Accelerated sequential bilateral theta-burst stimulation in major depression: an open trial

Theta burst stimulation (TBS) is approved and widely used in the treatment of treatment resistant-major depression. More recently, accelerated protocols delivering multiple treatments per day have been shown to be efficacious and potentially enhance outcomes compared to once daily protocols. Meanwhile, bilateral treatment protocols have also been increasingly tested to enhance outcomes. Here, we examined the efficacy and safety of accelerated bilateral TBS in major depressive disorder (MDD). In this open label pilot study, 25 patients with MDD (60%: women; mean age (SD): 45.24 (12.22)) resistant to at least one antidepressant, received bilateral TBS, consisting of 5 sequential bilateral intermittent TBS (iTBS) (600 pulses) and continuous TBS (cTBS) (600 pulses) treatments delivered to the left and right dorsolateral prefrontal cortex (DLPFC), respectively, daily for 5 days at 120% resting motor threshold. Outcome measures were post-treat treatment changes at day 5 and 2-weeks in Hamilton Depression Rating Scale (HDRS-17) scores and response (≥ 50% reduction from the baseline scores) and remission (≤ 7) rates. There was a significant reduction in HDRS scores at day 5 (p < 0.001) and 2-weeks post treatment (p < 0.001). The response rates increased from 20% at day 5 to 32% at 2-weeks post treatment suggesting delayed clinical effects. However, reduction in symptom scores between two post treatment endpoints was non-significant. 60% of patients could not tolerate the high intensity stimulation. No major adverse events occurred. Open label uncontrolled study with small sample size. These preliminary findings suggest that accelerated bilateral TBS may be clinically effective and safe for treatment resistant depression. Randomized sham-controlled trials are needed to establish the therapeutic role of accelerated bilateral TBS in depression.Trial registration: ClinicalTrials.gov, NCT10001858.

Multimodal imaging measures in the prediction of clinical response to deep brain stimulation for refractory depression: A machine learning approach

OBJECTIVES

This study compared machine learning models using unimodal imaging measures and combined multi-modal imaging measures for deep brain stimulation (DBS) outcome prediction in treatment resistant depression (TRD).

METHODS

Regional brain glucose metabolism (CMRGlu), cerebral blood flow (CBF), and grey matter volume (GMV) were measured at baseline using 18F-fluorodeoxy glucose (18F-FDG) positron emission tomography (PET), arterial spin labelling (ASL) magnetic resonance imaging (MRI), and T1-weighted MRI, respectively, in 19 patients with TRD receiving subcallosal cingulate (SCC)-DBS. Responders (n = 9) were defined by a 50% reduction in HAMD-17 at 6 months from the baseline. Using an atlas-based approach, values of each measure were determined for pre-selected brain regions. OneR feature selection algorithm and the naïve Bayes model was used for classification. Leave-out-one cross validation was used for classifier evaluation.

RESULTS

The performance accuracy of the CMRGlu classification model (84%) was greater than CBF (74%) or GMV (74%) models. The classification model using the three image modalities together led to a similar accuracy (84%0 compared to the CMRGlu classification model.

CONCLUSIONS

CMRGlu imaging measures may be useful for the development of multivariate prediction models for SCC-DBS studies for TRD. The future of multivariate methods for multimodal imaging may rest on the selection of complementing features and the developing better models.Clinical Trial Registration: ClinicalTrials.gov (#NCT01983904).

Functional brain network features specify DBS outcome for patients with treatment resistant depression

Deep brain stimulation (DBS) has shown therapeutic benefits for treatment resistant depression (TRD). Stimulation of the subcallosal cingulate gyrus (SCG) aims to alter dysregulation between subcortical and cortex. However, the 50% response rates for SCG-DBS indicates that selection of appropriate patients is challenging. Since stimulation influences large-scale network function, we hypothesized that network features can be used as biomarkers to inform outcome. In this pilot project, we used resting-state EEG recorded longitudinally from 10 TRD patients with SCG-DBS (11 at baseline). EEGs were recorded before DBS-surgery, 1-3 months, and 6 months post surgery. We used graph theoretical analysis to calculate clustering coefficient, global efficiency, eigenvector centrality, energy, and entropy of source-localized EEG networks to determine their topological/dynamical features. Patients were classified as responders based on achieving a 50% or greater reduction in Hamilton Depression (HAM-D) scores from baseline to 12 months post surgery. In the delta band, false discovery rate analysis revealed that global brain network features (segregation, integration, synchronization, and complexity) were significantly lower and centrality of subgenual anterior cingulate cortex (ACC) was higher in responders than in non-responders. Accordingly, longitudinal analysis showed SCG-DBS increased global network features and decreased centrality of subgenual ACC. Similarly, a clustering method separated two groups by network features and significant correlations were identified longitudinally between network changes and depression symptoms. Despite recent speculation that certain subtypes of TRD are more likely to respond to DBS, in the SCG it seems that underlying brain network features are associated with ability to respond to DBS. SCG-DBS increased segregation, integration, and synchronizability of brain networks, suggesting that information processing became faster and more efficient, in those patients in whom it was lower at baseline. Centrality results suggest these changes may occur via altered connectivity in specific brain regions especially ACC. We highlight potential mechanisms of therapeutic effect for SCG-DBS.

A computational neuroimaging study of reinforcement learning and goal-directed exploration in schizophrenia spectrum disorders

BACKGROUND

Prior evidence indicates that negative symptom severity and cognitive deficits, in people with schizophrenia (PSZ), relate to measures of reward-seeking and loss-avoidance behavior (implicating the ventral striatum/VS), as well as uncertainty-driven exploration (reliant on rostrolateral prefrontal cortex/rlPFC). While neural correlates of reward-seeking and loss-avoidance have been examined in PSZ, neural correlates of uncertainty-driven exploration have not. Understanding neural correlates of uncertainty-driven exploration is an important next step that could reveal insights to how this mechanism of cognitive and negative symptoms manifest at a neural level.

METHODS

We acquired fMRI data from 29 PSZ and 36 controls performing the Temporal Utility Integration decision-making task. Computational analyses estimated parameters corresponding to learning rates for both positive and negative reward prediction errors (RPEs) and the degree to which participates relied on representations of relative uncertainty. Trial-wise estimates of expected value, certainty, and RPEs were generated to model fMRI data.

RESULTS

Behaviorally, PSZ demonstrated reduced reward-seeking behavior compared to controls, and negative symptoms were positively correlated with loss-avoidance behavior. This finding of a bias toward loss avoidance learning in PSZ is consistent with previous work. Surprisingly, neither behavioral measures of exploration nor neural correlates of uncertainty in the rlPFC differed significantly between groups. However, we showed that trial-wise estimates of relative uncertainty in the rlPFC distinguished participants who engaged in exploratory behavior from those who did not. rlPFC activation was positively associated with intellectual function.

CONCLUSIONS

These results further elucidate the nature of reinforcement learning and decision-making in PSZ and healthy volunteers.

Early post-treatment blood oxygenation level-dependent responses to emotion processing associated with clinical response to pharmacological treatment in major depressive disorder

INTRODUCTION

Pre-treatment blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) has been used for the early identification of patients with major depressive disorder (MDD) who later respond or fail to respond to medication. However, BOLD responses early after treatment initiation may offer insight into early neural changes associated with later clinical response. The present study evaluated both pre-treatment and early post-treatment fMRI responses to an emotion processing task, to further our understanding of neural changes associated with a successful response to pharmacological intervention.

