Examining change in cortisol patterns during the 10-week transition to a new child-care setting.

The transition to out-of-home child care brings a number of challenges for children, including complex peer interactions and extended separations from parents. Children often show a midmorning to afternoon rise in cortisol on child-care days, compared to the typical diurnal decline seen at home. Changes in cortisol were examined in a wide age range of children (N = 168; 1.2 months to 8 years, M = 3.27 years) during the 10-week transition to a new child-care setting. Structural equation modeling using latent change scores showed that children experienced an increase in the cortisol rise at child care across the 10-week transition. Furthermore, child age moderated the difference between home- and child-care cortisol patterns. Findings are placed in a developmental context, and potential implications and future directions are discussed.

Incentive effect on inhibitory control in adolescents with early-life stress: an antisaccade study.

OBJECTIVE: Early-life stress (ES) such as adoption, change of caregiver, or experience of emotional neglect may influence the way in which affected individuals respond to emotional stimuli of positive or negative valence. These modified responses may stem from a direct alteration of how emotional stimuli are coded, and/or the cognitive function implicated in emotion modulation, such as self-regulation or inhibition. These ES effects have been probed on tasks either targeting reward and inhibitory function. Findings revealed deficits in both reward processing and inhibitory control in ES youths. However, no work has yet examined whether incentives can improve automatic response or inhibitory control in ES youths. METHOD: To determine whether incentives would only improve self-regulated voluntary actions or generalize to automated motoric responses, participants were tested on a mixed eye movement task that included reflex-like prosaccades and voluntary controlled antisaccade eye movements. Seventeen adopted children (10 females, mean age 11.3 years) with a documented history of neglect and 29 typical healthy youths (16 females, mean age 11.9 years) performed the mixed prosaccade/antisaccade task during monetary incentive conditions or during no-incentive conditions. RESULTS: Across both saccade types, ES adolescents responded more slowly than controls. As expected, control participants committed fewer errors on antisaccades during the monetary incentive condition relative to the no-incentive condition. By contrast, ES youths failed to show this incentive-related improvement on inhibitory control. No significant incentive effects were found with prepotent prosaccades trials in either group. Finally, co-morbid psychopathology did not modulate the findings. CONCLUSIONS: These data suggest that youths with experience of early stress exhibit deficient modulation of inhibitory control by reward processes, in tandem with a reward-independent deficit in preparation for both automatic and controlled responses. These data may be relevant to interventions in ES youths.

Early-life stress is associated with impairment in cognitive control in adolescence: an fMRI study.

Early-life stress (ES) has been associated with diverse forms of psychopathology. Some investigators suggest that these associations reflect the effects of stress on the neural circuits that support cognitive control. However, very few prior studies have examined the associations between ES, cognitive control, and underlying neural architecture. The present study compares adolescents with a documented history of ES to typical adolescents on a cognitive control task using functional magnetic resonance imaging (fMRI). Twelve ES adolescents who were adopted because of early caregiver deprivation (9 females, age=13 years+/-2.58) and 21 healthy control adolescents without a history of ES (10 females, age=13 years+/-1.96) who resided with their biological parents performed the change task (Nelson, Vinton et al., 2007)--a variant of the stop task--during fMRI. Behaviourally, ES adolescents took longer to switch from a prepotent response ("go") to an alternative response ("change") than control adolescents. During correct "change" responses vs. correct "go" responses, this behavioural group difference was accompanied by higher activation in ES subjects than controls. These differences were noted in regions involved in primary sensorimotor processes (pre- and postcentral gyri), conflict monitoring (dorsal anterior cingulate gyrus), inhibitory and response control (inferior prefrontal cortex and striatum), and somatic representations (posterior insula). Furthermore, correct "change" responses vs. incorrect "change" responses recruited the inferior prefrontal cortex (BA 44/46) more strongly in ES subjects than controls. These data suggest impaired cognitive control in youth who experienced ES.

