Brommelhoff Jessica A, Sultzer David L
Mental Health Services, VA Greater Los Angeles Healthcare System, and Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
J Alzheimers Dis. 2015;45(3):689-703. doi: 10.3233/JAD-148007.
The development of minimally invasive in vivo methods for imaging the brain has allowed for unprecedented advancement in our understanding of brain-behavior relationships. Structural, functional, and multimodal neuroimaging techniques have become more sophisticated in detecting structural and physiological abnormalities that may underlie various affective disorders and neurological illnesses such as depression in Alzheimer's disease (AD). In general, neuroimaging studies of depression in AD investigate whether depression is associated with damage to structures in specific neural networks involving frontal and subcortical structures or with functional disruption of cortical neural systems. This review provides an overview of how various imaging modalities have contributed to our understanding of the neurobiology of depression in AD. At present, the literature does not conclusively support any specific pathogenesis for depression, and it is not clear whether patients with AD and depression have histopathological and neurochemical characteristics that contribute to mood symptoms that are different from cognitively intact individuals with depression. Neuroimaging studies suggest that atrophy of temporal or frontal structures, white matter lesions in frontal lobe or subcortical systems, reduced activity in dorsolateral frontal cortex, or small vessel cerebrovascular disease may be associated with depression in AD. Conceptual, clinical, and methodological challenges in studying this relationship are discussed. Further work is needed to understand the specific brain structures, relevant white matter tracts, and interactions among them that are most important. This review concludes with potential directions for future research.
用于大脑成像的微创体内方法的发展，使我们对脑-行为关系的理解取得了前所未有的进展。结构、功能和多模态神经成像技术在检测可能是各种情感障碍和神经疾病（如阿尔茨海默病（AD）中的抑郁症）基础的结构和生理异常方面变得更加成熟。一般来说，AD中抑郁症的神经成像研究调查抑郁症是否与涉及额叶和皮质下结构的特定神经网络中的结构损伤或皮质神经系统的功能破坏有关。本综述概述了各种成像方式如何有助于我们理解AD中抑郁症的神经生物学。目前，文献并未确凿支持抑郁症的任何特定发病机制，并且尚不清楚AD合并抑郁症的患者是否具有导致情绪症状的组织病理学和神经化学特征，这些特征与认知健全的抑郁症患者不同。神经成像研究表明，颞叶或额叶结构萎缩、额叶或皮质下系统的白质病变、背外侧额叶皮质活动减少或小血管脑血管疾病可能与AD中的抑郁症有关。讨论了研究这种关系时在概念、临床和方法上的挑战。需要进一步开展工作来了解最重要的特定脑结构、相关白质束及其之间的相互作用。本综述最后提出了未来研究的潜在方向。
