Ritterband-Rosenbaum Anina, Herskind Anna, Li Xi, Willerslev-Olsen Maria, Olsen Mikkel Damgaard, Farmer Simon Francis, Nielsen Jens Bo
Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
Elsass Institute, Charlottenlund, Denmark.
J Physiol. 2017 Apr 15;595(8):2699-2713. doi: 10.1113/JP273090. Epub 2017 Feb 15.
The early postnatal development of functional corticospinal connections in human infants is not fully clarified. Corticospinal drive to upper and lower limb muscle shows developmental changes with an increased functional coupling in infants between 9 and 25 weeks in the beta frequency band. The changes in functional coupling coincide with the developmental period where fidgety movements are present in healthy infants. Data support a possible sensitive period where functional connections between corticospinal tract fibres and spinal motoneurones undergo activity-dependent reorganization.
The early postnatal development of functional corticospinal connections in human infants is not fully clarified. We used EEG and EMG to investigate the development of corticomuscular and intramuscular coherence as indicators of functional corticospinal connectivity in healthy infants aged 1-66 weeks. EEG was recorded over leg and hand area of motor cortex. EMG recordings were made from right ankle dorsiflexor and right wrist extensor muscles. Quantification of the amount of corticomuscular coherence in the 20-40 Hz frequency band showed a significantly larger coherence for infants aged 9-25 weeks compared to younger and older infants. Coherence between paired EMG recordings from tibialis anterior muscle in the 20-40 Hz frequency band was also significantly larger for the 9-25 week age group. A low-amplitude, broad-duration (40-50 ms) central peak of EMG-EMG synchronization was observed for infants younger than 9 weeks, whereas a short-lasting (10-20 ms) central peak was observed for EMG-EMG synchronization in older infants. This peak was largest for infants aged 9-25 weeks. These data suggest that the corticospinal drive to lower and upper limb muscles shows significant developmental changes with an increase in functional coupling in infants aged 9-25 weeks, a period which coincides partly with the developmental period of normal fidgety movements. We propose that these neurophysiological findings may reflect the existence of a sensitive period where the functional connections between corticospinal tract fibres and spinal motoneurones undergo activity-dependent reorganization. This may be relevant for the timing of early therapy interventions in infants with pre- and perinatal brain injury.
人类婴儿出生后早期功能性皮质脊髓连接的发育尚未完全阐明。皮质脊髓对上肢和下肢肌肉的驱动显示出发育变化，在9至25周的婴儿中，β频段的功能耦合增加。功能耦合的变化与健康婴儿出现烦躁运动的发育时期一致。数据支持一个可能的敏感期，即皮质脊髓束纤维与脊髓运动神经元之间的功能连接经历依赖活动的重组。
人类婴儿出生后早期功能性皮质脊髓连接的发育尚未完全阐明。我们使用脑电图（EEG）和肌电图（EMG）来研究皮质肌肉和肌肉内相干性的发育，以此作为1至66周健康婴儿功能性皮质脊髓连接性的指标。在运动皮层的腿部和手部区域记录脑电图。从右踝背屈肌和右腕伸肌进行肌电图记录。对20至40赫兹频段的皮质肌肉相干量进行量化显示，与 younger和 older婴儿相比，9至25周的婴儿相干性明显更大。9至25周龄组在20至40赫兹频段的胫前肌配对肌电图记录之间的相干性也明显更大。对于9周以下的婴儿，观察到肌电图 - 肌电图同步的低振幅、宽持续时间（40 - 50毫秒）的中央峰值，而对于 older婴儿，观察到肌电图 - 肌电图同步的短暂（10 - 20毫秒）中央峰值。这个峰值在9至25周的婴儿中最大。这些数据表明，皮质脊髓对下肢和上肢肌肉的驱动显示出显著的发育变化，在9至25周的婴儿中功能耦合增加，这一时期部分与正常烦躁运动的发育时期一致。我们提出，这些神经生理学发现可能反映了一个敏感期的存在，即皮质脊髓束纤维与脊髓运动神经元之间的功能连接经历依赖活动的重组。这可能与产前和围产期脑损伤婴儿早期治疗干预的时机有关。
