Turrini Sonia, Bevacqua Naomi, Cataneo Antonio, Chiappini Emilio, Fiori Francesca, Battaglia Simone, Romei Vincenzo, Avenanti Alessio
Centro Studi e Ricerche in Neuroscienze Cognitive, Dipartimento di Psicologia "Renzo Canestriari", Campus di Cesena, Alma Mater Studiorum Università di Bologna, 47521 Cesena, Italy.
Precision Neuroscience & Neuromodulation Program, Gordon Center for Medical Imaging, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, USA.
Biomedicines. 2023 May 17;11(5):1464. doi: 10.3390/biomedicines11051464.
Aging is commonly associated with a decline in motor control and neural plasticity. Tuning cortico-cortical interactions between premotor and motor areas is essential for controlling fine manual movements. However, whether plasticity in premotor-motor circuits predicts hand motor abilities in young and elderly humans remains unclear. Here, we administered transcranial magnetic stimulation (TMS) over the ventral premotor cortex (PMv) and primary motor cortex (M1) using the cortico-cortical paired-associative stimulation (ccPAS) protocol to manipulate the strength of PMv-to-M1 connectivity in 14 young and 14 elderly healthy adults. We assessed changes in motor-evoked potentials (MEPs) during ccPAS as an index of PMv-M1 network plasticity. We tested whether the magnitude of MEP changes might predict interindividual differences in performance in two motor tasks that rely on premotor-motor circuits, i.e., the nine-hole pegboard test and a choice reaction task. Results show lower motor performance and decreased PMv-M1 network plasticity in elderly adults. Critically, the slope of MEP changes during ccPAS accurately predicted performance at the two tasks across age groups, with larger slopes (i.e., MEP increase) predicting better motor performance at baseline in both young and elderly participants. These findings suggest that physiological indices of PMv-M1 plasticity could provide a neurophysiological marker of fine motor control across age-groups.
衰老通常与运动控制能力下降和神经可塑性降低有关。调节运动前区和运动区之间的皮质-皮质相互作用对于控制精细手部运动至关重要。然而，运动前区-运动回路的可塑性是否能预测年轻人和老年人的手部运动能力仍不清楚。在此，我们使用皮质-皮质配对联想刺激（ccPAS）方案，对14名年轻和14名老年健康成年人的腹侧运动前皮质（PMv）和初级运动皮质（M1）进行经颅磁刺激（TMS），以操纵PMv到M1的连接强度。我们评估了ccPAS期间运动诱发电位（MEP）的变化，作为PMv-M1网络可塑性的指标。我们测试了MEP变化的幅度是否可以预测两项依赖运动前区-运动回路的运动任务（即九孔插板试验和选择反应任务）中个体表现的差异。结果显示，老年人的运动表现较低，PMv-M1网络可塑性降低。至关重要的是，ccPAS期间MEP变化的斜率准确预测了各年龄组在这两项任务中的表现，斜率越大（即MEP增加），表明年轻和老年参与者在基线时的运动表现越好。这些发现表明，PMv-M1可塑性的生理指标可以为各年龄组的精细运动控制提供一种神经生理学标志物。
