Brain imaging and behavior
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With increasing survival, cognitive problems after systemic treatment for non-CNS cancers are a growing concern. Functional magnetic resonance imaging (fMRI) is a noninvasive neuroimaging technique that has the potential to uncover the neural circuitry underlying cognitive problems after systemic treatment in cancer patients. Here, we provide an in depth review of the 14 fMRI studies that have been published to date on potential neurotoxic side effects of systemic treatment for non-CNS cancers. ⋯ Two small studies in prostate cancer patients, finally, provide preliminary evidence for reduced activation in task-relevant brain regions after androgen deprivation therapy, suggestive of reduction of neural function. Statistical correction for multiple comparisons in the reviewed studies is typically quite lenient. We suggest that future studies should preferably include larger sample sizes to allow proper statistical correction for multiple comparisons and include comprehensive neurocognitive tests and multimodal MRI to facilitate the interpretation of the observed fMRI findings.
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Brain Imaging Behav · Dec 2013
Neuroimaging biomarkers and cognitive function in non-CNS cancer and its treatment: current status and recommendations for future research.
Cognitive changes in patients undergoing treatment for non-central nervous system (CNS) cancers have been recognized for several decades, yet the underlying mechanisms are not well understood. Structural, functional and molecular neuroimaging has the potential to help clarify the neural bases of these cognitive abnormalities. Structural magnetic resonance imaging (MRI), functional MRI (fMRI), diffusion tensor imaging (DTI), MR spectroscopy (MRS), and positron emission tomography (PET) have all been employed in the study of cognitive effects of cancer treatment, with most studies focusing on breast cancer and changes thought to be induced by chemotherapy. ⋯ A systems biology framework incorporating multimodality neuroimaging, genetics and other biomarkers will be highly informative regarding individual differences in risk and protective factors and disease- and treatment-related mechanisms. Studies of interventions targeting cognitive changes are also needed. These next steps are expected to identify novel protective strategies and facilitate a more personalized medicine for cancer patients.
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Brain Imaging Behav · Sep 2013
Neuronal fiber bundle lengths in healthy adult carriers of the ApoE4 allele: a quantitative tractography DTI study.
The epsilon 4 (e4) isoform of apolipoprotein E (ApoE) is a known genetic risk factor for suboptimal brain health. Morphometry studies of brains with Alzheimer's disease have reported significant alterations in temporal lobe brain structure of e4 carriers, yet it remains unclear if the presence of an e4 allele is associated with alterations in the microstructure of white matter fiber bundles in healthy populations. The present study used quantitative tractography based on diffusion tensor imaging (qtDTI) to examine the influence of the e4 allele on temporal lobe fiber bundle lengths (FBLs) in 64 healthy older adults with at least one e4 allele (carriers, N = 23) versus no e4 allele (non-carriers, N = 41). ⋯ This is the first study to utilize qtDTI to examine relationships between FBL and ApoE genotype. Results suggest that FBL in the UF is influenced by the presence of an ApoE e4 allele (ApoE4) in healthy older adults. Temporal lobe FBLs, however, are more vulnerable to aging than the presence of an e4 allele.
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Brain Imaging Behav · Sep 2013
Impact of body mass index on neuronal fiber bundle lengths among healthy older adults.
Increased body mass index (BMI) has been linked to various detrimental health outcomes, including cognitive dysfunction. Recent work investigating associations between obesity and the brain has revealed decreased white matter microstructural integrity in individuals with elevated BMI, independent of age or comorbid health conditions. However, the relationship between high BMI and white matter fiber bundle length (FBL), which represents a novel metric of microstructural brain integrity, remains unknown. ⋯ These findings indicate that, while increased age is an important factor associated with reduced FBL, high BMI is uniquely associated with reduced FBL in the temporal lobe. These data offer evidence for additive adverse effects of high BMI on the brain, especially in areas already vulnerable to aging processes and age-related neurodegenerative diseases. Further research is necessary to determine the physiological mechanisms associated with the shortening of FBL in individuals with high BMI.
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Brain Imaging Behav · Sep 2013
Brain correlates of pro-social personality traits: a voxel-based morphometry study.
Of the five personality dimensions described by the Big Five Personality Model (Costa and McCrae 1992), Extraversion and Agreeableness are the traits most commonly associated with a pro-social orientation. In this study we tested whether a pro-social orientation, as expressed in terms of Extraversion and Agreeableness, is associated with a specific grey matter phenotype. Fifty-two healthy participants underwent magnetic resonance imaging (MRI) and completed the NEO-Five Factor Inventory (NEO-FFI), a self-report measure of the Big Five personality traits. ⋯ We found that Extraversion was negatively correlated with grey matter density in the middle frontal and orbitofrontal gyri while Agreeableness was negatively correlated with grey matter density in the inferior parietal, middle occipital and posterior cingulate gyri. No positive correlations were found. These results suggest that pro-social personality traits seem to be associated with decreases in grey matter density in more frontal regions for Extraversion, and more posterior regions for Agreeableness.