Neurobehavioral Changes in Adolescence

Adolescents across a variety of species exhibit age-specific behavioral characteristics that may have evolved to help them attain the necessary skills for independence. These adolescent-related characteristics, such as an increase in risk taking, may be promoted less by the hormonal changes of puberty than by developmental events occurring in brain. Among the prominent brain transformations of adolescence are alterations in the prefrontal cortex, limbic brain areas, and their dopamine input, systems that are sensitive to stressors and form part of the neural circuitry modulating the motivational value of drugs and other reinforcing stimuli. Such developmental transformations of the adolescent brain may predispose adolescents to behave in particular ways and make them particularly likely to initiate use of alcohol and other drugs.     

Neurobehavioral phenotype of Klinefelter syndrome

A defined genetic syndrome with neurobehavioral components offers an unusual paradigm for the correlation of genetic defects with neurodevelopmental abnormalities. The power of the combination of detailed behavioral, neuroanatomical, and genetic studies has been demonstrated in studies of other conditions involving the sex chromosomes, such as Fragile X syndrome (Mazzocco [2000] Ment Retard Develop Disabil Res Rev. 6:96-106) and Turner syndrome (Ross [2000] Ment Retard Develop Disabil Res Rev. 6:135-141). Although the behavioral and neurologic difficulties that have been identified in Klinefelter syndrome (KS) are in most cases milder than the consequences of many other genetic syndromes, the deficits in KS cause significant morbidity, representing a more common, but poorly understood, subtype of those with learning disabilities. Both as children and as adults, KS subjects appear to offer a powerful genetic model for the study of language and language-based learning disabilities. Although it has been proposed that the language-based learning difficulties of KS boys are similar to those of nonaneuploidic dyslexics [Bender et al., 1986; Geschwind et al., 1998], this is not yet well established. The co-morbid frontal-executive dysfunction observed in KS is also a likely contributor to learning difficulties and, perhaps, social cognition, in many KS patients. It is also proposed that altered left-hemisphere functioning, whether causing, or due to, altered functional and anatomical cerebral dominance, is at the core of KS subjects' language problems. Although X chromosomal loci can provide only part of the picture, the study of KS subjects, a population with a relatively homogeneous etiology for dyslexia/dysphasia and frontal-executive dysfunction, offers many advantages over such a study in the general population, in which both dyslexia and attentional disorders are quite genetically heterogeneous [Decker and Bender, 1988; Pennington, 1990; Grigorenko et al., 1997; Geschwind et al., 1998]. Furthermore, the interaction of genetic factors and hormonal influences in the cognitive phenotypes described remains an unexplored area for future investigation. MRDD Research Reviews 2000;6:117-124.     

Neurobehavioral Correlates of Chronic Hepatitis C

Chronic infection with the hepatitis C virus is a major public health concern in the United States and worldwide, and persons with psychiatric histories are more likely to have chronic hepatitis C (CHC). Neurobehavioral consequences of CHC are common in all phases of the disease process and significantly contribute to morbidity. Antiviral treatment also is associated with neurobehavioral difficulties that can interfere with successful completion of treatment and result in fewer patients clearing the virus. Fatigue, depression, cognitive dysfunction, and anxiety are the most common neuropsychiatric symptoms reported by patients with CHC regardless of treatment status. Behavioral health care professionals can play a vital role in decreasing the personal and societal burden of CHC by being active members of the treatment team and by furthering knowledge of how to manage neurobehavioral correlates of CHC.     

Myrtle McGraw''s Neurobehavioral Theory of Development

Myrtle McGraw's contribution to understanding infant growth and development is undisputed, but controversy stubbornly persists regarding her views about how the brain contributes to behavioral development. McGraw conducted a more complex analysis of neurobehavior than is generally acknowledged by those who characterize her position as maturationist. McGraw drew on several streams of scientific knowledge and philosophy in a collaboration that included John Dewey to advance a unique analysis of the ontogeny of the brain and consciousness that singled-out the reciprocal relationship between neural growth processes and experience in early development. McGraw's studies of the role of gravity, inhibition, and judgment in the integration of behavior particularly remain pertinent to researchers examining the neurobiological and quantum processes through which brain and behavior undergo transformation.     

Neurobehavioral sequelae of child sexual abuse.

This study examined intellectual and memory functioning in a sample of sexually abused children compared to demographically and age-matched controls. The severity of abuse and other pertinent factors were also examined in relation to cognitive performance. Elevated levels of psychopathology were present in the abused children, as well as diminished performance on tasks influenced by attention/concentration. However, after controlling for differences in IQ and socioeconomic status (SES), significant differences in memory function were not found. Results are discussed in the context of stress effects on cognition and the potential resiliency of cognitive function in children undergoing treatment for sexual abuse.     

