Fetal Neurobehavioral Development

The ontogeny of fetal autonomic, motoric, state, and interactive functioning was investigated longitudinally in a sample of 31 healthy fetuses from 20 weeks through term. Fetal heart rate and movement data were collected during 50 min of Doppler-based fetal monitoring at 6 gestational ages. Measures of fetal heart rate and variability, activity level and vigor, behavioral state, and reactivity were derived from these digitized data. Weighted least squares analyses were conducted to model the developmental patterns and to examine the role of maternal and fetal covariates. With advancing gestation, fetuses displayed slower heart rate, increased heart rate variability, reduced but more vigorous motor behavior, coalescence of heart rate and movement patterns into distinct behavioral states, and increasing cardiac responsivity to stimulation. Male fetuses were more active than female fetuses, and greater maternal stress appraisal was associated with reduced fetal heart rate variability. An apparent period of neurobehavioral transition exists between 28 and 32 weeks. Fetal research methods are evaluated.     

Prenatal diagnosis of congenital fetal heart abnormalities and clinical analysis

INTRODUCTION Congenital heart disease (CHD) is the most common congenital disorder resulting in significant prenatal and postnatal morbidity and mortality (Gil- lum, 1994; Gembruch, 1997) and is believed to be a multifactorial disorder arising from the combined effect of genetic predisposition and environmental factors. Prenatal diagnosis of CHD is very important for both fetal prognosis and decreasing economic burden of family and society. It was demonstratedt t - l t recently that fe…     

Fetal heart rate and variability: stability and prediction to developmental outcomes in early childhood

Stability in cardiac indicators before birth and their utility in predicting variation in postnatal development were examined. Fetal heart rate and variability were measured longitudinally from 20 through 38 weeks gestation (n = 137) and again at age 2 (n = 79). Significant within-individual stability during the prenatal period and into childhood was demonstrated. Fetal heart rate variability at or after 28 weeks gestation and steeper developmental trajectories were significantly associated with mental and psychomotor development at 2 years (n = 82) and language ability at 2.5 years (n = 61). These data suggest that the foundations of individual differences in autonomic control originate during gestation and the developmental momentum of the fetal period continues after birth.     

Stress Reactivity and Self-Recognition

This study examined longitudinally whether early differences in reactivity to stress are related to self-recognition at 18 months of age. Adrenocortical and behavioral to Stress responses to routine inoculation at 2, and 4 months and at 6 and 18 months were obtained. Previous finding indicated a development shift in adrenocortical functioning by 6 months of age that included the emergence of stable individual differences in cortisol response from this point in development. Self-recognition was related to greater cortisol response and less rapid quieting at 6 to 18 months, whereas 2- to 4-month cortisol and quieting response did not differentiate self-recognizers and non-self-recognizators. These findings indicate a role for temperament differences in facilitating the emergence of self-recognition.     

Maturation of Human Fetal Responses to Vibroacoustic Stimulation

Maturation of human fetal response to vibroacoustic stimulation was examined in 60 fetuses from 23 to 36 weeks gestational age. Subjects received vibroacoustic or no-stimulus control trials (randomly assigned) while fetal heart rate (FHR) was recorded and movement was observed on real-time ultrasound scan. Initially, at 26-28 weeks, a small FHR deceleration response occurred; subsequently, FHR acceleration responses occurred. From 29 weeks, 83%-100% of subjects responded with an FHR acceleration > or = 10 BPM on the first vibrator trial and accelerations were observed on 83%-92% of all vibrator trials. From 26 to 36 weeks the percentage of fetuses responding with movement on the first vibrator trial increased from 58% to 100%; on all vibrator trials responses increased from 53% to 94%. It was concluded that maturation of human fetal response to vibroacoustic stimulation begins at about 26 weeks gestation, increases steadily over a 6-week period, and reaches maturity at about 32 weeks.     

Similarities and Differences in Behavioral State Organization during Sleep Periods in the Perinatal Infant Before and After Birth

The purpose of this study was to determine the degree of consistency in behavioral state organization for 30 low-risk human participants examined as fetuses at 38–40 weeks gestation and again as neonates at approximately 2 weeks postnatal age. behavioral states were assigned similarly for fetuses and neonmates in terms of heart rate pattern and the presence or absence of eye and gross body movements. We found that the time spent in a sleep period was distributed among quiet sleep (QS), active sleep (AS), and indeterminate states in virtually identical proportions for fetuses and neonates. However, the only within-subject consistency between the fetal and neonatal periods was in the duration of complete QS epochs. Fetuses made fewer transitions between QS and AS, but neonates had shorter and more structured AS → QS transitions. These findings suggest that, whereas central nervous system processes governing QS do not change appreciably, the control of AS undergoes significant changes in the 4 weeks spannig the fetal and neonatal periods. We believe that the duration of enclosed QS epochs provides the only stable measure of behavioral state development between the prenatal and postnatal periods.     

