Biomedical subjects

Nathan A Fox

Publications and source records attributed to Nathan A Fox.

29 records · Page 2Linked to original sources

PubMed2004

Temperament and early experience form social behavior.

Individual differences in the way persons respond to stimulation can have important consequences for their ability to learn and their choice of vocation. Temperament is the study of such individual differences, being thought of as the behavioral style of an individual. Common to all approaches in the study of temperament are the notions that it can be identified in infancy, is fairly stable across development, and influences adult personality. We have identified a specific temperament type in infancy that involves heightened distress to novel and unfamiliar stimuli. Infants who exhibit this temperament are likely, as they get older, to display behavioral inhibition-wariness and heightened vigilance of the unfamiliar-particularly in social situations. Our work has also described the underlying biology of this temperament and has linked it to neural systems supporting fear responses in animals. Children displaying behavioral inhibition are at-risk for behavioral problems related to anxiety and social withdrawal.

Adult↗

PubMed2004

Temperament and attachment disorders.

Reviewed in this article is research on children with reactive attachment disorder (RAD) who exhibit specific patterns of socially aberrant behavior resulting from being maltreated or having limited opportunities to form selective attachments. There are no data explaining why 2 different patterns of the disorder, an emotionally withdrawn-inhibited pattern and an indiscriminate-disinhibited pattern, arise from similarly aberrant environments. In this article, we consider whether temperamental differences might contribute to the different manifestations of reactive attachment disorder (RAD) in the context of adverse environments. Although the association between attachment and temperament has been studied extensively and has been the subject of spirited debate within the field of child development, there are no extant data on the influence of temperament on the development of attachment disorders. We consider possible directions for research efforts designed to explore the biological underpinnings of the complex phenomenon of attachment disorders.

Adolescent↗

PubMed2003

Mismatch negativity in socially withdrawn children.

BACKGROUND: Individual differences in auditory processing have been associated with social withdrawal, introversion, and other forms of dysfunction in social engagement. The goal of this study was to investigate the characteristics of an electrophysiologic response that is seen to index early cortical auditory processing (mismatch negativity, MMN) among socially withdrawn and more sociable control children. METHODS: Auditory event-related potentials to standard and deviant tone stimuli were computed for 23 socially withdrawn children and 22 control subjects. We calculated MMN difference waveforms for frontal, central, and parietal electrode sites. RESULTS: Socially withdrawn children had smaller MMN amplitude and longer MMN latencies compared with more sociable control children. CONCLUSION: The findings point to the involvement of individual differences in early cortical auditory processing in childhood social withdrawal. Reduced MMN amplitude and delayed latency may index a component of social withdrawal seen in socially withdrawn children and in depressed and schizophrenic patients. The existence of a secondary MMN generator in the frontal cortex may provide a link between the hypothesized frontal lobe involvement in childhood social withdrawal, schizophrenia, and depression and the MMN reductions seen in these conditions.

Acoustic Stimulation↗

PubMed2003

Individual differences in children's performance during an emotional Stroop task: a behavioral and electrophysiological study.

Two studies using the emotional Stroop with 11-year-old children were completed. In Study 1, children were assigned to either the "interference group" or the "facilitation group" based on their performance on the task. The interference group was slower to respond to emotion words (positive and negative) versus control words. The facilitation group was faster to respond to the emotion words. The groups were then compared on a set of cognitive, emotional, and social measures collected at ages 4, 7, and 11. The interference group showed greater signs of emotional and social, but not cognitive, maladjustment across time. Study 2 replicated the findings of Study 1. In addition, event-related potentials (ERPs) were collected in Study 2. The ERP data replicated earlier traditional Stroop studies. In addition, positive and negative words showed differences in processing across components. In particular, negative words appeared to tax attentional and processing resources more than positive words.

Affect↗

PubMed2003

Cognition and affective style: Individual differences in brain electrical activity during spatial and verbal tasks.

