BACKGROUND: Anxious temperament (AT) is identifiable early in life and predicts the later development of anxiety disorders and depression. Neuropeptide Y (NPY) is a putative endogenous anxiolytic neurotransmitter that adaptively regulates responses to stress and might confer resilience to stress-related psychopathology. With a well-validated nonhuman primate model of AT, we examined expression of the NPY system in the central nucleus (Ce) of the amygdala, a critical neural substrate for extreme anxiety.
METHODS: In 24 young rhesus monkeys, we measured Ce messenger RNA (mRNA) levels of all members of the NPY system that are detectable in the Ce with quantitative real time polymerase chain reaction. We then examined the relationship between these mRNA levels and both AT expression and brain metabolism.
RESULTS: Lower mRNA levels of neuropeptide Y receptor 1 (NPY1R) and NPY5R but not NPY or NPY2R in the Ce predicted elevated AT; mRNA levels for NPY1R and NPY5R in the motor cortex were not related to AT. In situ hybridization analysis provided for the first time a detailed description of NPY1R and NPY5R mRNA distribution in the rhesus amygdala and associated regions. Lastly, mRNA levels for these two receptors in the Ce predicted metabolic activity in several regions that have the capacity to regulate the Ce.
CONCLUSIONS: Decreased NPY signaling in the Ce might contribute to the altered metabolic activity that is a component of the neural substrate underlying AT. This suggests that enhancement of NPY signaling might reduce the risk to develop psychopathology.
Zotero Collections:
What is happiness? In the United States and in many other industrialized countries, it is often equated with money. Economists measure consumer confidence on the assumption that the resulting figure says something about progress and public welfare. The gross domestic product, or G.D.P., is routinely used as shorthand for the well-being of a nation.
Objective: To update and expand The North American Menopause Society's evidence-based position on nonhormonal management of menopause-associated vasomotor symptoms (VMS), previously a portion of the position statement on the management of VMS. Methods: NAMS enlisted clinical and research experts in the field and a reference librarian to identify and review available evidence. Five different electronic search engines were used to cull relevant literature. Using the literature, experts created a document for final approval by the NAMS Board of Trustees. Results: Nonhormonal management of VMS is an important consideration when hormone therapy is not an option, either because of medical contraindications or a woman's personal choice. Nonhormonal therapies include lifestyle changes, mind-body techniques, dietary management and supplements, prescription therapies, and others. The costs, time, and effort involved as well as adverse effects, lack of long-term studies, and potential interactions with medications all need to be carefully weighed against potential effectiveness during decision making. Conclusions: Clinicians need to be well informed about the level of evidence available for the wide array of nonhormonal management options currently available to midlife women to help prevent underuse of effective therapies or use of inappropriate or ineffective therapies. Recommended: Cognitive-behavioral therapy and, to a lesser extent, clinical hypnosis have been shown to be effective in reducing VMS. Paroxetine salt is the only nonhormonal medication approved by the US Food and Drug Administration for the management of VMS, although other selective serotonin reuptake/norepinephrine reuptake inhibitors, gabapentinoids, and clonidine show evidence of efficacy. Recommend with caution: Some therapies that may be beneficial for alleviating VMS are weight loss, mindfulness-based stress reduction, the S-equol derivatives of soy isoflavones, and stellate ganglion block, but additional studies of these therapies are warranted. Do not recommend at this time: There are negative, insufficient, or inconclusive data suggesting the following should not be recommended as proven therapies for managing VMS: cooling techniques, avoidance of triggers, exercise, yoga, paced respiration, relaxation, over-the-counter supplements and herbal therapies, acupuncture, calibration of neural oscillations, and chiropractic interventions. Incorporating the available evidence into clinical practice will help ensure that women receive evidence-based recommendations along with appropriate cautions for appropriate and timely management of VMS.
