OBJECTIVES: This study investigated the relationships between a mindfulness-based stress reduction meditation program for early stage breast and prostate cancer patients and quality of life, mood states, stress symptoms, lymphocyte counts, and cytokine production.
METHODS: Forty-nine patients with breast cancer and 10 with prostate cancer participated in an 8-week MBSR program that incorporated relaxation, meditation, gentle yoga, and daily home practice. Demographic and health behavior variables, quality of life (EORTC QLQ C-30), mood (POMS), stress (SOSI), and counts of NK, NKT, B, T total, T helper, and T cytotoxic cells, as well as NK and T cell production of TNF, IFN-γ, IL-4, and IL-10 were assessed pre- and postintervention.
RESULTS: Fifty-nine and 42 patients were assessed pre- and postintervention, respectively. Significant improvements were seen in overall quality of life, symptoms of stress, and sleep quality. Although there were no significant changes in the overall number of lymphocytes or cell subsets, T cell production of IL-4 increased and IFN-γ decreased, whereas NK cell production of IL-10 decreased. These results are consistent with a shift in immune profile from one associated with depressive symptoms to a more normal profile.
CONCLUSIONS: MBSR participation was associated with enhanced quality of life and decreased stress symptoms in breast and prostate cancer patients. This study is also the first to show changes in cancer-related cytokine production associated with program participation.
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<p>Mindfulness-based approaches are among the most innovative and interesting new approaches to mental health treatment. Mindfulness refers to patients developing an "awareness of present experience with acceptance." Interest in them is widespread, with presentations and workshops drawing large audiences all over the US and many other countries. This book provides a comprehensive introduction to the best-researched mindfulness-based treatments. It emphasizes detailed clinical illustration providing a close-up view of how these treatments are conducted, the skills required of therapists, and how they work. The book also has a solid foundation in theory and research and shows clearly how these treatments can be understood using accepted psychological principles and concepts. The evidence base for these treatments is concisely reviewed.* Comprehensive introduction to the best-researched mindfulness-based treatments* Covers wide range of problems & disorders (anxiety, depression, eating, psychosis, personality disorders, stress, pain, relationship problems, etc)* Discusses a wide range of populations (children, adolescents, older adults, couples)* Includes wide range of settings (outpatient, inpatient, medical, mental health, workplace)* Clinically rich, illustrative case study in every chapter* International perspectives represented (authors from US, Canada, Britain, Sweden)</p>
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Mindfulness-based approaches to medicine, psychology, neuroscience, healthcare, education, business leadership, and other major societal institutions have become increasingly common. New paradigms are emerging from a confluence of two powerful and potentially synergistic epistemologies: one arising from the wisdom traditions of Asia and the other arising from post-enlightenment empirical science. This book presents the work of internationally renowned experts in the fields of Buddhist scholarship and scientific research, as well as looking at the implementation of mindfulness in healthcare and education settings. Contributors consider the use of mindfulness throughout history and look at the actual meaning of mindfulness whilst identifying the most salient areas for potential synergy and for potential disjunction.Mindfulness: Diverse Perspectives on its Meanings, Origins and Applications provides a place where wisdom teachings, philosophy, history, science and personal meditation practice meet. It was originally published as a special issue of Contemporary Buddhism.
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Twenty-seven adult survivors of childhood sexual abuse participated in a pilot study comprising an 8-week mindfulness meditation-based stress reduction (MBSR) program and daily home practice of mindfulness skills. Three refresher classes were provided through final follow-up at 24 weeks. Assessments of depressive symptoms, post-traumatic stress disorder (PTSD), anxiety, and mindfulness, were conducted at baseline, 4, 8, and 24 weeks. At 8 weeks, depressive symptoms were reduced by 65%. Statistically significant improvements were observed in all outcomes post-MBSR, with effect sizes above 1.0. Improvements were largely sustained until 24 weeks. Of three PTSD symptom criteria, symptoms of avoidance/numbing were most greatly reduced. Compliance to class attendance and home practice was high, with the intervention proving safe and acceptable to participants. These results warrant further investigation of the MBSR approach in a randomized, controlled trial in this patient population. © 2009 Wiley Periodicals, Inc. J Clin Psychol 66: 1–18, 2010.
