PubMed Health⌕ Search

Biomedical subjects

W Fifer

Publications and source records attributed to W Fifer.

5 recordsLinked to original sources

Fetal Behavioral Development: Measurement of Habituation, State Transitions, and Movement to Assess Fetal Well Being and to Predict Outcome

> Objective: This paper describes the deliberations of an interdisciplinary group of clinical and basic scientists who met at the National Institute of Child Health and Human Development to discuss the potential role of fetal behavior in assessing fetal well being and predicting neonatal outcome. The conference focused on three aspects of fetal behavior: 1) habituation; 2) state transitions; and 3) movement. Methods: The participants consisted of 25 leaders in the fields of obstetrics, perinatal medicine, neonatology, developmental psychobiology, developmental neuroscience, developmental psychology, ethology, and mathematics. The meeting was divided into three parts. In each of these a plenary speaker (a recognized expert in his field) began the session with an overview of the scientific theme. Two respondents, with research expertise in fetal research (animal models or human fetuses) followed with remarks on the plenary talk and comments based on their own studies. At the conclusion of these comments, the participants met in small groups to discuss the plenary proceedings and their implications for assessing human fetal well being and predicting outcome. At the conclusion of the small group deliberations all of the participants reconvened in a plenary session. During this part of the meeting a rapporteur from each small group summarized their discussions. Results and Conclusions: 1) Fetal habituation: there was a general consensus that research on this aspect of fetal behavior may have a high payoff for assessing human fetal well being and predicting neonatal outcome. 2) Behavioral state transitions: participants agreed that transitions afford investigators with an indication of when (timing) and how (models) behavior changes within and between developmental periods. Knowledge of transitions during development allows for tracking of behaviors that may be necessary for the fetus to adapt to its in utero environment or prepare for its postnatal life. 3) Chaos theory and fetal movement: participants concluded that non-linear dynamics systems analysis models could be useful to analyze "noise" within a measurement system; better define time scales; and increase resolution and thereby better identify "signals."

Journal Article↗

Diet and infant behavior.

We studied 142 preterm infants (mean gestation 31 weeks, mean birthweight 1364 g) fed prospectively varied protein and energy intakes. Infants were grouped as either slow or rapid growers based on rate of weight gain. Rapid growers had increased heart rates (166 vs 160 beats/min), respiratory rates (55.7 vs 53.9 bpm), energy expenditure (64.8 vs 61.6 kcal kg(-1) day(-1)), urinary C-peptide levels (1.59 vs 0.79 ng ml(-1)) and time in active sleep (78.0 vs 75.2%), and decreased spectral edge frequency in the electroencephalogram (2.96 vs 4.45 Hz) compared to slow growers. We conclude that preterm infants growing at varying rates manifest physiological and behavioral differences, and that these patterns may reflect altered autonomic balance.

Diet↗

Relationships between breathing activity and heart rate in fetal baboons.

Coordination between breathing and heart rate (HR) is known to occur in many species and is commonly called respiratory sinus arrhythmia (RSA). In this report, we provide evidence that a homologous phenomenon can be demonstrated in the fetuses of nonhuman primates. In chronically instrumented fetal baboons we found cyclical variations in HR that were coincident with fetal breathing movements. We found clear instances of fetal RSA in each of three baboon fetuses. The average change in HR with each fetal breath was approximately 2 beats/min. Fetal breaths were associated with an acceleration/deceleration cycle in HR, and the onset of accelerations was coincident with the onset of inspiratory activity. These studies indicate that in baboons integration of respiratory and cardiovascular control mechanisms develop in utero.

Animals↗

Recombination of nonchromosomal mutations: a 3-point cross in the green alga Chlamydomonas reinhardi.

The heterothallic, unicellular green alga Chlamydomonas reinhardi possesses both chromosomal and nonchromosomal systems of inheritance. Mutations belonging to the latter system are capable of recombination. The experiments reported show that double and triple recombinants can be obtained from crosses employing three phenotypically distinct mutations and that certain pairs of mutants recombine more freely than others.

Crosses, Genetic↗