The time course effect of moderate intensity exercise on response execution and response inhibition

This research aimed to investigate the time course effect of a moderate steady-state exercise session on response execution and response inhibition using a stop-task paradigm. Ten participants performed a stop-signal task whilst cycling at a carefully controlled workload intensity (40% of maximal aerobic power), immediately following exercise and 30 min after exercise cessation. Results showed that moderate exercise enhances a subjects’ ability to execute responses under time pressure (shorter Go reaction time, RT without a change in accuracy) but also enhances a subjects’ ability to withhold ongoing motor responses (shorter stop-signal RT). The present outcomes reveal that the beneficial effect of exercise is neither limited to motor response tasks, nor to cognitive tasks performed during exercise. Beneficial effects of exercise remain present on both response execution and response inhibition performance for up to 52 min after exercise cessation.     

Experiencing and regulating sadness: Physiological and cognitive effects

No prior study has examined the two most prominent response-focused regulation strategies (suppression and exaggeration) using a within-subjects design. Utilizing this design allows for a direct comparison of physiological patterns and cognitive impairment associated with such efforts. One hundred and nine participants were asked to view a series of three films, each preceded by a 10-second instructional slide which indicated the regulation strategy they were to perform (natural-watch, exaggerate, or suppress). Exaggeration was associated with increased sympathetic activation as indicated by an increase in galvanic skin conductance level (GSL) and shortened pre-ejection period (PEP). Suppression, much like the natural-watch condition, was associated with greater sympathetic withdrawal (i.e., decreased GSL, longer PEP). Both suppression and exaggeration led to reduced memory for the emotional movie, with exaggeration causing more impairment than suppression. Results suggest that exaggeration and suppression not only have very different behavioral manifestations, but physiological outcomes as well when utilized during a sad context.     

Prescriptive Analysis: Further Individualization of Hypothesis Testing in Brief Experimental Analysis of Reading Fluency

Brief experimental analyses (BEA) have been used to identify effective individualized interventions for improving reading fluency with school-age children. Interventions involving incentives, modeling, repeated reading, and error correction are most often tested in a BEA. However, these interventions are rarely modified according to individual student needs. The current study examined the effects of varied levels of modeling (passage, sentence, word) and varied contingencies (tracking and fluency) on fluency in non-treated high-word overlap passages and general outcome measure passages. BEA-identified interventions were effective for improving reading fluency on non-treated passages for both second grade students and the third grade student. Notably, the effects reversed when intervention was withdrawn with one of the second grade students. Results are discussed in terms of considerations in the application of BEA technology in the schools.     

A Preventive Coping Perspective of Individual Response to Terrorism in Canada

A plethora of studies on terrorism underscores the challenges of managing the psychological and behavioural impacts of terrorist events. This literature also emphasizes the idea that the global pending threat of terrorism, prior to the occurrence of any event, may also give rise to significant reactions among members of the public. Drawing from the literature on proactive coping, the current study presents the results of factor analyses performed on sections of a national survey that assessed appraisals of as well as actual responses to the threat of terrorism in Canada (N = 1,502). Findings revealed that items assessing individual response to terrorism were represented by three factors in this context: Individual Preparedness, Information Seeking, and Avoidance Behaviour. Further analyses demonstrated a tendency for actual preparedness behaviours to be associated with decreased psychological stress, and actual avoidance behaviours to be associated with heightened psychological stress. Furthermore, the divergent patterns of relationships of terrorism response appraisals and corresponding actual responses with psychological stress emphasized the need to distinguish different stages in the process of preventive coping with terrorism. Theoretical and practical implications of findings for individual preparedness in Canada are discussed.

Confidence to Foster Across Cultures: Caregiver Perspectives

It is important to understand how cultural values, beliefs and traditions of foster parents are related to placement success because a substantial proportion of children in care come from culturally diverse backgrounds. In the present study participants were asked about resources they saw as necessary to improve their confidence fostering children from culturally diverse backgrounds. Sixty-one foster parents from a central Canadian province participated in a telephone interview that included the question: “what would help you feel more confident about fostering children with different values, beliefs and traditions?” A total of 35 unique responses were obtained and grouped together by 13 foster parents. Multidimensional scaling and cluster analysis were used to analyze the grouping data. Foster parents described six themes: understanding different cultures, training, self awareness, agency support, open discussion and community services. There were several similarities and differences between the perspectives of foster parents interviewed and the literature. Implications for future research are discussed.     

Depressive Symptoms in Young Adults: The Role of Attachment Orientations and Romantic Relationship Conflict

Although romantic involvement in adulthood has generally been associated with enhanced well-being, some aspects of adults’ romantic relationships (e.g., maladaptive conflict behaviors) have been linked with depressive symptoms. In order to better understand the role of romantic involvement in well-being, the present study examined links among attachment orientations, conflict behaviors with romantic partners, and depressive symptoms in an undergraduate sample of young adults (N = 110). Correlational analyses generally supported the hypothesized links. When a regression series was applied to the data in order to determine whether young adults’ conflict behaviors serve as a mediator in the link between their attachment orientations and depressive symptoms, mediation was not supported. Instead, results supported a model wherein attachment orientations and conflict behaviors (attacking) were independent predictors, explaining unique variance in young adults’ depressive symptoms. Findings underscore the importance of considering specific aspects of young adults’ romantic relationships in the prediction of their depressive symptoms and illuminate the role attachment orientations and conflict behaviors in their depressive symptoms.     