The Relations among Infant Temperament, Security of Attachment, and Behavioral Inhibition at Twenty-Four Months

The purpose of this study was to examine the relations among infant temperament, attachment, and behavioral inhibition. 52 infants were seen at 2 days, 5, 14, and 24 months of age. Assessments were made of temperament at 2 days and 5 months of age, and attachment and behavioral inhibition were assessed at 14 and 24 months, respectively. EKG was recorded at each assessment, and measures of heart period and vagal tone were computed. Distress to pacifier withdrawal at 2 days of age was related to insecure attachment at 14 months. 2 types of distress reactivity at 5 months, reactivity to frustration and reactivity to novelty, were identified and related to high vagal tone. Attachment classification at 14 months was directly related to inhibited behavior at 24 months. Infants classified as insecure/resistant were more inhibited than those classified as insecure/avoidant. In addition, an interaction of infant reactivity to frustration and attachment classification was found to predict inhibition at 24 months. Infants classified as insecure/resistant and who had not cried to the arm restraint procedure at 5 months were the most inhibited at 24 months. These findings are discussed in terms of hypotheses regarding multiple modes of distress reactivity and regulation in early infancy and their different social and behavioral outcomes.     

Neonatal Stress Reactivity: Predictions to Later Emotional Temperament

To investigate the relations among popular measures of neonatal stress and their link to subsequent temperament, 50 full-term newborns from a normal care nursery were examined responding to a heelstick blood draw. Baseline and heelstick measures of behavioral state, heart period, vagal tone, and salivary cortisol were obtained. Recovery measures of behavioral and cardiac activity were also analyzed. Mothers completed Rothbart's Infant Behavior Questionnaire when their infants reached 6 months of age. Baseline vagal tone predicted cortisol in response to the heelstick, suggesting that baseline vagal tone reflects the infants' ability to react to stressors. Greater reactivity to the heelstick (more crying, shorter heart periods, lower vagal tone, and higher cortisol) was associated with lower scores on "Distress-to-Limitations" temperament at 6 months. This finding was consistent with the expectation that the capacity to react strongly to an aversive stimulus would reflect better neurobehavioral organization in the newborn. Recovery measures of cardiac activity approximated and were correlated with baseline measures indicating the strong self-righting properties of the healthy newborn. Finally, vagal tone and salivary cortisol measures were not significantly related, suggesting the importance of assessing both systems in studies of the ontogeny of stress-temperament relations.     

Prenatal Antecedents of Newborn Neurological Maturation

Fetal neurobehavioral development was modeled longitudinally using data collected at weekly intervals from 24 to 38 weeks gestation in a sample of 112 healthy pregnancies. Predictive associations between 3 measures of fetal neurobehavioral functioning and their developmental trajectories to neurological maturation in the first weeks after birth were examined. Prenatal measures included fetal heart rate (FHR) variability, fetal movement, and coupling between fetal motor activity and heart rate patterning; neonatal outcomes include a standard neurologic examination ( n  =   97) and brainstem auditory evoked potential (BAEP; n  =   47). Optimality in newborn motor activity and reflexes was predicted by fetal motor activity, FHR variability, and somatic–cardiac coupling predicted BAEP parameters. Maternal pregnancy-specific psychological stress was associated with accelerated neurologic maturation.     

Neonatal Temperament in Monozygotic and Dizygotic Twin Pairs

To determine if neonatal temperament was influenced by genetic factors, temperament was assessed in 316 newborn twins from 47 pairs of monozygotic (MZ) twins, 39 pairs of same-sex dizygotic (DZ) twins, and 72 pairs of opposite-sex dizygotic twins. The neonatal assessment focused on irritability, resistance to soothing, activity level, reactivity, and reinforcement value. Examination of intraclass correlations for MZ and DZ twins and the results of model-fitting analyses indicated that heritability estimates for neonatal temperament were not significantly different from zero, and that there was substantial environmental influence on neonatal temperament. Specific perinatal indicators of risk were found to account for some of the intrapair differences observed for the behavioral variables. It was concluded that there is no clear pattern of genetic influence on temperament in the neonatal period.     

