Faculty Bibliography

Memory flexibility is a hallmark of the human memory system. As indexed by generalization between perceptually dissimilar objects, memory flexibility develops gradually during infancy. A recent study has found a bilingual advantage in memory generalization at 18 months of age [Brito and Barr [2012] Developmental Science, 15, 812-816], and the present study examines when this advantage may first emerge. In the current study, bilingual 6-month-olds were more likely than monolinguals to generalize to a puppet that differed in two features (shape and color) than monolingual 6-month-olds. When challenged with a less complex change, two puppets that differed only in one feature--color, monolingual 6-month-olds were also able to generalize. These findings demonstrate early emerging differences in memory generalization in bilingual infants, and have important implications for our understanding of how early environmental variations shape the trajectory of memory development.

OBJECTIVE: This study aims to examine trajectories of attention-deficit/hyperactivity disorder (ADHD) symptoms in the Longitudinal Assessment of Manic Symptoms (LAMS) sample. METHOD: The LAMS study assessed 684 children aged 6 to 12 years with the Kiddie-Schedule for Affective Disorders and Schizophrenia (K-SADS) and rating scales semi-annually for 3 years. Although they were selected for elevated manic symptoms, 526 children had baseline ADHD diagnoses. With growth mixture modeling (GMM), we separately analyzed inattentive and hyperactive/impulsive symptoms, covarying baseline age. Multiple standard methods determined optimal fit. The chi(2) and Kruskal-Wallis analysis of variance compared resulting latent classes/trajectories on clinical characteristics and medication. RESULTS: Three latent class trajectories best described inattentive symptoms, and 4 classes best described hyperactive/impulsive symptoms. Inattentive trajectories maintained their relative position over time. Hyperactive/impulsive symptoms had 2 consistent trajectories (least and most severe). A third trajectory (4.5%) started mild, then escalated; and a fourth (14%) started severe but improved dramatically. The improving trajectory was associated with the highest rate of ADHD and lowest rate of bipolar diagnoses. Three-fourths of the mildest inattention class were also in the mildest hyperactive/impulsive class; 72% of the severest inattentive class were in the severest hyperactive/impulsive class, but the severest inattention class also included 62% of the improving hyperactive-impulsive class. CONCLUSION: An ADHD rather than bipolar diagnosis prognosticates a better course of hyperactive/impulsive, but not inattentive, symptoms. High overlap of relative severity between inattention and hyperactivity/impulsivity confirms the link between these symptom clusters. Hyperactive/impulsive symptoms wane more over time. Group means are insufficient to understand individual ADHD prognosis. A small subgroup deteriorates over time in hyperactivity/impulsivity and needs better treatments than currently provided.

OBJECTIVE: The objective of this study was to determine whether daytime sleepiness is independently associated with coronary heart disease (CHD) and stroke or whether the positive association is explained by short sleep duration, disturbed sleep, and circadian disruption, conditions that are associated with cardiometabolic risk factors for vascular events. METHODS: Longitudinal analyses of data from the Nurses' Health Study II comprising 84,003 female registered nurses aged 37-54 at baseline were conducted in 2001 with follow-up until 2009. Multivariate Cox regression was used to explore the relationship between reported daytime sleepiness and the incidence of either CHD or stroke (n=500 cases). RESULTS: Women who reported daytime sleepiness almost every day, compared with rarely/never, had an elevated adjusted risk of cardiovascular disease (CVD) (hazard ratio (HR)=1.58, 95% confidence interval (CI) 1.15-2.17). Controlling for sleep variables (sleep duration, snoring, shift work, and sleep adequacy) or potential metabolic biological mediators of disrupted sleep (diabetes, hypercholesterolemia, and hypertension) appreciably attenuated the relationship (HR=1.17, 95% CI 0.84-1.65; and HR=1.34, 95% CI 0.97-1.85, respectively). Controlling for both sleep variables and metabolic risk factors eliminated an independent association (HR=1.09, 95% CI 0.77-1.53). A similar pattern was observed for CHD and stroke individually. CONCLUSIONS: Daytime sleepiness was not an independent risk factor for CVD in this cohort of women, but rather, was associated with sleep characteristics and metabolic abnormalities that are risk factors for CVD.

OBJECTIVE: Suboptimal functioning of the basal ganglia is implicated in attention-deficit/hyperactivity disorder (ADHD). These structures are important to the acquisition of associative knowledge, leading some to theorize that associative learning deficits might be expected, despite the fact that most extant research in ADHD has focused on effortful control. We present 2 studies that examined the acquisition of explicit rule-based (RB) and associative information integration (II) category learning among school-age children with ADHD. METHOD AND RESULTS: In Study 1, we found deficits in both RB and II category learning tasks among children with ADHD (n = 81) versus controls (n = 42). Children with ADHD tended to sort by the more salient but irrelevant dimension (in the RB paradigm) and were unable to acquire a consistent sorting strategy (in the II paradigm). To disentangle whether the deficit was localized to II category learning versus a generalized inability to consider more than 1 stimulus dimension, in Study 2 children completed a conjunctive RB paradigm that required consideration of 2 stimulus dimensions. Children with ADHD (n = 50) continued to underperform controls (n = 33). CONCLUSIONS: Results provide partial support for neurocognitive developmental theories of ADHD that suggest that associative learning deficits should be found, and highlight the importance of using analytic approaches that go beyond asking whether an ADHD-related deficit exists to why such deficits exist.