METHODS

MDD patients who responded (n = 22) and failed to respond (n = 12) after 8 weeks of treatment with either citalopram or quetiapine extended release, and healthy controls (n = 18) underwent two fMRI scans, baseline (pre-treatment), and early post-treatment (one week after treatment commencement). Participants completed an emotional face matching task at both scans.

RESULTS

Using threshold-free cluster enhancement (TFCE) and non-parametric permutation testing, fMRI activation maps showed that after one week of treatment, responders demonstrated increased activation in the left parietal lobule, precentral gyrus, and bilateral insula (all P < 0.05 threshold-free cluster enhancement (TFCE) family-wise error-corrected) to negative facial expressions. Non-responders showed some small increases in the precentral gyrus, while controls showed no differences between scans. Compared to non-responders, responders showed some increased activation in the superior parietal lobule and middle temporal gyrus at the post-treatment scan. There were no group differences between responders, non-responders, and controls at baseline.

CONCLUSIONS

One week after treatment commencement, BOLD signal changes in the parietal lobules, insula, and middle temporal gyrus were related to clinical response to pharmacological treatment.

Unchanged food approach-avoidance behaviour of healthy men after oxytocin administration

The oxytocinergic system has been assumed to contribute to food intake, possibly via interactions with dopamine. However, so far, it is unknown whether oxytocin influences the underlying motivational behaviour towards food. In the present study, we used a food-based approach-avoidance task (AAT) in a randomised, placebo-controlled, double-blind, cross-over design to compare intranasal oxytocin with a placebo. In the AAT, participants pushed or pulled a joystick when images of foods with a high or low craving rating were presented, where differences in response times typically reflect approach and avoidance motivational biases towards positively and negatively valence stimuli, respectively. Thirty-three healthy male participants (age = 25.12 ± 3.51 years; body mass index = 24.25 ± 2.48 kg/m² ) completed the two-session study, one with placebo and the other with oxytocin. We used mixed-effects models to investigate effects of treatment (oxytocin, placebo), response type (approach, avoid) and stimulus (high, low craving). The results showed that both approach and avoid responses tended to be faster for foods higher in craving compared to foods lower in craving. Most importantly, we did not observe any significant effects of oxytocin compared to placebo in motivational behaviour towards food. Our study demonstrates a general response bias towards foods with different craving values, which could have implications for future studies investigating food-related behaviour. We discuss possible explanations for the null effects of oxytocin and suggest further investigation of the relationship between oxytocin, dopamine and food-reward processing.

Approach and Avoidance Behavior in Female Patients With Borderline Personality Disorder

Objectives

Borderline personality disorder (BPD) is portrayed by unstable relationships, fears of abandonment and heightened sensitivity to social rejection. Research has shown that these characteristics may lead to inappropriate social behavior including altered approach-avoidance behavior. However, it has remained unclear how social exclusion may affect approach-avoidance behavior in patients with BPD.

Design

We assessed social approach-avoidance behavior and the impact of social exclusion in a sample of 38 patients with BPD and 40 healthy control participants.

Methods

We used an explicit joystick-based approach-avoidance task (AAT) after playing a virtual ball-tossing game (Cyberball), which simulates the exclusion of the participant by two other players. In the AAT, participants were required to push or pull emotional stimuli, more specifically happy and angry facial expressions, with either direct or averted gaze direction.

Results

Patients with BPD approached happy stimuli less and showed overall less differential approach-avoidance behavior toward individuals expressing positive or negative facial emotions compared to healthy participants, who showed more approach behavior for happy compared to angry facial expressions. Moreover, borderline symptom severity correlated inversely with the AAT score for happy facial expressions and positively with subjective unpleasantness during social exclusion as well as rejection sensitivity. However, social exclusion did not influence approach-avoidance tendencies.

Conclusion

Patients with BPD showed altered approach-avoidance behavior, which might affect social interactions in the patient’s everyday lives and may therefore impede social interaction.

Rostral anterior cingulate glutamate predicts response to subcallosal deep brain stimulation for resistant depression

BACKGROUND

Deep brain stimulation (DBS) of the subcallosal cingulate (SCC) provided benefit for treatment-resistant depression (TRD) in open-label studies but failed in a recent randomized sham-controlled trial. Informed patient selection, based on reliable biomarkers, is needed to optimize outcome. We investigated if rostral anterior cingulate (rACC) glutamate/glutamine concentration could serve as a potential biomarker of response.

METHODS

Sixteen adults with TRD (Major Depression; MDD = 14; Bipolar Depression; BD =2) underwent proton magnetic resonance spectroscopy using a short-echo proton spectroscopy with a voxel placed in the rACC, prior to DBS. Improvement in depression was assessed using the 17-item Hamilton Rating Scale for Depression (HDRS). Glutamate and glutamine concentrations at baseline in the rACC were examined in relation to clinical outcomes at six months.

RESULTS

Lower baseline glutamate predicted significant reduction in HDRS scores in all TRD patients (p = 0.018), and predicted both HDRS reduction (p = 0.002) and 6-month response outcome in MDD-TRD patients (p = 0.013). Neither baseline glutamine nor glutamine/glutamate ratio significantly related to outcome or symptom improvement.

LIMITATIONS

Our study was limited by sample size, though it is large for a DBS study. We measured from a single voxel in the brain, so we cannot be certain our findings are specific to the rACC.

CONCLUSIONS

These preliminary results suggest that baseline rACC-glutamate concentration could serve as a response-predictive biomarker for SCC-DBS, particularly in patients with resistant major depression. If our findings are replicated and validated, rACC-glutamate may provide a basis to prospectively select TRD patients to improve likelihood of response to SCC-DBS.

Thalamocortical connectivity in electroconvulsive therapy for major depressive disorder

BACKGROUND

Electroconvulsive therapy (ECT) can lead to rapid and effective responses in major depressive disorder (MDD). However, the precise neural mechanisms of ECT for MDD are still unclear. Previous work has confirmed that thalamocortical circuits play an important role in emotion and cognition. However, the relationship between mechanisms of ECT for MDD and thalamocortical connectivity has not yet been investigated.

METHOD

Thalamocortical functional connectivity analysis was performed on resting-state functional magnetic resonance imaging (fMRI) data collected from 28 MDD patients both pre- and post-ECT treatment, as well as 20 healthy controls. The cortex was parceled into six regions of interest (ROIs), which were used as seeds to assess the functional connectivity between the cortex and each voxel in the thalamus. Then, functional connectivity between the identified thalamic subregions and the rest of the brain was quantified to better localize thalamocortical connectivity related to ECT. Structural connectivity among the functionally abnormal regions was also determined using probabilistic tractography from diffusion tensor imaging (DTI) data.

RESULTS

There was decreased parietal cortex-left pulvinar and left pulvinar-bilateral precuneus functional connectivity in post-ECT MDD patients, compared to pre-ECT MDD patients. Furthermore, functional connectivity strength of parietal cortex-left pulvinar and left pulvinar-bilateral precuneus was negative correlation with verbal fluency test scores in post-ECT MDD patients. No significant change was found in structural connectivity analysis.

LIMITATIONS

The sample size of our study was not large.

