) images. Similar results were also observed in animal models of increased blood flow by hypercapnia. The study highlights the potential of functional MRI to provide a spatial-temporal window into individual brain physiology, offering advantages over other imaging techniques such as positron emission tomography (PET) due to its noninvasive nature and repeatable imaging capabilities.This study demonstrates the use of dynamic magnetic resonance imaging (MRI) to map human brain activity during primary sensory stimulation. The researchers developed high-speed echo planar imaging techniques to detect changes in cerebral blood flow and blood oxygenation, which are indicators of neuronal activity. Using these techniques, they acquired continuous images during visual and motor tasks, showing significant increases in signal intensity in the primary visual cortex (V1) and primary motor cortex (M1) of seven normal volunteers. The changes were observed during 8-Hz patterned-flash photic stimulation, with a mean rise-time constant of 4.4 ± 2.2 seconds for gradient echo (GE) images and 8.9 ± 2.8 seconds for inversion recovery (IR) images. Similar results were also observed in animal models of increased blood flow by hypercapnia. The study highlights the potential of functional MRI to provide a spatial-temporal window into individual brain physiology, offering advantages over other imaging techniques such as positron emission tomography (PET) due to its noninvasive nature and repeatable imaging capabilities.