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Mindfulness practice is an ancient tradition in Eastern philosophy that forms the basis for meditation, and it is increasingly making its way into Western approaches to health care. Although it has been applied to the treatment of many different mental health disorders, it has not been discussed in the context of therapy for sexual problems. In a previous qualitative study of female meditation practitioners who did not have sexual concerns, mindfulness practice was found to be associated with greater sexual response and higher levels of sexual satisfaction. We have recently developed a psychoeducational program for women with sexual arousal disorder subsequent to gynecologic cancer and have included a component of mindfulness training in the intervention. In this paper, we will attempt to provide a rationale for the use of mindfulness in the treatment of women with sexual problems, and will include transcript excerpts from women who participated in our research trial that illustrate how mindfulness was effective in improving their sexuality and quality of life. Although these findings are preliminary, they suggest that mindfulness may have a place in the treatment of sexual concerns.
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<p>Interest in mindfulness and its enhancement has burgeoned in recent years. In this article, we discuss in detail the nature of mindfulness and its relation to other, established theories of attention and awareness in day-to-day life. We then examine theory and evidence for the role of mindfulness in curtailing negative functioning and enhancing positive outcomes in several important life domains, including mental health, physical health, behavioral regulation, and interpersonal relationships. The processes through which mindfulness is theorized to have its beneficial effects are then discussed, along with proposed directions for theoretical development and empirical research.</p>
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Theories of memory organisation propose that activity knowledge organises autobiographical memory globally. According to these views, memories that share a participant, location, or time are only organised together if they also share an activity. If they do not, they are nested within their respective activity organisations locally rather than being organised together globally. Two experiments that assessed people's clustering of laboratory events consistently obtained findings that contradict this view. Both experiments found that people organise event memories globally in non-activity clusters, cross-classify events into multiple organisations, and pivot between activity and non-activity clusters. Consistent with studies of naturalistic events, these studies of laboratory events indicate that people cross-classify event memories simultaneously into multiple global organisations.
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A review of behavioral and neurobiological data on mood and mood regulation as they pertain to an understanding of mood disorders is presented. Four approaches are considered: 1) behavioral and cognitive; 2) neurobiological; 3) computational; and 4) developmental. Within each of these four sections, we summarize the current status of the field and present our vision for the future, including particular challenges and opportunities. We conclude with a series of specific recommendations for National Institute of Mental Health priorities. Recommendations are presented for the behavioral domain, the neural domain, the domain of behavioral-neural interaction, for training, and for dissemination. It is in the domain of behavioral-neural interaction, in particular, that new research is required that brings together traditions that have developed relatively independently. Training interdisciplinary clinical scientists who meaningfully draw upon both behavioral and neuroscientific literatures and methods is critically required for the realization of these goals.
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OBJECTIVE: The purpose of this study was to use functional magnetic resonance imaging (fMRI) to probe the neural circuitry associated with reactivity to negative and positive affective stimuli in patients with major depressive disorder before treatment and after 2 and 8 weeks of treatment with venlafaxine. Relations between baseline neural activation and response to treatment were also evaluated.
METHOD: Patients with major depressive disorder (N=12) and healthy comparison subjects (N=5) were scanned on three occasions, during which trials of alternating blocks of affective and neutral pictorial visual stimuli were presented. Symptoms were evaluated at each testing occasion, and both groups completed self-report measures of mood. Statistical parametric mapping was used to examine the fMRI data with a focus on the group-by-time interactions.
RESULTS: Patients showed a significant reduction in depressive symptoms with treatment. Group-by-time interactions in response to the negative versus neutral stimuli were found in the left insular cortex and the left anterior cingulate. At baseline, both groups showed bilateral activation in the visual cortices, lateral prefrontal cortex, and amygdala in response to the negative versus neutral stimuli, with patients showing greater activation in the visual cortex and less activation in the left lateral prefrontal cortex. Patients with greater relative anterior cingulate activation at baseline in response to the negative versus neutral stimuli showed the most robust treatment response.
CONCLUSIONS: The findings underscore the importance of the neural circuitry activated by negative affect in depression and indicate that components of this circuitry can be changed within 2 weeks of treatment with antidepressant medication.
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'Mindfulness' is a capacity for heightened present-moment awareness that we all possess to a greater or lesser extent. Enhancing this capacity through training has been shown to alleviate stress and promote physical and mental well-being. As a consequence, interest in mindfulness is growing and so is the need to better understand it. This study employed functional magnetic resonance imaging (fMRI) to identify the brain regions involved in state mindfulness and to shed light on its mechanisms of action. Significant signal decreases were observed during mindfulness meditation in midline cortical structures associated with interoception, including bilateral anterior insula, left ventral anterior cingulate cortex, right medial prefrontal cortex, and bilateral precuneus. Significant signal increase was noted in the right posterior cingulate cortex. These findings lend support to the theory that mindfulness achieves its positive outcomes through a process of disidentification.