CONCLUSION

Our findings implicate that the specific abnormalities in thalamocortical circuit may be associated with cognitive impairment induced by ECT.

Author Correction: Obesity and addiction

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Intrinsic thalamocortical connectivity varies in the age of onset subtypes in major depressive disorder

BACKGROUND

Differences in the thalamocortical system have been shown in patients with major depressive disorder (MDD). Given prior evidence of phenotypic heterogeneity by the age of onset in MDD, we examined whether differences in thalamocortical connectivity could identify biological subtypes of MDD defined by the age of illness onset.

METHODS

A total of 94 subjects including 20 early-onset (EO) MDD (onset, 18 years), 34 adult-onset (AO) MDD, and 40 healthy controls (HCs) underwent resting-state functional MRI. Blood-oxygen-level-dependent time courses were extracted from six cortical regions of interest (ROIs) consisting of frontal, temporal, parietal, and occipital lobes and precentral and postcentral gyri. Each ROI's time course was then correlated with each voxel in thalamus, while covarying out signal from every other ROI.

RESULTS

The analysis of variance results showed significant main effects of group in frontal and temporal connectivity with thalamus. Group contrasts showed a right fronto-thalamic hypo-connectivity only in AO-MDD, but not in EO-MDD, when compared to HCs. However, direct comparison between EO-MDD and AO-MDD showed no differences. Furthermore, there was a right temporal-thalamic hyperconnectivity in both EO-MDD and AO-MDD patients relative to HCs. These results were not accounted for by sex, age, or illness burden.

CONCLUSION

The age of illness onset may be a source of heterogeneity in fronto-thalamic intrinsic connectivity in MDD.

Impaired Expected Value Computations in Schizophrenia Are Associated With a Reduced Ability to Integrate Reward Probability and Magnitude of Recent Outcomes

BACKGROUND

Motivational deficits in people with schizophrenia (PSZ) are associated with an inability to integrate the magnitude and probability of previous outcomes. The mechanisms that underlie probability-magnitude integration deficits, however, are poorly understood. We hypothesized that increased reliance on "valueless" stimulus-response associations, in lieu of expected value (EV)-based learning, could drive probability-magnitude integration deficits in PSZ with motivational deficits.

METHODS

Healthy volunteers (n = 38) and PSZ (n = 49) completed a learning paradigm consisting of four stimulus pairs. Reward magnitude (3, 2, 1, 0 points) and probability (90%, 80%, 20%, 10%) determined each stimulus's EV. Following a learning phase, new and familiar stimulus pairings were presented. Participants were asked to select stimuli with the highest reward value.

RESULTS

PSZ with high motivational deficits made increasingly less optimal choices as the difference in reward value (probability × magnitude) between two competing stimuli increased. Using a previously validated computational hybrid model, PSZ relied less on EV ("Q-learning") and more on stimulus-response learning ("actor-critic"), which correlated with Scale for the Assessment of Negative Symptoms motivational deficit severity. PSZ specifically failed to represent reward magnitude, consistent with model demonstrations showing that response tendencies in the actor-critic were preferentially driven by reward probability.

CONCLUSIONS

Probability-magnitude deficits in PSZ with motivational deficits arise from underutilization of EV in favor of reliance on valueless stimulus-response associations. Confirmed by our computational hybrid framework, probability-magnitude integration deficits were driven specifically by a failure to represent reward magnitude. This work provides a first mechanistic explanation of complex EV-based learning deficits in PSZ with motivational deficits that arise from an inability to combine information from different reward modalities.

The impact of age of onset on amygdala intrinsic connectivity in major depression

BACKGROUND

Early-onset major depressive disorder (EO-MDD), beginning during childhood and adolescence, is associated with more illness burden and a worse prognosis than adult-onset MDD (AO-MDD), but little is known about the neural features distinguishing these subgroup phenotypes. Functional abnormalities of the amygdala are central to major depressive disorder (MDD) neurobiology; therefore, we examined whether amygdala intrinsic connectivity (IC) can differentiate EO-MDD from AO-MDD in a cohort of adult MDD patients.

SUBJECTS AND METHODS

Twenty-one EO-MDD (age of onset ≤18 years), 31 AO-MDD patients (age of onset ≥19 years), and 19 healthy controls (HCs) underwent resting-state functional magnetic resonance imaging (7 minutes). Amygdala seed-based resting-state functional connectivity was compared between groups.

RESULTS

AO-MDD patients showed loss of inverse left amygdala-left dorsolateral prefrontal cortex IC and increased inverse left amygdala-left inferior parietal IC, compared to both HCs and EO-MDD. EO-MDD showed a switch from inverse to positive IC with right dorsomedial prefrontal cortex, compared to HCs and AO-MDD. This effect was removed when we controlled for illness burden.

CONCLUSION

Alterations in amygdala IC with the default-mode network were specifically related to EO-MDD, whereas amygdala IC with executive cognitive control regions was preferentially disrupted in AO-MDD. Increased illness burden, an important clinical marker of EO-MDD, accounted for its specific effects on amygdala IC. Brain imaging has the potential for validation of clinical subtypes and can provide markers of prognostic value in MDD patients.

Motivational Deficits in Schizophrenia Are Associated With Reduced Differentiation Between Gain and Loss-Avoidance Feedback in the Striatum

BACKGROUND

The current study was designed to test the hypothesis that motivational deficits in schizophrenia (SZ) are tied to a reduced ability to differentially signal gains and instances of loss-avoidance in the brain, leading to reduced ability to form adaptive representations of expected value.

METHODS

We administered a reinforcement learning paradigm to 27 medicated SZ patients and 27 control subjects in which participants learned three probabilistic discriminations. In regions of interest in reward networks identified a priori, we examined contrasts between trial types with different expected values (e.g., expected gain-nonmonetary) and between outcomes with the same prediction error valence but different experienced values (e.g., gain-loss-avoidance outcome, miss-loss outcome).

RESULTS

Both whole-brain and region of interest analyses revealed that SZ patients showed reduced differentiation between gain and loss-avoidance outcomes in the dorsal anterior cingulate cortex and bilateral anterior insula. That is, SZ patients showed reduced contrasts between positive prediction errors of different objective values in these areas. In addition, we observed significant correlations between gain-loss-avoidance outcome contrasts in the ventral striatum and ratings for avolition/anhedonia and between expected gain-nonmonetary contrasts in the ventral striatum and ventromedial prefrontal cortex.

CONCLUSIONS

These results provide further evidence for intact prediction error signaling in medicated SZ patients, especially with regard to loss-avoidance. By contrast, components of frontostriatal circuits appear to show reduced sensitivity to the absolute valence of expected and experienced outcomes, suggesting a mechanism by which motivational deficits may emerge.

Thalamocortical connectivity in major depressive disorder

BACKGROUND

Major Depressive Disorder (MDD) is highly prevalent and potentially devastating, with widespread aberrations in brain activity. Thalamocortical networks are a potential candidate marker for psychopathology in MDD, but have not yet been thoroughly investigated. Here we examined functional connectivity between major cortical areas and thalamus.

METHOD

Resting-state fMRI from 54 MDD patients and 40 healthy controls were collected. The cortex was segmented into six regions of interest (ROIs) consisting of frontal, temporal, parietal, and occipital lobes and pre-central and post-central gyri. BOLD signal time courses were extracted from each ROI and correlated with voxels in thalamus, while removing signals from every other ROI.

