INTRINSIC DYNAMICS AND MECHANOSENSORY MODULATION OF NONNUTRITIVE SUCKING IN HUMAN INFANTS

The human infant is endowed with a complex mechanism for the ingestion of nutrients that becomes functional in late fetal life. The sucking motor pattern is generally accepted to be under the control of pattern generating circuitry located in the brainstem reticular formation. Sy stems under the control of a central pattern generator (CPG) may use a fferent feedback to allow for changing environmental conditions. Altho ugh it is clear that afferent pathways serving the orofacial region be come responsive to mechanical stimulation early in fetal life, little is known about the integration of afferent information into the suck C PG. The actifier, a device for the mechanical stimulation of intraoral and perioral tissues, was designed and used to investigate the respon se properties of the human infant suck CPG to patterned mechanical sti mulation. Sinusoid and square waveform stimuli elicited responses incl uding modulation of jaw kinematics and synchronization [entrainment] o f non-nutritive suck motor patterns to the mechanical stimulus. These data provide evidence that the suck CPG is responsive to mechanical st imulation of perioral and intraoral soft tissues. (C) 1998 Elsevier Sc ience Ireland Ltd. All rights reserved.