Fitness to Stand Trial is a critical concept in the adjudication of justice-involved persons. A retrospective study was conducted to examine criminal defendants' specific psychiatric symptoms and those symptoms' associations with expert opinions on Competence to Stand Trial. One hundred charts were reviewed: 50 Cases (opined as Not Fit) were compared against 50 Controls (opined as Fit) with respect to ratings on the Brief Psychiatric Rating Scale (BPRS). A significance level of 0.001 was selected a priori. Statistically significant differences were found in seven of the eighteen BPRS symptom constructs (with the highest differences in Conceptual Disorganization and Unusual Thought Content) and two of the four BPRS higher-order syndrome factors (Thinking Disorder and Hostile-Suspiciousness). Consistent with previous reports, psychotic symptoms are found in this study to be inversely associated with Fitness. Validity, reliability, and limitations of this study, as well as directions for future research, are discussed herein.

Growth in executive functioning (EF) skills play a role children's academic success, and the transition to elementary school is an important time for the development of these abilities. Despite this, evidence concerning the development of the ERP components linked to EF, including the error-related negativity (ERN) and the error positivity (Pe), over this period is inconclusive. Data were recorded in a school setting from 3- to 7-year-old children (N=96, mean age=5 years 11 months) as they performed a Go/No-Go task. Results revealed the presence of the ERN and Pe on error relative to correct trials at all age levels. Older children showed increased response inhibition as evidenced by faster, more accurate responses. Although developmental changes in the ERN were not identified, the Pe increased with age. In addition, girls made fewer mistakes and showed elevated Pe amplitudes relative to boys. Based on a representative school-based sample, findings indicate that the ERN is present in children as young as 3, and that development can be seen in the Pe between ages 3 and 7. Results varied as a function of gender, providing insight into the range of factors associated with developmental changes in the complex relations between behavioral and electrophysiological measures of error processing.

This study examined: (1) qualitative aspects of close working relationships between family support organizations and child mental health agencies, including effective and ineffective characteristics of the relationship and aspects that they would change, and (2) the impact of the working relationship upon the family support organization. Semi-structured interviews were conducted with 40 directors of family support organizations characterized as having a close working relationship with a child mental health agency. Three main themes emerged regarding the quality of the working relationship: (a) interactional factors, including shared trust, communication, collaboration and service coordination; (b) aspects of the inner context of the family support organization, mental health agency, or both, including alignment of goals and values and perceptions of mental health services; and (c) outer contextual factors external to the organizations, such as financial and county regulations. Responses to the perceived impact of the relationship was divided into two themes: positive impacts (e.g. gained respect, influence and visibility), and negative impacts (e.g. lack of trust). This study lays the foundation for future research to better understand the mechanisms underlying interorganizational relationships in communities among different types of providers to create a more seamless continuum of services for families of children with mental health conditions.

There is growing evidence that astrocytes, long held to merely provide metabolic support in the adult brain, participate in both synaptic plasticity and learning and memory. Astrocytic processes are sometimes present at the synaptic cleft, suggesting that they might act directly at individual synapses. Associative learning induces synaptic plasticity and morphological changes at synapses in the lateral amygdala (LA). To determine whether astrocytic contacts are involved in these changes, we examined LA synapses after either threat conditioning (also called fear conditioning) or conditioned inhibition in adult rats using serial section transmission electron microscopy (ssTEM) reconstructions. There was a transient increase in the density of synapses with no astrocytic contact after threat conditioning, especially on enlarged spines containing both polyribosomes and a spine apparatus. In contrast, synapses with astrocytic contacts were smaller after conditioned inhibition. This suggests that during memory consolidation astrocytic processes are absent if synapses are enlarging but present if they are shrinking. We measured the perimeter of each synapse and its degree of astrocyte coverage, and found that only about 20-30% of each synapse was ensheathed. The amount of synapse perimeter surrounded by astrocyte did not scale with synapse size, giving large synapses a disproportionately long astrocyte-free perimeter and resulting in a net increase in astrocyte-free perimeter after threat conditioning. Thus astrocytic processes do not mechanically isolate LA synapses, but may instead interact through local signaling, possibly via cell-surface receptors. Our results suggest that contact with astrocytic processes opposes synapse growth during memory consolidation. J. Comp. Neurol., 2013. (c) 2013 Wiley Periodicals, Inc.

This article presents novel sequential methods of sample coordination appropriate for a repeated survey, with a stratified design and simple random sampling without replacement (SRSWOR) selection within each stratum, when the composition or definition of strata changes. Such changes could be the result of updating the frame for births, deaths, or the modification of the industry classification system. Given that a sample has already been selected according to a first (before the frame updates) SRSWOR design, our general aim is to select a minimum number of new units for the second (after the updates) survey while preserving the first-order inclusion probabilities of units in the second SRSWOR design. Sequential methods presently in use can attain a large expected overlap, but do not control the overlap on each pair of selected samples. In this article we present a set of new methods for maximizing the expected overlap, which can handle realistic situations when strata and the associated sample sizes are large. These methods include one that not only maximizes the expected overlap but, for any initially selected sample, maximizes its overlap with the second sample; its superior performance is illustrated with numerical examples. (C) 2014 Elsevier B.V. All rights reserved.