RESULTS

Our main findings showed that MDD patients had predominantly increased connectivity between medial thalamus and temporal areas, and between medial thalamus and somatosensory areas. Furthermore, a positive correlation was found between thalamo-temporal connectivity and severity of symptoms.

LIMITATIONS

Most of the patients in this study were not medication naïve and therefore we cannot rule out possible long-term effects of antidepressant use on the findings.

CONCLUSION

The abnormal connectivity between thalamus and temporal, and thalamus and somatosensory regions may represent impaired cortico-thalamo-cortical modulation underlying emotional, and sensory disturbances in MDD. In the context of similar abnormalities in thalamocortical systems across major psychiatric disorders, thalamocortical dysconnectivity could be a reliable transdiagnostic marker.

Alterations in event-related potential responses to empathy for pain in schizophrenia

Lack of empathy is a critical factor impacting on social functioning and quality of life in schizophrenia. There is, however, a paucity of research into the underlying neurophysiological correlates of empathy deficits in this disorder. Accordingly, we sought: (1) to identify whether dysfunctional empathic abilities in schizophrenia are related to alterations in early or late brain processes, and (2) to explore the potential relationship between brain activity and mood, self-reported empathy and symptom severity. Eighteen patients with schizophrenia and 21 healthy matched controls performed an empathy-for-pain paradigm where photographs of hands in neutral or painful situations were shown while we recorded their electroencephalography (EEG), and we examined mood, empathic concern for others and symptom severity. Significant group differences between patients and controls emerged in early (50-150ms after stimulus onset) and late (after 300ms) timeframes. Moreover, brain activity was related with unpleasantness ratings in all participants, with self-reported empathic concern only in controls and with negative mood and personal distress only in patients. Differences in social behavior in schizophrenia may be explained by early as well as late differences, affecting mostly the early frontocentral ERPs, i.e. those suggested to correspond to the emotional sharing component of empathy.

EEG power, cordance and coherence differences between unipolar and bipolar depression

INTRODUCTION

Understanding the biological underpinnings of unipolar (UD) and bipolar depression (BD) is vital for avoiding inappropriate treatment through the misdiagnosis of bipolar patients in their first depressive episode. One plausible way to distinguish between UD and BD is to compare EEG brain dynamics to identify potential neurophysiological biomarkers. Here we aimed to test group differences in EEG power, cordance and coherence values between UD and BD.

METHODS

Twenty-five bipolar and 56 unipolar depression patients were recruited. Sociodemographic and clinical variables were collected in addition to resting state EEG. Data was analyzed with multivariate and repeated analyses of variance where parametric assumptions were met.

RESULTS

Accordingly, we did not find any differences in the EEG absolute power and frontal asymmetry indexes between UD and BD. Regarding cordance, significant group differences were observed in the right theta cordance values (p=0.031). Regarding coherence, BD patients (as compared to UD) exhibited greater central-temporal theta (p=0.003), and parietal-temporal alpha (p=0.007) and theta (p=0.001) coherence. Lastly, less alpha coherence in BD was present at right frontal-central (p=0.007) and central inter-hemispheric (p=0.019) regions.

CONCLUSIONS

Our results demonstrate that EEG cordance and coherence values have potential to discriminate between UD and BD. The loss of temporal synchronization in the frontal interhemispheric and right sided frontolimbic neuronal networks may be a unique feature that distinguishes between BD and UD.

Integrating frequency and magnitude information in decision-making in schizophrenia: An account of patient performance on the Iowa Gambling Task

BACKGROUND

The Iowa Gambling Task (IGT; Bechara et al., 1994) has frequently been used to assess risky decision making in clinical populations, including patients with schizophrenia (SZ). Poor performance on the IGT is often attributed to reduced sensitivity to punishment, which contrasts with recent findings from reinforcement learning studies in schizophrenia.

METHODS

In order to investigate possible sources of IGT performance deficits in SZ patients, we combined data from the IGT from 59 SZ patients and 43 demographically-matched controls with data from the Balloon Analog Risk Task (BART) in the same participants. Our analyses sought to specifically uncover the role of punishment sensitivity and delineate the capacity to integrate frequency and magnitude information in decision-making under risk.

RESULTS

Although SZ patients, on average, made more choices from disadvantageous decks than controls did on the IGT, they avoided decks with frequent punishments at a rate similar to controls. Patients also exhibited excessive loss-avoidance behavior on the BART.

CONCLUSIONS

We argue that, rather than stemming from reduced sensitivity to negative consequences, performance deficits on the IGT in SZ patients are more likely the result of a reinforcement learning deficit, specifically involving the integration of frequencies and magnitudes of rewards and punishments in the trial-by-trial estimation of expected value.

Metacognition in psychosis: comparison of schizophrenia with bipolar disorder

While deficits in metacognition have been observed in schizophrenia (SZ), it is less clear whether these are specific to the disorder. Accordingly, this study compared metacognitive abilities of patients with schizophrenia and bipolar disorder (BD) and examined the degree to which neurocognition contributed to metacognitive deficits in both groups. Participants were 30 patients with SZ and 30 with BD. Metacognitive capacity was measured using the Metacognition Assessment Scale Abbreviated (MAS-A). This scale comprises four domains: self-reflectivity, understanding others' minds, decentration and mastery. Verbal memory, executive functioning and symptoms were concurrently assessed. Group comparisons revealed that SZ patients had greater deficits in metacognitive self-reflectivity, which correctly classified 85.2% of patients with SZ in a logistic regression. Self-reflectivity and understanding others'minds were related to verbal memory and executive functioning in the SZ group, but not in the BD group. Furthermore, greater positive and general psychotic symptoms were associated with poorer metacognition in SZ. Results suggest SZ involves unique deficits in the ability to self-reflect and that these deficits may be uniquely linked with neurocognition.

Oxidative stress in schizophrenia: a case-control study on the effects on social cognition and neurocognition

BACKGROUND

Schizophrenia is a debilitating mental disorder that presents impairments in neurocognition and social cognition. Several studies have suggested that the etiology of schizophrenia can be partly explained by oxidative stress. However, our knowledge about the implications of oxidative stress on illness-related cognitive deficits is still far from being clear. The aim of this work was to study the role of oxidative stress molecules on social cognition and neurocognition in patients with schizophrenia.

METHODS

We assessed the peripheral levels of several molecules associated with oxidative stress, namely nitric oxide (NO), malondialdehyde (MDA), glutathione (GSH), homocysteine, superoxide dismutase (SOD) and neurotrophin 4/5 (NT4/5), in forty-one patients with schizophrenia and forty-three healthy participants. A battery of tests to measure neurocognition and social cognition was also administered to the schizophrenia group.

RESULTS

We found that the schizophrenia group presented substantially higher levels of oxidative stress than the control group, as revealed by elevated quantities of the pro-oxidants NO and MDA, and decreased levels of the antioxidants GSH, SOD and NT4/5. Interestingly, the levels of NT4/5, which have been shown to have antioxidant effects, correlated with executive functioning, as measured by two distinct tests (WCST and TMT). However, social cognition and symptom severity were not found to be associated with oxidative stress.

CONCLUSIONS

We propose a protective role of NT4/5 against oxidative stress, which appears to have a potentially beneficial impact on neurocognition in schizophrenia.