胎儿大脑皮层枕极突触超微结构的形态学观察与分析

本文用 H-600型透射电子显微镜观察了6例眙儿大脑皮层枕极245个突触的超微结构,结果表明在4.5个月胎儿枕极大脑皮层未见到突触,在5个月胎儿仅观察到少量突触,以后随胎龄的增加,突触数逐渐增多。在六个月以后胎儿大脑皮层,突触数明显增多,在新观察到的245个突触中,次轴树突触占绝大多数,占胎儿突触观察总数的77.6%。其次为轴棘突触,占胎儿突触观察总数的4.5%,从五个月胎脑开始观察到轴极突触,且这些轴棘突出的后成分中均不含有棘器。另外在胎儿枕极皮层,还观察到较多的轴-体突触,占胎儿突触观察总数的3.7%。此外,尚见到少量轴-轴,树-树,树-棘突触和串,并联突触。     

Infant behavior and development in relation to fetal movement and habituation

Fetal movement and habituation were examined in relation to behavior and development in early infancy. 39 fetuses were evaluated between 28 and 37 weeks gestation. A vibrating stimulus was repeatedly applied to the maternal abdomen until the fetus habituated (i.e., ceased moving in response). Fetal movements were observed on an ultrasound monitor by 2 observers who recorded their observations onto a strip chart. Using a median split, fetuses were placed into high- or low-movement groups and fast- or slow-habituating groups. The groups were compared after birth on the Brazelton Neonatal Behavior Assessment Scale and the Bayley Scales of Infant Development. Preliminary evidence is presented that fetal rate of habituation predicts some aspects of infant behavior and development.     

Infant Temperament: Stability by Age,Gender, Birth Order,Term Status,and Socioeconomic Status

Two complementary studies focused on stability of infant temperament across the 1st year and considered infant age, gender, birth order, term status, and socioeconomic status (SES) as moderators. Study 1 consisted of 73 mothers of firstborn term girls and boys queried at 2, 5, and 13 months of age. Study 2 consisted of 335 mothers of infants of different gender, birth order, term status, and SES queried at 6 and 12 months. Consistent positive and negative affectivity factors emerged at all time points across both studies. Infant temperament proved stable and robust across gender, birth order, term status, and SES. Stability coefficients for temperament factors and scales were medium to large for shorter (< 9 months) interassessment intervals and small to medium for longer (> 10 months) intervals.     

Environmental control, social context, and individual differences in behavioral and cortisol responses to novelty in infant rhesus monkeys

The effects of appetitive controllability on behavioral and cortisol reactivity to novelty in 12 infant rhesus monkeys were studied. Surrogate-peer-reared infants had homecage access to food treats contingently via lever pressing ("master") or noncontingently ("yoked") for 12 weeks from postnatal month 2. Masters lever-pressed more, but did not differ in baseline cortisol. At month 5, infants were exposed to a novel environment in social groups and individually. Masters were significantly more active and exhibited significantly lower cortisol reactivity to the novel environment, but only in the individual context. Also, individual differences in operant behavior were positively correlated with behavioral activity and negatively correlated with cortisol reactivity to the novel environment. The results reveal context-specific benefits of contingent stimulation in infancy.     

Down Syndrome Temperament: The Stereotype at Middle Childhood and Adolescence

MOTHERS AND TEACHERS of 94 children (53 boys) with Down syndrome, between 8 and 14 years of age, rated the children on a temperament scale and provided an overall impression as to whether the child was difficult in comparison with other children. Maternal ratings on the Middle Childhood Questionnaire showed significant differences from standardization scores. Children with Down syndrome were given ratings as less active, more predictable, of more positive mood, less persistent, and more distractible. Some of these dimensions favour the amiable personality stereotype for the syndrome but low persistence was associated with maternal impressions of difficulty. There was little agreement between mothers and teachers regarding the individual children who were rated as being significantly easier or more difficult than other children. Results with a subgroup (n = 32) showed that externalizing behaviours were significantly related to both mother and teacher impressions of difficulty and that mothers also found intense, active, distractible behaviour difficult.     