Relations between brain electrical activity and performance on two cognitive tasks were examined in a normal population selected to be high on self-reported measures of Positive or Negative Affectivity. Twenty-five right-handed women, from an original pool of 308 college undergraduates, were the participants. EEG was recorded during baseline and during psychometrically matched spatial and verbal tasks. As predicted, participants who were high in Positive Affectivity performed equally well on the verbal and spatial tasks, while participants who were high in Negative Affectivity had spatial scores that were lower than their verbal scores. There were no group differences in baseline EEG. Both groups exhibited left central activation (i.e., alpha suppression) during the verbal and spatial tasks. When EEG data were analyzed separately for the group high in Positive Affectivity, there was evidence of parietal activation for the spatial task relative to the verbal task. The EEG data for the group high in Negative Affectivity had comparable EEG power values during verbal and spatial tasks at parietal scalp locations. These data suggest that, within a selected normal population, differences in affective style may interact with cognitive performance and with the brain electrical activity associated with that performance.

Adolescent↗

PubMed2003

Designing research to study the effects of institutionalization on brain and behavioral development: the Bucharest Early Intervention Project.

This paper provides an overview of the largest longitudinal investigation of institutionalized children less than 2 years old ever conducted. The Bucharest Early Intervention Project is an ongoing randomized controlled trial of foster placement as an alternative to institutionalization in abandoned infants and toddlers being conducted in Bucharest, Romania. In addition to describing the contexts in which this study is imbedded, we also provide an overview of the sample, the measures, and the intervention. We hope that the natural experiment of institutionalization will allow us to examine directly the effects of intervention on early deprivation. We hope it will provide answers to many of the critical questions that developmentalists have asked about the effects of early experience, the timing of deprivation, and the ameliorating effects of early intervention and provide clues to which underlying neurobiological processes are compromised by, and resilient to, dramatic changes in early experience.

Brain↗

PubMed2003

Infant attachment and temperament as predictors of subsequent externalizing problems and cardiac physiology.

BACKGROUND: The primary objective of this study was to examine the extent to which both individual child temperament and parent-child relationship quality independently and/or interactively predicted physiological, psychosocial, and behavioral 'outcomes'. Employing a longitudinal prospective design over three years, statistical associations were found among infant attachment, uninhibited temperament, and 4-year behavioral and physiological functioning that supported a bio-psychosocial model of development. METHOD: Three cohorts totaling 140 children and their mothers visited the laboratory for observational assessments of attachment classification at age 14 months (Strange Situation), behavioral inhibition at 24 months, and social behaviors with unfamiliar peers at age 4 years. Cardiac measures of heart rate and respiratory sinus arrhythmia (RSA) were collected at every time point. At age 4 years maternal ratings of child temperament and behaviors were also obtained. RESULTS: Analyses of variance (ANOVAs) with inhibition group (high, moderate, low) and attachment classification (A, B, C) revealed that the low inhibited group had significantly higher activity level scores and displayed significantly less reticence at 4 years compared to the moderately and highly inhibited groups. Infants who had an avoidant attachment with their mothers had more externalizing problems (aggressive behaviors) at age 4 than either securely or ambivalently attached infants. This predictive relation, however, was qualified by an interaction whereby avoidant attachment and uninhibited temperament together predicted a higher incidence of externalizing behavior problems. Moreover, infants' avoidant attachment was not concurrently but predictively associated with lower heart rate and high RSA at age 4 years. Therefore, an avoidant mother-child relationship in infancy could influence the development of an underaroused autonomic profile in early childhood. CONCLUSIONS: Consistent with bio-psychosocial models of development, these findings support the contention that both early child temperament and parent-child relationship quality contribute to subsequent psychological/behavioral and physiological functioning.

Analysis of Variance↗

PubMed2002

Development of the EEG from 5 months to 4 years of age.