Metakognitive und sozial-kognitive Defizite bei Schizophrenien. Funktionelle Bedeutung und Behandlungsstrategien

Die Gruppe der Schizophrenien umfasst heterogene psychopathologische Syndrome, die oft mit neurokognitiven Störungen und niedrigem psychosozialen Funktionsniveau assoziiert sind. Empirische Studien legen nahe, dass viele mit Schizophrenie assoziierte Symptome auf Störungen der sozialen Kognition bzw. metakognitive Störungen zurückgeführt werden können. Diese Konzepte beziehen sich auf die Fähigkeit, soziale Signale wahrnehmen und interpretieren, eigene und psychische Zustände Anderer reflektieren und dieses Wissen flexibel in sozialen Interaktionen und zur Problemlösung einsetzen zu können. Der vorliegende Artikel gibt eine Übersicht über sozial-kognitive und metakognitive Defizite bei Schizophrenien und wie über das Training dieser Kernkompetenzen das psychosoziale Funktionsniveau von Patienten mit Schizophrenie verbessert werden kann. Bei Schizophrenien sind soziale Kognition und Metakognition eng mit dem psychosozialen Funktionsniveau verbunden, zum Teil jedoch auch abhängig von neurokognitiven Fähigkeiten. Sozial-kognitives bzw. metakognitives Training kann zur Verbesserung des psychosozialen Funktionsniveaus beitragen, möglicherweise aber in Abhängigkeit vom Lernpotential und der Motivation der Patienten. Zukünftige Studien sollten untersuchen, welche Subtypen innerhalb des Schizophrenie-Spektrums am ehesten von sozial-kognitivem und metakognitivem Training profitieren können und welche Gruppen ggf. zusätzlich neurokognitives Training benötigen, um das psychosoziale Funktionsniveau zu verbessern.

Intrinsic motivation and metacognition as predictors of learning potential in patients with remitted schizophrenia

BACKGROUND

Previous research has suggested that neurocognitive functioning predicts best the potential of patients with schizophrenia to acquire newly learned material, which, in turn may impact patients' social functioning. Recent studies have also shown that intrinsic motivation and metacognitive abilities play a decisive role in social functioning in schizophrenia. Accordingly, the present study sought to examine the relationship between intelligence, motivation, metacognition, and learning during a cognitive remediation experimental training. We hypothesized that metacognition and intrinsic motivation would have a strong relationship and independently predict learning potential.

METHOD

Thirty-two patients with schizophrenia who fulfilled the criteria of functional remission were recruited. In a pre-training-post experimental design, patients' learning potential was assessed using previously defined cognitive remediation training for WCST. Intrinsic motivation was examined using Intrinsic Motivation Inventory for schizophrenia; mastery, a domain of metacognition, was measured using the Metacognitive Assessment Scale.

RESULTS

Metacognition significantly correlated with subdomains of intrinsic motivation. Patients with higher intrinsic motivation and preserved metacognition improved more in the learning paradigm compared to poorly motivated patients and patients with reduced metacognitive abilities. In particular, "mastery" was determined as an independent predictor of learning potential.

CONCLUSIONS

Motivation and metacognition are important predictors of learning in schizophrenia. Psychological interventions in schizophrenia may therefore consider incorporating techniques to stimulate metacognitive and motivational abilities as well as developing individualized training programs.

The role of prediction in social neuroscience

Research has shown that the brain is constantly making predictions about future events. Theories of prediction in perception, action and learning suggest that the brain serves to reduce the discrepancies between expectation and actual experience, i.e., by reducing the prediction error. Forward models of action and perception propose the generation of a predictive internal representation of the expected sensory outcome, which is matched to the actual sensory feedback. Shared neural representations have been found when experiencing one's own and observing other's actions, rewards, errors, and emotions such as fear and pain. These general principles of the “predictive brain” are well established and have already begun to be applied to social aspects of cognition. The application and relevance of these predictive principles to social cognition are discussed in this article. Evidence is presented to argue that simple non-social cognitive processes can be extended to explain complex cognitive processes required for social interaction, with common neural activity seen for both social and non-social cognitions. A number of studies are included which demonstrate that bottom-up sensory input and top-down expectancies can be modulated by social information. The concept of competing social forward models and a partially distinct category of social prediction errors are introduced. The evolutionary implications of a “social predictive brain” are also mentioned, along with the implications on psychopathology. The review presents a number of testable hypotheses and novel comparisons that aim to stimulate further discussion and integration between currently disparate fields of research, with regard to computational models, behavioral and neurophysiological data. This promotes a relatively new platform for inquiry in social neuroscience with implications in social learning, theory of mind, empathy, the evolution of the social brain, and potential strategies for treating social cognitive deficits.

Potential therapeutic avenues to tackle social cognition problems in schizophrenia

Therapeutic strategies for improving social cognition in patients with schizophrenia have shown much promise in improving social functioning, as well as remediating core psychotic symptoms. However, the efficacy of previous interventions has often been limited by the ambiguity and inconsistency of the categorized subdomains of social cognition, including theory of mind, emotion processing, social perception and attributional bias. Recent research in social and cognitive neuroscience has revealed many new issues that could contribute to the development of more integrated approaches for improving social functioning. The application of such neuroscientific work to a therapeutic and diagnostic context is likely to encourage more effective transference of learned skills to real-world social functioning. This article seeks to provide a comprehensive review of previous social cognitive interventions for schizophrenia, highlight some crucial limitations of these and present the relevance of recent advances in neuroscientific research in possible future treatment strategies. It is emphasized that a more integrated and naturalistic approach for improving social functioning with greater sensitivity for neuroscientific findings related to the psychopathology of schizophrenia is warranted.

Raman spectroscopic studies of the cure of dicyclopentadiene (DCPD)

The cure of polydicyclopentadiene conducted by ring-opening metathesis polymerisation in the presence of a Grubbs catalyst was studied using non-invasive Raman spectroscopy. The spectra of the monomer precursor and polymerised product were fully characterised and all stages of polymerisation monitored. Because of the monomer's high reactivity, the cure process is adaptable to reaction injection moulding and reactive rotational moulding. The viscosity of the dicyclopentadiene undergoes a rapid change at the beginning of the polymerisation process and it is critical that the induction time of the viscosity increase is determined and controlled for successful manufacturing. The results from this work show non-invasive Raman spectroscopic monitoring to be an effective method for monitoring the degree of cure, paving the way for possible implementation of the technique as a method of real-time analysis for control and optimisation during reactive processing. Agreement is shown between Raman measurements and ultrasonic time of flight data acquired during the initial induction period of the curing process.

