Autonomic Cardiac Rhythm Regulation and Temperament in Infancy

The specific features of the cardiac rhythm (CR) and temperament were studied in 92 children aged from 15 to 31 months. The average cardiac interval in a recumbent position and its variability (standard deviation) were determined. The parasympathetic tone (PT) was determined by analyzing the CR wave structure according to CR spectrum power within the range of 0.2 to 1.2 Hz. The sympathetic tone was measured by subtracting the PT contribution from the spectrum power within the range of 0 to 0.2 Hz by means of regression. The children's temperament was measured using their parents' questionnaires. Repeated examination showed the stability of the CR characteristics. The PT was shown to correlate with the children's motor activity (0.52), approaching a new subject (0.39), distraction (–0.34), and the age of entering a nursery (–0.35). The results evidenced a relationship between the parasympathetic tone and the behavioral activity during the first years of life and the role of the parasympathetic tone in physiological regulation of approach/avoidance responses and sustained attention.     

Eye-Catching Odors: Olfaction Elicits Sustained Gazing to Faces and Eyes in 4-Month-Old Infants

This study investigated whether an odor can affect infants'' attention to visually presented objects and whether it can selectively direct visual gaze at visual targets as a function of their meaning. Four-month-old infants (n = 48) were exposed to their mother''s body odors while their visual exploration was recorded with an eye-movement tracking system. Two groups of infants, who were assigned to either an odor condition or a control condition, looked at a scene composed of still pictures of faces and cars. As expected, infants looked longer at the faces than at the cars but this spontaneous preference for faces was significantly enhanced in presence of the odor. As expected also, when looking at the face, the infants looked longer at the eyes than at any other facial regions, but, again, they looked at the eyes significantly longer in the presence of the odor. Thus, 4-month-old infants are sensitive to the contextual effects of odors while looking at faces. This suggests that early social attention to faces is mediated by visual as well as non-visual cues.     

The Influence of Shyness on the Scanning of Own- and Other-Race Faces in Adults

The current study explored the relationship between shyness and face scanning patterns for own- and other-race faces in adults. Participants completed a shyness inventory and a face recognition task in which their eye movements were recorded by a Tobii 1750 eye tracker. We found that: (1) Participants’ shyness scores were negatively correlated with the fixation proportion on the eyes, regardless of the race of face they viewed. The shyer the participants were, the less time they spent fixating on the eye region; (2) High shyness participants tended to fixate significantly more than low shyness participants on the regions just below the eyes as if to avoid direct eye contact; (3) When participants were recognizing own-race faces, their shyness scores were positively correlated with the normalized criterion. The shyer they were, the more apt they were to judge the faces as novel, regardless of whether they were target or foil faces. The present results support an avoidance hypothesis of shyness, suggesting that shy individuals tend to avoid directly fixating on others’ eyes, regardless of face race.     

Trajectories of Sensory Over-Responsivity from Early to Middle Childhood: Birth and Temperament Risk Factors

Sensory over-responsivity, a subtype of sensory modulation disorder, is characterized by extreme negative reactions to normative sensory experiences. These over-reactions can interfere with daily activities and cause stress to children and their families. The etiology and developmental course of sensory over-responsivity is still largely unknown. We measured tactile and auditory over-responsivity in a population-based, typically developing sample of twins (N=978) at age two years via a caregiver report temperament questionnaire and again at age seven years via a sensory over-responsivity symptom inventory. Participating twins were treated as singletons although all analyses controlled for clustering within families. Children were divided into four trajectory groups based on risk status at both ages: low symptom (N=768), remitted (N=75), late-onset (N=112), and chronic (N=24). A subset of children who screened positive for SOR in toddlerhood (N = 102) took part in a pilot study focused on sensory over-responsivity at four years of age. Children in the chronic group had more severe symptoms of sensory sensitivity at age four years, including more motion sensitivity, than the other trajectory groups. Children in the chronic group had a younger gestational age and were more likely to be low birth-weight than the low symptom group. Differences between remitted and late-onset groups and the low-symptoms group were inconsistent across measures. Sensory over-responsivity was modestly correlated across ages (r = .22 for tactile over-responsivity and r = .11 for auditory over-responsivity), but symptoms were more stable among children born prematurely or who had more fearful and less soothable temperaments. A clear implication is that assessment over development may be necessary for a valid sensory processing disorder diagnosis, and a speculative implication is that sensory over-responsivity symptoms may be etiologically heterogeneous, with different causes of transient and stable symptoms.     