A preliminary study of medial temporal lobe function in youths with a history of caregiver deprivation and emotional neglect.

Previous research findings have linked caregiver deprivation and emotional neglect with sensitivity to threatening cues. The present preliminary study investigated whether dysfunctions of the medial temporal lobe could underlie these associations. Using fMRI, we measured medial temporal lobe responses to emotional faces (angry, fearful, happy, neutral) among 30 youths. Eleven of the youths had a history of caregiver deprivation and emotional neglect. Attention states (i.e., attention to anger, fear, or physical attributes, or passive viewing) were systematically manipulated. Relative to comparison youths, youths with a history of caregiver deprivation and emotional neglect showed significantly greater left amygdala and left anterior hippocampus activation during the processing of threatening information. To our knowledge, these findings are the first to demonstrate altered medial temporal lobe function during the processing of threat cues in youths with a history of caregiver deprivation and emotional neglect.

Effects of a Foster Parent Training Program on Young Children's Attachment Behaviors: Preliminary Evidence from a Randomized Clinical Trial.

Young children who enter foster care experience disruptions in care and maltreatment at a point when maintaining attachment relationships is a key, biologically based task. In previous research, we have found that young children experience challenges as they form attachments with new caregivers. They tend to push their new caregivers away, even though such children are especially in need of nurturing care. Further, many caregivers do not respond in nurturing ways when their children are distressed, which we have found is problematic for young children in foster care. We developed an intervention that is designed to help caregivers provide nurturance even when children do not elicit it, and even when it does not come naturally to them. This paper presents preliminary findings of the effectiveness of this intervention on children's attachment behaviors. Forty-six children were randomly assigned to either the experimental intervention or to an educational intervention. For three consecutive days, attachment behaviors were reported across three distress-eliciting situations. Children whose parents had received the experimental intervention showed significantly less avoidance than children whose parents had received the educational intervention. These preliminary results suggest that the intervention is successful in helping children develop trusting relationships with new caregivers.

Effects of an attachment-based intervention on the cortisol production of infants and toddlers in foster care.

Studies with nonhuman primates and rodents, as well as with human children, have suggested that early separations from caregivers are often associated with changes in the functioning of the hypothalamus-pituitary-adrenal (HPA) axis. On the basis of these findings, we designed a relational intervention that was intended to normalize HPA functioning among children in foster care. This paper presents findings from a randomized clinical trial that assessed the effectiveness of a relational intervention (Attachment and Biobehavioral Catch-up [ABC]) with regard to HPA functioning. The ABC intervention was intended to enhance children's ability to regulate physiology and behavior. The control intervention (Developmental Education for Families) was intended to enhance children's cognitive skills. A comparison group of children who had never been in foster care was also included. Children's cortisol production was assessed upon arrival at the lab, and 15 and 30 min following the Strange Situation. Random effects analyses of variance were performed to assess differences in initial values and change between children in the two intervention groups. Children in the ABC intervention and comparison group children showed lower initial values of cortisol than children in the treatment control group, considering arrival at lab as initial values (p < .05). Groups did not differ significantly in change over time. These results suggest that the ABC intervention is effective in helping children regulate biology in ways more characteristic of children who have not experienced early adversity.

A warmer ambient temperature increases the passage of interleukin-1beta into the brains of old rats.

We have demonstrated that after intraperitoneal lipopolysaccharide (LPS) injection, old rats mount fevers similar to those of young rats at an ambient temperature (Ta) of 31 degrees C, but not at 21 degrees C. The same is true for intraperitoneal or intravenous IL-1beta administration. The underlying mechanism responsible for blunted fever in old rats may be a deficiency in communication between the periphery and the brain. Possibly, peripheral cytokine actions are altered in old rats, such that the signal that reaches the brain is diminished. Here, we hypothesized that at standard laboratory temperatures, not enough IL-1beta is reaching the brain for fever to occur and that a warmer Ta would increase the influx of IL-1beta into the brain, enabling old rats to generate fever. Young (3-5 mo) and old (23-29 mo) Long-Evans rats were maintained for 3 days at either Ta 21 or 31 degrees C prior to intravenous injection with radiolabeled IL-1beta to measure passage across the blood-brain barrier. Young rats showed similar influx of IL-1beta into the brain at the two Tas, but old rats showed significant influx only at the warmer Ta. These data suggest that the lack of fever at a cool Ta may be due to a reduced influx of IL-1beta into the brain.

