Obenaus Andre, Kinney-Lang Eli, Jullienne Amandine, Haddad Elizabeth, Wendel Kara M, Shereen A Duke, Solodkin Ana, Dunn Jeffrey F, Baram Tallie Z
Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
Department of Pediatrics, University of California, Irvine, CA 92697, USA.
Biomedicines. 2023 Feb 13;11(2):535. doi: 10.3390/biomedicines11020535.
The amygdaloid complex, including the basolateral nucleus (BLA), contributes crucially to emotional and cognitive brain functions, and is a major target of research in both humans and rodents. However, delineating structural amygdala plasticity in both normal and disease-related contexts using neuroimaging has been hampered by the difficulty of unequivocally identifying the boundaries of the BLA. This challenge is a result of the poor contrast between BLA and the surrounding gray matter, including other amygdala nuclei. Here, we describe a novel diffusion tensor imaging (DTI) approach to enhance contrast, enabling the optimal identification of BLA in the rodent brain from magnetic resonance (MR) images. We employed this methodology together with a slice-shifting approach to accurately measure BLA volumes. We then validated the results by direct comparison to both histological and cellular-identity (parvalbumin)-based conventional techniques for defining BLA in the same brains used for MRI. We also confirmed BLA connectivity targets using DTI-based tractography. The novel approach enables the accurate and reliable delineation of BLA. Because this nucleus is involved in and changed by developmental, degenerative and adaptive processes, the instruments provided here should be highly useful to a broad range of neuroimaging studies. Finally, the principles used here are readily applicable to numerous brain regions and across species.
杏仁核复合体，包括基底外侧核（BLA），对大脑的情感和认知功能起着至关重要的作用，是人类和啮齿动物研究的主要目标。然而，由于难以明确识别BLA的边界，利用神经成像技术描绘正常和疾病相关背景下杏仁核的结构可塑性受到了阻碍。这一挑战是由于BLA与周围灰质（包括其他杏仁核核团）之间的对比度较差所致。在此，我们描述了一种新的扩散张量成像（DTI）方法来增强对比度，从而能够从磁共振（MR）图像中最佳地识别啮齿动物大脑中的BLA。我们将这种方法与切片移位方法相结合，以准确测量BLA的体积。然后，我们通过与用于MRI的同一大脑中基于组织学和细胞身份（小白蛋白）的传统技术进行直接比较，验证了结果。我们还使用基于DTI的纤维束成像技术确认了BLA的连接靶点。这种新方法能够准确可靠地描绘BLA。由于该核团参与发育、退化和适应性过程并受其影响，此处提供的工具对广泛的神经成像研究应该非常有用。最后，这里使用的原理很容易应用于许多脑区和跨物种研究。
