Global Brain Involvement in Posterior Cortical Atrophy: Multimodal MR Imaging Investigation.

Posterior cortical atrophy (PCA), considered a visual variant of Alzheimer's disease, has similar pathological characteristics yet shows a selective visual manifestation with relative preservation of other cortical areas, at least at early stages of disease. Using a gamut of imaging methods, we aim to evaluate the global aspect of this relatively local disease and describe the interplay of the involvement of the different brain components. Ten PCA patients and 14 age-matched controls underwent MRI scans.

Characterizing directed functional pathways in the visual system by multivariate nonlinear coherence of fMRI data.

A multivariate measure of directed functional connectivity is used with resting-state fMRI data of 40 healthy subjects to identify directed pathways of signal progression in the human visual system. The method utilizes 4-nodes networks of mutual interacted BOLD signals to obtains their temporal hierarchy and functional connectivity. Patterns of signal progression were defined at frequency windows by appealing to a hierarchy based upon phase differences, and their significance was assessed by permutation testing.

Sex differences during emotion processing are dependent on the menstrual cycle phase.

Sex differences in the neural processing of emotion are of special interest considering that mood and anxiety disorders predominant in females. However, these sex-related differences were typically studied without considering the hormonal status of female subjects, although emotion processing in the brain was shown to differ between phases of the menstrual cycle. In this functional MRI study, we demonstrated the influence of the menstrual cycle phase on sex differences in brain activity and functional connectivity during negative and positive emotions, using two different paradigms: emotion perception and emotion experience.