LET'S-ISTC-CNR, Department of Neuroscience, Fatebenefratelli Hospital-Isola Tiberina, Rome, Italy.
Brain Topogr. 2013 Jan;26(1):186-99. doi: 10.1007/s10548-012-0240-3. Epub 2012 Jul 4.
To hone knowledge of sensorimotor cerebral organization changes with physiological aging, we focused on the primary somatosensory cortical area (S1). S1 neuronal pools (FS_S1) were identified by the functional source separation (FSS) algorithm applied to magnetoencephalographic recordings during median nerve stimulation. Age-dependence of FS_S1 was then studied at rest separately in the left and right hemispheres of 26 healthy, right-handed subjects between the ages of 24 and 95 years. The resting state FS_S1 spectral features changed with increasing age: (1) alpha activity slowed down; (2) total power increased only in the right hemisphere; (3) right>left interhemispheric asymmetry increased in the whole spectrum; (4) spectral entropy increased with age selectively in the left hemisphere. The present FSS-enriched electrophysiological procedure provided measures of resting state hand representation area sensitive to changes with age. Alterations were stronger in the right hemisphere. Relationships between resting state S1 activity and its responsiveness to external stimuli, revealed that the interhemispheric unbalances which emerged with age were conceivably due to an increased excitability within the right thalamocortical circuit impacting left versus right unbalances of spontaneous firing rates and of local inhibitory-excitatory networks.
为了深入了解感觉运动大脑组织随生理衰老的变化，我们专注于初级体感皮层区（S1）。通过应用于正中神经刺激期间的脑磁图记录的功能源分离（FSS）算法，鉴定了 S1 神经元池（FS_S1）。然后，我们在 26 名健康右利手受试者的左右半球中，分别在 24 至 95 岁的年龄范围内，研究了 FS_S1 在静息状态下的年龄依赖性。随着年龄的增长，静息状态下 FS_S1 的频谱特征发生了变化：（1）alpha 活动减慢；（2）总功率仅在右半球增加；（3）整个频谱中右半球与左半球的半球间不对称性增加；（4）选择性地在左半球中，频谱熵随年龄增加。本研究中丰富的 FSS 电生理程序提供了对与年龄相关的静息状态手代表区变化敏感的测量值。右半球的变化更强。静息状态下 S1 活动与其对外部刺激的反应性之间的关系表明，随年龄出现的半球间不平衡可能是由于右侧丘脑皮质回路的兴奋性增加，从而影响自发性放电率和局部抑制兴奋网络的左右不平衡。
