The study by Fox et al. (2006) investigates the spontaneous neuronal activity in the human brain to distinguish between the dorsal and ventral attention systems. These systems, traditionally defined based on task-related imaging studies, are believed to mediate top-down and bottom-up attentional processes, respectively. The researchers used resting-state functional MRI (fMRI) to examine spontaneous fluctuations in the blood oxygen level-dependent (BOLD) signal, which is a measure of neural activity. They found that the dorsal attention system, composed of the intraparietal sulcus (IPS) and the frontal eye field (FEF), showed bilateral correlations, while the ventral attention system, composed of the temporal-parietal junction (TPJ) and the ventral frontal cortex (VFC), showed right-lateralized correlations. These findings suggest that the functional organization of the dorsal and ventral attention systems is not solely dependent on external tasks or stimuli but is also reflected in the spontaneous dynamics of brain activity. Additionally, regions in the prefrontal cortex, such as the supplementary motor area (SMA) and middle frontal gyrus, were correlated with both systems, indicating potential mechanisms for their interaction. The study provides evidence that the neuroanatomical substrates of human attention persist in the absence of external events, highlighting the importance of spontaneous activity in understanding the brain's functional architecture.The study by Fox et al. (2006) investigates the spontaneous neuronal activity in the human brain to distinguish between the dorsal and ventral attention systems. These systems, traditionally defined based on task-related imaging studies, are believed to mediate top-down and bottom-up attentional processes, respectively. The researchers used resting-state functional MRI (fMRI) to examine spontaneous fluctuations in the blood oxygen level-dependent (BOLD) signal, which is a measure of neural activity. They found that the dorsal attention system, composed of the intraparietal sulcus (IPS) and the frontal eye field (FEF), showed bilateral correlations, while the ventral attention system, composed of the temporal-parietal junction (TPJ) and the ventral frontal cortex (VFC), showed right-lateralized correlations. These findings suggest that the functional organization of the dorsal and ventral attention systems is not solely dependent on external tasks or stimuli but is also reflected in the spontaneous dynamics of brain activity. Additionally, regions in the prefrontal cortex, such as the supplementary motor area (SMA) and middle frontal gyrus, were correlated with both systems, indicating potential mechanisms for their interaction. The study provides evidence that the neuroanatomical substrates of human attention persist in the absence of external events, highlighting the importance of spontaneous activity in understanding the brain's functional architecture.