Interlimb coordination of stance in children: divergent modulation of spinal reflex responses and cerebral evoked potentials in terms of age.
EMG responses in the gastrocnemius (GM) and tibialis anterior muscles (TA) of both legs together with cerebral evoked potentials (CP), were recorded following perturbations of stance on a treadmill with split belts, in two age groups of children. Unilateral displacements were followed by ipsilateral short latency and bilateral long latency EMG responses. The CP was similar in both tasks. When displacements were simultaneously induced in opposite directions, a significant reduction in the long latency components of EMG responses occurred, while the amplitude of the CP was maximal in this condition. In the older children the CP and long latency EMG responses were larger and the short latency reflex potentials smaller in all conditions compared to the younger children. It is concluded that (1) CP and EMG responses reflect a divergent modulation of a given somatosensory input; (2) developmental changes are reflected in alterations in the amplitude of CP and EMG responses; (3) there is no evidence of transcortically mediated muscle responses.
Berger
W
W
Department of Clinical Neurology and Neurophysiology, University of Freiburg, F.R.G.
Horstmann
G A
GA
Dietz
V
V
D000375:Aging; D001921:Brain / Q000254:growth & development* / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D004576:Electromyography; D005071:Evoked Potentials; D006801:Humans; D007866:Leg / Q000294:innervation; D024510:Muscle Development; D009132:Muscles / Q000294:innervation* / Q000502:physiology; D011187:Posture; D012018:Reflex; D013116:Spinal Cord / Q000254:growth & development* / Q000502:physiology