Transdiagnostic internet-delivered cognitive behavioural therapies (iCBT) are effective for treating anxiety and depression, but there is room for improvement. In this study we developed a new Mindfulness-Enhanced iCBT intervention by incorporating formal and informal mindfulness exercises within an existing transdiagnostic iCBT program for mixed depression and anxiety. We examined the acceptability, feasibility, and outcomes of this new program in a sample of 22 adults with anxiety disorders and/or major depression. Participants took part in the 7-lesson clinician-guided online intervention over 14 weeks, and completed measures of distress (K-10), anxiety (GAD-7), depression (PHQ-9), mindfulness (FFMQ) and well-being (WEMBWS) at pre-, mid-, post-treatment, and three months post-treatment. Treatment engagement, satisfaction, and side-effects were assessed. We found large, significant reductions in distress (Hedges g = 1.55), anxiety (g = 1.39), and depression (g = 1.96), and improvements in trait mindfulness (g = 0.98) and well-being (g = 1.26) between baseline and post-treatment, all of which were maintained at follow-up. Treatment satisfaction was high for treatment-completers, with minimal side-effects reported, although adherence was lower than expected (59.1% completed). These findings show that it is feasible to integrate online mindfulness training with iCBT for the treatment of anxiety and depression, but further research is needed to improve adherence. A randomised controlled trial is needed to explore the efficacy of this program.
Transdiagnostic internet-delivered cognitive behavioural therapies (iCBT) are effective for treating anxiety and depression, but there is room for improvement. In this study we developed a new Mindfulness-Enhanced iCBT intervention by incorporating formal and informal mindfulness exercises within an existing transdiagnostic iCBT program for mixed depression and anxiety. We examined the acceptability, feasibility, and outcomes of this new program in a sample of 22 adults with anxiety disorders and/or major depression. Participants took part in the 7-lesson clinician-guided online intervention over 14 weeks, and completed measures of distress (K-10), anxiety (GAD-7), depression (PHQ-9), mindfulness (FFMQ) and well-being (WEMBWS) at pre-, mid-, post-treatment, and three months post-treatment. Treatment engagement, satisfaction, and side-effects were assessed. We found large, significant reductions in distress (Hedges g = 1.55), anxiety (g = 1.39), and depression (g = 1.96), and improvements in trait mindfulness (g = 0.98) and well-being (g = 1.26) between baseline and post-treatment, all of which were maintained at follow-up. Treatment satisfaction was high for treatment-completers, with minimal side-effects reported, although adherence was lower than expected (59.1% completed). These findings show that it is feasible to integrate online mindfulness training with iCBT for the treatment of anxiety and depression, but further research is needed to improve adherence. A randomised controlled trial is needed to explore the efficacy of this program.
In children, behavioral inhibition (BI) in response to potential threat predicts the development of anxiety and affective disorders, and primate lesion studies suggest involvement of the orbitofrontal cortex (OFC) in mediating BI. Lesion studies are essential for establishing causality in brain-behavior relationships, but should be interpreted cautiously because the impact of a discrete lesion on a complex neural circuit extends beyond the lesion location. Complementary functional imaging methods assessing how lesions influence other parts of the circuit can aid in precisely understanding how lesions affect behavior. Using this combination of approaches in monkeys, we found that OFC lesions concomitantly alter BI and metabolism in the bed nucleus of stria terminalis (BNST) region and that individual differences in BNST activity predict BI. Thus it appears that an important function of the OFC in response to threat is to modulate the BNST, which may more directly influence the expression of BI.