Vibrational spectroscopic and ultrasound analysis for in-process characterization of high-density polyethylene/polypropylene blends during melt extrusion

Spectroscopic techniques such as Raman, mid-infrared (MIR), and near-infrared (NIR) have become indispensable analytical tools for rapid chemical quality control and process monitoring. This paper presents the application of in-line Fourier transform near-infrared (FT-NIR) spectroscopy, Raman spectroscopy, and ultrasound transit time measurements for in-line monitoring of the composition of a series of high-density polyethylene (HDPE)/polypropylene (PP) blends during single-screw extrusion. Melt composition was determined by employing univariate analysis of the ultrasound transit time data and partial least squares (PLS) multivariate analysis of the data from both spectroscopic techniques. Each analytical technique was determined to be highly sensitive to changes in melt composition, allowing accurate prediction of blend content to within +/- 1% w/w (1sigma) during monitoring under fixed extrusion conditions. FT-NIR was determined to be the most sensitive of the three techniques to changes in melt composition. A four-factor PLS model of the NIR blend spectra allowed determination of melt content with a standard prediction error of +/- 0.30% w/w (1sigma). However, the NIR transmission probes employed for analysis were invasive into the melt stream, whereas the single probes adopted for Raman and ultrasound analysis were noninvasive, making these two techniques more versatile. All three measurement techniques were robust to the high temperatures and pressures experienced during melt extrusion, demonstrating each system's suitability for process monitoring and control.

Maternal choline availability alters the localization of p15Ink4B and p27Kip1 cyclin-dependent kinase inhibitors in the developing fetal rat brain hippocampus

Previously we have shown that changes in maternal dietary choline are associated with permanent behavioral changes in offspring. Importantly, in adult male rats, feeding a choline-deficient diet increases the localization of cyclin-dependent kinase inhibitors (CDKIs) in the liver, whereas young adult CDKI knockout mice (p15Ink4B or p27Kip1) exhibit behavioral abnormalities. Thus, maternal dietary choline-CDKI interactions could underlie the changes we observe in fetal hippocampal development and cognitive function in offspring. Here, timed-pregnant rats on embryonic day E12 were fed the AIN-76 diet with varying levels of dietary choline for 6 days, and, on E18, fetal brain sections were collected, and the localization of CDKI proteins was studied using immunohistochemistry and an unbiased image analysis method. In choline-supplemented animals compared to controls, the number of cells with nuclear immunoreactivity for p15Ink4b CDKI protein was decreased 2- to 3-fold in neuroepithelial ventricular zones and adjacent subventricular zones corresponding to the fimbria, primordial dentate gyrus and Ammon's horn regions in the fetal hippocampus. In contrast, maternal dietary choline deficiency significantly decreased nuclear p15Ink4b immunoreactivity in the neuroepithelial layer of the dentate gyrus. Unlike p15Ink4b, the CDKI protein p27Kip1 was observed almost exclusively in the cytoplasm, though the protein was distributed throughout the proliferating and postmitotic zones in the E18 fetal hippocampus. Maternal dietary choline supplementation decreased the cytoplasmic staining intensity for p27Kip1 throughout the fetal hippocampus compared to control animals. Choline deficiency increased the staining intensity of p27Kip1 throughout the hippocampus in association with increased expression of MAP-1 and vimentin proteins. These results link maternal dietary choline availability to CDKI protein immunoreactivity and commitment to differentiation during fetal hippocampal development.

Differential alternative splicing activity of isoforms of polypyrimidine tract binding protein (PTB)

Polypyrimidine tract binding protein (PTB) is an RNA-binding protein that regulates splicing by repressing specific splicing events. It also has roles in 3'-end processing, internal initiation of translation, and RNA localization. PTB exists in three alternatively spliced isoforms, PTB1, PTB2, and PTB4, which differ by the insertion of 19 or 26 amino acids, respectively, between the second and third RNA recognition motif domains. Here we show that the PTB isoforms have distinct activities upon alpha-tropomyosin (TM) alternative splicing. PTB1 reduced the repression of TM exon 3 in transfected smooth muscle cells, whereas PTB4 enhanced TM exon 3 skipping in vivo and in vitro. PTB2 had an intermediate effect. The PTB4 > PTB2 > PTB1 repressive hierarchy was observed in all in vivo and in vitro assays with TM, but the isoforms were equally active in inducing skipping of alpha-actinin exons and showed the opposite hierarchy of activity when tested for activation of IRES-driven translation. These findings establish that the ratio of PTB isoforms could form part of a cellular code that in turn controls the splicing of various other pre-mRNAs.

Protein factor requirements of the Apaf-1 internal ribosome entry segment: roles of polypyrimidine tract binding protein and upstream of N-ras

It has been reported previously that the 5' untranslated region of the mRNA encoding Apaf-1 (apoptotic protease-activating factor 1) has an internal ribosome entry site (IRES), whose activity varies widely among different cell types. Here it is shown that the Apaf-1 IRES is active in rabbit reticulocyte lysates, provided that the system is supplemented with polypyrimidine tract binding protein (PTB) and upstream of N-ras (unr), two cellular RNA binding proteins previously identified to be required for rhinovirus IRES activity. In UV cross-linking assays and electrophoretic mobility shift assays with individual recombinant proteins, the Apaf-1 IRES binds unr but not PTB; however, PTB binding occurs if unr is present. Over a range of different cell types there is a broad correlation between the activity of the Apaf-1 IRES and their content of PTB and unr. In cell lines deficient in these proteins, overexpression of PTB and unr stimulated Apaf-1 IRES function. This is the first example where an IRES in a cellular mRNA has been shown to be functionally dependent, both in vitro and in vivo, on specific cellular RNA binding proteins. Given the critical role of Apaf-1 in apoptosis, these results have important implications for the control of the apoptotic cascade.

The characterization of mice with a targeted combined deficiency of protein c and factor XI

Activated protein C functions directly as an anticoagulant and indirectly as a profibrinolytic enzyme. To determine whether the fibrin deposition previously observed in PC(-/-) murine embryos and neonates was mediated through the FXI pathway, PC(+/-)/FXI(-/-) mice were generated and crossbred to produce double-deficient progeny (PC(-/-)/FXI(-/-)). PC(-/-)/FXI(-/-) mice survived the early lethality observed in the PC(-/-)/FXI(+/+) neonates, with the oldest PC(-/-)/FXI(-/-) animal living to 3 months of age. However, the majority of these animals was sedentary and significantly growth-retarded. On sacrifice or natural death, all of these PC(-/-)/FXI(-/-) mice demonstrated massive systemic fibrin deposition with concomitant hemorrhage and fibrosis, as confirmed through histological analyses. Several of these animals also presented with enlarged lymph nodes and extensive lymphatic fluid in the thoracic cavity. Thus, although a number of the PC(-/-)/FXI(-/-) mice survived the lethal perinatal coagulopathy seen in the PC(-/-) neonates, they nonetheless succumbed to overwhelming thrombotic disease in later life. This combined deficiency state provided the first clear indication that the course of a severe thrombotic disorder could be manipulated by blocking the intrinsic pathway and provided the first opportunity to study a total protein C deficiency in an adult animal.

Tobravirus 2b protein acts in trans to facilitate transmission by nematodes

Analysis of RNA2 of TRV PaY4 showed it to be recombinant, carrying 3'-terminal sequences derived from RNA1. Virus produced using an infectious cDNA clone of PaY4 RNA2 was nematode transmissible, demonstrating that natural TRV recombinant isolates are not necessarily defective. Mutations introduced into PaY4 RNA2 showed that the 2b gene, but not the 2c gene, is required for transmission by both Paratrichodorus pachydermus and P. anemones nematodes. Experiments examined whether infection of plants with two different virus clones would impact upon nematode transmission of either virus. Simultaneous inoculation with TRV clones expressing green or red fluorescent proteins revealed that mixing of the two virus populations did not occur, although, in roots, adjacent cells were found containing green- or red-tagged viruses. Subsequently, in similar experiments it was found that a TRV PaY4 2b mutant was transmitted when combined with wild-type TRV PaY4. Also, transmission of a 2b mutant of an in vitro TRV/PEBV recombinant virus (TRV-C1) occurred after coinfection with wild-type virus. Thus, the tobravirus 2b transmission protein is trans-acting. Although TRV PaY4 and TRV PpK20 are both transmitted by P. pachydermus, a 2b mutant of TRV PaY4 was not transmitted when coinoculated to plants with TRV PpK20.

