Search

Infants' pointing is associated with concurrent and later language development. The communicative intention behind the point-i.e., imperative versus declarative-can affect both the nature and strength of these associations, and is therefore a critical factor to consider. Parents' pointing is associated with both infant pointing and infant language; however, less work has examined the intent behind parents' points. We explore relations between parents' and infants' pointing at the level of communicative intention, and examine how pointing relates to concurrent and longitudinal infant language skills. In a sample of 52 mother-infant dyads, we measured mother and infant pointing at infant age 12-months, and infant expressive and receptive language at 12-, 18-, and 24-months. We found that mothers produced points with a variety of intentions, however we did not find relations between mother and infant pointing within the different communicative intentions. Replicating previous research, infant declarative pointing was related both concurrently and longitudinally to their language ability. Mothers' declarative pointing was related to their infants' concurrent language, while their imperative pointing was not. Further, there was an interaction between parent and infant declarative pointing, such that the positive relation between parents' declarative pointing and their infants' concurrent receptive language was present only for those infants who were also producing declarative points themselves. Findings suggest that parents' declarative pointing may support both their infants' early word learning and, perhaps, provides a model for their infant to begin using points as well. This study constitutes an important initial exploration of these relations.

Limited options exist to evaluate the development of hippocampal function in young children. Research has established that trace eyeblink conditioning (EBC) relies on a functional hippocampus. Hence, we set out to investigate whether trace EBC is linked to hippocampal structure, potentially serving as a valuable indicator of hippocampal development. Our study explored potential associations between individual differences in hippocampal volume and neurite density with trace EBC performance in young children. We used onset latency of conditioned responses(CR) and percentage of conditioned responses (% CR) as measures of hippocampal‐dependent associative learning. Using a sample of typically developing children aged 4 to 6 years (N = 30; 14 girls; M = 5.70 years), participants underwent T1‐ and diffusion‐weighted MRI scans and completed a 15‐min trace eyeblink conditioning task conducted outside the MRI. % CR and CRonset latency were calculated based on all trials involving tone‐puff presentations and tone‐alone trials. Findings revealed a connection between greater left hippocampal neurite density and delayed CR onset latency. Children with higher neurite density in the left hippocampus tended to blink closer to the onset of the unconditioned stimulus, indicating that structural variations in the hippocampus were associated with more precise timing of conditioned responses. No other relationships were observed between hippocampal volume, cerebellum volume or neurite density, hippocampal white matter connectivity and any EBC measures. Preliminary results suggest that trace EBC may serve as a straightforward yet innovative approach for studying hippocampal development in young children and populations with atypical development. [ABSTRACT FROM AUTHOR]

Quantifying surface–atmosphere exchange rates of particles is important for understanding the role of suspended particulate matter in radiative transfer, clouds, precipitation, and climate change. Emissions of coarse-mode particles with a diameter greater than 0.5 µm provide giant cloud condensation nuclei and ice nuclei. These emissions are critical for understanding the evolution of cloud microphysical properties yet remain poorly understood. Here we introduce a new method that uses lidar retrievals of the elastic backscatter and Doppler velocity to obtain surface number emissions of particles with a diameter greater than 0.53 µm. The technique is applied to study particle number fluxes over a 2-month period from 1 June to 10 August 2022 during the TRACER campaign at an urban site near Houston, TX, USA. We found that all the observed fluxes were positive (upwards), indicating particle emission from the surface. The fluxes followed a diurnal pattern and peaked near noon local time. Flux intensity varied through the 2 months with multi-day periods of strong fluxes and multi-day periods of weak fluxes. Emission particle number fluxes peaked near ∼ 100 cm -2 s -1. The daily averaged emission fluxes correlated with friction velocity and were anticorrelated with surface relative humidity. The emission flux can be parameterized as F= 3000 u*4 , where u* is the friction velocity in m s -1 and the emission flux F is in cm -2 s -1. The u* dependence is consistent with emission from wind-driven erosion. Estimated values for the mass flux are in the lower range of literature values from non-urban sites. These results demonstrate that urban environments may play an important role in supplying coarse-mode particles to the boundary layer. We anticipate that quantification of these emissions will help constrain aerosol–cloud interaction models that use prognostic aerosol schemes. [ABSTRACT FROM AUTHOR]