Zotero Collections:
Positive affect elicited in a mother toward her newborn infant may be one of the most powerful and evolutionarily preserved forms of positive affect in the emotional landscape of human behavior. This study examined the neurobiology of this form of positive emotion and in so doing, sought to overcome the difficulty of eliciting robust positive affect in response to visual stimuli in the physiological laboratory. Six primiparous human mothers with no indications of postpartum depression brought their infants into the laboratory for a photo shoot. Approximately 6 weeks later, they viewed photographs of their infant, another infant, and adult faces during acquisition of functional magnetic resonance images (fMRI). Mothers exhibited bilateral activation of the orbitofrontal cortex (OFC) while viewing pictures of their own versus unfamiliar infants. While in the scanner, mothers rated their mood more positively for pictures of their own infants than for unfamiliar infants, adults, or at baseline. The orbitofrontal activation correlated positively with pleasant mood ratings. In contrast, areas of visual cortex that also discriminated between own and unfamiliar infants were unrelated to mood ratings. These data implicate the orbitofrontal cortex in a mother's affective responses to her infant, a form of positive emotion that has received scant attention in prior human neurobiological studies. Furthermore, individual variations in orbitofrontal activation to infant stimuli may reflect an important dimension of maternal attachment.
Zotero Collections:
Background/Aims: The typical physical therapist's workday involves teaching patients exercises to strengthen muscles. It is important for physical therapists to 'practice what they preach' by modelling good health behaviours in their own personal lives. The purpose of this study was to determine: i) whether strength training participation among physical therapists meets or exceeds commonly accepted standards for maintaining health; ii) how physical therapists participate in strength training. Methods: A Psychdata survey was developed and administered electronically to members (n=800) of the American Physical Therapy Association nationwide as part of a cross-sectional study design. A final sample of 153 surveys was collected and analysed in SPSS 15.0 for a 19% response rate. Frequency analysis was performed for all relevant survey items. Results: Approximately 67% of physical therapists regularly participate in traditional strength training that meets the American College of Sports Medicine exercise guidelines, and 55% regularly participate in alternative strength training, such as yoga and pilates, working all major muscle groups at moderate-to high-intensity at least two days per week. Conclusions: Most physical therapists appear to be good role models for engaging in strength training; more than half the physical therapists surveyed meet minimum guidelines for strength training whereas less than 20% of the general population meets the same minimum guidelines.
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.
Zotero Collections:
Our outside world changes continuously, for example, when driving through traffic. An important question is how our brain deals with this constant barrage of rapidly changing sensory input and flexibly selects only newly goal-relevant information for further capacity-limited processing in working memory. The challenge our brain faces is experimentally captured by the attentional blink (AB): an impairment in detecting the second of two target stimuli presented in close temporal proximity among distracters. Many theories have been proposed to explain this deficit in processing goal-relevant information, with some attributing the AB to capacity limitations related to encoding of the first target and others assigning a critical role to on-line selection mechanisms that control access to working memory. The current study examined the role of striatal dopamine in the AB, given its known role in regulating the contents of working memory. Specifically, participants performed an AB task and their basal level of dopamine D2-like receptor binding was measured using PET and [F-18]fallypride. As predicted, individual differences analyses showed that greater D2-like receptor binding in the striatum was associated with a larger AB, implicating striatal dopamine and mechanisms that control access to working memory in the AB. Specifically, we propose that striatal dopamine may determine the AB by regulating the threshold for working memory updating, providing a testable physiological basis for this deficit in gating rapidly changing visual information. A challenge for current models of the AB lies in connecting more directly to these neurobiological data.
Zotero Collections:
<p>In this article, Miller examines theories of modern linguistics apparent in the work of Tibetan grammarians, particularly with regard to their treatment of concepts analogous to phonemics and phonetics. (Ben Deitle 2005-11-01)</p>
BACKGROUND: With continual improvements in screening uptake and adjuvant cancer treatments, the number of Canadian women surviving breast cancer continues to grow. Preliminary findings suggest yoga can improve quality of life (QoL) in breast cancer survivors, but few studies have focused on Iyengar yoga (IY).OBJECTIVE: The purpose of this pilot study was to evaluate the impact of IY on QoL and psychosocial functioning in a select sample of breast cancer survivors.
METHODS: Breast cancer survivors (N = 24) participating in IY classes completed a questionnaire measuring generic and disease-specific QoL and psychosocial functioning, before and after the 12-week classes.