Discrimination learning and reversal of the conditioned eyeblink reflex in a rodent model of autism.

Offspring of rats exposed to valproic acid (VPA) on gestational day (GD) 12 have been advocated as a rodent model of autism because they show neuron loss in brainstem nuclei and the cerebellum resembling that seen in human autistic cases . Studies of autistic children have reported alterations in acquisition of classical eyeblink conditioning and in reversal of instrumental discrimination learning . Acquisition of discriminative eyeblink conditioning depends on known brainstem-cerebellar circuitry whereas reversal depends on interactions of this circuitry with the hippocampus and prefrontal cortex. In order to explore behavioral parallels of the VPA rodent model with human autism, the present study exposed pregnant Long-Evans rats to 600 mg/kg VPA on GD12 and tested their offspring from Postnatal Day (PND26-31) on discriminative eyeblink conditioning and reversal. VPA rats showed faster eyeblink conditioning, consistent with studies in autistic children . This suggests that previously reported parallels between human autism and the VPA rodent model with respect to injury to brainstem-cerebellar circuitry are accompanied by behavioral parallels when a conditioning task engaging this circuitry is used. VPA rats also showed impaired reversal learning, but this likely reflected "carry-over" of enhanced conditioning during acquisition rather than a reversal learning deficit like that seen in human autism. Further studies of eyeblink conditioning in human autism and in various animal models may help to identify the etiology of this developmental disorder.

Influence of ambient temperature on peripherally induced interleukin-1 beta fever in young and old rats.

We have previously demonstrated that old and young rats mount similar fevers after intraperitoneal (i.p.) LPS injection at a warm ambient temperature (Ta) of 31 degrees C, but not at a cooler Ta of 21 degrees C. LPS stimulates the synthesis and release of proinflammatory cytokines, particularly interleukin-1 beta (IL-1 beta), necessary for fever development, and possibly this is attenuated at the lower Ta. If so, then administration of exogenous IL-1 beta should enable old rats to mount fevers equivalent to those of young rats regardless of Ta. Here, young (3-5 months) and old (23-29 months) Long-Evans rats were maintained at Ta 21 or 31 degrees C for 3 days prior to i.p. or intravenous (i.v.) injection of rat recombinant IL-1 beta (1 microg/kg) or vehicle. Three days later, rats were given the alternate injection at the same T(a). At least 5 days later, the same rats were injected at the other Ta. Body temperature was continuously monitored throughout the experiments. Young rats mounted fevers after LPS at both Ta's and i.p. fevers were lower than i.v. fevers. Old rats developed fevers that were equivalent to those of young rats at 31 degrees C regardless of route of administration, but no fever responses were evident at 21 degrees C. These data suggest that the attenuated fever of old rats is not due to an inability to produce IL-1 beta, but rather to a deficiency further along in the fever pathway. In addition, these results show that, as with LPS, Ta plays a role in the ability of old rats to mount fever in response to IL-1 beta.

Foster children's diurnal production of cortisol: an exploratory study.