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OBJECTIVE: Positron emission tomography was used to investigate the neural substrates of normal human emotional and their dependence on the types of emotional stimulus.
METHOD: Twelve healthy female subjects underwent 12 measurements of regional brain activity following the intravenous bolus administration of [15O]H2O as they alternated between emotion-generating and control film and recall tasks. Automated image analysis techniques were used to characterize and compare the increases in regional brain activity associated with the emotional response to complex visual (film) and cognitive (recall) stimuli.
RESULTS: Film- and recall-generated emotion were each associated with significantly increased activity in the vicinity of the medial prefrontal cortex and thalamus, suggesting that these regions participate in aspects of emotion that do not depend on the nature of the emotional stimulus. Film-generated emotion was associated with significantly greater increases in activity bilaterally in the occipitotemporparietal cortex, lateral cerebellum, hypothalamus, and a region that includes the anterior temporal cortex, amygdala, and hippocampal formation, suggesting that these regions participate in the emotional response to certain exteroceptive sensory stimuli. Recall-generated sadness was associated with significantly greater increases in activity in the vicinity of the anterior insular cortex, suggesting that this region participates in the emotional response to potentially distressing cognitive or interoceptive sensory stimuli.
CONCLUSIONS: While this study should be considered preliminary, it identified brain regions that participate in externally and internally generated human emotion.
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Recent theoretical and empirical work in cognitive science and neuroscience is brought into contact with the concept of the flow experience. After a brief exposition of brain function, the explicit-implicit distinction is applied to the effortless information processing that is so characteristic of the flow state. The explicit system is associated with the higher cognitive functions of the frontal lobe and medial temporal lobe structures and has evolved to increase cognitive flexibility. In contrast, the implicit system is associated with the skill-based knowledge supported primarily by the basal ganglia and has the advantage of being more efficient. From the analysis of this flexibility/efficiency trade-off emerges a thesis that identifies the flow state as a period during which a highly practiced skill that is represented in the implicit system's knowledge base is implemented without interference from the explicit system. It is proposed that a necessary prerequisite to the experience of flow is a state of transient hypofrontality that enables the temporary suppression of the analytical and meta-conscious capacities of the explicit system. Examining sensory-motor integration skills that seem to typify flow such as athletic performance, writing, and free-jazz improvisation, the new framework clarifies how this concept relates to creativity and opens new avenues of research.
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Neuroimage phenotyping for psychiatric and neurological disorders is performed using voxelwise analyses also known as voxel based analyses or morphometry (VBM). A typical voxelwise analysis treats measurements at each voxel (e.g., fractional anisotropy, gray matter probability) as outcome measures to study the effects of possible explanatory variables (e.g., age, group) in a linear regression setting. Furthermore, each voxel is treated independently until the stage of correction for multiple comparisons. Recently, multi-voxel pattern analyses (MVPA), such as classification, have arisen as an alternative to VBM. The main advantage of MVPA over VBM is that the former employ multivariate methods which can account for interactions among voxels in identifying significant patterns. They also provide ways for computer-aided diagnosis and prognosis at individual subject level. However, compared to VBM, the results of MVPA are often more difficult to interpret and prone to arbitrary conclusions. In this paper, first we use penalized likelihood modeling to provide a unified framework for understanding both VBM and MVPA. We then utilize statistical learning theory to provide practical methods for interpreting the results of MVPA beyond commonly used performance metrics, such as leave-one-out-cross validation accuracy and area under the receiver operating characteristic (ROC) curve. Additionally, we demonstrate that there are challenges in MVPA when trying to obtain image phenotyping information in the form of statistical parametric maps (SPMs), which are commonly obtained from VBM, and provide a bootstrap strategy as a potential solution for generating SPMs using MVPA. This technique also allows us to maximize the use of available training data. We illustrate the empirical performance of the proposed framework using two different neuroimaging studies that pose different levels of challenge for classification using MVPA.
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OBJECTIVES: To examine whether mindfulness meditation (MM) was associated with changes in objectively measured polysomnographic (PSG) sleep profiles and to relate changes in PSG sleep to subjectively reported changes in sleep and depression within the context of a randomized controlled trial. Previous studies have indicated that mindfulness and other forms of meditation training are associated with improvements in sleep quality. However, none of these studies used objective PSG sleep recordings within longitudinal randomized controlled trials of naïve subjects.