Sequential dependencies in the Eriksen flanker task: A direct comparison of two competing accounts

In the conflict/control loop theory proposed by Botvinick, Braver, Barch, Carter, and Cohen (2001), conflict monitored in a trial leads to an increase in cognitive control on the subsequent trial. The critical data pattern supporting this assertion is the so-called Gratton effect—the decrease in flanker interference following incongruent trials—which was initially observed in the Eriksen flanker task. Recently, however, the validity of the idea that this pattern supports a general conflict/control mechanism has been questioned on the grounds that the Gratton effect is only observed with stimulus repetition. We present an experiment testing whether the Gratton effect reflects a stimulus-independent increase in cognitive control or stimulus-specific repetition priming. Although our results support the latter hypothesis, the priming effect is modulated by the congruency of the previous trial. We discuss a new mechanism through which monitored conflict is used to exert executive control by modulating stimulus-response associations.     

LTP in hippocampal area CA1 is induced by burst stimulation over a broad frequency range centered around delta

Long-term potentiation (LTP) is typically studied using either continuous high-frequency stimulation or theta burst stimulation. Previous studies emphasized the physiological relevance of theta frequency; however, synchronized hippocampal activity occurs over a broader frequency range. We therefore tested burst stimulation at intervals from 100 msec to 20 sec (10 Hz to 0.05 Hz). LTP at Schaffer collateral–CA1 synapses was obtained at intervals from 100 msec to 5 sec, with maximal LTP at 350–500 msec (2–3 Hz, delta frequency). In addition, a short-duration potentiation was present over the entire range of burst intervals. We found that N-methyl-d-aspartic acid (NMDA) receptors were more important for LTP induction by burst stimulation, but L-type calcium channels were more important for LTP induction by continuous high-frequency stimulation. NMDA receptors were even more critical for short-duration potentiation than they were for LTP. We also compared repeated burst stimulation with a single primed burst. In contrast to results from repeated burst stimulation, primed burst potentiation was greater when a 200-msec interval (theta frequency) was used, and a 500-msec interval was ineffective. Whole-cell recordings of postsynaptic membrane potential during burst stimulation revealed two factors that may determine the interval dependence of LTP. First, excitatory postsynaptic potentials facilitated across bursts at 500-msec intervals but not 200-msec or 1-sec intervals. Second, synaptic inhibition was suppressed by burst stimulation at intervals between 200 msec and 1 sec. Our data show that CA1 synapses are more broadly tuned for potentiation than previously appreciated.Long-term potentiation (LTP) is used as a model for studying synaptic events during learning and memory (Bliss and Collingridge 1993; Morris 2003; Lynch 2004). At most synapses, LTP is triggered by postsynaptic Ca²⁺ influx through N-methyl-d-aspartic acid (NMDA) glutamate receptors (Collingridge et al. 1983; Harris et al. 1984; Herron et al. 1986) and, under some conditions, through L-type voltage-gated Ca²⁺ channels (Grover and Teyler 1990, 1994; Morgan and Teyler 1999). LTP was discovered in the dentate gyrus (Bliss and Lomo 1973) following several seconds of 10–100 Hz stimulation of the perforant path. Since then, many LTP studies have used similar long, high-frequency stimulation (HFS) protocols, most typically 100 Hz, 1 sec (Bliss and Collingridge 1993). Although effective, HFS does not resemble physiological patterns of activity (Albensi et al. 2007). Patterned stimulation resembling physiological activity, in particular theta burst stimulation, is also effective for LTP induction (Larson et al. 1986; Staubli and Lynch 1987; Capocchi et al. 1992; Nguyen and Kandel 1997). Theta burst stimulation consists of short bursts (4–5 stimuli at 100 Hz) repeated at 5 Hz, which lies within the hippocampal theta frequency range (4–12 Hz) (Bland 1986; Buzsáki 2002). Primed burst stimulation, another form of patterned stimulation, involves delivery of a priming stimulus followed by a single short burst (Larson and Lynch 1986; Rose and Dunwiddie 1986). The temporal requirements for primed burst LTP are quite precise (Diamond et al. 1988; Greenstein et al. 1988; Larson and Lynch 1989): Intervals less than 140 msec or greater than 200 msec are ineffective.The mechanisms underlying theta frequency-dependent LTP have been studied primarily using the primed burst protocol (Larson and Lynch 1986, 1988, 1989; Pacelli et al. 1989; Davies and Collingridge 1996). Activation of GABA_B autoreceptors during the priming stimulus suppresses GABA release during the following burst (Davies et al. 1990; Lambert and Wilson 1994; Olpe et al. 1994), allowing greater postsynaptic depolarization (Larson and Lynch 1986; Pacelli et al. 1989) and more effective NMDA receptor activation (Davies and Collingridge 1996). Consequently, temporal requirements for primed burst potentiation match the time course of GABA_B autoreceptor-mediated suppression of GABA release (Davies et al. 1990; Davies and Collingridge 1993; Mott et al. 1993).Besides theta, hippocampal activity is observed at other frequencies, notably sharp waves (0.01–5 Hz) (Buzsáki 1986, 1989; Suzuki and Smith 1987) and low-frequency oscillations (≤1 Hz) (Wolansky et al. 2006; Moroni et al. 2007). These lower frequencies dominate during slow wave sleep (Buzsáki 1986; Suzuki and Smith 1987; Wolansky et al. 2006; Moroni et al. 2007), and contribute to hippocampal memory processing (Buzsáki 1989; Pennartz et al. 2002). While synchronized population activity over frequencies from <1 Hz to 12 Hz is associated with hippocampal memory function, previous LTP studies have focused on theta. We therefore investigated burst stimulation at frequencies from 0.05 Hz to 10 Hz. We found that CA1 synapses potentiate to some degree over this entire range and that maximal potentiation occurs around delta frequency rather than theta.