Neurobehavioral effects of caffeine on the neonate

This study examined the behavioral effects of caffeine, measured in cord blood and saliva, on infant behavior. In order to examine these effects, 40 full-term, healthy, vaginally delivered, breast-fed neonates and their healthy, nonsmoking mothers were studied. A nutritional questionnaire was developed and given to each participating mother to determine her approximate caffeine intake during the last three days before delivery. For each infant subject, cord blood samples from delivery and saliva samples taken on the day of behavioral testing were assayed for caffeine. Statistical analyses revealed a significant effect of caffeine level on certain interactive behaviors in response to stimulation but little or no observed effect upon spontaneous sleep states.     

恐惧学习的发展认知神经机制研究回顾与展望

恐惧可以帮助个体快速地评估危险情景,并调动生理和行为反应来应对危险刺激。恐惧发展始于婴儿时期,神经回路表现为杏仁核未参与恐惧反应,但杏仁核功能连接可以预测早期恐惧反应;发展到童年期的恐惧学习特点为安全学习不足和过度泛化,其根源是负责辨别刺激的海马还处于发育中;进入青春期恐惧加工主要特征是由于前额叶发育较晚导致的消退能力弱。恐惧虽有益于人类生存,但恐惧异常会引发焦虑障碍,本文从恐惧的习得、消退和泛化三个阶段,对比了焦虑与健康青少年的恐惧学习差异。最后,文章从增加婴儿时期研究、创新青少年恐惧研究范式和开发安全有效的干预手段三个方面对未来研究提出展望,以期进一步推动恐惧研究的发展。     

Neurobehavioral Characteristics of Children with Duchenne Muscular Dystrophy

This study investigated cognitive, metacognitive, and psychosocial aspects of neurobehavioral functioning in 22 boys with Duchenne muscular dystrophy (DMD) and 18 unaffected siblings, all between the ages of 6 and 16 years. Probands and siblings completed the Wechsler Abbreviated Scale of Intelligence, as well as selected subtests from the Children's Memory Scale and from the Delis-Kaplan Executive Function System, while parents completed the Child Behavior Checklist and the Behavior Rating Inventory of Executive Function. Compared to siblings, probands demonstrated relative weaknesses on both verbal and nonverbal measures of delayed recall and response generation and were rated by parents as having more difficulties with social interaction, initiation, and adaptation. It is concluded that DMD is associated with mild but potentially significant difficulties in a range of neurobehavioral areas, likely related to deficient dystrophin levels in an integrated brain circuit that includes the cerebellum, hippocampus, and association neocortex.     

Neurobehavioral Assessment of Children Presenting Diverse Congenital Cardiopathologies

Brain maturation in 1–36 month old children suffering from congenital cardiopathologies was assessed after a study of psychomotor development. The Rogers’ test (Rogers et al., Developmental programming for infants and young children. Volume 2. Early intervention developmental profile, Revised edition, ESL/ELT Michigan, Ann Arbor, 1981) was applied to 65 children, of whom 21 presented with simple cardiopathologies (CpS) and 22 with complex cardiopathologies (CpC). All children were matched by age, sex and socioeconomic status to 22 healthy children in a control group (C). Mean differences between the three groups were established by applying the Kruskal–Wallis test, and mean differences between the C and CpS/CpC groups were determined using the Mann–Whitney test. The proportion of cases evaluated as “low” in each group was calculated by applying the Rogers’ test, and a test of proportion differences was applied between the C and CpS/CpC groups. CpS children performed similarly to the C, whereas CpC children scored significantly lower than C children on all variables. It is highly likely that the suboptimal psychomotor performance observed in CpC children was due to compromised hemodynamics and related to subclinical immaturity of cerebral development.     

Neurobehavioral Functioning in Children with Fetal Alcohol Spectrum Disorder

Neurobehavioral functioning of 50 Canadian children diagnosed with Fetal Alcohol Spectrum Disorder (FASD) was evaluated. The aims of this study were to identify specific areas of weakness in neurobehavioral functioning, to examine whether neurobehavioral functioning was related to various predictor variables, and to determine which measures differentiated between children given a brain score of 2 (possible dysfunction) and 3 (probable dysfunction). Participants displayed difficulties with many aspects of intelligence, memory, executive functioning, and attention. Measures of Full scale and Verbal IQ, as well as memory for faces and numbers differentiated between children with a brain 2 and 3 ranking. An interesting pattern of strengths and weaknesses emerged as well as significant differences related to ethnic background, gender, and age. Aboriginal children and Caucasian children with FASD do not appear to show the same pattern of strengths and weaknesses in neurobehavioral functioning.     

Neurobehavioral Evaluation System (NES) and school performance

The aims of this study were to explore the validity of a set of computerized tests, and to explore the validity of reaction time variability as an index of sustained attention. In Phase 1, 105 children 7–10 years old were presented with five tests from the Neurobehavioral Evaluation System (NES). The children were able to complete four of the tests: the Continuous Performance, Simple Reaction Time, Symbol-Digit Substitution, and Digit Span tests. In Phase 2, a follow-up of 88 children, performance on these tests was significantly associated with teachers' ratings of attention and with standardized academic achievement measures. Moreover, variability on the Simple Reaction Time and performance on the Digit Span and Symbol-Digit tests significantly predicted reading achievement. Similarly, performance on the Digit Span and Symbol-Digit tests significantly predicted mathematics achievement. In addition, variability on the Simple Reaction Time and Digit Span test performance were significant predictors of reading achievement above and beyond the prediction provided by teachers' ratings.     

