Implicit or explicit self-associations with life and death? Predicting short-term self-injurious thoughts and behaviors among adolescents.

Implicit self-association with death, measured by the Death/Suicide-Implicit Association Test (D/S-IAT), predicts short-term Self-Injurious Thoughts and Behaviors (SITBs) among adolescents. However, comparing the predictive utility of the D/S-IAT with explicit (i.e. self-report) self-association with life and death was not examined previously. The current study sought to examine whether the D/S-IAT and explicit self-association with life and death predict current and prospective SITBs, and to examine the association between the two measures. One-hundred and thirty-one Jewish Israeli adolescents with SITBs, aged 10-18 years (74.8% female) were assessed at clinic intake. Participants completed D/S-IAT, depression, attitudes toward life and death and suicide risk assessment at intake and one-month follow-up. Implicit, rather than explicit, attitudes toward life and death predicted SITBs at one-month follow-up, beyond depression and past SITBs. The implicit and explicit measures were not significantly related at intake, indicating that they might capture different aspects of SITBs.

The association between metacognitive abilities and outcome measures among people with schizophrenia: A meta-analysis.

BACKGROUND: Deficits in metacognition are one of the major causes of the difficulties experienced by individuals with schizophrenia. Studies have linked these deficits to symptom exacerbation and deterioration in psychosocial functioning. The aim of the present meta-analysis was to examine the extensive existing literature regarding metacognitive deficits among persons with schizophrenia; a further aim was to assess the extent to which metacognitive abilities are linked to outcome measures of symptoms and psychosocial functioning. METHOD: We conducted a systematic literature search of studies examining the relationship between metacognitive abilities and outcome measures among people with schizophrenia. We then analyzed the data using a random-effects meta-analytic model with Cohen's d standardized mean effect size. RESULTS: Heterogeneity analyses (k=32, Cohen's d=-.12, 95% CI.-1.92 to 1.7) produced a significant Q-statistic (Q=456.89) and a high amount of heterogeneity, as indicated by the I2 statistic (93.04%), suggesting that moderator analyses were appropriate. As hypothesized, measure type moderated the metacognitive deficit with homogenous effect for psychosocial functioning measures (Q=9.81, I2=19.47%, d=.94. 95% CI .58 to 1.2) and symptoms (Q=19.87, I2=0%, d=-1.07, 95% CI -1.18 to -.75). Further analysis found homogenous effects for MAS-A subscales as well as PANSS factors of symptoms. CONCLUSION: Our meta-analysis results illustrated a significant association between metacognitive deficits and both symptomatic and psychosocial functioning measures. These links suggest that the associations between metacognitive abilities and symptomatic outcomes are different from those between metacognitive abilities and psychosocial functioning measures. Intriguing hypotheses are raised regarding the role that metacognitive abilities play in both symptoms and psychosocial functioning measures of people diagnosed with schizophrenia spectrum disorders.

Enhancing switching abilities: Improving practice effect by stimulating the dorsolateral pre frontal cortex.

Task switching is our ability to abandon an old, irrelevant task in order to perform a new, more relevant one. Data from neuropsychology and neuroimaging studies indicate hemispheric asymmetries in task switching, however the neural mechanisms subtending switching, and in particular protocols to improve switching abilities are yet to be established. The present study aimed to assess hemispheric asymmetry and practice effects in task switching by using transcranial direct current stimulation (tDCS). To this end, tDCS has been applied to the dorsolateral prefrontal cortex (DLPFC) of both hemispheres while subjects were performing a well-established task-switching paradigm. The task was repeated three times in three separate sessions in order to test practice effects with and without stimulation. Results show that increased hemispheric asymmetry in dorsolateral prefrontal areas improved switching performance as measured by a better practice effect, compared to sham condition. Our results support the hypothesis of dynamic hemispheric asymmetry in task switching and reinforce the notion of utilizing brain stimulation with traditional training methods in order to enhance cognitive abilities.

Magnetic stimulation intensity modulates motor inhibition.

Repetitive transcranial magnetic stimulation (rTMS) is a standard tool in neuroscience research and therapy. Here we study one rTMS property that has not received adequate attention, the interaction of subthreshold intensity stimulation and low frequencies. We applied 1Hz rTMS over the motor cortex at three intensities, 40%, 80% and 100% of the resting motor threshold (rMT), and measured cortical excitability before and after the stimulation sessions. When comparing motor evoked potential (MEP) measured from the abductor pollicis brevis (APB) muscle before and after rTMS stimulation, we found that low intensity (40% MT) stimulation significantly decreased MEP magnitude, some smaller (non-significant) inhibition was found for the 80% MT intensity and increased MEP was found for the high intensity (100% MT) stimulation. Our results indicate that when explaining the input-output relationship of motor cortex induced activation as an intensity-dependent function, there might be a need to split it into separate functions associated with separate processes mediated by different cell types such as interneurons, pyramidal neurons and others.

Evaluating a split fovea model of visual word recognition: effects of case alternation in the two visual fields and in the left and right halves of words presented at the fovea.

