Neural correlates involved in perspective-taking in early childhood.

Learning to consider another person's perspective is pivotal in early social development. Still, little is known about the neural underpinnings involved in perspective-taking in early childhood. In this EEG study, we examined 4-year-old children's brain activity during a live, social interaction that involved perspective-taking. Children were asked to pass one of two toys to another person. To decide which toy to pass, they had to consider either their partner's perspective (perspective-taking) or visual features unrelated to their partner's perspective (control). We analyzed power changes in midfrontal and temporal-parietal EEG channels. The results indicated that children showed higher power around 7 Hz at right temporal-parietal channels for perspective-taking compared to control trials. This power difference was positively correlated with children's perspective-taking performance, specifically for trials in which they needed to pass the toy their partner could not see. A similar power difference at right temporal-parietal channels was seen when comparing perspective-taking trials where children's visual access mismatched rather than matched that of their partner. No differences were detected for midfrontal channels. In sum, we identified distinct neural activity as 4-year-olds considered another person's perspective in a live interaction; this activity converges with neural findings of adults' social processing network.

An obligate role for T-cell receptor alphabeta+ T cells but not T-cell receptor gammadelta+ T cells, B cells, or CD40/CD40L interactions in a mouse model of atopic dermatitis.

BACKGROUND: We recently described a murine model of atopic dermatitis (AD) elicited by epicutaneous sensitization with ovalbumin (OVA). The skin lesions in these mice were characterized by a dermal infiltrate consisting of eosinophils and T cells and by increased expression of the TH2 cytokines IL-4 and IL-5. Epicutaneous sensitization induces a rise in the levels of serum total IgE and OVA-specific antibodies, further indicating that it elicits a predominantly TH2 response. OBJECTIVE: This study was undertaken to assess the roles of T cells, B cells, and CD40L-CD40 interactions in AD. METHODS: Mice with targeted gene deletions were sensitized with OVA. Histologic and immunohistochemical examinations, as well as measurements of IL-4 mRNA, were performed on OVA-sensitized skin. Total and antigen-specific serum IgE levels were determined. RESULTS: RAG2(-/-) mice, which lack both T and B cells, did not exhibit cellular infiltration, induction of dermal IL-4 mRNA, or elevation of serum IgE after OVA sensitization; all of these features were present in B-cell-deficient IgH(-/-) mice. T-cell receptor alpha(-/-) mice did not display cellular infiltration, IL-4 mRNA expression, or increased IgE levels after OVA sensitization, but these responses were elicited in T-cell receptor delta(-/-) mice after sensitization. Absence of CD40 had no effect on these responses. CONCLUSION: These results suggest that alphabeta T cells, but not gammadelta T cells, B cells, or CD40L-CD40 interactions, are critical for skin inflammation and the TH2 response in AD.

Twelve-month-old infants interpret action in context.

Two experiments assessed infants' understanding that actions that occur in sequence may be related to an overarching goal. Experiment 1 tested whether embedding an ambiguous action (touching the lid of a box) in a sequence that culminated with an action infants readily construe as goal-directed (grasping a toy inside the box) would alter infants' construal of the ambiguous action. Having seen the ambiguous action in this context, infants later construed this action in isolation as being directed at the toy within the box. Experiment 2 tested whether infants related the two actions on the basis of the temporal or the causal relation between them. When the causal relation was disrupted but the temporal relation was preserved, infants no longer related the two actions. These findings indicate that 12-month-old infants relate single actions to overarching goals and that they do so by construing goal-directed action in a causal framework.

Infants' learning about words and sounds in relation to objects.

In acquiring language, babies learn not only that people can communicate about objects and events, but also that they typically use a particular kind of act as the communicative signal. The current studies asked whether 1-year-olds' learning of names during joint attention is guided by the expectation that names will be in the form of spoken words. In the first study, 13-month-olds were introduced to either a novel word or a novel sound-producing action (using a small noisemaker). Both the word and the sound were produced by a researcher as she showed the baby a new toy during a joint attention episode. The baby's memory for the link between the word or sound and the object was tested in a multiple choice procedure. Thirteen-month-olds learned both the word-object and sound-object correspondences, as evidenced by their choosing the target reliably in response to hearing the word or sound on test trials, but not on control trials when no word or sound was present. In the second study, 13-month-olds, but not 20-month-olds, learned a new sound-object correspondence. These results indicate that infants initially accept a broad range of signals in communicative contexts and narrow the range with development.

