Poststimulation time interval-dependent effects of motor cortex anodal tDCS on reaction-time task performance

Anodal transcranial direct current stimulation (tDCS) induces long-term potentiation-like plasticity, which is associated with long-lasting effects on different cognitive, emotional, and motor performances. Specifically, tDCS applied over the motor cortex is considered to improve reaction time in simple and complex tasks. The timing of tDCS relative to task performance could determine the efficacy of tDCS to modulate performance. The aim of this study was to compare the effects of a single session of anodal tDCS (1.5 mA, for 15 min) applied over the left primary motor cortex (M1) versus sham stimulation on performance of a go/no-go simple reaction-time task carried out at three different time points after tDCS—namely, 0, 30, or 60 min after stimulation. Performance zero min after anodal tDCS was improved during the whole course of the task. Performance 30 min after anodal tDCS was improved only in the last block of the reaction-time task. Performance 60 min after anodal tDCS was not significantly different throughout the entire task. These findings suggest that the motor cortex excitability changes induced by tDCS can improve motor responses, and these effects critically depend on the time interval between stimulation and task performance.     

Assessing adolescent mindfulness: validation of an adapted Mindful Attention Awareness Scale in adolescent normative and psychiatric populations

Interest in mindfulness-based interventions for children and adolescents is burgeoning, bringing with it the need for validated instruments to assess mindfulness in youths. The present studies were designed to validate among adolescents a measure of mindfulness previously validated for adults (e.g., Brown & Ryan, 2003), which we herein call the Mindful Attention Awareness Scale-Adolescent (MAAS-A). In 2 large samples of healthy 14- to 18-year-olds (N = 595), Study 1 supported a single-factor MAAS-A structure, along with acceptably high internal consistency, test-retest reliability, and both concurrent and incremental validity. In Study 2, with a sample of 102 psychiatric outpatient adolescents age 14-18 years, participants randomized to a mindfulness-based stress reduction intervention showed significant increases in MAAS-A scores from baseline to 3-month follow-up, relative to nonsignificant score changes among treatment-as-usual participants. Increases in MAAS-A scores among mindfulness-based stress reduction participants were significantly related to beneficial changes in numerous mental health indicators. The findings support the reliability and validity of the MAAS-A in normative and mixed psychiatric adolescent populations and suggest that the MAAS-A has utility in mindfulness intervention research.     

Age and gender comparisons of driving while sleepy: Behaviours and risk perceptions

To assist road safety professionals in developing effective strategies to combat the risk associated with driving while fatigued, a survey was administered to 1000 Australian drivers. Participants reported their past behaviours in regards to driving while sleepy and their perceptions of risk associated with driving fatigued as compared to speeding and driving under the influence of alcohol. Although participants appeared to be aware of the substantial risk associated with driving while sleepy, many drivers reported that they frequently drive when sleepy. Age and gender comparisons, revealed that risk taking behaviour in regards to driving while sleepy is occurring across all age groups and in both male and female drivers. Overall young to middle age drivers and male drivers reported the highest frequency of driving while sleepy and reported the lowest perceived personal risk in regards to driving while sleepy.     

Aging, source memory, and emotion

In 2 experiments we assessed younger and older adults' ability to remember contextual information about an event. Each experiment examined memory for 3 different types of contextual information: (a) perceptual information (e.g., location of an item); (b) conceptual, nonemotional information (e.g., quality of an item); and (c) conceptual, emotional information (e.g., safety of an item). Consistent with a large literature on aging and source memory, younger adults outperformed older adults when the contextual information was perceptual in nature and when it was conceptual, but not emotional. Age differences in source memory were eliminated, however, when participants recalled emotional source information. These findings suggest that emotional information differentially engages older adults, possibly evoking enhanced elaborations and associations. The data are also consistent with a growing literature, suggesting that emotional processing remains stable with age (e.g., Carstensen & Turk-Charles, 1994, 1998; Isaacowitz, Charles, & Carstensen, 2000).     