Precoated femoral component in total hip arthroplasty. Results of 5- to 9-year followup

One hundred nineteen consecutive primary hybrid total hip arthroplasties with a precoated femoral component were performed by one surgeon in 100 patients and followed up prospectively. Ninety-eight hips in 82 patients (mean age, 67 years) were evaluated clinically and radiographically at a mean of 6.5 years (range, 5-9 years). The hips were evaluated clinically using the Harris hip score, and radiographs were evaluated for femoral cement grade, loosening, and osteolysis. Ninety-five hips remained in place at the most recent followup. Two femoral components were revised for definite loosening, and one well fixed femoral component was removed because of late hematogenous infection. Excluding the three hips that were revised, the clinical result was excellent or good in 79 hips (83%), fair in 12 hips (13%), and poor in four hips (4%). All other femoral components were well fixed. There were defects of the cement mantles (C1 and C2) in 90 hips. No femoral component had a stem and cement radiolucent line. Focal femoral osteolysis was seen in only two hips. One acetabular component was removed at 5 years because of late hematogenous infection. One acetabular component had asymptomatic migration. The remaining 96 acetabular components were well fixed. Focal acetabular osteolysis was present in four hips. The mean linear polyethylene wear rate was 0.06 (+/- 0.05) mm per year. In contrast to other reports of early failure and osteolysis, the use of a precoated femoral component in this study did not adversely affect the fixation of hybrid total hip arthroplasty, with definite failure of only 2% (two of 98) of the femoral components.

Maternal dietary choline availability alters mitosis, apoptosis and the localization of TOAD-64 protein in the developing fetal rat septum

Maternal changes in dietary choline availability alter brain biochemistry and hippocampal development in the offspring resulting in lifelong behavioral changes in the offspring. In order to better understand the relationship between maternal diet, brain cytoarchitecture and behavior, we investigated the effects of choline availability on cell proliferation, apoptosis and differentiation in the fetal rat brain septum. Timed-pregnant rats on day E12 were fed AIN-76 diet with varying levels of dietary choline for 6 days. We found that choline deficiency (CD) significantly decreased the rate of mitosis in the progenitor neuroepithelium adjacent to the septum. In addition, we found an increased number of apoptotic cells in the septum of CD animals compared to controls (3.5+/-0.5 vs. 1.7+/-0.5 apoptotic cells per section; p<0.05). However, CD had no effect on apoptosis in the indusium griseum (IG), a region of cortex dorsal to the septum. Using an unbiased image analysis method and a monoclonal antibody we found a decreased expression of the TOAD-64 kDa protein, a marker of commitment to neuronal differentiation during fetal development, in the dorsal lateral septum of CD animals. CD also decreased the expression of TOAD-64 kDa protein in the IG and cortical plate adjacent to the septum. These results show that dietary choline availability during pregnancy alters the timing of mitosis, apoptosis and the early commitment to neuronal differentiation by progenitor cells in regions of the fetal brain septum, as well as hippocampus, two brain regions known to be associated with learning and memory.

TRIP: a novel double stranded RNA binding protein which interacts with the leucine rich repeat of flightless I

A northwestern screen of a CHO-K1 cell line cDNA library with radiolabelled HIV-1 TAR RNA identified a novel TAR RNA interacting protein, TRIP. The human trip cDNA was also cloned and its expression is induced by phorbol esters. The N-terminus of TRIP shows high homology to the coiled coil domain of FLAP, a protein which binds the leucine-rich repeat (LRR) of Flightless I (FLI) and the interaction of TRIP with the FLI LRR has been confirmed in vitro . TRIP does not bind single stranded DNA or RNA significantly and binds double stranded DNA weakly. In contrast, TRIP binds double stranded RNA with high affinity and two molecules of TRIP bind the TAR stem. The RNA binding domain has been identified and encompasses a lysine-rich motif. A TRIP-GFP fusion is localised in the cytoplasm and excluded from the nucleus. FLI has a C-terminal gelsolin-like domain which binds actin and therefore the association of TRIP with the FLI LRR may provide a link between the actin cytoskeleton and RNA in mammalian cells.

Alcohol expectancies among adolescents with conduct disorder: prediction and mediation of drinking

Among adolescents with conduct disorder, alcohol expectancies were examined for both predictive utility and mediation of other predictors of alcohol use (i.e., delinquency, family history, demographic and psychopathology variables). Data were collected from 260 adolescents with conduct disorder 11-18 years of age, who had been in either mental health residential facilities or community-based special education programs for adolescents with serious emotional disturbances. Zero-order correlations and structural path models assessed relationships between expectancies, alcohol use, and other predictors of alcohol use. Results indicated: (a) expectancies of enhanced social and cognitive behavior were significant (p < .05) univariate predictors of drinking, (b) among all of the selected predictors, expectancies of enhanced social behavior (i.e., Subscale 2 of the Alcohol Expectancy Questionnaire--Adolescent Form; AEQ-A) had the strongest association with alcohol use (r = .54) and mediated between 31% to 44% of the drinking variance associated with other significant predictors (p < .01). Results were discussed as supporting similar expectancy-drinking relationships among CD and nonclinical youth.

Morphometric analysis of T lymphocyte compartmentation in experimental autoimmune uveoretinitis

Experimental autoimmune uveoretinitis (EAU) in the Lewis rat is characterized by extensive infiltration of inflammatory cells into all compartments of the eye, only some of which become irreversibly damaged. The apparent differences in the pathogenic impact of inflammatory cells within different ocular compartments may suggest that different mechanisms underlie cellular infiltration and selective tissue destruction. In order to investigate the importance of T lymphocyte infiltration, we carried out a precise topographical and temporal analysis of T cell infiltration into five compartments of the eye using an improved method for the fixation of ocular tissue. Our study showed that T cell infiltration began in the ciliary body and was most numerous and sustained in this area during EAU. The peak of T cell infiltration into the retina was comparatively delayed and was of lesser magnitude. Analysis of T cell subsets revealed a tendency for the helper phenotype to predominant during the course of disease in all ocular compartments except the retina where both helper and cytotoxic/suppressor T cells were equally represented at the height of inflammation. We suggest that the pathogenetic impact of autoreactive lymphocytes in EAU depends on the accessibility of relevant tissue antigen and on local microenvironmental features of lymphocytic traffic within different ocular compartments.