Two experiments are reported exploring the effect of cAsE aLtErNaTiOn on lexical decisions to words and nonwords presented laterally or centrally. In line with previous research, Experiment 1 found that case alternation slowed lexical decision responses to words more in the right visual field (RVF) than in the left visual field (LVF). In Experiment 2, the words and nonwords were all presented centrally. There were three conditions, a condition in which the word and nonwords were presented in lower case letters, a condition in which the letters to the left of the central fixation were case alternated (e.g., aMbItion, mOdLants) and a condition in which the letters to the right of fixation were case alternated (e.g., collApSe, pireNtOl). Alternating the case of letters to the right of fixation slowed lexical decision responses more than alternating letter case to the left of fixation. The results provide further support for a split fovea account of visual word recognition according to which those letters of a centrally-fixated word that fall to the left of fixation are processed initially by the right cerebral hemisphere while those letters that fall to the right of fixation are processed initially by the left cerebral hemisphere, with the characteristics of the left and right hemispheres being revealed in the processing of initial and final letters in centrally presented words.

Evaluating a split processing model of visual word recognition: effects of word length.

A new theory of visual word recognition is based on the fact that the fovea is split in humans. When a reader fixates the center of a written word, the initial letters of the word that are to the left of fixation are projected first to the right cerebral hemisphere (RH) while the final letters are projected to the left cerebral hemisphere (LH). This paper explores the possibility that this has consequences for the early processing of the beginning and ends of centrally fixated words: specifically that lexical decision RTs are affected by the number of letters to the left of fixation but not by the number of letters to the right of fixation. For centrally presented five- and eight-letter words, we manipulated number of letters presented to the right or to the left of a fixation point (Experiment 1). We found that longer latencies to longer letter strings characterised the processing of the initial letters of words while LH word recognition features characterised the ends of words. Experiment 2 was a lateralized version of Experiment 1, and revealed the well established visual field and word length interaction. The results supported the split fovea theory.

Mixed-case effects in lateralized word recognition.

Effects of case alternation and word length were studied in a lateralized visual lexical decision task. The previously reported visual field and word length interaction was found for upper- and lowercase presentations, but not for MiXeD CaSe, where both fields were affected by word length. We discuss the results in light of two contrasting models of lateralized word recognition.

Analysis of standard and non-standard visual word format in the two hemispheres.

A dual-route model for the recognition of written words is hypothesised. The model postulates that the two cerebral hemispheres differ in their sensitivity to the visual format of verbal stimuli. Such stimuli may be 'standard', that is in Standard Visual Format (SVF), or "non-standard", i.e. in non-standard Visual Format (NSVF). In the left hemisphere (LH), SVF words are routed directly to the lexicon, while NSVF words must go through an additional encoding phase prior to lexicon access. In the right hemisphere (RH) all words (SVF and NSVF) must proceed to an additional encoding phase prior to accessing the lexicon. Two lateralized lexical decision experiments are reported. In Section 2, angle of orientation was used to define SVF and NSVF. In Section 3, presentation of verbal stimuli was preceded by a cue indicating whether the coming lexical stimulus was in SVF or NSVF, while SVF was defined as in Section 2. The results showed that the difference in RT, favouring RVF stimulation was found for orientations up to 30 degrees. Greater angles of presentation significantly reduced RVF superiority. The largest differences between responses to stimuli presented to the two visual fields was found when word stimuli were in SVF (up to 30 degrees ) and presented after a priming cue. The results are discussed in terms of the model, but alternative explanations are suggested.

Lexical decision, visual hemifield and angle of orientation.

Varying the orientation of word or nonword target stimuli from 0 degree to 90 degrees in a lexical decision-visual hemifield task results in an increase in RT and a decrease in accuracy and d'. RVF superiority, as measured by d' was found at all orientations. RVF superiority, as measured by RT was only found for stimulation by words at orientations of 0 degree and 15 degrees. There was a significant bias to respond 'word' (log beta) only for stimulation of the RVF at orientations of 0 degree and 15 degrees. Under all other conditions, there was no significant response bias. A 'normal' (horizontal) presentation format seems to be necessary for the finding of a greater RVF bias to respond 'word' and for RVF superiority in speed of processing linguistic stimuli. However, a horizontal presentation format does not seem to be necessary for the RVF superiority in its capability to discriminate words from nonwords.

A comparison of prospective and retrospective assessments of sleep.

The main purpose of this study was to evaluate the correlations between retrospective and prospective assessments of sleep. Subjective reports of sleep characteristics and sleep quality were obtained from 146 young (20-40 years, average age 29.15) healthy men (n = 43), nonpregnant (n = 70) and pregnant women (n = 33). Three types of subjective sleep reports were obtained: (1) general estimates of sleep habits (retrospective measures); (2) sleep logs completed upon awakening on three successive workdays (prospective measures); and (3) general sleep complaints. Men showed the greatest stability in the sleep log reports, followed by nonpregnant women, with pregnant women showing the least stability. Significant positive correlations between prospective (log reported) and retrospective (general estimates) sleep measures were found only for men. However, for measures of sleep quality, such as feelings of fatigue upon awakening, women showed greater agreement between their general estimates and three nightly reports. The limitations of using retrospective estimates in sleep surveys are discussed.