Developmental Trajectories of Amygdala and Hippocampus from Infancy to Early Adulthood in Healthy Individuals

Knowledge of amygdalar and hippocampal development as they pertain to sex differences and laterality would help to understand not only brain development but also the relationship between brain volume and brain functions. However, few studies investigated development of these two regions, especially during infancy. The purpose of this study was to examine typical volumetric trajectories of amygdala and hippocampus from infancy to early adulthood by predicting sexual dimorphism and laterality. We performed a cross-sectional morphometric MRI study of amygdalar and hippocampal growth from 1 month to 25 years old, using 109 healthy individuals. The findings indicated significant non-linear age-related volume changes, especially during the first few years of life, in both the amygdala and hippocampus regardless of sex. The peak ages of amygdalar and hippocampal volumes came at the timing of preadolescence (9–11 years old). The female amygdala reached its peak age about one year and a half earlier than the male amygdala did. In addition, its rate of growth change decreased earlier in the females. Furthermore, both females and males displayed rightward laterality in the hippocampus, but only the males in the amygdala. The robust growth of the amygdala and hippocampus during infancy highlight the importance of this period for neural and functional development. The sex differences and laterality during development of these two regions suggest that sex-related factors such as sex hormones and functional laterality might affect brain development.     

I Can't Take My Eyes Off of You: Attentional Allocation to Infant,Child, Adolescent and Adult Faces in Mothers and Non-Mothers

It has been reported previously that infant faces elicit enhanced attentional allocation compared to adult faces in adult women, particularly when these faces are emotional and when the participants are mothers, as compared to non-mothers [1]. However, it remains unclear whether this increased salience of infant faces as compared to adult faces extends to children older than infant age, or whether infant faces have a unique capacity to elicit preferential attentional allocation compared to juvenile or adult faces. Therefore, this study investigated attentional allocation to a variety of different aged faces (infants, pre-adolescent children, adolescents, and adults) in 84 adult women, 39 of whom were mothers. Consistent with previous findings, infant faces were found to elicit greater attentional engagement compared to pre-adolescent, adolescent, or adult faces, particularly when the infants displayed distress; again, this effect was more pronounced in mothers compared to non-mothers. Pre-adolescent child faces were also found to elicit greater attentional engagement compared to adolescent and adult faces, but only when they displayed distress. No preferential attentional allocation was observed for adolescent compared to adult faces. These findings indicate that cues potentially signalling vulnerability, specifically age and sad affect, interact to engage attention. They point to a potentially important mechanism, which helps facilitate caregiving behaviour.     

Pituitary Stalk Interruption Syndrome from Infancy to Adulthood: Clinical,Hormonal, and Radiological Assessment According to the Initial Presentation

Background

Patients with pituitary stalk interruption syndrome (PSIS) are initially referred for hypoglycemia during the neonatal period or growth retardation during childhood. PSIS is either isolated (nonsyndromic) or associated with extra-pituitary malformations (syndromic).

Objective

To compare baseline characteristics and long-term evolution in patients with PSIS according to the initial presentation.

Study Design

Sixty-seven patients with PSIS were included. Data from subgroups were compared: neonates (n = 10) versus growth retardation patients (n = 47), and syndromic (n = 32) versus nonsyndromic patients (n = 35).

Results

Neonates displayed a more severe hormonal and radiological phenotype than children referred for growth retardation, with a higher incidence of multiple hormonal deficiencies (100% versus 34%; P = 0.0005) and a nonvisible anterior pituitary lobe (33% versus 2%; P = 0.0017). Regular follow-up of growth might have allowed earlier diagnosis in the children with growth retardation, as decreased growth velocity and growth retardation were present respectively 3 and 2 years before referral. We documented a progressive worsening of endocrine impairment throughout childhood in these patients. Presence of extra-pituitary malformations (found in 48%) was not associated with more severe hormonal and radiological characteristics. Growth under GH treatment was similar in the patient groups and did not vary according to the pituitary MRI findings.

