The cerebral cortex is organized into functional networks in which a particular set of regions has disproportionately numerous connections, called “cortical hubs” of connectivity.^1-3 Recent methodologic developments allow characterization of cortical hubs in the human brain from structural or functional magnetic resonance imaging (fMRI) data.^2-4 For example, estimation of degree connectivity, a fundamental network measure indexing the number of connections that link one network component to the rest of the network,³ allows for identification of cortical hubs on the basis of blood oxygen level–dependent (BOLD) signal voxel time-series data.² Moreover, assessment of degree connectivity allows testing for alterations in network integrity or hub topography in neuropsychiatric populations.³ For instance, network alterations and correlation with pathophysiologic mechanisms have been demonstrated in Alzheimer disease and schizophrenia.^2,3,5 More precisely, degree connectivity correlated with amyloid β deposition in Alzheimer disease,² and in schizophrenia, network integrity was globally reduced, consistent with dysconnection hypotheses.⁵ The present study sought to test for degree connectivity alterations in obsessive-compulsive disorder (OCD) and to determine whether altered network properties are present in areas predicted by neurobiological models of OCD.^6-8

The amygdala, a small deep brain structure involved in behavioral processing through interactions with other brain regions, has garnered increased attention in recent years in relation to pain processing. As pain is a multidimensional experience that encompasses physical sensation, affect, and cognition, the amygdala is well suited to play a part in this process. Multiple neuroimaging studies of pain in humans have reported activation in the amygdala. Here, we summarize these studies by performing a coordinate‐based meta‐analysis within experimentally induced and clinical pain studies using an activation likelihood estimate analysis. The results are presented in relation to locations of peak activation within and outside of amygdala subregions. The majority of studies identified coordinates consistent with human amygdala cytoarchitecture indicating reproducibility in neuroanatomical labeling across labs, analysis methods, and imaging modalities. Differences were noted between healthy and clinical pain studies: in clinical pain studies, peak activation was located in the laterobasal region, suggestive of the cognitive‐affective overlay present among individuals suffering from chronic pain; while the less understood superficial region of the amygdala was prominent among experimental pain studies. Taken together, these findings suggest several important directions for further research exploring the amygdala's role in pain processing. Hum Brain Mapp 35:527–538, 2014.

Migraine is twice as common in females as in males, but the mechanisms behind this difference are still poorly understood. We used high-field magnetic resonance imaging in male and female age-matched interictal (migraine free) migraineurs and matched healthy controls to determine alterations in brain structure. Female migraineurs had thicker posterior insula and precuneus cortices compared with male migraineurs and healthy controls of both sexes. Furthermore, evaluation of functional responses to heat within the migraine groups indicated concurrent functional differences in male and female migraineurs and a sex-specific pattern of functional connectivity of these two regions with the rest of the brain. The results support the notion of a ‘sex phenotype’ in migraine and indicate that brains are differentially affected by migraine in females compared with males. Furthermore, the results also support the notion that sex differences involve both brain structure as well as functional circuits, in that emotional circuitry compared with sensory processing appears involved to a greater degree in female than male migraineurs.