Brain connectivity in positive and negative syndrome schizophrenia

If, as is widely believed, schizophrenia is characterized by abnormalities of brain functional connectivity, then it seems reasonable to expect that different subtypes of schizophrenia could be discriminated in the same way. However, evidence for differences in functional connectivity between the subtypes of schizophrenia is largely lacking and, where it exists, it could be accounted for by clinical differences between the patients (e.g. medication) or by the limitations of the measures used. In this study, we measured EEG functional connectivity in unmedicated male patients diagnosed with either positive or negative syndrome schizophrenia and compared them with age and sex matched healthy controls. Using new methodology (Medkour et al., 2009) based on partial coherence, brain connectivity plots were constructed for positive and negative syndrome patients and controls. Reliable differences in the pattern of functional connectivity were found with both syndromes showing not only an absence of some of the connections that were seen in controls but also the presence of connections that the controls did not show. Comparing connectivity graphs using the Hamming distance, the negative-syndrome patients were found to be more distant from the controls than were the positive syndrome patients. Bootstrap distributions of these distances were created which showed a significant difference in the mean distances that was consistent with the observation that negative-syndrome diagnosis is associated with a more severe form of schizophrenia. We conclude that schizophrenia is characterized by widespread changes in functional connectivity with negative syndrome patients showing a more extreme pattern of abnormality than positive syndrome patients.

Development of a binary positive and negative protein fragment complementation assay using yeast cytosine deaminase

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Development of a binary positive and negative protein fragment complementation assay using yeast cytosine deaminase

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Understanding Adolescents’ Positive and Negative Developmental Experiences in Sport

The purpose of this study was to gain understanding of adolescents’ positive and negative developmental experiences in sport. Twenty-two purposefully sampled adolescent competitive swimmers participated in a semistructured qualitative interview. Content analysis led to the organization of meaning units into themes and categories (Patton, 2002). Athletes suggested their sport involvement facilitated many positive developmental experiences (i.e., related to challenge, meaningful adult and peer relationships, a sense of community, and other life experiences) and some negative developmental experiences (i.e., related to poor coach relationships, negative peer influences, parent pressure, and the challenging psychological environment of competitive sport). Findings underline the important roles of sport programmers, clubs, coaches, and parents in facilitating youths’ positive developmental experiences in sport, while highlighting numerous important directions for future research. Implications for coach training and practice are outlined.

Vocational rehabilitation improves cognition and negative symptoms in schizophrenia

Several studies in schizophrenia found a positive association between cognitive performance and work status, and it has been reported that good cognitive performance at the outset does predict the success of vocational interventions. However little has been done to investigate whether vocational interventions itself benefit cognitive performance. To test this hypothesis we performed a randomized, placebo-controlled trial to investigate in remitted schizophrenic patients the effect of a 6-months vocational rehabilitation program on cognitive performance. We recruited 112 remitted and clinically stable schizophrenic patients who aimed to enter a vocational rehabilitation program. From these, 57 immediately entered a 6-months vocational rehabilitation program, whereas the remaining 55 were allocated to a waiting-list; the latter formed our control group, which received during the 6 months out-clinic follow-up treatment. Before and after the 6-months period we assessed changes in cognitive performance through a neuropsychological test battery, as well as changes in the psychopathological status and in quality of life. We found that vocational rehabilitation significantly improved patients` performance in cognitive measures that assess executive functions (concept formation, shifting ability, flexibility, inhibitory control, and judgment and critics abilities). Moreover, after 6 months the vocational group improved significantly in the negative symptoms and in quality of life, as compared to controls. Together with results from the literature, our findings reinforce the notion that the inclusion of vocational interventions may enhance the effectiveness of therapeutic strategies for schizophrenia patients. (C) 2010 Elsevier B.V. All rights reserved.

Correlations between negative-induced cerebral dynamics and idiopathic intellectual disability: an EEG study

Intellectual disability has long been associated with deficits in socio-emotional processing. However, studies investigating brain dynamics of maladaptive socio-emotional skills associated with intellectual disability are scarce. Here, we compared differences in brain activity between low intelligence quotient (I.Q.<75, N=13) and normal controls (N=15) while evaluating their subjective emotions. Positive (P) and negative (N) valenced pictures were presented one at a time to participants of both groups, at a rate of ¾. The task required that each participant evaluate their subjective emotion and press a predefined push-button when done, alternatively P and N. Electroencephalographic (EEG) signals were continuously recorded, and the 1000ms time window following each picture was analyzed offline for power in frequency domain. Alpha low (8-10Hz) and upper (10-13Hz) frequency bands were then compared for both groups and for both P and N emotions in 12 distributed scalp electrodes. The qualitative evaluation of emotions was similar between both groups, with constant longer reaction times for the low IQ participants. The EEG signal comparison shows marked power decrease in upper alpha frequency range for N emotions in low intelligence group. Otherwise no significant difference was noticed between low and normal IQ. Main findings of the present study are (1) results do not support the hypothesis that impairment in developmental intelligence roots in maladaptive emotional processing; (2) the strong alpha power suppression during negative-induced emotions suggests the involvement of an extended neural network and more effortful inhibition processes than positive ones. We call for further studies with a larger sample.