Infants selectively encode the goal object of an actor's reach.

Research with young children has shown that, like adults, they focus selectively on the aspects of an actor's behavior that are relevant to his or her underlying intentions. The current studies used the visual habituation paradigm to ask whether infants would similarly attend to those aspects of an action that are related to the actor's goals. Infants saw an actor reach for and grasp one of two toys sitting side by side on a curtained stage. After habituation, the positions of the toys were switched and babies saw test events in which there was a change in either the path of motion taken by the actor's arm or the object that was grasped by the actor. In the first study, 9-month-old infants looked longer when the actor grasped a new toy than when she moved through a new path. Nine-month-olds who saw an inanimate object of approximately the same dimensions as the actor's arm touch the toy did not show this pattern in test. In the second study, 5-month-old infants showed similar, though weaker, patterns. A third study provided evidence that the findings for the events involving a person were not due to perceptual changes in the objects caused by occlusion by the hand. A fourth study replicated the 9 month results for a human grasp at 6 months, and revealed that these effects did not emerge when infants saw an inanimate object with digits that moved to grasp the toy. Taken together, these findings indicate that young infants distinguish in their reasoning about human action and object motion, and that by 6 months infants encode the actions of other people in ways that are consistent with more mature understandings of goal-directed action.

Distinct 15q genotypes in Russell-Silver and ring 15 syndromes.

Individuals with a ring 15 chromosome [r(15)] and those with Russell-Silver syndrome have short stature, developmental delay, triangular face, and clinodactyly. To assess whether the apparent phenotypic overlap of these conditions reflects a common genetic cause, the extent of deletions in chromosome 15q was determined in 5 patients with r(15), 1 patient with del 15q26.1-qter, and 5 patients with Russell-Silver syndrome. All patients with Russell-Silver syndrome were diploid for genetic markers in distal 15q, indicating that Russell-Silver syndrome in these individuals was unlikely to be related to the expression of single alleles at these or linked genetic loci. At least 3 distinct sites of chromosome breakage close to the telomere were found in the r(15) and del 15q25.1-qter patients, with 1 r(15) patient having both a terminal and an interstitial deletion. Although the patient with del 15q25.1-qter exhibited the largest deletion and the most profound growth retardation, the degree of growth impairment among the r(15) patients was not correlated with the size of the deleted interval. Rather, the parental origin of the ring chromosome in several patients was associated with phenotypes that are also seen in patients with either Prader-Willi (PWS) or Angelman (AS) syndromes, conditions that result from uniparental expression of genes on chromosome 15. In fact, unequal representation of chromosome 15 alleles in 1 patient with r(15) suggests the possibility that a mosaic karyotype composed of the constitutional cell line and cell line(s) possibly deficient in the ring chromosome might be present. The PWS-like or AS-like phenotypes could be explained by postzygotic loss of the ring chromosome, leading to uniparental inheritance of the intact chromosome in some tissues of r(15) patients.

Infants' sensitivity to word boundaries in fluent speech.

Infants' sensitivity to word units in fluent speech was examined by inserting I sec pauses either at boundaries between successive words (Coincident versions) or between syllables within words (Noncoincident versions). In Experiment 1, 24 11-month-olds listened significantly longer to the Coincident versions. In Experiment 2, 24 four-and-a-half- and 24 nine-month-olds did not exhibit the preference for the Coincident versions that the 11-month-olds showed. When the stimuli were low-pass filtered in Experiment 3, 24 11-month-olds showed no preference for the Coincident versions, suggesting they rely on more than prosodic cues. New stimulus materials in Experiment 4 indicated that responses by 24 11-month-olds to the Coincident and Noncoindent versions did not depend solely on prior familiarity with the targets. Two groups of 30 11-month-olds tested in Experiment 5 were as sensitive to groups of 30 11-month-olds tested in Experiment 5 were as sensitive to boundaries for Strong/Weak words as for Weak/Strong words. Taken together, the results suggest that, by 11 months, infants are sensitive to word boundaries in fluent speech, and that this sensitivity depends on more than just prosodic information or prior knowledge of the words.