RESULTS: Postprogram questionnaires were completed by 17 participants (71%) who attended an average of 78.9% of the IY sessions. Several indicators of generic QoL improved significantly, including mental health (mean change, +4.2; P = .045), vitality (mean change, +4.9; P = .033), role-emotional (mean change, +6.4; P = .010), and bodily pain (mean change, +4.4; P = .024). Other improvements in QoL and psychosocial functioning were meaningful but were not statistically significant. Findings were further substantiated by participant's evaluation of the program's benefits and motivational value.
CONCLUSION: In this pilot study of breast cancer survivors participating in IY, we found improvements in QoL and psychosocial functioning. Moreover, positive program evaluation and motivational profile provide support for the acceptability of IY with breast cancer survivors. Randomized controlled trials comparing IY to usual care and other forms of yoga in breast cancer survivors are warranted.
IMPLICATIONS FOR PRACTICE: Nurses may consider IY as a possible intervention strategy to help breast cancer survivors improve their QoL and psychosocial functioning.
OBJECTIVE: ADHD affects between 2% and 8% of college students and is associated with broad functional impairment. No prior randomized controlled trials with this population have been published. The present study is a pilot randomized controlled trial evaluating dialectical behavior therapy (DBT) group skills training adapted for college students with ADHD.METHOD: Thirty-three undergraduates with ADHD between ages 18 and 24 were randomized to receive either DBT group skills training or skills handouts during an 8-week intervention phase. ADHD symptoms, executive functioning (EF), and related outcomes were assessed at baseline, post-treatment, and 3-month follow-up.
RESULTS: Participants receiving DBT group skills training showed greater treatment response rates (59-65% vs. 19-25%) and clinical recovery rates (53-59% vs. 6-13%) on ADHD symptoms and EF, and greater improvements in quality of life.
CONCLUSION: DBT group skills training may be efficacious, acceptable, and feasible for treating ADHD among college students. A larger randomized trial is needed for further evaluation.
Randomized controlled trials have demonstrated that mindfulness-based cognitive therapy (MBCT) is efficacious in reducing residual depressive symptoms and preventing future depressive episodes (Kuyken et al., 2016). One potential treatment effect of MBCT may be improvement of positive affect (PA), due to improved awareness of daily positive events (Geschwind et al., 2011). Considering social anxiety disorder (SAD) is characterized by diminished PA (Brown et al., 1998; Kashdan, 2007), we sought to determine whether MBCT would reduce social anxiety symptoms, and whether this reduction would be associated with improvement of PA deficits. Adults (N = 22) who met criteria for varied anxiety disorders participated in a small, open-label trial of an 8-week manualized MBCT intervention. Most participants presented with either a diagnosis (primary, secondary, or tertiary) of generalized anxiety disorder (GAD) (N = 15) and/or SAD (N = 14) prior to treatment, with eight individuals meeting diagnostic criteria for both GAD and SAD. We hypothesized participants would demonstrate improvements in social anxiety symptoms, which would be predicted by improvements in PA, not reductions in negative affect (NA). Results of several hierarchical linear regression analyses (completed in both full and disorder-specific samples) indicated that improvements in PA but not reductions in NA predicted social anxiety improvement. This effect was not observed for symptoms of worry, which were instead predicted by decreased NA for individuals diagnosed with GAD and both decreased NA and increased PA in the entire sample. Results suggest that MBCT may be efficacious in mitigating social anxiety symptoms, and this therapeutic effect may be linked to improvements in PA. However, further work is necessary considering the small, heterogeneous sample, uncontrolled study design, and exploratory nature of the study.
While the concept of the Anthropocene reflects the past and present nature, scale and magnitude of human impacts on the Earth System, its true significance lies in how it can be used to guide attitudes, choices, policies and actions that influence the future. Yet, to date much of the research on the Anthropocene has focused on interpreting past and present changes, while saying little about the future. Likewise, many futures studies have been insufficiently rooted in an understanding of past changes, in particular the long-term co-evolution of bio-physical and human systems. The Anthropocene perspective is one that encapsulates a world of intertwined drivers, complex dynamic structures, emergent phenomena and unintended consequences, manifest across different scales and within interlinked biophysical constraints and social conditions. In this paper we discuss the changing role of science and the theoretical, methodological and analytical challenges in considering futures of the Anthropocene. We present three broad groups of research questions on: (1) societal goals for the future; (2) major trends and dynamics that might favor or hinder them; (3) and factors that might propel or impede transformations towards desirable futures. Tackling these questions requires the development of novel approaches integrating natural and social sciences as well as the humanities beyond what is current today. We present three examples, one from each group of questions, illustrating how science might contribute to the identification of desirable and plausible futures and pave the way for transformations towards them. We argue that it is time for debates on the sustainability of the Anthropocene to focus on opportunities for realizing desirable and plausible futures.
In “Poeticizing Ecology/Ecologizing Poetry: Reading Elizabeth Bishop’s ‘Poem’ Ecologically,” we argue that ecological poetry is a kind of ecopoetry that undergirds “nature poetry” and environmental/activist poetry. Ecological poetry is also best put into conversation with deconstruction. This argument, informed by Timothy Morton’s claim that “deconstruction and ecology should talk to one another,” entails challenging previous arguments about what counts as ecopoetry but also the status of the lyric in general. We synthesize James Longenbach’s position in The Resistance of Poetry with Nick Selby’s argument in “Ecopoetries in America” to examine the relationship between close reading and reading ecologically. Rather than an ethical stance perceived in the content of the poem, to read ecologically requires attention to form and linguistic indeterminacy, not only because deconstruction and ecology are alike, but also because poetry is comprised of language, the usage of which “revels in duplicity and disjunction.” Deconstruction is the best approach to divergent perspectives on nature, or the way a poem offers, in Nick Selby’s view, not a clear purchase or single overarching view, but “a struggle to get nature right.” We contend that to give space to alterity, to allow the otherness not only of nature but also of language itself in its capacity for referentiality is to expand the “marked” space of ecology (in the terms set forth by G. Spencer Brown’s Laws of Form). We support this claim with a reading of Bishop’s “Poem,” which we acknowledge as an atypical choice for what constitutes ecological poetry. A borderline ekphrastic poem, “Poem” allows us to talk not only about the space inherent in nature and language but between text and image, or poem and painting. What we find in our reading of Bishop’s “Poem” is a contingency between the poem and the painting, rather than a classical attempt of one to overpower the other, to speak for the other as the more authoritative sign. We find the uncanny or strange quality of Bishop’s ekphrastic approach to an amateurish painting that she calls “sketch” a way to further substantiate Morton’s claim about the relevance of deconstruction to ecology. Through our reading of the poem we argue that no entity completely coincides with itself because ecological thinking has helped us to see how every entity is shot-through with traces of the other; we ourselves are made up of other lifeforms; life is made up of nonlife. To think ecologically is to think the other within the self (especially including all the nonhuman others), within any entity whatsoever.
CONTEXT: Despite the known health benefits of physical activity, participation rates in cancer survivor groups remain low. Researchers have attempted to identify alternative modes of nontraditional physical activities that may increase participation and adherence rates. This study investigated the determinants of yoga in breast cancer survivors.AIM: To examine predictors of Iyengar yoga adherence in breast cancer survivors using the theory of planned behaviour.
SETTINGS AND DESIGN: Classes were held either in Campus Recreation facilities or at the Behavioral Medicine Fitness Center at the University of Alberta in Edmonton, Canada. The study was an evaluation of an existing yoga program.
MATERIALS AND METHODS: Twenty-three post adjuvant therapy breast cancer survivors participating in a community-based, twice weekly, 12 week Iyengar yoga program were asked to complete baseline measures of the theory of planned behavior, demographic, medical, health/fitness, and psychosocial variables. Adherence was measured by objective attendance to the classes.