METHODS: Twenty-six individuals with partially remitted depression were randomized into an 8-week Mindfulness-Based Cognitive Therapy (MBCT) course or a waitlist control condition. Pre-post measurements included PSG sleep studies and subjectively reported sleep and depression symptoms.
RESULTS: According to PSG sleep, MM practice was associated with several indices of increased cortical arousal, including more awakenings and stage 1 sleep and less slow-wave sleep relative to controls, in proportion to amount of MM practice. According to sleep diaries, subjectively reported sleep improved post MBCT but not above and beyond controls. Beck Depression Inventory scores decreased more in the MBCT group than controls. Improvements in depression were associated with increased subjective sleep continuity and increased PSG arousal.
CONCLUSIONS: MM is associated with increases in objectively measured arousal during sleep with simultaneous improvements in subjectively reported sleep quality and mood disturbance. This pattern is similar to the profiles of positive responders to common antidepressant medications.
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Individuals with fragile X syndrome (FXS) commonly display characteristics of social anxiety, including gaze aversion, increased time to initiate social interaction, and difficulty forming meaningful peer relationships. While neural correlates of face processing, an important component of social interaction, are altered in FXS, studies have not examined whether social anxiety in this population is related to higher cognitive processes, such as memory. This study aimed to determine whether the neural circuitry involved in face encoding was disrupted in individuals with FXS, and whether brain activity during face encoding was related to levels of social anxiety. A group of 11 individuals with FXS (5 M) and 11 age- and gender-matched control participants underwent fMRI scanning while performing a face encoding task with online eye-tracking. Results indicate that compared to the control group, individuals with FXS exhibited decreased activation of prefrontal regions associated with complex social cognition, including the medial and superior frontal cortex, during successful face encoding. Further, the FXS and control groups showed significantly different relationships between measures of social anxiety (including gaze-fixation) and brain activity during face encoding. These data indicate that social anxiety in FXS may be related to the inability to successfully recruit higher level social cognition regions during the initial phases of memory formation.
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Temperamentally anxious individuals can be identified in childhood and are at risk to develop anxiety and depressive disorders. In addition, these individuals tend to have extreme asymmetric right prefrontal brain activity. Although common and clinically important, little is known about the pathophysiology of anxious temperament. Regardless, indirect evidence from rodent studies and difficult to interpret primate studies is used to support the hypothesis that the amygdala plays a central role. In previous studies using rhesus monkeys, we characterized an anxious temperament endophenotype that is associated with excessive anxiety and fear-related responses and increased electrical activity in right frontal brain regions. To examine the role of the amygdala in mediating this endophenotype and other fearful responses, we prepared monkeys with selective fiber sparing ibotenic acid lesions of the amygdala. Unconditioned trait-like anxiety-fear responses remained intact in monkeys with >95% bilateral amygdala destruction. In addition, the lesions did not affect EEG frontal asymmetry. However, acute unconditioned fear responses, such as those elicited by exposure to a snake and to an unfamiliar threatening conspecific were blunted in monkeys with >70% lesions. These findings demonstrate that the primate amygdala is involved in mediating some acute unconditioned fear responses but challenge the notion that the amygdala is the key structure underlying the dispositional behavioral and physiological characteristics of anxious temperament.
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<p>Virtually all developmental neuropsychiatric disorders involve some dysfunction or dysregulation of emotion. Moreover, many psychiatric disorders with adult onset have early subclinical manifestations in children. This essay selectively reviews the literature on the neuroimaging of affect and disorders of affect in children. Some critical definitional and conceptual issues are first addressed, including the distinctions between the perception and production of emotion and between emotional states and traits. Developmental changes in morphometric measures of brain structure are then discussed and the implications of such findings for studies of functional brain activity are considered. Data on functional neuroimaging and childhood depression are then reviewed. While the extant data in this area are meager, they are consistent with studies in adults that have observed decreased left-sided anterolateral prefrontal cortex activation in depression. Studies in children on the recognition of emotion and affective intent in faces using functional magnetic resonance imaging are then reviewed. These findings indicate that the amygdala plays an important role in such affective face processing in children, similar to the patterns of activation observed in adults. Moreover, one study has reported abnormalities in amygdala activation during a task requiring the judgment of affective intent from the eye region of the face in subjects with autism. Some of the methodological complexities of developmental research in this area are discussed, and directions for future research are suggested.</p>
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BACKGROUND: Anhedonia, a reduced ability to experience pleasure, is a chief symptom of major depressive disorder and is related to reduced frontostriatal connectivity when attempting to upregulate positive emotion. The present study examined another facet of positive emotion regulation associated with anhedonia-namely, the downregulation of positive affect-and its relation to prefrontal cortex (PFC) activity.
