Although there are many imaging studies on traditional ROI-based amygdala volumetry, there are very few studies on modeling amygdala shape variations. This paper presents a unified computational and statistical framework for modeling amygdala shape variations in a clinical population. The weighted spherical harmonic representation is used to parameterize, smooth out, and normalize amygdala surfaces. The representation is subsequently used as an input for multivariate linear models accounting for nuisance covariates such as age and brain size difference using the SurfStat package that completely avoids the complexity of specifying design matrices. The methodology has been applied for quantifying abnormal local amygdala shape variations in 22 high functioning autistic subjects.
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BACKGROUND: Although it has been hypothesized that glucocorticoid hypersecretion in depressed patients leads to neuronal atrophy in the hippocampus, magnetic resonance imaging (MRI) -based morphometry studies of the hippocampus to date have produced mixed results.
METHODS: In our MRI study, hippocampal volumes were measured in 25 depressed patients (13 with melancholia and 12 without melancholia) and 15 control subjects.
RESULTS: No significant differences in hippocampus volumes were found between any of the subject groups, although within subjects right hippocampal volumes were found to be significantly larger than left hippocampal volumes. Additionally, right and total (left + right) hippocampal volumes in control and depressed subjects were found to be positively correlated with trait anxiety as measured by the state/trait anxiety inventory.
CONCLUSIONS: Because our subject group is younger than those in studies reporting hippocampal atrophy, we conclude that longitudinal studies will be necessary for investigation of the lifelong course of hippocampal volumetry.
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Cultivation of mindfulness, the nonjudgmental awareness of experiences in the present moment, produces beneficial effects on well-being and ameliorates psychiatric and stress-related symptoms. Mindfulness meditation has therefore increasingly been incorporated into psychotherapeutic interventions. Although the number of publications in the field has sharply increased over the last two decades, there is a paucity of theoretical reviews that integrate the existing literature into a comprehensive theoretical framework. In this article, we explore several components through which mindfulness meditation exerts its effects: (a) attention regulation, (b) body awareness, (c) emotion regulation (including reappraisal and exposure, extinction, and reconsolidation), and (d) change in perspective on the self. Recent empirical research, including practitioners’ self-reports and experimental data, provides evidence supporting these mechanisms. Functional and structural neuroimaging studies have begun to explore the neuroscientific processes underlying these components. Evidence suggests that mindfulness practice is associated with neuroplastic changes in the anterior cingulate cortex, insula, temporo-parietal junction, fronto-limbic network, and default mode network structures. The authors suggest that the mechanisms described here work synergistically, establishing a process of enhanced self-regulation. Differentiating between these components seems useful to guide future basic research and to specifically target areas of development in the treatment of psychological disorders.
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Neurosurgical treatment of psychiatric disorders has been influenced by evolving neurobiological models of symptom generation. The advent of functional neuroimaging and advances in the neurosciences have revolutionized understanding of the functional neuroanatomy of psychiatric disorders. This article reviews neuroimaging studies of depression from the last 3 decades and describes an emerging neurocircuitry model of mood disorders, focusing on critical circuits of cognition and emotion, particularly those networks involved in the regulation of evaluative, expressive and experiential aspects of emotion. The relevance of this model for neurotherapeutics is discussed, as well as the role of functional neuroimaging of psychiatric disorders.
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<p>Several recent studies using functional magnetic resonance imaging (fMRI) during recognition memory tests have suggested that the ability to neuromodulate as a function of cognitive demand may be impaired in older adults due to age-related cell loss and neural volume reduction in memory specific regions. In the current study, older adults (ages 59-77) were tested with fMRI during a delayed-recognition task in which memory load for faces was varied across trials. Activity was greater in amplitude for three- versus one-face stimuli within the superior, middle, and inferior frontal gyri, intraparietal sulcus, and fusiform gyrus. It was concluded that the ability to modulate activity with increasing load is preserved in older adults despite reductions in neural volume.</p>
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<p>We conducted two fMRI studies to investigate the sensitivity of delay-period activity to changes in memory load during a delayed-recognition task for faces. In Experiment 1, each trial began with the presentation of a memory array consisting of one, two, or three faces that lasted for 3 sec. A 15-sec delay period followed during which no stimuli were present. The delay interval concluded with a one-face probe to which subjects made a button press response indicating whether this face was part of the memory array. Experiment 2 was similar in design except that the delay period was lengthened to 24 sec, and the memory array consisted of only one or three faces. We hypothesized that memory maintenance processes that spanned the delay interval would be revealed by their sensitivity to memory load. Long delay intervals were employed to temporally dissociate phasic activity engendered by the memory array from sustained activity reflecting maintenance. Regions of interest (ROIs) were defined anatomically for the superior frontal gyri (SFG), middle frontal gyri (MFG), and inferior frontal gyri (IFG), intraparietal sulci (IPS), and fusiform gyri (FFG) on a subject-by-subject basis. The mean time course of activity was determined for all voxels within these regions and for that subset of voxels within each ROI that correlated significantly with an empirically determined reference waveform. In both experiments, memory load significantly influenced activation 6--9 sec following the onset of the memory array with larger amplitude responses for higher load levels. Responses were greatest within MFG, IPS, and FFG. In both experiments, however, these load-sensitive differences declined over successive time intervals and were no longer significant at the end of the delay interval. Although insensitive to our load manipulation, sustained activation was present at the conclusion of the delay interval within MFG and other prefrontal regions. IPS delay activity returned to prestimulus baseline levels prior to the end of the delay period in Experiment 2, but not in Experiment 1. Within FFG, delay activity returned to prestimulus baseline levels prior to the conclusion of the delay interval in both experiments. Thus, while phasic processes engendered by the memory array were strongly affected by memory load, no evidence for load-sensitive delay-spanning maintenance processes was obtained.</p>
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Lesions of the dorsal hippocampus have been shown to disrupt both the acquisition and the consolidation of memories associated with contextual fear (fear of the place of conditioning), but do not affect fear conditioning to discrete cues (e.g., a tone). Blockade of central muscarinic cholinergic receptor activation results in selective acquisition deficits of contextual fear conditioning, but reportedly has little effect on consolidation. Here we show for the first time that direct infusion of the muscarinic cholinergic receptor antagonist, scopolamine, into the dorsal hippocampus produces a dose-dependent deficit in both acquisition and consolidation of contextual fear conditioning, while having no impact on simple tone conditioning.
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We investigated whether mindfulness training (MT) influences information processing in a working memory task with complex visual stimuli. Participants were tested before (T1) and after (T2) participation in an intensive one-month MT retreat, and their performance was compared with that of an age- and education-matched control group. Accuracy did not differ across groups at either time point. Response times were faster and significantly less variable in the MT versus the control group at T2. Since these results could be due to changes in mnemonic processes, speed-accuracy trade-off, or nondecisional factors (e.g., motor execution), we used a mathematical modeling approach to disentangle these factors. The EZ-diffusion model (Wagenmakers, van der Maas, & Grasman, Psychonomic Bulletin & Review 14:(1), 3-22, 2007) suggested that MT leads to improved information quality and reduced response conservativeness, with no changes in nondecisional factors. The noisy exemplar model further suggested that the increase in information quality reflected a decrease in encoding noise and not an increase in forgetting. Thus, mathematical modeling may help clarify the mechanisms by which MT produces salutary effects on performance.
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Baseline resting electroencephalogram activity was recorded with 3 different reference montages from 15 clinically depressed and 13 control subjects. Power in all frequency bands was extracted by fast Fourier transformation. There was a significant Group X Hemisphere interaction in the mid-frontal region, for the alpha band power only. Depressed subjects had less left-sided activation (i.e., more alpha activity) than did normal control subjects. This pattern of diminished left-sided frontal activation is interpreted as indicating a deficit in approach mechanisms in depressed subjects.
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Autism is a neurodevelopmental disorder affecting behavioral and social cognition, but there is little understanding about the link between the functional deficit and its underlying neuroanatomy. We applied a 2D version of voxel-based morphometry (VBM) in differentiating the white matter concentration of the corpus callosum for the group of 16 high functioning autistic and 12 normal subjects. Using the white matter density as an index for neural connectivity, autism is shown to exhibit less white matter concentration in the region of the genu, rostrum, and splenium removing the effect of age based on the general linear model (GLM) framework. Further, it is shown that the less white matter concentration in the corpus callosum in autism is due to hypoplasia rather than atrophy.
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This paper briefly reviews the evidence for multistore theories of memory and points out some difficulties with the approach. An alternative framework for human memory research is then outlined in terms of depth or levels of processing. Some current data and arguments are reexamined in the light of this alternative framework and implications for further research considered.
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INTRODUCTION: Major depressive disorder (MDD) is characterized by cognitive biases in attention, memory and language use. Language use biases often parallel depression symptoms, and contain over-representations of both negative emotive and death words as well as low levels of positive emotive words. This study further explores cognitive biases in depression by comparing the effect of current depression status to cumulative depression history on an elaborated verbal recall of emotional photographs.
METHODS: Following a negative mood induction, fifty-two individuals (42 women) with partially-remitted depression viewed - then recalled and verbally described - slides from the International Affective Picture System (IAPS). Descriptions were transcribed and frequency of depression-related word use (positive emotion, negative emotion, sex, ingestion and death) was analyzed using the Linguistic Inquiry and Word Count program (LIWC).
