NeuroImage
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Medial temporal lobe (MTL) atrophy is one of the key biomarkers to detect early neurodegenerative changes in the course of Alzheimer's disease (AD). There is active research aimed at identifying automated methodologies able to extract accurate classification indexes from T1-weighted magnetic resonance images (MRI). Such indexes should be fit for identifying AD patients as early as possible. ⋯ The present automated MRI-based technique revealed a strong relationship between highly localized baseline-MRI features and the baseline clinical assessment. In addition, the classification index was also used to predict the probability of AD conversion within a time frame of two years. The definition of a single index combining local analysis of several regions can be useful to detect AD neurodegeneration in a typical MCI population.
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Spontaneous fluctuations in the blood oxygenation level-dependent (BOLD) signal, as measured by functional magnetic resonance imaging (fMRI) at rest, exhibit a temporally coherent activity thought to reflect functionally relevant networks. Antero-mesial temporal structures are the site of early pathological changes in Alzheimer's disease and have been shown to be critical for declarative memory. Our study aimed at exploring the functional impact of basal connectivity of an anterior temporal network (ATN) on declarative memory. ⋯ These correlations were specific to the ATN, as no correlation between performance on memory tasks and the other selected networks was found. Taken together, these findings provide evidence that basal connectivity inside the ATN network has a functional role in object-related, context-free memory. They also suggest that increased connectivity at rest within the ATN could reflect compensatory mechanisms that occur in response to early pathological insult.
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Randomized Controlled Trial
Ketamine effects on brain function--simultaneous fMRI/EEG during a visual oddball task.
Behavioral and electrophysiological human ketamine models of schizophrenia are used for testing compounds that target the glutamatergic system. However, corresponding functional neuroimaging models are difficult to reconcile with functional imaging and electrophysiological findings in schizophrenia. Resolving the discrepancies between different observational levels is critical to understand the complex pharmacological ketamine action and its usefulness for modeling schizophrenia pathophysiology. ⋯ The findings from our ketamine experiment are consistent across modalities and directly related to observations in schizophrenia supporting the validity of the model. Our investigation provides the first prototypic example of a pharmacoimaging study using simultaneously acquired fMRI/EEG.
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Review Meta Analysis
Fear is only as deep as the mind allows: a coordinate-based meta-analysis of neuroimaging studies on the regulation of negative affect.
Humans have the ability to control negative affect and perceived fear. Nevertheless, it is still unclear whether this affect regulation capacity relies on a common neural mechanism in different experimental domains. Here, we sought to identify commonalities in regulatory brain activation in the domains of fear extinction, placebo, and cognitive emotion regulation. ⋯ Finally, the soothing effect of placebo treatments and cognitive reappraisal strategies, but not extinction retrieval, was specifically accompanied by a coherent hyperactivation in the anterior cingulate and the insular cortex. Collectively, our data strongly imply that the human VMPFC may represent a domain-general controller of perceived fear and aversiveness that modulates negative affective responses in phylogenetically older structures of the emotion processing system. In addition, higher-level regulation strategies may further engage complementary neural resources to effectively deal with the emotion-eliciting events.
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Emotion regulation and brain plasticity: expressive suppression use predicts anterior insula volume.
Expressive suppression is an emotion regulation strategy that requires interoceptive and emotional awareness. These processes both recruit the anterior insula. It is not known, however, whether increased use of expressive suppression is associated with increased anterior insula volume. ⋯ Participants also completed trait measures of expressive suppression usage, cognitive reappraisal usage, and negative emotional reactivity (the latter two served as control measures). As predicted, both ROI and VBM methods found that expressive suppression usage, but not negative affect and cognitive reappraisal, was positively related to anterior insula volume. These findings are consistent with the idea that trait patterns of emotion processing are related to brain structure.