STATISTICAL ANALYSIS: We analyzed univariate associations between predictors and yoga adherence with independent t-tests.
RESULTS: Adherence to the Iyengar yoga program was 63.9% and was predicted by stronger intention (P<0.001), greater self-efficacy (P=0.003), more positive instrumental attitude (Ps=0.025), higher disease stage (P=0.018), yoga experience in the past year, (P=0.044), diagnosis of a second cancer (P=0.008), lower fatigue (P=0.037), and greater happiness (P=0.023).
CONCLUSIONS: Adherence to Iyengar yoga in breast cancer survivors was strongly related to motivational variables from the theory of planned behaviour. Researchers attempting to improve yoga adherence in breast cancer survivors may benefit from targeting the key constructs in the theory of planned behaviour.
<p>The article is a socio-cultural study of the Langtang region of Nepal. The brief survey of the Langtang region reveals that although the different population groupings living there share much in terms of a common economy, mutually intelligible languages, and a common religious tradition, relations between them, while cordial, are never intimate. Each household prefers to maintain their own ceremonies with their own religious specialities, avoiding intermarriage or close economic ties. Tibetans are the most outward looking by force of circumstance, realizing their need to create new economic opportunities and fully endorsing the value of modern education. Tamangs have been most affected by the influence of Hinduism and while there seems no likelihood that Buddhism will decline in the foreseeable future they accept their place in the multi-ethnic mosaic of Nepal. (Rajeev Ranjan Singh 2007-01-15)</p>
Living things are organized in a hierarchy of levels. Genes group together in cells, cells group together in organisms, and organisms group together in societies. Even different species form mutualistic partnerships. In the history of life, previously independent units have formed groups that, in time, have come to resemble individuals in their own right. Biologists term such events the major transitions. The process common to them all is social evolution. Each occurs only if natural selection favours one unit joining with another in a new kind of group. This book presents a fresh synthesis of the principles of social evolution that underlie the major transitions, and explains how the basic theory underpinning social evolution, inclusive fitness theory, is central to understanding each event. At the same time, it defends inclusive fitness theory against recent critiques. The book defines the key stages in a major transition, then picks out the shared principles operating at each stage across the transitions as a whole. It addresses in new ways the question of how, once they have arisen, organisms and societies can become more individualistic. Ranging from the evolution of cells to the evolution of social insects, and drawing examples from the latest studies of microbes, plants, insects, birds, and mammals, the book presents the first integrated treatment of the topic since Maynard Smith and Szathmáry's landmark volume of 1995. By demonstrating how deeply the major transitions resemble one another, it places social evolution at the heart of the history of life.
Humanity appears to be in a planet-scale, teen-style growth spurt.
Mindfulness has been hypothesized to directly facilitate well-being, and to indirectly do so by enhancing self-regulated functioning. No prior research has examined these relationships in the domain of academic achievement. The current study tested relationships among mindfulness, achievement-related self-regulation (e.g., delay-of-gratification, help-seeking, and self-control) and achievement emotions among a sample of 290 undergraduate students. Results revealed that indices of mindfulness, achievement-related self-regulation, and achievement emotions were significantly inter-correlated. And, results supported the hypothesis that the prediction of achievement emotions by mindfulness was mediated by greater self-regulation over achievement. Results are considered in light of recent evidence for associations among mindfulness, self-regulation, and well-being in other domains of functioning; with respect to theoretical and practical implications; and with respect to the possible fruitfulness of research bridging self-regulation as a character strength and achievement-related functioning.
The current study tested predictions that well-being and mindfulness are positively associated with sleep quality and with a morning circadian preference. A model was also tested wherein mindfulness directly predicts well-being and indirectly predicts well-being through improved sleep quality. Results from a sample of 305 undergraduates revealed positive associations among measures of emotional, psychological, and social well-being, mindfulness, sleep quality, and morningness. A path analysis yielded support for mindfulness as a direct predictor of well-being and for mindfulness as an indirect predictor of well-being, mediated by sleep quality. Results are considered in terms of additional plausible relationships between mental health and sleep, and in terms of suggestions for future work.