Anti-Leishmania titers and positive skin tests in patients cured of kala-azar

Visceral leishmaniasis (VL), also known as kala-azar, is an important public health problem. If not treated, virtually all clinically symptomatic patients die within months. The diagnosis is based on the Montenegro skin test (MST) and anti-Leishmania titers. Nevertheless, the time required for cured individuals living in a leishmaniasis-endemic area to present a positive skin test and negative anti-Leishmania serology is known. To determine the cellular and humoral immune response profile in relation to different times post-VL cure, a cross-sectional study was conducted on subjects from a kala-azar endemic area in Paço do Lumiar, MA, Brazil, on the basis of 1995-2005 notifications reported by the National Health Foundation/Regional Coordination of Maranhão. We visited cured individuals with a history of VL within the last 10 years. Seventy-four subjects (30 females) ranging in age from 1 to 44 years were included, all of them symptom free at the time of the study. A cellular immune response was observed in 73 (98.6%) subjects, whereas no significant antibody titers were detected by indirect immunofluorescence (IIF) in the sera of 69 (93.2%) cases. Ten years post-cure, 39 (52%) subjects had a positive MST and negative IIF reaction, while in one subject the skin and anti-Leishmania serology tests were negative. Two other subjects were positive in both tests 1 year after cure. These data suggest that a cellular immune response may still be present in subjects cured of VL regardless of post-cure time, and that the parasite persists in the host after clinical cure of the disease. This would explain the persistence of significant Leishmania sp antibody titers in some subjects after treatment.

Longitudinal associations between passions and adjustment in adolescence: Positive mood and unstructured leisure activities as mediators

Passions are activities that people find important, like or enjoy, and on which they spend large amounts of time. Research examining passions in adolescence has been limited, despite a tendency for adolescents to explore their identity by trying new activities (Dworkin et aI., 2003). The purpose of the present study was to examine the association between adolescent passions and positive adjustment (psychological well-being, optimism, purpose in life, and low risktaking), as well as investigate possible underlying mechanisms for the link between passions and adjustment. High school students (N=2270, 48.7% female) from Southern Ontario completed questionnaires in grades 10, 11, and 12. Path analyses were conducted to examine cross-lag paths among all study variables. Passions predicted higher optimism and purpose, as well as lower negative risk-taking, over time, but these adjustment indicators in tum did not predict higher passions over time. Additionally, positive mood and unstructured leisure activities partially mediated these associations. Passions appears to be important for adolescent adjustment, and may serve as a protective factor or help to foster thriving.

Aging is associated with positive responding to neutral information but reduced recovery from negative information

Studies on aging and emotion suggest an increase in reported positive affect, a processing bias of positive over negative information, as well as increasingly adaptive regulation in response to negative events with advancing age. These findings imply that older individuals evaluate information differently, resulting in lowered reactivity to, and/or faster recovery from, negative information, while maintaining more positive responding to positive information. We examined this hypothesis in an ongoing study on Midlife in the US (MIDUS II) where emotional reactivity and recovery were assessed in a large number of respondents (N = 159) from a wide age range (36–84 years). We recorded eye-blink startle magnitudes and corrugator activity during and after the presentation of positive, neutral and negative pictures. The most robust age effect was found in response to neutral stimuli, where increasing age is associated with a decreased corrugator and eyeblink startle response to neutral stimuli. These data suggest that an age-related positivity effect does not essentially alter the response to emotion-laden information, but is reflected in a more positive interpretation of affectively ambiguous information. Furthermore, older women showed reduced corrugator recovery from negative pictures relative to the younger women and men, suggesting that an age-related prioritization of well-being is not necessarily reflected in adaptive regulation of negative affect.

Can Rachman’s indirect pathways be used to un-learn fear? A prospective paradigm to test whether children’s fears can be reduced using positive information and modelling a non-anxious response

This study investigated whether children’s fears could be un-learned using Rachman’s indirect pathways for learning fear. We hypothesised that positive information and modelling a non-anxious response are effective methods of un-learning fears acquired through verbal information. One hundred and seven children aged 6–8 years received negative information about one animal and no information about another. Fear beliefs and behavioural avoidance were measured. Children were randomised to receive positive verbal information, modelling, or a control task. Fear beliefs and behavioural avoidance were measured again. Positive information and modelling led to lower fear beliefs and behavioural avoidance than the control condition. Positive information was more effective than modelling in reducing fear beliefs and both methods significantly reduced behavioural avoidance. The results support Rachman’s indirect pathways as viable fear un-learning pathways and supports associative learning theories.