Conclusions

PSIS diagnosed in the neonatal period has a particularly severe hormonal and radiological phenotype. The progressive worsening of endocrine impairment throughout childhood justifies periodic follow-up to check for additional hormonal deficiencies.     

Selective Leptin Insensitivity and Alterations in Female-Reproductive Patterns Linked to Hyperleptinemia during Infancy

The dramatic increase in the prevalence of childhood obesity worldwide makes the investigation of its early developmental stages and effective prevention strategies an urgent issue. CCK₁ deficient OLETF rats are a model of obesity previously used to study the early phases of this disorder. Here, we exposed wild type (LETO) females to an early obesogenic environment and genetically obese OLETF females to a lean postnatal environment, to assess long term alterations in leptin sensitivity, predisposition to diet induced obesity and adult female health. We found that genetically lean females reared by obese mothers presented early postnatal hyperleptemia, selectively reduced response to leptin and sensitivity to diet induced obesity when exposed to a high palatable diet as adults. The estrous cycle structure and intake profile were permanently disrupted, despite presenting normal adiposity/body weight/food intake. Genetically obese females reared by lean dams showed normalized early levels of leptin and reduced body weight, food intake and body fat at adulthood; normalized estrous cycle structure and food intake across the cycle, improved hormonal profile and peripheral leptin sensitivity and a remarkable progress in self-control when exposed to a high fat/palatable diet. Altogether, it appears that the early postnatal environment plays a critical role in determining later life coping with metabolic challenges and has an additive effect on the genetic predisposition that makes OLETF females morbidly obese as adults. This work also links, for the first time, alterations in the leptin system during early development to later life abnormalities related to female reproduction and health.     

Developmental Changes in the Corpus Callosum from Infancy to Early Adulthood: A Structural Magnetic Resonance Imaging Study

Previous research has reported on the development trajectory of the corpus callosum morphology. However, there have been only a few studies that have included data on infants. The goal of the present study was to examine the morphology of the corpus callosum in healthy participants of both sexes, from infancy to early adulthood. We sought to characterize normal development of the corpus callosum and possible sex differences in development. We performed a morphometric magnetic resonance imaging (MRI) study of 114 healthy individuals, aged 1 month to 25 years old, measuring the size of the corpus callosum. The corpus callosum was segmented into seven subareas of the rostrum, genu, rostral body, anterior midbody, posterior midbody, isthmus and splenium. Locally weighted regression analysis (LOESS) indicated significant non-linear age-related changes regardless of sex, particularly during the first few years of life. After this increase, curve slopes gradually became flat during adolescence and adulthood in both sexes. Age of local maximum for each subarea of the corpus callosum differed across the sexes. Ratios of total corpus callosum and genu, posterior midbody, as well as splenium to the whole brain were significantly higher in females compared with males. The present results demonstrate that the developmental trajectory of the corpus callosum during early life in healthy individuals is non-linear and dynamic. This pattern resembles that found for the cerebral cortex, further suggesting that this period plays a very important role in neural and functional development. In addition, developmental trajectories and changes in growth do show some sex differences.     

Our Faces in the Dog's Brain: Functional Imaging Reveals Temporal Cortex Activation during Perception of Human Faces

Dogs have a rich social relationship with humans. One fundamental aspect of it is how dogs pay close attention to human faces in order to guide their behavior, for example, by recognizing their owner and his/her emotional state using visual cues. It is well known that humans have specific brain regions for the processing of other human faces, yet it is unclear how dogs’ brains process human faces. For this reason, our study focuses on describing the brain correlates of perception of human faces in dogs using functional magnetic resonance imaging (fMRI). We trained seven domestic dogs to remain awake, still and unrestrained inside an MRI scanner. We used a visual stimulation paradigm with block design to compare activity elicited by human faces against everyday objects. Brain activity related to the perception of faces changed significantly in several brain regions, but mainly in the bilateral temporal cortex. The opposite contrast (i.e., everyday objects against human faces) showed no significant brain activity change. The temporal cortex is part of the ventral visual pathway, and our results are consistent with reports in other species like primates and sheep, that suggest a high degree of evolutionary conservation of this pathway for face processing. This study introduces the temporal cortex as candidate to process human faces, a pillar of social cognition in dogs.     