RESULTS: Contrary to expectations and previous findings, current depression status did not affect word use in any categories of interest. However, individuals with more than 5 years of previous depression used fewer words related to positive emotion (t(50) = 2.10, p = .04, (d = 0.57)), and sex (t(48) = 2.50, p = .013 (d = 0.81)), and there was also a trend for these individuals to use fewer ingestion words (t(50) = 1.95, p = .057 (d = 0.58)), suggesting a deficit in appetitive processing.
CONCLUSIONS: Our findings suggest that depression duration affects appetitive information processing and that appetitive word use may be a behavioral marker for duration related brain changes which may be used to inform treatment.
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Self-conscious emotions such as embarrassment and shame are associated with 2 aspects of theory of mind (ToM): (a) the ability to understand that behavior has social consequences in the eyes of others and (b) an understanding of social norms violations. The present study aimed to link ToM with the recognition of self-conscious emotion. Children with and without autism identified facial expressions conscious of self-conscious and non-self-conscious emotions from photographs. ToM was also measured. Children with autism performed more poorly than comparison children at identifying self-conscious emotions, though they did not differ in the recognition of non-self-conscious emotions. When ToM ability was statistically controlled, group differences in the recognition of self-conscious emotion disappeared. Discussion focused on the links between ToM and self-conscious emotion.
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The capacity to stabilize the content of attention over time varies among individuals, and its impairment is a hallmark of several mental illnesses. Impairments in sustained attention in patients with attention disorders have been associated with increased trial-to-trial variability in reaction time and event-related potential deficits during attention tasks. At present, it is unclear whether the ability to sustain attention and its underlying brain circuitry are transformable through training. Here, we show, with dichotic listening task performance and electroencephalography, that training attention, as cultivated by meditation, can improve the ability to sustain attention. Three months of intensive meditation training reduced variability in attentional processing of target tones, as indicated by both enhanced theta-band phase consistency of oscillatory neural responses over anterior brain areas and reduced reaction time variability. Furthermore, those individuals who showed the greatest increase in neural response consistency showed the largest decrease in behavioral response variability. Notably, we also observed reduced variability in neural processing, in particular in low-frequency bands, regardless of whether the deviant tone was attended or unattended. Focused attention meditation may thus affect both distracter and target processing, perhaps by enhancing entrainment of neuronal oscillations to sensory input rhythms, a mechanism important for controlling the content of attention. These novel findings highlight the mechanisms underlying focused attention meditation and support the notion that mental training can significantly affect attention and brain function.
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The high likelihood of recurrence in depression is linked to a progressive increase in emotional reactivity to stress (stress sensitization). Mindfulness-based therapies teach mindfulness skills designed to decrease emotional reactivity in the face of negative affect-producing stressors. The primary aim of the current study was to assess whether Mindfulness-Based Cognitive Therapy (MBCT) is efficacious in reducing emotional reactivity to social evaluative threat in a clinical sample with recurrent depression. A secondary aim was to assess whether improvement in emotional reactivity mediates improvements in depressive symptoms. Fifty-two individuals with partially remitted depression were randomized into an 8-week MBCT course or a waitlist control condition. All participants underwent the Trier Social Stress Test (TSST) before and after the 8-week trial period. Emotional reactivity to stress was assessed with the Spielberger State Anxiety Inventory at several time points before, during, and after the stressor. MBCT was associated with decreased emotional reactivity to social stress, specifically during the recovery (post-stressor) phase of the TSST. Waitlist controls showed an increase in anticipatory (pre-stressor) anxiety that was absent in the MBCT group. Improvements in emotional reactivity partially mediated improvements in depressive symptoms. Limitations include small sample size, lack of objective or treatment adherence measures, and non-generalizability to more severely depressed populations. Given that emotional reactivity to stress is an important psychopathological process underlying the chronic and recurrent nature of depression, these findings suggest that mindfulness skills are important in adaptive emotion regulation when coping with stress.
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BACKGROUND: Many antidepressant medications (ADM) are associated with disruptions in sleep continuity that can compromise medication adherence and impede successful treatment. The present study investigated whether mindfulness meditation (MM) training could improve self-reported and objectively measured polysomnographic (PSG) sleep profiles in depressed individuals who had achieved at least partial remission with ADM, but still had residual sleep complaints.
METHODS: Twenty-three ADM users with sleep complaints 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, residual depression symptoms.
RESULTS: Compared to controls, the MBCT participants improved on both PSG and subjective measures of sleep. They showed a pattern of decreased wake time and increased sleep efficiency. Sleep depth, as measured by stage 1 and slow-wave sleep, did not change as a result of mindfulness training.
