caa a22 4500 445354410 CHVBK 20180317142855.0 cr unu---uuuuu 170323e20110201xx s 000 0 eng 10.1007/s00221-010-2506-x doi (NATIONALLICENCE)springer-10.1007/s00221-010-2506-x Functioning of peripheral Ia pathways in infants with typical development: responses in antagonist muscle pairs [Elektronische Daten] [Caroline Teulier, Beverly Ulrich, Bernard Martin] In muscle responses of proprioceptive origin, including the stretch/tendon reflex (T-reflex), the corresponding reciprocal excitation and irradiation to distant muscles have been described from newborn infants to older adults. However, the functioning of other responses mediated primarily by Ia-afferents has not been investigated in infants. Understanding the typical development of these multiple pathways is critical to determining potential problems in their development in populations affected by neurological disease, such as spina bifida or cerebral palsy. Hence, the goal of the present study was to quantify the excitability of Ia-mediated responses in lower limb muscles of infants with typical development. These responses were elicited by mechanical stimulation applied to the distal tendons of the gastrocnemius-soleus (GS), tibialis anterior (TA) and quadriceps (QAD) muscles of both legs in twelve 2- to 10-month-old infants and recorded simultaneously in antagonist muscle pairs by surface EMG. Tendon taps alone elicited responses in either, both or neither muscle. The homonymous response (T-reflex) was less frequent in the TA than the GS or QAD muscle. An 80Hz vibration superimposed on tendon taps induced primarily an inhibition of monosynaptic responses; however, facilitation also occurred in either muscle of the recorded pair. These responses were not influenced significantly by age or gender. Vibration alone produced a tonic reflex response in the vibrated muscle (TVR) and/or the antagonist muscle (AVR). However, for the TA muscle the TVR was more frequently elicited in older than younger infants. High variability was common to all responses. Overall, the random distribution and inconsistency of muscle responses suggests that the gain of Ia-mediated feedback is unstable. We propose that during infancy the central nervous system needs to learn to set stable feedback gain, or destination of proprioceptive assistance, based on their use during functional movements. This will tailor the neuromuscular connectivity to support adaptive motor behaviors. Springer-Verlag, 2010 T-reflex nationallicence Tonic vibration reflex nationallicence Development nationallicence Proprioception nationallicence Teulier Caroline Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland aut Ulrich Beverly Department of Movement Science, School of Kinesiology, University of Michigan, 401 Washtenaw Avenue, Room 4745H, 48109-2214, Ann Arbor, MI, USA aut Martin Bernard Department of Industrial Operations Engineering, University of Michigan, 1205 beal Avenue, 48109-2117, Ann Arbor, MI, USA aut Experimental Brain Research Springer-Verlag 208/4(2011-02-01), 581-593 0014-4819 208:4<581 2011 208 221 https://doi.org/10.1007/s00221-010-2506-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00221-010-2506-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Teulier Caroline Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland aut NATIONALLICENCE 700 1- Ulrich Beverly Department of Movement Science, School of Kinesiology, University of Michigan, 401 Washtenaw Avenue, Room 4745H, 48109-2214, Ann Arbor, MI, USA aut NATIONALLICENCE 700 1- Martin Bernard Department of Industrial Operations Engineering, University of Michigan, 1205 beal Avenue, 48109-2117, Ann Arbor, MI, USA aut NATIONALLICENCE 773 0- Experimental Brain Research Springer-Verlag 208/4(2011-02-01), 581-593 0014-4819 208:4<581 2011 208 221 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer