Table_2_Melody Processing Characterizes Functional Neuroanatomy in the Aging Brain.pdf

The functional neuroanatomical mechanisms underpinning cognition in the normal older brain remain poorly defined, but have important implications for understanding the neurobiology of aging and the impact of neurodegenerative diseases. Auditory processing is an attractive model system for addressing these issues. Here, we used fMRI of melody processing to investigate auditory pattern processing in normal older individuals. We manipulated the temporal (rhythmic) structure and familiarity of melodies in a passive listening, ‘sparse’ fMRI protocol. A distributed cortico-subcortical network was activated by auditory stimulation compared with silence; and within this network, we identified separable signatures of anisochrony processing in bilateral posterior superior temporal lobes; melodic familiarity in bilateral anterior temporal and inferior frontal cortices; and melodic novelty in bilateral temporal and left parietal cortices. Left planum temporale emerged as a ‘hub’ region functionally partitioned for processing different melody dimensions. Activation of Heschl’s gyrus by auditory stimulation correlated with the integrity of underlying cortical tissue architecture, measured using multi-parameter mapping. Our findings delineate neural substrates for analyzing perceptual and semantic properties of melodies in normal aging. Melody (auditory pattern) processing may be a useful candidate paradigm for assessing cerebral networks in the older brain and potentially, in neurodegenerative diseases of later life.

正常衰老大脑中支撑认知功能的功能性神经解剖机制迄今仍未得到充分阐明，但该机制对于理解衰老的神经生物学基础以及神经退行性疾病的影响具有重要意义。听觉加工是解决上述问题的理想模型系统。本研究采用旋律加工的功能磁共振成像（functional magnetic resonance imaging, fMRI）技术，探究正常衰老个体的听觉模式加工机制。我们在被动聆听的“稀疏”功能磁共振成像协议中，对旋律的时间（节律）结构与熟悉度进行了操控。与静息状态相比，听觉刺激可激活广泛分布的皮层-皮层下网络；在该网络内，我们识别出可分离的神经特征信号：双侧颞上回后部参与非等时节律加工，双侧颞叶前部与额下回皮层参与旋律熟悉度加工，双侧颞叶及左侧顶叶皮层参与旋律新颖性加工。左侧颞平面（planum temporale）作为功能分区枢纽，负责加工不同维度的旋律信息。听觉刺激引发的赫歇尔回（Heschl's gyrus）激活程度，与采用多参数成像（multi-parameter mapping）测得的皮层组织结构完整性显著相关。本研究结果阐明了正常衰老个体中用于分析旋律感知与语义属性的神经基础。旋律（听觉模式）加工或可成为评估衰老大脑乃至晚年神经退行性疾病患者大脑网络的有效候选范式。