Eyeblink conditioning (EBC) is a classical conditioning paradigm typically used to study the underlying neural processes of learning and memory. EBC has a well-defined neural circuitry, is non-invasive, and can be employed in human infants shortly after birth making it an ideal tool to use in both developing and special populations. In addition, abnormalities in the cerebellum, a region of the brain highly involved in EBC, have been implicated in a number of neurodevelopmental disorders including autism spectrum disorders (ASDs). In the current paper, we review studies that have employed EBC as a biomarker for several neurodevelopmental disorders including fetal alcohol syndrome, Down syndrome, fragile X syndrome, attention deficit/hyperactivity disorder, dyslexia, specific language impairment, and schizophrenia. In addition, we discuss the benefits of using such a tool in individuals with ASD.

Although infants display preferences for social stimuli early in their lives, we know relatively little about the mechanisms of infant learning about the social world. In the current set of studies, 1-month-old infants underwent an adapted eyeblink conditioning paradigm to examine learning to both "social" and non-social cues. While infants were asleep, they were presented with either a "social" stimulus (a female voice) or one of two non-social stimuli (tone or backward voice) followed by an airpuff presented to the eyelid. Infants in the experimental groups displayed increased learning across trials, regardless of stimulus type. However, infants conditioned to the "social" stimulus showed increased learning compared to infants conditioned to either of the non-social stimuli. These results suggest a mechanism by which learning about the social world occurs early in life and the power of ecologically valid cues in facilitating that learning.

Behaviorally inhibited children display a temperamental profile characterized by social withdrawal and anxious behaviors. Previous research, focused largely on adolescents, suggests that attention biases to threat may sustain high levels of behavioral inhibition (BI) over time, helping link early temperament to social outcomes. However, no prior studies examine the association between attention bias and BI before adolescence. The current study examined the interrelations among BI, attention biases to threat, and social withdrawal already manifest in early childhood. Children (N = 187, 83 Male, M age = 61.96 months) were characterized for BI in toddlerhood (24 & 36 months). At 5 years, they completed an attention bias task and concurrent social withdrawal was measured. As expected, BI in toddlerhood predicted high levels of social withdrawal in early childhood. However, this relation was moderated by attention bias. The BI-withdrawal association was only evident for children who displayed an attention bias toward threat. The data provide further support for models associating attention with socioemotional development and the later emergence of clinical anxiety.

Background: Individual differences in specific components of attention contribute to behavioral reactivity and regulation. Children with the temperament of behavioral inhibition (BI) provide a good context for considering the manner in which certain components of attention shape behavior. Infants and children characterized as behaviorally inhibited manifest signs of heightened orienting to novelty. The current study considers whether this attention profile moderates risk for clinical anxiety disorders among adolescents with a history of BI. Methods: Participants were assessed at multiple time points for BI, beginning in early childhood. At adolescence, event-related potentials (ERPs) were recorded during a three-stimulus auditory novelty oddball task, which employed frequent standard and infrequent deviant tones as well as a set of complex, novel sounds. Clinical diagnosis was carried out using the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version (K-SADS-PL). P3 and mismatch negativity (MMN) components were examined at midline frontal, central, and parietal electrode sites. Results: Individuals who displayed high levels of BI during childhood and increased P3 amplitude to novelty in adolescence were more likely to have a history of anxiety disorders compared to behaviorally inhibited adolescents with lower P3 amplitudes. Groups did not differ on measures of MMN. Conclusions: Increased neural responses to novelty moderate risk for anxiety disorders amongst individuals with a history of BI.

Quantifying teleconnections and discovering new ones is a complex, difficult process. Using transfer functions, we introduce a new method of identifying teleconnections in climate models on arbitrary timescales. We validate this method by perturbing temperature in the Nino3.4 region in a climate model. Temperature and precipitation responses in the model match known El Nino-Southern Oscillation (ENSO)-like teleconnection features, consistent with modes of tropical variability. Perturbing the Nino3.4 region results in temperature responses consistent with the Pacific Meridional Mode, the Pacific Decadal Oscillation, and the Indian Ocean Dipole, all of which have strong ties to ENSO. Some precipitation features are also consistent with these modes of variability, although because precipitation is noisier than temperature, obtaining robust responses is more difficult. While much work remains to develop this method further, transfer functions show promise in quantifying teleconnections or, perhaps, identifying new ones. [ABSTRACT FROM AUTHOR]