Young children in foster care have often experienced inadequate early care and separations from caregivers. Preclinical studies suggest that early inadequate care and separations are associated with long-term changes in regulation of the hypothalamic-pituitary-adrenal (HPA) axis. In this study, the daytime pattern of cortisol production was examined among 55 young children who had been placed into foster care and 104 children who had not. Saliva samples were taken at wake-up, in the afternoon, and bedtime for 2 days. Average salivary cortisol values for each time of day were computed. A group (foster vs. comparison) time (morning, afternoon, night) interaction emerged, reflecting less decline in levels across the day for foster than comparison children. Daytime patterns were categorized as typical, low, or high. Children who had been in foster care had higher incidences of atypical patterns of cortisol production than children who had not. These differences suggest that conditions associated with foster care interfere with children's ability to regulate neuroendocrine functioning.

Effect of flavored beverage crystals on salivary cortisol enzyme-immunoreactive assay measurements.

We examined the effects of using flavored drink crystals as a salivary stimulant on salivary cortisol values. The effects of both amount and method of flavored crystal administration on cortisol values were evaluated using a high sensitivity enzyme immunoassay (EIA) kit to measure cortisol. Repeated saliva sampling, one sample without the drink crystal stimulant, followed immediately by a second sample using the drink crystal stimulant, allowed direct analysis of the effect of the stimulant on cortisol values. Repeated sampling, with the stimulant used when obtaining both the first and second samples, allowed analysis of the repeatability of cortisol measurements using the drink crystals. The results suggest that the use of drink mix crystals as an oral stimulant causes a small increase in measured cortisol values, as well as an increase in the variability of these values. The results also suggest that the effect of drink crystals is sufficiently regular so that it will not distort either within or between subject comparisons as long as there is consistency in use or non-use of the stimulant.

Thermoregulatory and metabolic changes during fever in young and old rats.

We injected old and young rats with lipopolysaccharide (LPS; 50 microg/kg ip) at two ambient temperatures (Ta; 21 and 31 degrees C). Young rats mounted equivalent fevers at both Tas [peak body temperatures (Tb) of 38.3 and 38.7 degrees C, respectively]. The Tb of old rats was not different from baseline (37.3 degrees C) after LPS at Ta 21 degrees C, whereas, at 31 degrees C, their Tb rose to a mean peak of 38.4 degrees C. We also measured the associated thermoregulatory responses by use of calorimetry. At 21 degrees C, young rats developed a fever by increasing both O2 consumption and heat conservation. Old rats did not become febrile, and O2 consumption fell by 15%. Heat loss was the same in old and young rats. At 31 degrees C, young and old rats developed similar fevers with similar increases in heat production and conservation. Our results suggest that the lack of LPS fever in old rats at 21 degrees C is due mainly to the lowered metabolic rate.

Stress-induced hyperthermia depends on both time of day and light condition.

Rats placed in an environment other than their home cage increase their body temperature (Tb) by more than 1 degree C. This stress-induced hyperthermia is considered to be a fever, in the sense that the Tb rise seems to reflect an upward shift in the level of regulated Tb (set point). The circadian rhythm of Tb also reflects changes in set point. One might therefore expect to see differences in response to such stress during various phases of the light-dark (LD) cycle as Tb fluctuates between L and D. To test this, 3- to 6-month-old male Long-Evans rats were taken from their home cages (12:12 LD) and placed individually in a Plexiglas container for 30 min. Tb and activity were measured via telemetry. In the first experiment, rats were placed in the container during day (from 1 to 3 h after lights on) and night (from 1 to 3 h after lights off), with light on or off during the test. There was a significant Tb rise in response to placement in the container at all times except when the rats were tested during the night with light on in the container; in that condition there was no Tb rise. In the second experiment, the authors determined that 30 min of light in the home cage before the test did not affect Tb: If the light was on in the test situation, hyperthermia was inhibited, and if it was off, hyperthermia was as high as control levels. In the third experiment, to determine whether this effect was time dependent, the test was performed at 4-h intervals, with light on or off during the test. The strongest inhibiting effect of light was in early night. In the fourth experiment, the authors turned the lights on during early night while the rats were in their home cages. This reduced their Tb significantly by less than 0.3 degrees C. The authors conclude that both clock time and light condition during testing are factors affecting the Tb rise in response to stress.