METHODS: Neuroimaging data were collected from 27 individuals meeting criteria for major depressive disorder as they attempted to suppress positive emotion during a positive emotion regulation task. Their PFC activation pattern was compared with the PFC activation pattern exhibited by 19 healthy control subjects during the same task. Anhedonia scores were collected at three time points: at baseline (time 1), 8 weeks after time 1 (i.e., time 2), and 6 months after time 1 (i.e., time 3). Prefrontal cortex activity at time 1 was used to predict change in anhedonia over time. Analyses were conducted utilizing hierarchical linear modeling software.
RESULTS: Depressed individuals who could not inhibit positive emotion-evinced by reduced right ventrolateral prefrontal cortex activity during attempts to dampen their experience of positive emotion in response to positive visual stimuli-exhibited a steeper anhedonia reduction slope between baseline and 8 weeks of treatment with antidepressant medication (p < .05). Control subjects showed a similar trend between baseline and time 3.
CONCLUSIONS: To reduce anhedonia, it may be necessary to teach individuals how to counteract the functioning of an overactive pleasure-dampening prefrontal inhibitory system.
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Baseline resting electroencephalogram (EEG) activity was recorded from 6 normothymic depressives and 8 controls using three different reference montages. Power in all frequency bands was extracted by Fourier transformation. Significant Group X Region X Hemisphere interactions were found consistently for alpha band power only. Previously depressed subjects had less left-sided anterior and less right-sided posterior activation (i.e., more alpha activity) than did never depressed subjects. Previously depressed subjects had no history of pharmacological treatment and did not differ from controls in emotional state at the time of testing. The pattern of anterior and posterior asymmetry in the previously depressed subjects is similar to that found in acutely depressed subjects and suggests that this may be a state-independent marker for depression.
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Electroencephalogram (EEG) alpha power has been demonstrated to be inversely related to mental activity and has subsequently been used as an indirect measure of brain activation. The thalamus has been proposed as an important site for modulation of rhythmic alpha activity. Studies in animals have suggested that cortical alpha rhythms are correlated with alpha rhythms in the thalamus. However, little empirical evidence exists for this relation in humans. In the current study, resting EEG and a fluorodeoxyglucose positron emission tomography scan were measured during the same experimental session. Over a 30-min period, average EEG alpha power across 28 electrodes from 27 participants was robustly inversely correlated with glucose metabolic activity in the thalamus. These data provide the first evidence for a relation between alpha EEG power and thalamic activity in humans.
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OBJECTIVE Deficits in positive affect and their neural bases have been associated with major depression. However, whether reductions in positive affect result solely from an overall reduction in nucleus accumbens activity and fronto-striatal connectivity or the additional inability to sustain engagement of this network over time is unknown. The authors sought to determine whether treatment-induced changes in the ability to sustain nucleus accumbens activity and fronto-striatal connectivity during the regulation of positive affect are associated with gains in positive affect. METHOD Using fMRI, the authors assessed the ability to sustain activity in reward-related networks when attempting to increase positive emotion during performance of an emotion regulation paradigm in 21 depressed patients before and after 2 months of antidepressant treatment. Over the same interval, 14 healthy comparison subjects underwent scanning as well. RESULTS After 2 months of treatment, self-reported positive affect increased. The patients who demonstrated the largest increases in sustained nucleus accumbens activity over the 2 months were those who demonstrated the largest increases in positive affect. In addition, the patients who demonstrated the largest increases in sustained fronto-striatal connectivity were also those who demonstrated the largest increases in positive affect when controlling for negative affect. None of these associations were observed in healthy comparison subjects. CONCLUSIONS Treatment-induced change in the sustained engagement of fronto-striatal circuitry tracks the experience of positive emotion in daily life. Studies examining reduced positive affect in a variety of psychiatric disorders might benefit from examining the temporal dynamics of brain activity when attempting to understand changes in daily positive affect.
