Table_3_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至今仍未被充分阐明，但其对于理解衰老的神经生物学基础以及神经退行性疾病的致病影响具有重要意义。听觉加工是探究这类科学问题的极具吸引力的模型系统。本研究采用旋律加工的功能磁共振成像（fMRI）技术，旨在探究正常老年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。实验结果显示，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；在此网络中，我们识别出三类可分离的加工特征：双侧颞上后部皮层对非等时节律加工的特异性特征、双侧颞前叶与额下回皮层对旋律熟悉度加工的特征，以及双侧颞叶与左侧顶叶皮层对旋律新颖性加工的特征。左侧颞平面（planum temporale）作为一个“枢纽”脑区，其功能分区对应不同旋律维度的加工。听觉刺激激活的赫歇尔回（Heschl’s gyrus）的激活强度与底层皮层组织架构的完整性呈正相关，该完整性通过多参数映射（multi-parameter mapping）进行测量。本研究结果明确了正常衰老大脑中分析旋律感知与语义属性的神经底物。旋律（听觉模式）加工或许可作为评估衰老大脑以及晚年潜在神经退行性疾病患者大脑网络的有效候选范式。