OBJECTIVES: This report provides a systematic longitudinal analysis of the EEG from infancy into early childhood. Particular emphasis is placed on the empirical confirmation of a 6-9 Hz alpha-range frequency band that has previously been used in the infant EEG literature. METHODS: EEG data in 1-Hz bins from 3 to 12 Hz were analyzed from a longitudinal sample of 29 participants at 5, 10, 14, 24, and 51 months of age. RESULTS: Inspection of power spectra averaged across the whole sample indicated the emergence of a peak in the 6-9 Hz range across multiple scalp regions. Coding of peaks in the power spectra of individual infants showed a clear developmental increase in the frequency of this peak. A rhythm in the 6-9 Hz emerged at central sites that was independent of the classical alpha rhythm at posterior sites. The relative amplitude of this central rhythm peaked in the second year of life, when major changes are occurring in locomotor behavior. CONCLUSIONS: The 6-9 Hz band is a useful alpha-range band from the end of the first year of life into early childhood. The findings also complement other research relating the infant central rhythm with the adult sensorimotor mu rhythm.

Aging↗

PubMed2002

Self-regulatory processes in early personality development: a multilevel approach to the study of childhood social withdrawal and aggression.

Self-regulatory processes are believed to be critical to early personality and behavioral adjustment. Such processes can be observed on multiple levels, including the physiological, attentional, emotional, cognitive, and interpersonal domains of functioning. Data from several longitudinal studies suggest links between early temperamental tendencies such as behavioral inhibition and frustration tolerance, and regulatory developments at the levels of physiological, attentional, and emotional regulation. Deficits in these particular levels of self-regulation may underlie childhood social withdrawal and aggression. Significant gaps remain in our knowledge of the pathways to disordered behavior and the role that self-regulation plays in such pathways. Suggestions are made for the ways in which future longitudinal studies might address these gaps.

Affect↗

PubMed2002

Regional patterns of brain activity in adults with a history of childhood-onset depression: gender differences and clinical variability.

OBJECTIVE: The study investigated the hypothesis that EEG asymmetry scores (indicating higher right and lower left frontal brain activity) are associated with vulnerability to negative mood states and depressive disorders. Gender and clinical history variables were examined as factors that may influence the relation between EEG and depression. METHOD: EEG measures of asymmetrical alpha frequency (7.5-12.5 Hz) suppression were analyzed in 55 young adults with a documented clinical history of childhood-onset depression and 55 comparison subjects with no history of major psychopathology. EEG patterns were examined in relation to operational diagnoses of mental disorders during childhood and adulthood. RESULTS: Differences in EEG asymmetry between childhood depression probands and comparison subjects varied with gender, diagnostic history, and current symptoms. Women with childhood depression had higher right midfrontal alpha suppression, and men with childhood depression had higher left midfrontal alpha suppression, relative to comparison subjects. At all scalp sites, women showed greater alpha power than men. Probands with a bipolar spectrum course had the most extreme midfrontal asymmetry. Frontal asymmetry was more extreme in probands with current depressive symptoms than in those without current symptoms. CONCLUSIONS: Regional brain activity is influenced by gender and variability in clinical course. The findings have implications for investigating brain correlates of mood disorder and may help to develop more refined phenotypes.

Adult↗

PubMedDate not supplied

Psychophysiological and behavioral evidence for varying forms and functions of nonsocial behavior in preschoolers.

Four-year-old children showing low levels of social behavior in a laboratory play session with unfamiliar peers were classified as reticent (unoccupied or onlooking behaviors) or solitary-passive (solitary constructive or exploratory play). Compared with a group of more social children, the children in both low-social groups were rated high on maternal reports of shyness and displayed a pattern of right frontal EEG asymmetry. However, only the reticent group was elevated on measures indicative of a fearful temperament, both concurrently and retrospectively. A subset of children in the solitary-passive group showed increasing levels of reticent behavior over the course of the visit, suggesting that for some children solitary-passive behaviors provide a means for coping with feelings of unease.

Adaptation, Psychological↗