TY - JOUR

T1 - A critical period of corticomuscular and EMG-EMG coherence detection in healthy infants aged 9-25weeks

AU - Ritterband-Rosenbaum, Anina

AU - Herskind, Anna

AU - Li, Xi

AU - Willerslev-Olsen, Maria

AU - Olsen, Mikkel Damgaard

AU - Farmer, Simon Francis

AU - Nielsen, Jens Bo

PY - 2017/4/15

Y1 - 2017/4/15

N2 - 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.

AB - 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.

U2 - 10.1113/JP273090

DO - 10.1113/JP273090

M3 - Journal article

C2 - 28004392

VL - 595

SP - 2699

EP - 2713

JO - The Journal of Physiology

JF - The Journal of Physiology

SN - 0022-3751

IS - 8

ER -