Alcohol: Effects on Neurobehavioral Functions and the Brain

Alcoholism results from an interplay between genetic and environmental factors, and is linked to brain defects and associated cognitive, emotional, and behavioral impairments. A confluence of findings from neuroimaging, physiological, neuropathological, and neuropsychological studies of alcoholics indicate that the frontal lobes, limbic system, and cerebellum are particularly vulnerable to damage and dysfunction. An integrative approach employing a variety of neuroscientific technologies is essential for recognizing the interconnectivity of the different functional systems affected by alcoholism. In that way, relevant experimental techniques can be applied to assist in determining the degree to which abstinence and treatment contribute to the reversal of atrophy and dysfunction.     

Psychological Predictors of Neurobehavioral Symptoms in a Polytrauma Veteran Sample

Given the high prevalence of comorbid conditions found in polytrauma settings, effective screening measures are needed. Several screening tools are commonly used in polytrauma clinics within the Department of Veterans Affairs (VA). This study examined the use of three screening measures—the Beck Depression Inventory-II (BDI-II), Beck Anxiety Inventory (BAI), and PTSD Checklist–Civilian Version (PCL-C)—to predict scores on the Neurobehavioral Symptom Inventory (NSI). Research suggests that the presence of mental health conditions, such as PTSD, shares a significant amount of variance with postconcussive symptoms. The investigators hypothesized that the PCL-C would be the best predictor of scores on the NSI. All subjects were administered the screening measures as part of an evaluation in an outpatient Level III polytrauma clinic. Regression analysis was used to determine which instrument might serve as the best predictor of NSI total scores. Regression analysis revealed that BAI, BDI-II, and PCL-C total scores were good predictors of NSI total scores, with the BAI accounting for the majority of the variance. Mental health conditions can account for higher scores on the NSI, and screening of other mental health conditions should be taken into account when reviewing the NSI for individuals in polytrauma settings.     

Neurobehavioral functioning in children with fetal alcohol spectrum disorder.

Neurobehavioral functioning of 50 Canadian children diagnosed with Fetal Alcohol Spectrum Disorder (FASD) was evaluated. The aims of this study were to identify specific areas of weakness in neurobehavioral functioning, to examine whether neurobehavioral functioning was related to various predictor variables, and to determine which measures differentiated between children given a brain score of 2 (possible dysfunction) and 3 (probable dysfunction). Participants displayed difficulties with many aspects of intelligence, memory, executive functioning, and attention. Measures of Full scale and Verbal IQ, as well as memory for faces and numbers differentiated between children with a brain 2 and 3 ranking. An interesting pattern of strengths and weaknesses emerged as well as significant differences related to ethnic background, gender, and age. Aboriginal children and Caucasian children with FASD do not appear to show the same pattern of strengths and weaknesses in neurobehavioral functioning.     

Neurobehavioral evidence for the "Near-Miss" effect in pathological gamblers

The purpose of this translational study was twofold: (1) to contrast behavioral and brain activity between pathological and nonpathological gamblers, and (2) to examine differences as a function of the outcome of the spin of a slot machine, focusing predominately on the "Near-Miss"--when two reels stop on the same symbol, and that symbol is just above or below the payoff line on the third reel. Twenty-two participants (11 nonpathological; 11 pathological) completed the study by rating the closeness of various outcomes of slot machine displays (wins, losses, and near-misses) to a win. No behavioral differences were observed between groups of participants, however, differences in brain activity were found in the left midbrain, near the substantia nigra and ventral tegmental area (SN / VTA). Near-miss outcomes uniquely activated brain regions associated with wins for the pathological gamblers and regions associated with losses for the nonpathological gamblers. Thus, near-miss outcomes on slot machines may contain both functional and neurological properties of wins for pathological gamblers. Such a translational approach to the study of gambling behavior may be considered an example that gives life to B. F. Skinner's conceptualization of the physiologist of the future.     

Neurobehavioral and psychosocial functioning of women exposed to high altitude in mountaineering

The effects of chronic hypoxemia upon cognition and behavior were studied in women exposed to high altitude in mountaineering. Neuropsychological tests and psychosocial and physiological questionnaires were given to eight women before, during, and immediately after a Himalayan climb to 20,500 feet. Cognitive functioning remained relatively intact with only two significant decrements, complex abstract reasoning and word-finding ability. Significant changes were found on all psychosocial and physiological questionnaires. Feelings of acceptance of others and anxiety declined significantly. Physical symptoms were greatest during the first five days of ascent. Subjects' self-ratings of mental functioning were significantly better after the expedition than either before or during the climb. Self-assessments were correlated with emotions and physical symptoms, not with actual performances on the test battery. It is suggested that complex cognitive tasks and psychosocial functioning be studied in more detail as these were more influenced by exposure to high altitude in mountaineering.