This study presents a noninvasive method for mapping human brain activity using dynamic magnetic resonance imaging (MRI). The technique relies on changes in cerebral blood flow (CBF) and blood oxygenation, detected using high-speed echo planar imaging. By applying visual and motor stimulation paradigms, the researchers obtained tomographic maps of brain activity with a temporal resolution of seconds. The method uses a gradient echo (GE) sequence sensitive to blood oxygenation and a spin-echo inversion recovery (IR) sequence sensitive to CBF. During 8-Hz photic stimulation, a significant increase in signal intensity was observed in the primary visual cortex (V1) of seven normal volunteers, with an average increase of 1.8% ± 0.8% using GE and 1.8% ± 0.9% using IR. The rise time constants were 4.4 ± 2.2 s for GE and 8.9 ± 2.8 s for IR. These results agree with previous positron emission tomography (PET) observations, showing the largest MR signal response at 8 Hz. Similar signal changes were observed in the primary motor cortex (M1) during hand squeezing and in animal models of increased blood flow by hypercapnia. The study demonstrates that functional MRI (fMRI) can provide a spatial-temporal window into individual brain physiology by using intrinsic blood-tissue contrast. The results show that changes in neuronal activity lead to subtle but detectable changes in T1- and T2* weighted MR images. The study also confirms that activation-induced changes in blood flow and volume are accompanied by little or no increase in tissue oxygen consumption. The observed signal changes are in good agreement with theoretical modeling. The study highlights the advantages of fMRI over previous brain-mapping approaches, including its noninvasive nature and ability to provide high spatial-temporal resolution. The results suggest that fMRI can be used to study both primary sensory activation and higher cognitive functions. The study also discusses the limitations of the current technique, such as the single-slice limitation, and suggests that future improvements in imaging technology could enhance the spatial and temporal resolution of fMRI. The study concludes that fMRI has the potential to revolutionize the understanding of brain function by providing unprecedented spatial-temporal resolution.This study presents a noninvasive method for mapping human brain activity using dynamic magnetic resonance imaging (MRI). The technique relies on changes in cerebral blood flow (CBF) and blood oxygenation, detected using high-speed echo planar imaging. By applying visual and motor stimulation paradigms, the researchers obtained tomographic maps of brain activity with a temporal resolution of seconds. The method uses a gradient echo (GE) sequence sensitive to blood oxygenation and a spin-echo inversion recovery (IR) sequence sensitive to CBF. During 8-Hz photic stimulation, a significant increase in signal intensity was observed in the primary visual cortex (V1) of seven normal volunteers, with an average increase of 1.8% ± 0.8% using GE and 1.8% ± 0.9% using IR. The rise time constants were 4.4 ± 2.2 s for GE and 8.9 ± 2.8 s for IR. These results agree with previous positron emission tomography (PET) observations, showing the largest MR signal response at 8 Hz. Similar signal changes were observed in the primary motor cortex (M1) during hand squeezing and in animal models of increased blood flow by hypercapnia. The study demonstrates that functional MRI (fMRI) can provide a spatial-temporal window into individual brain physiology by using intrinsic blood-tissue contrast. The results show that changes in neuronal activity lead to subtle but detectable changes in T1- and T2* weighted MR images. The study also confirms that activation-induced changes in blood flow and volume are accompanied by little or no increase in tissue oxygen consumption. The observed signal changes are in good agreement with theoretical modeling. The study highlights the advantages of fMRI over previous brain-mapping approaches, including its noninvasive nature and ability to provide high spatial-temporal resolution. The results suggest that fMRI can be used to study both primary sensory activation and higher cognitive functions. The study also discusses the limitations of the current technique, such as the single-slice limitation, and suggests that future improvements in imaging technology could enhance the spatial and temporal resolution of fMRI. The study concludes that fMRI has the potential to revolutionize the understanding of brain function by providing unprecedented spatial-temporal resolution.