Pain behavior of neonates was compared across sleep/waking states and sex. From Gate-Control Theory (Melzack and Wall, 1982) it was hypothesized that pain behavior would vary depending on the ongoing functional state of the infant, in contrast with Specificity Theory (Mountcastle, 1980), from which one would expect neonatal pain expression to be solely a function of degree of tissue damage. The findings of facial action variation across sleep/waking state was interpreted as consistent with Gate-Control Theory. Awake alert infants responded with the most facial activity, which supported Brazelton's (1973) view that infants in this state are most receptive to environmental stimulation. Fundamental frequency of cry was not related to sleep/waking state. This suggested that findings from the cry literature on pain cry as a reflection of nervous system "stress", in unwell newborns, do not generalize directly to healthy infants under varying degrees of stress as a function of state. Sex differences were apparent in speed of response, with boys showing shorter time to cry and facial action following heel-lance. Issues raised by the study include the importance of using measurement techniques which are independent of pre-conceived categories of affective response, and the surprising degree of responsivity of the neonate to ongoing events. Exploratory analyses suggested obstetric factors were related to overall facial action. Caution was expressed in this interpretation due to the great complexity of the inter-relationships of medical, physiological and maternal variables which go far beyond the scope of this study. It was concluded that obstetric features such as mode of delivery should be considered in sample selection for neonatal pain studies, in contrast to current practise which has been to assume healthy newborns form an homogeneous population. It was clear from these findings that the issues are multifaceted, and the optimal way to proceed with research in the area of neonatal pain is with an interdisciplinary team format. / Graduate and Postdoctoral Studies / Graduate

Despite considerable evidence in older populations that food intake can improve mental performance, little is known about the acute effects of feeding on cognition in the newborn period, a time when learning and memory are critical for discovering and adapting to everyday experiences. Feeding occurs well over 2500 times in the first year of life, raising the possibility that iterative effects on cognition may have cumulative effects over time. We recently demonstrated feeding enhancement of memory in two-to-three day old infants. Infants tested after a feed (versus before) displayed better memory for unfamiliar spoken words they previously habituated to and that were represented after a 100s delay. In this Doctoral Thesis, Studies 1 and 2 explore further the influence of feeding on short-term retention of spoken words. Memory was assessed using headturning and the Habituation-Recovery response. Study 1 extended the effect to older infants aged two-to-three weeks. Memory was enhanced after a feed over even longer delays, including 100s, 200s, 300s, 400s, and 500s. The overall gain in memory as measured by prefeed and postfeed differences at each delay was over two minutes long. Because newborn infants are more likely to hear recurrent words spoken by familiar voices, auditory experiences that they preferentially recognize, Study 2 looked at the separate effects of familiarity and feeding. Two day-old infants were assessed for either familiar speech-sound ("baby" spoken by the mother) or unfamiliar speech-sound from Study 1 ("beagle" spoken by a female stranger). The baby-mother sound stimulus was remembered better over a retention interval of 85 seconds than unfamiliar beagle-stranger, suggesting a strong influence of familiarity. To define the extent of the feeding effect, Study 3 examined sensorimotor processing of a reflex response. Three day-olds were assessed on habituation and retention of habituation of the glabella blink reflex over delays of 8s and l8s. No effect of feeding was found. Taken together, the implications of these findings are twofold. First, enhancement of memory for speech-sound by iterative feeding or recurrent exposure to familiar speech-sound stimuli may facilitate the acquisition of language. Second, feeding effects on cognition may depend on the nature of the task and previous experience with the stimulus. Further research is necessary for identifying what kinds of information and what processing abilities are more susceptible to the effects of feeding in early infancy.

Dissertation (Ph.D.).--University of Texas Graduate School of Biomedical Sciences at San Antonio, 2006. / Vita. Includes bibliographical references.

Thesis (Ph.D.). / Written for the Dept. of BioMedical Engineering. Title from title page of PDF (viewed 2008/02/12). Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1981. / eContent provider-neutral record in process. Description based on print version record.

Thesis (M.S.)--University of Michigan, 1988.

Thesis (M.S.)--University of Michigan, 1977.

Thesis (M.S.)--University of Michigan, 1987.

Thesis (M.S.)--University of Michigan, 1988.

Thesis (M.S.)--University of Michigan, 1977.