Comparison of hyperbaric and plain bupivacaine with hyperbaric cinchocaine as spinal anaesthetic agents

In a double-blind study, 90 patients (ASA 1 or 2) received spinal anaesthesia with 2 ml hyperbaric cinchocaine 0.5%, 4 ml hyperbaric bupivacaine 0.5% or 4 ml plain bupivacaine 0.5%. All injections were made in the left lateral position, and the patients turned supine immediately. Hyperbaric bupivacaine produced a significantly faster and a higher dermatomal level of bilateral complete sensory blockade than the other solutions (p less than 0.005 for each). The duration of sensory blockade was significantly longer with plain bupivacaine than with either hyperbaric solution (p less than 0.0005). The intensity of sensory blockade was significantly greater with both bupivacaine solutions than with hyperbaric cinchocaine (p less than 0.05). Onset and intensity of motor blockade were similar with all agents, but motor blockade was of significantly shorter duration with hyperbaric bupivacaine than the other agents (p less than 0.0005). Hyperbaric bupivacaine appears to be the best agent for rapid and intense sensory blockade of intermediate duration. Plain bupivacaine is more appropriate if a longer duration of action but a lower height of blockade are required, and has the advantage of less cardiovascular disturbance.

Differential effect of Bordetella pertussis on experimental posterior uveitis in the black-hooded Lister rat

The effect of an additional adjuvant, Bordetella pertussis, on the clinical and histopathologic features of experimental autoimmune uveitis in black-hooded Lister rats was investigated. Disease was induced by a single footpad injection of purified retinal S-antigen in Freund's complete adjuvant. In those animals that did not receive B Pertussis the clinical features were those of a retinal vasculitis with disc edema, periphlebitis, and deep retinal infiltrates. In contrast, animals that received B pertussis developed lesions in the pigment epithelium and choroid. Histopathologic studies disclosed focal photoreceptor necrosis associated with mononuclear cell infiltration in both groups of animals. However, in the group that did not receive B pertussis the disease was predominantly a retinitis associated with perivascular infiltration of retinal vessels, whereas in the group that did receive B pertussis the main feature was a focal choroiditis, with superficial retinal lesions being rarely observed. Retinal photoreceptors were the target tissue in both groups of rats, but the route by which they were damaged was altered from predominantly retinal to choroidal by the addition of Bordetella pertussis as an adjuvant. This change may be ascribed to the ability of B pertussis toxin to sensitize vascular endothelium to local mast cell products, these cells being plentiful around choroidal vessels but absent in the retinal circulation.

Neuropeptidergic systems in plaques of Alzheimer's disease

Polyclonal antibodies directed against substance P, somatostatin, neurotensin, cholecystokinin (CCK), leucine enkephalin, and vasoactive intestinal polypeptide (VIP) were employed to determine the immunoreactivities of neurites of senile plaques (SP) in Alzheimer's disease (AD). All of the antibodies labeled some neurites in some SP. The transmitter specificities of immunoreactive neurites tended to reflect the distribution of transmitter-associated fibers in normal tissue. This investigation also documented the presence of abnormal axons (as distinct from neurites within plaques) in the neuropil in brains of individuals with AD and in some aged controls. These findings suggest that a variety of transmitter systems are involved in the formation of neuropil abnormalities of SP. They also indicate that a greater number of neuronal systems are affected in AD than have been documented by neurochemical studies.

Experimental posterior uveitis. I: A clinical, angiographic, and pathological study

The clinical, angiographic, and histopathological features of experimental posterior uveitis in the black hooded Lister rat are described. This mild form of experimental allergic uveoretinitis (EAU) is induced by sensitisation with retinal S antigen in Freund's complete adjuvant, and the inflammation produced is confined to the posterior segment of the eye. This allows for the first time precise photographic and angiographic documentation of the evolution of clinical signs, because there is minimal clouding of the vitreous by inflammatory cells. Clinically the disease is characterised by the appearance of disc oedema and periphlebitis, followed by focal infiltrates in the deep retinal layers, with eventual atrophy of the pigment epithelium. Histologically, retinal vasculitis is associated with focal mononuclear cell infiltration and necrosis of the photoreceptor layers. This model closely resembles the clinical features of idiopathic retinal vasculitis seen in man.

An improved method for the purification of retinal S-antigen using selective hydrophobic adsorption chromatography

This paper describes the use of phenyl-Sepharose CL-4B as a solid-phase hydrophobic adsorbent in the purification of S-antigen from protein extracts of bovine, porcine and human retina. Chromatographic conditions were ascertained whereby the majority of contaminating proteins were bound to the adsorbent leaving S-antigen in the liquid phase. In combination with size fractionation on Ultrogel AcA, the method conveniently yielded porcine and bovine S-antigen preparations up to 100% purity. Immunogenicity of purified S-antigens was verified by induction of experimental autoimmune uveoretinitis in albino Lewis rats. The method is preparative in scale, fast in performance and yields S-antigen in high purity and antigenic potency.

Translational regulation in rat brain hemispheres

Present studies on the sensitivity of the transcription process in rat cerebral hemispheres showed that the relative abundance and translation of free and bound poly (A)+ mRNAs in a reticulocyte mRNA-dependent system were reduced following 1 h and 4 h of ethanol or pentobarbital administration with free being affected to a greater extent than the bound poly (A)+ mRNAs. In addition, the energy-dependent nucleocytoplasmic transport of in vivo [3H]labeled nuclear RNA to surrogate cytoplasm was modified in response to ethanol exposure. The translocation of the labeled nuclear RNA fraction occurred only to the microsomal/ribosomal fractions of the cytoplasm, was stimulated by cyclic cAMP and abolished when the cytoplasm was depleted of its protein factors following streptomycin treatment, thereby establishing the translocated RNA as messenger RNA. It is concluded that the neural cell, in response to ethanol exposure, modifies the efficiency of nuclear processing and transport of mRNA. This nuclear restriction probably occurs at multi-levels during the post-transcriptional modification of mRNAs.

Retinal vasculitis: correlation of animal and human disease

A form of experimental retinal vasculitis was induced in black hooded Lister rats by the inoculation of retinal S-antigen. Comparison of this disease with retinal vasculitis in man showed striking clinical, angiographic and pathological similarities. Clinically disc oedema, periphlebitis and retinal infiltrates were observed with corresponding leakage of dye on fluorescein angiography. Pathologically the disease showed perivascular lymphocytic infiltrates with focal photoreceptor necrosis. These characteristic features make this an ideal model for the study of the pathogenesis of retinal vasculitis in man.

The role of religious values in coping with cancer

The relationship between transcendent meaning attribution, religious orientation, and psychological well-being was studied in cancer and noncancer patients to test the hypotheses that intrinsic religious values and life meaning enhance coping and well-being during the course of the life-threatening illness. Subjects were 44 patients receiving medical treatment for cancer and noncancer medical conditions. In the cancer group, higher levels of attributed life meaning were positively linked with intrinsic religious orientation, and associated with lower levels of despiar, anger-hostility, and social isolation. Cancer patients scored higher than noncancer patients on depersonalization, suggesting the presence of psychic numbing in response to their illness. Noncancer group results were characterized by positive correlations between the two groups in coping styles and salience of life meaning attribution. A rationale for the observed differences in coping styles between the two groups is presented, highlighting perceived life threat as a key differentiating variable.

Amyloidosis in Reiter's syndrome

A patient with a 27-year-history of chronic relapsing Reiter's syndrome who developed secondary amyloidosis is described. While there are only 2 reports of this association in the English literature, additional cases are suggested in the light of our present concepts. The patient represents the only case of clinically apparent secondary amyloidosis among 158 patients with HLA B27 associated arthropathies currently followed at our institution. Our patient's amyloidosis was treated for nearly 1 year with colchicine without response.