Social anxiety and negative early life events in university students

INTRODUCTION: There is substantial evidence regarding the impact of negative life events during childhood on the aetiology of psychiatric disorders. We examined the association between negative early life events and social anxiety in a sample of 571 Spanish University students. METHODS: In a cross-sectional survey conducted in 2007, we collected data through a semistructured questionnaire of sociodemographic variables, personal and family psychiatric history, and substance abuse. We assessed the five early negative life events: (i) the loss of someone close, (ii) emotional abuse, (iii) physical abuse, (iv) family violence, and (v) sexual abuse. All participants completed the Liebowitz Social Anxiety Scale. RESULTS: Mean (SD) age was 21 (4.5), 75% female, LSAS score was 40 (DP = 22), 14.2% had a psychiatric family history and 50.6% had negative life events during childhood. Linear regression analyses, after controlling for age, gender, and family psychiatric history, showed a positive association between family violence and social score (p = 0.03). None of the remaining stressors produced a significant increase in LSAS score (p > 0.05). CONCLUSION: University students with high levels of social anxiety presented higher prevalence of negative early life events. Thus, childhood family violence could be a risk factor for social anxiety in such a population.

Positive Affect and Sleep in Spousal Alzheimer Caregivers: A Longitudinal Study.

This article examines the longitudinal relation between positive affect (PA) and sleep in 126 spousal Alzheimer's disease caregivers. Caregivers underwent 4 yearly assessments for the Positive and Negative Affect Schedule, the self-rated Pittsburgh Sleep Quality Index, and actigraphy to objectify nighttime total sleep time, wake after sleep onset, and percentage of sleep. Increased levels of PA and a greater positivity (i.e., positive-to-negative affect) ratio were significantly associated with better subjective sleep over the entire study period. Yearly increases in PA-even when controlling for negative affect (NA)-and in the positivity ratio were also associated with better subjective sleep. PA and actigraphy measures showed no significant relations. Increased PA is longitudinally associated with better sleep in dementia caregivers largely independent of NA.

Examining invisible social control as predictor of daily smoking and negative affect after a self-set quit date

Objectives: The dual-effects model of social control proposes that social control leads to better health practices, but also arouses psychological distress. However, findings are inconsistent in relation to health behavior and psychological distress. Recent research suggests that the most effective control is unnoticed by the receiver (i.e., invisible). There is some evidence that invisible social control is beneficial for positive and negative affective reactions. Yet, investigations of the influence of invisible social control on daily smoking and distress have been limited. In daily diaries, we investigated how invisible social control is associated with number of cigarettes smoked and negative affect on a daily basis. Methods: Overall, 99 smokers (72.0% men, mean age M = 40.48, SD = 9.82) and their non-smoking partners completed electronic diaries from a self-set quit date for 22 consecutive days within the hour before going to bed, reporting received and provided social control, daily number of cigarettes smoked, and negative affect. Results: Multilevel analyses indicated that between-person levels of invisible social control were associated with lower negative affect, whereas they were unrelated to number of cigarettes smoked. On days with higher-than-average invisible social control, smokers reported less cigarettes smoked and more negative affect. Conclusions: Between-person level findings indicate that invisible social control can be beneficial for negative affect. However, findings on the within-person level are in line with the assumptions of the dual-effects model of social control: Invisible social control reduced daily smoking and simultaneously increased daily negative affect within person.

Magnetic resonance imaging (MRI) detection of the murine brain response to light: temporal differentiation and negative functional MRI changes.

Using a 9.4 T MRI instrument, we have obtained images of the mouse brain response to photic stimulation during a period between deep anesthesia and the early stages of arousal. The large image enhancements we observe (often >30%) are consistent with literature results extrapolated to 9.4 T. However, there are also two unusual aspects to our findings. (i) The visual area of the brain responds only to changes in stimulus intensity, suggesting that we directly detect operations of the M visual system pathway. Such a channel has been observed in mice by invasive electrophysiology, and described in detail for primates. (ii) Along with the typical positive response in the area of the occipital portion of the brain containing the visual cortex, another area displays decreased signal intensity upon stimulation.

Investigation of the coping antecedents to positive outcomes and distress in multiple sclerosis (MS)

This study examined relations between stress and coping predictors and distress and positive outcomes in multiple sclerosis (MS). A total of 502 people with MS completed a questionnaire at Time 1 and, 3 months later, Time 2 (n= 404). Predictors included Time 1 illness (duration, number of symptoms, course), number of problems, appraisal and coping (acceptance, problem solving, emotional release, avoidance, personal health control, energy conservation). Dependent variables were Time 2 distress (anxiety, depression) and positive outcomes (life satisfaction, positive affect, benefits). Results indicated that as hypothesised, personal health control, emotional release and physical assistance were related to the positive outcomes, whereas avoidance was related to distress, and acceptance was associated with the positive outcomes and distress. Findings highlight the differential relations between coping strategies and positive and negative outcomes and the role of appraisal and coping in regulating distress and promoting positive psychological states while managing a chronic illness.