A Longitudinal Twin Study on the Association Between Inattentive and Hyperactive-Impulsive ADHD Symptoms

DSM-IV distinguishes two symptom domains of attention deficit hyperactivity disorder (ADHD): inattentiveness and hyperactivity-impulsivity. The present study examines the aetiologies and developmental relations underlying the associations between inattentiveness and hyperactivity-impulsivity over time, based on a representative population sample from the United Kingdom of approximately 7,000 twin pairs. ADHD symptoms were assessed as continuous dimensions using the DSM-IV items from the Conners’ Parent Rating Scale at two ages: middle childhood (age 1) and early adolescence (age 2). Quantitative genetic cross-lagged analyses showed that the association of the ADHD dimensions over time is influenced by stable as well as newly developing genetic factors. Moreover the longitudinal relationship between the ADHD dimensions appears to be unidirectional, with hyperactivity-impulsivity in middle childhood predicting the presence of inattentiveness in early adolescence, but not vice versa. Thus, hyperactivity-impulsivity may serve to exacerbate inattentiveness over time. Findings are discussed in the context of developmental changes in ADHD symptoms.     

The organization of narrative discourse in Lewy body spectrum disorder

Narrative discourse is an essential component of day-to-day communication, but little is known about narrative in Lewy body spectrum disorder (LBSD), including Parkinson’s disease (PD), Parkinson’s disease with dementia (PDD), and dementia with Lewy bodies (DLB). We performed a detailed analysis of a semi-structured speech sample in 32 non-aphasic patients with LBSD, and we related their narrative impairments to gray matter (GM) atrophy using voxel-based morphometry. We found that patients with PDD and DLB have significant difficulty organizing their narrative speech. This was correlated with deficits on measures of executive functioning and speech fluency. Regression analyses associated this deficit with reduced cortical volume in inferior frontal and anterior cingulate regions. These findings are consistent with a model of narrative discourse that includes executive as well as language components and with an impairment of the organizational component of narrative discourse in patients with PDD and DLB.     

An economic perspective on the Reinforcement Sensitivity Theory of personality

Reinforcement Sensitivity Theory postulates personality factors of ‘reward sensitivity’ and ‘punishment sensitivity’ linked to neural systems that control approach and avoidance, respectively. In contrast, behavioural economics distinguishes gain (‘reward’) and loss (‘punishment’) valuation systems that are orthogonal to approach/avoidance behaviour. We combined gain and loss with both their presentation and omission and found evidence for separate gain valuation, loss valuation, approach, and avoidance systems. This suggests that it is possible to integrate valuation/input and behaviour/output views of ‘reward’ and ‘punishment’ in a way that may be of use to both personality theory and economics and so forge closer links between these two major perspectives on decision-making and behaviour.     

Magnitude and chronometry of neural mechanisms of emotion regulation in subtypes of aggressive children

Emotion regulation is a key social skill and children who fail to master it are at risk for clinical disorders. Specific styles of emotion regulation have been associated with particular patterns of prefrontal activation. We investigated whether anxious aggressive children would reveal a different pattern of cortical activation than non-anxious aggressive children and normally-developing children. We examined the magnitude and timing of source activation underlying the N2—an ERP associated with inhibitory control—during a go/nogo task with a negative emotion induction component (loss of earned points). We estimated cortical activation for two regions of interest—a ventral prefrontal and a dorsomedial prefrontal region—for three 100-ms windows over the range of the N2 (200–500 ms). Anxious aggressive children showed high ventral prefrontal activation in the early window; non-anxious aggressive children showed high ventral prefrontal activation in the late window, but only for the duration of the emotion induction; and normally-developing children showed low ventral prefrontal activation throughout. There were no group differences in dorsomedial prefrontal activation. These results suggest that anxious aggressive children recruit ventral prefrontal activation quickly and indiscriminately, possibly giving rise to their rigid, threat-oriented approach to conflict. The late ventral prefrontal activation seen for non-anxious aggressive children may underlie a more delayed, situation-specific, but ineffective response to frustration.     