Relationships among compulsive hoarding, trauma, and attention-deficit/hyperactivity disorder

The current study investigated aspects of post-traumatic stress disorder and attention deficit/ hyperactivity disorder (ADHD) among hoarders. Compared to a sample of 36 controls, hoarders (n=26) reported a significantly greater number of different types of trauma, more frequent traumatic experiences, more symptoms of inattention, hyperactivity, and greater comfort derived from possessions. These findings are consistent with previous reports of extensive comorbidity associated with hoarding behaviors, and may reflect the potential usefulness of assessing PTSD and ADHD symptoms at the outset of hoarding treatments, as well as considering alternative pharmacological interventions.     

Level of alliance, pattern of alliance, and outcome in short-term group therapy

This study investigated the relationships between initial level of alliance, pattern of alliance over sessions, and outcome in a sample of 107 patients who completed short-term group therapy for complicated grief. Both patient-rated alliance and therapist-rated alliance were studied. For patient-rated alliance, both the initial level of alliance and the linear pattern of alliance were directly and significantly related to favorable outcome. For therapist-rated alliance, no significant direct relationships with outcome were found. Instead, significant interaction effects were found. For patients with relatively high initial alliance, the greater the increase in alliance over sessions, the better the outcome. For patients with relatively low initial alliance, the greater the decrease in alliance over sessions, the better the outcome. Explanations for the findings are considered as well as possible clinical implications.     

ALTERING SHOPPERS' SUPERMARKET PURCHASES TO FIT NUTRITIONAL GUIDELINES: AN INTERACTIVE INFORMATION SYSTEM

This study reports the results of one effort to help supermarket shoppers alter food purchases to make purchases (and meals) that are lower in fat and higher in fiber. A prototype interactive information system using instructional video programs, feedback on purchases with specific goals for change, weekly programs, and the ability to track user interactions and intended purchases was evaluated. The major dependent measure was users' actual food purchases as derived from participants' highly detailed supermarket receipts. After a 5- to 7-week baseline phase, participants were randomly assigned to an experimental or control condition for the 7- to 8-week intervention phase. A follow-up phase began 5 to 8 weeks after participants completed the intervention and discontinued use of the system. The results indicated that experimental participants, when compared to control participants, decreased high fat purchases and increased high fiber purchases during intervention, with evidence for some maintenance of effect in follow-up. Plans for increasing the use and impact of the system are discussed.     

Conservation as a predictor of individual differences in children’s susceptibility to leading questions

The relationships between susceptibility to leading questions and several individual differences variables—namely number and mass conservation; self-rated social desirability; and teacher-rated assertive social skills, shyness-anxiousness, and acting out—were examined for 36 first graders. As predicted, children whose conservation skills were more advanced were least susceptible to leading questions. However, there was no reliable direct association with any of the four personality variables assessed. Results were interpreted as evidence that the ability to simultaneously consider multiple dimensions may be one general cognitive factor underlying developmental and individual differences in susceptibility to leading questions.     

Understanding words in sentence contexts: the time course of ambiguity resolution

Spoken language comprehension requires rapid integration of information from multiple linguistic sources. In the present study we addressed the temporal aspects of this integration process by focusing on the time course of the selection of the appropriate meaning of lexical ambiguities ("bank") in sentence contexts. Successful selection of the contextually appropriate meaning of the ambiguous word is dependent upon the rapid binding of the contextual information in the sentence to the appropriate meaning of the ambiguity. We used the N400 to identify the time course of this binding process. The N400 was measured to target words that followed three types of context sentences. In the concordant context, the sentence biased the meaning of the sentence-final ambiguous word so that it was related to the target. In the discordant context, the sentence context biased the meaning so that it was not related to the target. In the unrelated control condition, the sentences ended in an unambiguous noun that was unrelated to the target. Half of the concordant sentences biased the dominant meaning, and the other half biased the subordinate meaning of the sentence-final ambiguous words. The ISI between onset of the target word and offset of the sentence-final word of the context sentence was 100 ms in one version of the experiment, and 1250 ms in the second version. We found that (i) the lexically dominant meaning is always partly activated, independent of context, (ii) initially both dominant and subordinate meaning are (partly) activated, which suggests that contextual and lexical factors both contribute to sentence interpretation without context completely overriding lexical information, and (iii) strong lexical influences remain present for a relatively long period of time.