Given the central role of the amygdala in fear perception and expression and its likely abnormality in affective disorders and autism, there is great demand for a technique to measure differences in neurochemistry of the human amygdala. Unfortunately, it is also a technically complex target for magnetic resonance spectroscopy (MRS) due to a small volume, high field inhomogeneity and a shared boundary with hippocampus, which can undergo opposite changes in response to stress. We attempted to achieve reliable PRESS-localized single-voxel MRS at 3T of the isolated human amygdala by using anatomy to guide voxel size and location. We present data from 106 amygdala-MRS sessions from 58 volunteers aged 10 to 52 years, including two tests of one-week stability and a feasibility study in an adolescent sample. Our main outcomes were indices of spectral quality, repeated measurement variability (within- and between-subject standard deviations), and sensitivity to stable individual differences measured by intra-class correlation (ICC). We present metrics of amygdala-MRS reliability for n-acetyl-aspartate, creatine, choline, myo-Inositol, and glutamate+glutamine (Glx). We found that scan quality suffers an age-related difference in field homogeneity and modified our protocol to compensate. We further identified an effect of anatomical inclusion near the endorhinal sulcus, a region of high synaptic density, that contributes up to 29% of within-subject variability across 4 sessions (n=14). Remaining variability in line width but not signal-to-noise also detracts from reliability. Statistical correction for partial inclusion of these strong neurochemical gradients decreases n-acetyl-aspartate reliability from an intraclass correlation of 0.84 to 0.56 for 7-minute acquisitions. This suggests that systematic differences in anatomical inclusion can contribute greatly to apparent neurochemical concentrations and could produce false group differences in experimental studies. Precise, anatomically-based prescriptions that avoid age-related sources of inhomogeneity and use longer scan times may permit study of individual differences in neurochemistry throughout development in this late-maturing structure.
Zotero Collections:
Given the central role of the amygdala in fear perception and expression and its likely abnormality in affective disorders and autism, there is great demand for a technique to measure differences in neurochemistry of the human amygdala. Unfortunately, it is also a technically complex target for magnetic resonance spectroscopy (MRS) due to a small volume, high field inhomogeneity and a shared boundary with hippocampus, which can undergo opposite changes in response to stress. We attempted to achieve reliable PRESS-localized single-voxel MRS at 3T of the isolated human amygdala by using anatomy to guide voxel size and location. We present data from 106 amygdala-MRS sessions from 58 volunteers aged 10 to 52 years, including two tests of one-week stability and a feasibility study in an adolescent sample. Our main outcomes were indices of spectral quality, repeated measurement variability (within- and between-subject standard deviations), and sensitivity to stable individual differences measured by intra-class correlation (ICC). We present metrics of amygdala-MRS reliability for n-acetyl-aspartate, creatine, choline, myo-Inositol, and glutamate+glutamine (Glx). We found that scan quality suffers an age-related difference in field homogeneity and modified our protocol to compensate. We further identified an effect of anatomical inclusion near the endorhinal sulcus, a region of high synaptic density, that contributes up to 29% of within-subject variability across 4 sessions (n=14). Remaining variability in line width but not signal-to-noise also detracts from reliability. Statistical correction for partial inclusion of these strong neurochemical gradients decreases n-acetyl-aspartate reliability from an intraclass correlation of 0.84 to 0.56 for 7-minute acquisitions. This suggests that systematic differences in anatomical inclusion can contribute greatly to apparent neurochemical concentrations and could produce false group differences in experimental studies. Precise, anatomically-based prescriptions that avoid age-related sources of inhomogeneity and use longer scan times may permit study of individual differences in neurochemistry throughout development in this late-maturing structure.
Pages |