Early Life Experiences Affect Adult Delayed-Type Hypersensitivity in Short and Long Photoperiods

Environmental experiences during development provide animals with important information about future conditions. Siberian hamsters are photoperiodic rodents that dramatically adjust their physiology and behavior to adapt to seasonal changes. For example, during short winter-like days, hamsters enhance some components of immune function putatively to cope with increasing environmental challenges. Furthermore, early life stress alters the developmental course of the immune system. Overall, immune function is typically suppressed in response to chronic stress, but responses vary depending on the type of stress and components of immune function assessed. This led us to hypothesize that delayed-type hypersensitivity (DTH), an antigen-specific, cell-mediated immune response, would be differentially modulated in hamsters that underwent early life maternal separation (MS) in either short or long photoperiods. At birth, hamsters were assigned to either short (SD; 8?h light/day) or long (LD; 16?h light/day) photoperiods and either daily 3?h MS, daily 15-min brief maternal separation (BMS), or no manipulation from postnatal day 2 through 14. In adulthood DTH was assessed. Hamsters reared in short days enhanced DTH responses. MS and BMS attenuated DTH responses in both short and long days. However, BMS long-day female hamsters did not suppress pinna swelling, suggesting a protective effect of female sex steroids on immune function. As is typical in short days, reproductive tissue was regressed. Reproductive tissue mass was also decreased in long-day MS female hamsters. Furthermore, MS altered photoperiod-induced changes in body mass. Taken together, these findings suggest that manipulations of early life mother-pup interactions in Siberian hamsters result in physiological changes and suppressed cell-mediated immunity. (Author correspondence: fonken.1@osu.edu).     

Optic Disc Change during Childhood Myopic Shift: Comparison between Eyes with an Enlarged Cup-To-Disc Ratio and Childhood Glaucoma Compared to Normal Myopic Eyes

BackgroundProgressive disc tilting and the development or enlargement of peripapillary atrophy (PPA) are observed during a myopic shift in children. This could be related to the changes around the optic nerve head during eyeball elongation. If the biomechanical properties at or around the optic nerve head are changed after exposure to elevated intraocular pressure (IOP) in glaucoma eyes, different response of the disc tilting and PPA changes could take place during eyeball elongation by myopic shift. On the basis of this background, the aim of this study was to compare the morphological changes in the optic disc induced by a myopic shift during childhood between normal control eyes, eyes from disc suspects with an enlarged cup-to-disc ratio (CDR), and eyes with childhood glaucoma.MethodsTotal of 82 eyes from 82 subjects younger than 14 years of age were included in the study. Serial disc photographs were classified into one of two groups: eyes with an optic nerve head (ONH) or peripapillary atrophy (PPA) change or without an ONH/PPA change. Using ImageJ software, the outlines of the optic disc and PPA were plotted, and the vertical disc diameter (VDD), horizontal disc diameter (HDD), and maximum PPA width (PPW) were measured. The changes in the ratios of these parameters and the relationships between the degree of myopic shift or the ONH/PPA change were analyzed.ResultsTwenty-five eyes with normal optic disc appearance, 36 eyes with enlarged cup-to-disc ratio, and 21 eyes of glaucoma patients were analyzed. The initial intraocular pressure (IOP) at diagnosis was significantly different among the groups (P<0.001). The degree of myopic shift during follow-up period was not significantly different among the groups (P=0.612). However, the changes in the HDD/VDD and PPW/VDD ratios were significantly greater in the disc suspect group and significantly smaller in the glaucoma group. Among the 42 eyes with an ONH/PPA change, 16 (38.1%) were from the normal control group, 24 (57.1%) were from the disc suspect group, and 2 (4.8%) were from the glaucoma group (P < 0.001).

Conclusions and Relevance

The optic disc change during childhood myopic shift was different in eyes with various conditions. Eyes of childhood glaucoma showed less change in the disc morphology during myopic shift compared to eyes with normal disc or enlarged cup-to-disc ratio.