Probabilities in implicit learning

The visual system possesses a remarkable ability in learning regularities from the environment. In the case of contextual cuing, predictive visual contexts such as spatial configurations are implicitly learned, retained, and used to facilitate visual search-all without one's subjective awareness and conscious effort. Here we investigated whether implicit learning and its facilitatory effects are sensitive to the statistical property of such implicit knowledge. In other words, are highly probable events learned better than less probable ones even when such learning is implicit? We systematically varied the frequencies of context repetition to alter the degrees of learning. Our results showed that search efficiency increased consistently as contextual probabilities increased. Thus, the visual contexts, along with their probability of occurrences, were both picked up by the visual system. Furthermore, even when the total number of exposures was held constant between each probability, the highest probability still enjoyed a greater cuing effect, suggesting that the temporal aspect of implicit learning is also an important factor to consider in addition to the effect of mere frequency. Together, these findings suggest that implicit learning, although bypassing observers' conscious encoding and retrieval effort, behaves much like explicit learning in the sense that its facilitatory effect also varies as a function of its associative strengths.     

The role of constant curvature in 2-D contour shape representations

In early cortex, visual information is encoded by retinotopic orientation-selective units. Higher-level representations of abstract properties, such as shape, require encodings that are invariant to changes in size, position, and orientation. Within the domain of open, 2-D contours, we consider how an economical representation that supports viewpoint-invariant shape comparisons can be derived from early encodings. We explore the idea that 2-D contour shapes are encoded as joined segments of constant curvature. We report three experiments in which participants compared sequentially presented 2-D contour shapes comprised of constant curvature (CC) or non-constant curvature (NCC) segments. We show that, when shapes are compared across viewpoint or for a retention interval of 1000 ms, performance is better for CC shapes. Similar recognition performance is observed for both shape types, however, if they are compared at the same viewpoint and the retention interval is reduced to 500 ms. These findings are consistent with a symbolic encoding of 2-D contour shapes into CC parts when the retention intervals over which shapes must be stored exceed the duration of initial, transient, visual representations.     

Hope as a Mediator and Moderator of Multidimensional Perfectionism and Depression in Middle School Students

The authors examined the relationship of perfectionism, hope, and depression in a sample of 153 middle school students. Adaptive perfectionists differed significantly from both maladaptive perfectionists and nonperfectionists on their levels of hope and depression. Hope mediated the relationship between maladaptive perfectionism and depression and supported an indirect effects model for hope and the relationship between adaptive perfectionism and depression. No evidence was found for hope as a moderator in the relationship between perfectionism and depression.     

Exploring the basis and boundary conditions of SenseCam-facilitated recollection

SenseCam review has been shown to promote and sustain subsequent access to memories that might otherwise remain inaccessible. While SenseCam review facilitates recollection for personally experienced events, we know little about the boundary conditions under which this operates and about how underlying processing mechanisms can be optimally recruited to offset memory impairments of the sort that occur in dementia. This paper considers some of these issues with a view to targeting future research that not only clarifies our evolving body of theory about how memory works, but also informs about how memory-assistive technologies for patients might be employed to maximal effect. We begin by outlining key factors that are known to influence recollection. We then examine variability in the decline of memory function both in normal ageing and in dementia. Attention is drawn to similarities in the recollection deficits associated with depression and dementia, and we suggest that this may reflect shared underlying mechanisms. We conclude by discussing how one particular theoretical rationale can be intersected with key SenseCam capabilities to define priorities for ongoing and future SenseCam research.     

SenseCam, imagery and bias in memory for wellbeing

Identifying and modifying the negative interpretation bias that characterises depression is central to successful treatment. While accumulating evidence indicates that mental imagery is particularly effective in the modification of emotional bias, this research typically incorporates static and unrelated ambiguous stimuli. SenseCam technology, and the resulting video-like footage, offers an opportunity to produce training stimuli that are dynamic and self-relevant. Here participants experienced several ambiguous tasks and subsequently viewed SenseCam footage of the same tasks, paired with negative or positive captions. Participants were trained to use mental imagery to inter-relate SenseCam footage and captions. Participants reported increased levels of happy mood, reduced levels of sad mood, and increased task enjoyment following SenseCam review with positive versus negative captions. This shift in emotional bias was also evident at 24-hour follow-up, as participants recollected greater task enjoyment for those tasks previously paired with positive captions. Mental imagery appears to play an important role in this process. These preliminary results indicate that in healthy volunteers, SenseCam can be used within a bias modification paradigm to shift mood and memory for wellbeing associated with performing everyday activities. Further refinements are necessary before similar methods can be applied to individuals suffering from subclinical and clinical depression.     

Corrigendum to “From Poisson shot noise to the integrated Ornstein-Uhlenbeck process: Neurally principled models of information accumulation in decision-making and response time” [J. Math. Psychol. 54 (2010) 266-283]

The Corrigendum reports an error in the derivation by Smith (2010) of the moment generating function for a random-amplitude, time-inhomogeneous, Poisson shot noise process. The correct derivation of the moment generating function is given, together with corrected expressions for the moments.