Temperament and Self-soothing Behavior in Children: Object Attachment, Thumbsucking, and Pacifier Use

Research Findings. Mothers of 4-, 6-, and 8-year-olds completed two questionnaires: (1) the Object Attachment Questionnaire, which was designed to provide information on children's attachments to soft objects, thumbsucking habits, and pacifier use, and (2) Rothbart's Children's Behavior Questionnaire (CBQ), which rated children on sixteen temperament dimensions. Discriminant function analysis showed that the best predictors for distinguishing between children who had never had an attachment to a soft object and children who had were: low intensity pleasure, impulsivity, approach/anticipation, attentional focusing, and sad- ness. Children with soft object attachments were rated higher (i.e. showed more) on all of these dimensions. None of the temperament dimensions distinguished between children who rarely sucked their thumbs and those who frequently did so, while children who had used a pacifier scored higher on two dimensions (activity level and approach/anticipation) than children who had not used a pacifier even though one was available. Results support the hypothesis that individual differences in temperament are associated with the development of attachment to objects. Practice. Children with attachments to soft objects and thumbs were not generally insecure or difficult to manage. The pattern of temperament differences, however, suggests strengths that teachers might make use of in the classroom as well as difficulties that might require staff intervention.     

Associations Between Teacher-Rated Versus Self-Rated Student Temperament and School Achievement

This study examined whether teacher-rated versus self-rated student temperaments are different in relation to the school grades in Maths and Mother language (ML) instruction in a nationally representative sample of Finnish Secondary School students (n?=?1,063, mean age 15.1 years). The results indicated that teacher-rated temperament was more strongly associated with students' Maths and ML grades than self-rated temperament. All the teacher-rated temperament traits were associated with school grades, accounting for 38% and 45% of the variance in Maths and ML, respectively. Of the self-rated temperaments, high task orientation and its components, high persistence and low distractibility, were associated with better school grades both in Maths and ML. Low reactivity and low negative emotionality were associated only with better ML grades, whereas high inhibition was associated only with better Maths grades. A temperament-conscious education needs to be taken into account in future teacher training.     

Temperament, Emotion, and Cognition at Fourteen Months: The MacArthur Longitudinal Twin Study

200 pairs of twins were assessed at 14 months of age in the laboratory and home. Measures were obtained of temperament, emotion, and cognition/language. Comparisons between identical and fraternal twin correlations suggest that individual differences are due in part to heritable influences. For temperament, genetic influence was significant for behavioral observations of inhibition to the unfamiliar, tester ratings of activity, and parental ratings of temperament. For emotion, significant genetic influence was found for empathy and parental ratings of negative emotion. The estimate of heritability for parental report of expression of negative emotions was relatively high, whereas that for expression of positive emotions was low, a finding consistent with previous research. For cognition and language, genetic influence was significant for behavioral indices of spatial memory, categorization, and word comprehension. Shared rearing environment appears influential for parental reports of language and for positive emotions, but not for other measures of emotion or for temperament.     

Socioeconomic status impacts genetic influences on the longitudinal dynamic relationship between temperament and general cognitive ability in childhood: The Louisville Twin Study

The current analysis investigates genetic and environmental influences on the bidirectional relationships between temperament and general cognitive ability (GCA). Measures of GCA and three temperament factors (persistence, approach, and reactivity) were collected from 486 children ages 4–9 years (80% white, 50% female) from the Louisville Twin Study from 1976 to 1998. The results indicated a bidirectional dynamic model of temperament influencing subsequent GCA and GCA influencing subsequent temperament. The dynamic relationship between temperament and GCA arose primarily from shared genetic variance, particularly in families with higher socioeconomic status, where input from temperament contributed on average 20% to genetic variance in GCA versus 0% in lower SES families.     

Aspects of Fetal Learning and Memory

Ninety-three pregnant women were recruited to assess fetal learning and memory, based on habituation to repeated vibroacoustic stimulation of fetuses of 30–38 weeks gestational age (GA). Each habituation test was repeated 10 min later to estimate the fetal short-term memory. For Groups 30–36, both measurements were replicated in a second session at 38 weeks GA for the assessment of fetal long-term memory. Within the time frame considered, fetal learning appeared GA independent. Furthermore, fetuses were observed to have a short-term (10-min) memory from at least 30 weeks GA onward, which also appeared independent of fetal age. In addition, results indicated that 34-week-old fetuses are able to store information and retrieve it 4 weeks later.