Age differences in enumerating things that move: Implications for the development of multiple-object tracking

The attentional theory of spatial enumeration (Trick & Pylyshyn, 1994) predicts that subitizing, the rapid process (40-120 msec/item) used to enumerate 1-4 items, employs the same mechanism that permits individuals to track 4-5 moving items simultaneously, whereas enumerating more items requires moving attentional focus from area to area in the display. To test this theory, enumeration of static and moving items was investigated in 8-, 10-, 12-, and 20-year-old participants using a number discrimination task. As was predicted, random independent item motion did not substantially impede enumeration of 1-4 items regardless of age. However, even movement within a 1.14 degree square area slowed enumeration of 6-9 items, although on average the interference decreased with age from 788 msec for the 8-year-olds to 136 msec for the 20-year-olds. The relevance of this finding for theories of enumeration, multiple-object tracking, visual working memory, and object-based attention is discussed.     

BDNF Regulates the Intrinsic Excitability of Cortical Neurons

Neocortical pyramidal neurons respond to prolonged activity blockade by modulating their balance of inward and outward currents to become more sensitive to synaptic input, possibly as a means of homeostatically regulating firing rates during periods of intense change in synapse number or strength. Here we show that this activity-dependent regulation of intrinsic excitability depends on the neurotrophin brain-derived neurotrophic factor (BDNF). In experiments on rat visual cortical cultures, we found that exogenous BDNF prevented, and a TrkB–IgG fusion protein reproduced, the change in pyramidal neuron excitability produced by activity blockade. Most of these effects were also observed in bipolar interneurons, indicating a very general role for BDNF in regulating neuronal excitability. Moreover, earlier work has demonstrated that BDNF mediates a different kind of homeostatic plasticity present in these same cultures: scaling of the quantal amplitude of AMPA-mediated synaptic inputs up or down as a function of activity. Taken together, these results suggest that BDNF may be the signal controlling a coordinated regulation of synaptic and intrinsic properties aimed at allowing cortical networks to adapt to long-lasting changes in activity.     

Parent engagement in an original and culturally adapted evidence-based parenting program,Legacy for Children™

Legacy for Children™ (Legacy) is an evidence-based program focused on promoting sensitive, responsive parenting for socioeconomically disadvantaged families. Legacy has recently been culturally and linguistically adapted for Spanish-monolingual Latino families and is being piloted in partnership with an early childhood education program. We conducted a mixed methods study to identify barriers and facilitators to engagement, using program monitoring data sources from both participant and group leader perspectives. We conducted qualitative analyses of open-ended data to identify distinct barriers (e.g., employment challenges, health-related challenges and appointments) and facilitators (e.g., other mothers in group, interest in program topics) to engagement that emerged across English and Spanish language curriculum versions; curriculum-specific barriers and facilitators were also documented. We interpret these findings in light of quantitative data on measures of engagement, showing that participants in the Spanish curriculum evidenced comparable levels of parent–group leader relationship quality relative to the English group, and higher levels of parent's group support/connectedness and overall satisfaction. These results offer promising considerations for optimizing families’ engagement in parenting programs in the context of early care and education settings.     

Effect of motivation on academic fluency performance in survivors of pediatric medulloblastoma

It has been proposed previously that extrinsic motivation may enable survivors of childhood medulloblastoma to significantly improve aspects of neurocognitive performance. In healthy populations, enhanced motivation has been shown to promote academic fluency, a domain likely more relevant to the educational outcomes of pediatric medulloblastoma survivors than academic skill development. The present study investigates the effect of enhanced extrinsic motivation on fluent (i.e., accurate and efficient) academic performance in pediatric medulloblastoma survivors. Participants were 36 children, ages 7–18, who had completed treatment for medulloblastoma. Participants completed a neuropsychological battery that included administration of equivalent tasks on Forms A and B of the Woodcock-Johnson III Tests of Achievement. Half were randomly assigned to an incentive condition prior to the administration of Form B. Provision of a performance-based incentive resulted in statistically significant improvement, but not normalization of function, in performance on measures of academic fluency. No demographic, treatment-related, academic, neuropsychological, or self-perception variables predicted response to incentive. Findings suggest that academic performance of survivors may significantly improve under highly motivating conditions. In addition to implications for educational services, this finding raises the novel possibility that decreased motivation represents an inherent neuropsychological deficit in this population and provides a rationale for further investigation of factors affecting individual differences in motivational processes. Further, by examining effort in a context where effort is not inherently suspect, present findings also significantly contribute to the debate regarding the effects of effort and motivation on neuropsychological performance.     

Technological advances in the assessment of impulse control in offenders: A systematic review

Deficits in impulse control have been linked to criminal offending, risk of recidivism, and other maladaptive behaviours relevant to the criminal justice system (e.g. substance use). Impulse control can be conceptualized as encompassing the broad domains of response inhibition and impulsive/risky decision‐making. Advancements in technology have led to the development of computerized behavioural measures to assess performance in these domains, such as go/no‐go and delay discounting tasks. Despite a relatively large literature examining these tasks in offenders, findings are not universally consistent. This systematic review aims to synthesize the literature using computerized neurocognitive tasks to assess two domains of impulse control in offenders: response inhibition and impulsive/risky decision‐making. The review included 28 studies from diverse geographic locations, settings, and offender populations. The results largely support the general conclusion that offenders exhibit deficits in impulse control compared with non‐offenders, with studies of response inhibition more consistently reporting differences than studies using impulsive and risky decision‐making tasks. Findings are discussed in the context of contemporary neuroimaging research emphasizing dysfunction in prefrontal cortex as a key contributor to impulse control deficits in offenders.     

Locomotor experience and use of social information are posture specific

The authors examined the effects of locomotor experience on infants' perceptual judgments in a potentially risky situation--descending steep and shallow slopes--while manipulating social incentives to determine where perceptual judgments are most malleable. Twelve-month-old experienced crawlers and novice walkers were tested on an adjustable sloping walkway as their mothers encouraged and discouraged descent. A psychophysical procedure was used to estimate infants' ability to crawl/walk down slopes, followed by test trials in which mothers encouraged and discouraged infants to crawl/walk down. Both locomotor experience and social incentives affected perceptual judgments. In the encourage condition, crawlers only attempted safe slopes within their abilities, but walkers repeatedly attempted impossibly risky slopes, replicating previous work. The discourage condition showed where judgments are most malleable. When mothers provided negative social incentives, crawlers occasionally avoided safe slopes, and walkers occasionally avoided the most extreme 50 degrees increment, although they attempted to walk on more than half the trials. Findings indicate that both locomotor experience and social incentives play key roles in adaptive responding, but the benefits are specific to the posture that infants use for balance and locomotion.     

Sequential tapping interferes selectively with multiple-object tracking: do finger-tapping and tracking share a common resource?

Multiple-object tracking involves simultaneously monitoring positions of a number of target items as they move among distractors. Young adults are capable of tracking only 3-5 items at once. In this study we investigated the origin of this limitation by looking for secondary tasks that interfere with tracking. We compared tracking performance (baseline condition), with performance when participants tapped three fingers in a specific order while tracking (sequential tapping) or articulated three syllables in a specific order while tracking (sequential articulation). The articulation task was used to ensure that the interference produced by sequential tapping was more than would be expected by the executive demands of carrying out any two “attention-demanding” tasks at once. Even though sequential tapping does not require vision or memorizing the positions of external items, it produced significantly more interference than did sequential articulation, as might be expected if tracking and sequential tapping shared a common (limited) resource.