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<p>OBJECTIVES: The study objectives were to develop and objectively assess the therapeutic effect of a novel movement-based complementary and alternative medicine approach for children with an autism-spectrum disorder (ASD). DESIGN: A within-subject analysis comparing pre- to post-treatment scores on two standard measures of childhood behavioral problems was used. SETTINGS AND LOCATION: The intervention and data analysis occurred at a tertiary care, medical school teaching hospital. SUBJECTS: Twenty-four (24) children aged 3-16 years with a diagnosis of an ASD comprised the study group. INTERVENTION: The efficacy of an 8-week multimodal yoga, dance, and music therapy program based on the relaxation response (RR) was developed and examined. OUTCOME MEASURES: The study outcome was measured using The Behavioral Assessment System for Children, Second Edition (BASC-2) and the Aberrant Behavioral Checklist (ABC). RESULTS: Robust changes were found on the BASC-2, primarily for 5-12-year-old children. Unexpectedly, the post-treatment scores on the Atypicality scale of the BASC-2, which measures some of the core features of autism, changed significantly (p=0.003). CONCLUSIONS: A movement-based, modified RR program, involving yoga and dance, showed efficacy in treating behavioral and some core features of autism, particularly for latency-age children.</p>
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Depression has been associated with dysfunctional executive functions and abnormal activity within the anterior cingulate cortex (ACC), a region critically involved in action regulation. Prior research invites the possibility that executive deficits in depression may arise from abnormal responses to negative feedback or errors, but the underlying neural substrates remain unknown. We hypothesized that abnormal reactions to error would be associated with dysfunctional rostral ACC activity, a region previously implicated in error detection and evaluation of the emotional significance of events. To test this hypothesis, subjects with low and high Beck Depression Inventory (BDI) scores performed an Eriksen Flanker task. To assess whether tonic activity within the rostral ACC predicted post-error adjustments, 128-channel resting EEG data were collected before the task and analyzed with low-resolution electromagnetic tomography (LORETA) using a region-of-interest approach. High BDI subjects were uniquely characterized by significantly lower accuracy after incorrect than correct trials. Mirroring the behavioral findings, high BDI subjects had significantly reduced pretask gamma (36.5-44 Hz) current density within the affective (rostral; BA24, BA25, BA32) but not cognitive (dorsal; BA24', BA32') ACC subdivision. For low, but not high, BDI subjects pretask gamma within the affective ACC subdivision predicted post-error adjustments even after controlling for activity within the cognitive ACC subdivision. Abnormal responses to errors may thus arise due to lower activity within regions subserving affective and/or motivational responses to salient cues. Because rostral ACC regions have been implicated in treatment response in depression, our findings provide initial insight into putative mechanisms fostering treatment response.
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Several different models postulate that depression is associated with decreased approach-related behavior. Relatively little has been done to date to specifically investigate this issue. In the present study, a signal-detection analysis was used to examine the response biases of dysphoric and nondysphoric female undergraduates during 3 payoff conditions: neutral, reward, and punishment. As predicted, the dysphoric subjects had a smaller change in bias from the neutral to the reward condition compared with the nondysphoric group. The 2 groups did not differ during the neutral and punishment conditions. These findings are consistent with the hypothesis that the left frontal hypoactivation observed in depression reflects a deficit in approach-related behavior.
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<p>Subregional analyses of the hippocampus have suggested a selective role for the CA1 subregion in intermediate/long-term spatial memory and consolidation, but not short-term acquisition or encoding processes. It remains unclear how the direct cortical projection to CA1 via the perforant path (pp) contributes to these CA1-dependent processes. It has been suggested that dopamine selectively modulates the pp projection to CA1 while having little to no effect on the Schaffer collateral (SC) projection to CA1. This series of behavioral and electrophysiological experiments takes advantage of this pharmacological dissociation to demonstrate that the direct pp inputs to CA1 are critical in CA1-dependent intermediate-term retention and retrieval function. Here we demonstrate that local infusion of the nonselective dopamine agonist, apomorphine (10, 15 microg), into the CA1 subregion of awake animals produces impairments in between-day retention and retrieval, sparing within-day encoding of a modified Hebb-Williams maze and contextual conditioning of fear. In contrast, apomorphine produces no deficits when infused into the CA3 subregion. To complement the behavioral analyses, electrophysiological data was collected. In anesthetized animals, local infusion of the same doses of apomorphine significantly modifies evoked responses in the distal dendrites of CA1 following angular bundle stimulation, but produces no significant effects in the more proximal dendritic layer following stimulation of the SC. These results support a modulatory role for dopamine in the EC-CA1, but not CA3-CA1 circuitry, and suggest the possibility of a more fundamental role for EC-CA1 synaptic transmission in terms of intermediate-term, but not short-term spatial memory.</p>
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