CONCLUSIONS: MM is associated with increases in both objectively and subjectively measured sleep continuity in ADM users. MM training may serve as more desirable and cost-effective alternative to discontinuation or supplementation with hypnotics, and may contribute to a more sustainable recovery from depression.
<p>BACKGROUND: Many antidepressant medications (ADM) are associated with disruptions in sleep continuity that can compromise medication adherence and impede successful treatment. The present study investigated whether mindfulness meditation (MM) training could improve self-reported and objectively measured polysomnographic (PSG) sleep profiles in depressed individuals who had achieved at least partial remission with ADM, but still had residual sleep complaints. METHODS: Twenty-three ADM users with sleep complaints 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, residual depression symptoms. RESULTS: Compared to controls, the MBCT participants improved on both PSG and subjective measures of sleep. They showed a pattern of decreased wake time and increased sleep efficiency. Sleep depth, as measured by stage 1 and slow-wave sleep, did not change as a result of mindfulness training. CONCLUSIONS: MM is associated with increases in both objectively and subjectively measured sleep continuity in ADM users. MM training may serve as more desirable and cost-effective alternative to discontinuation or supplementation with hypnotics, and may contribute to a more sustainable recovery from depression.</p>
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Objective: Mindfulness-based stress reduction (MBSR) is a structured group program that employs mindfulness meditation to alleviate suffering associated with physical, psychosomatic and psychiatric disorders. The program, nonreligious and nonesoteric, is based upon a systematic procedure to develop enhanced awareness of moment-to-moment experience of perceptible mental processes. The approach assumes that greater awareness will provide more veridical perception, reduce negative affect and improve vitality and coping. In the last two decades, a number of research reports appeared that seem to support many of these claims. We performed a comprehensive review and meta-analysis of published and unpublished studies of health-related studies related to MBSR. Methods: Sixty-four empirical studies were found, but only 20 reports met criteria of acceptable quality or relevance to be included in the meta-analysis. Reports were excluded due to (I) insufficient information about interventions, (2) poor quantitative health evaluation, (3) inadequate statistical analysis, (4) mindfulness not being the central component of intervention, or (5) the setting of intervention or sample composition deviating too widely from the health-related MBSR program. Acceptable studies covered a wide spectrum of clinical populations (e.g., pain, cancer, heart disease, depression, and anxiety), as well as stressed nonclinical groups. Both controlled and observational investigations were included. Standardized measures of physical and mental well-being constituted the dependent variables of the analysis. Results: Overall, both controlled and uncontrolled studies showed similar effect sizes of approximately 0.5 (P <.0001) with homogeneity of distribution. Conclusion: Although derived from a relatively small number of studies, these results suggest that MBSR may help a broad range of individuals to cope with their clinical and nonclinical problems.
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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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Although research has found that long-term mindfulness meditation practice promotes executive functioning and the ability to sustain attention, the effects of brief mindfulness meditation training have not been fully explored. We examined whether brief meditation training affects cognition and mood when compared to an active control group. After four sessions of either meditation training or listening to a recorded book, participants with no prior meditation experience were assessed with measures of mood, verbal fluency, visual coding, and working memory. Both interventions were effective at improving mood but only brief meditation training reduced fatigue, anxiety, and increased mindfulness. Moreover, brief mindfulness training significantly improved visuo-spatial processing, working memory, and executive functioning. Our findings suggest that 4 days of meditation training can enhance the ability to sustain attention; benefits that have previously been reported with long-term meditators.
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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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Different forms of learning and memory depend on functionally and anatomically separable neural circuits [Squire, L. R. (1992) Psychol. Rev. 99, 195–231]. Declarative memory relies on a medial temporal lobe system, whereas habit learning relies on the striatum [Cohen, N. J. & Eichenbaum, H. (1993) Memory, Amnesia, and the Hippocampal System (MIT Press, Cambridge, MA)]. How these systems are engaged to optimize learning and behavior is not clear. Here, we present results from functional neuroimaging showing that the presence of a demanding secondary task during learning modulates the degree to which subjects solve a problem using either declarative memory or habit learning. Dual-task conditions did not reduce accuracy but reduced the amount of declarative learning about the task. Medial temporal lobe activity was correlated with task performance and declarative knowledge after learning under single-task conditions, whereas performance was correlated with striatal activity after dual-task learning conditions. These results demonstrate a fundamental difference in these memory systems in their sensitivity to concurrent distraction. The results are consistent with the notion that declarative and habit learning compete to mediate task performance, and they suggest that the presence of distraction can bias this competition. These results have implications for learning in multitask situations, suggesting that, even if distraction does not decrease the overall level of learning, it can result in the acquisition of knowledge that can be applied less flexibly in new situations.
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