Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 191
Filtrar
Más filtros

Bases de datos
Tipo del documento
Intervalo de año de publicación
1.
PLoS Biol ; 21(3): e3002031, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36917567

RESUMEN

Obsessive-compulsive disorder (OCD) and pathological gambling (PG) are accompanied by deficits in behavioural flexibility. In reinforcement learning, this inflexibility can reflect asymmetric learning from outcomes above and below expectations. In alternative frameworks, it reflects perseveration independent of learning. Here, we examine evidence for asymmetric reward-learning in OCD and PG by leveraging model-based functional magnetic resonance imaging (fMRI). Compared with healthy controls (HC), OCD patients exhibited a lower learning rate for worse-than-expected outcomes, which was associated with the attenuated encoding of negative reward prediction errors in the dorsomedial prefrontal cortex and the dorsal striatum. PG patients showed higher and lower learning rates for better- and worse-than-expected outcomes, respectively, accompanied by higher encoding of positive reward prediction errors in the anterior insula than HC. Perseveration did not differ considerably between the patient groups and HC. These findings elucidate the neural computations of reward-learning that are altered in OCD and PG, providing a potential account of behavioural inflexibility in those mental disorders.


Asunto(s)
Juego de Azar , Trastorno Obsesivo Compulsivo , Humanos , Refuerzo en Psicología , Recompensa , Trastorno Obsesivo Compulsivo/diagnóstico por imagen , Corteza Prefrontal/diagnóstico por imagen , Imagen por Resonancia Magnética
2.
Hum Brain Mapp ; 45(10): e26768, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-38949537

RESUMEN

Structural neuroimaging data have been used to compute an estimate of the biological age of the brain (brain-age) which has been associated with other biologically and behaviorally meaningful measures of brain development and aging. The ongoing research interest in brain-age has highlighted the need for robust and publicly available brain-age models pre-trained on data from large samples of healthy individuals. To address this need we have previously released a developmental brain-age model. Here we expand this work to develop, empirically validate, and disseminate a pre-trained brain-age model to cover most of the human lifespan. To achieve this, we selected the best-performing model after systematically examining the impact of seven site harmonization strategies, age range, and sample size on brain-age prediction in a discovery sample of brain morphometric measures from 35,683 healthy individuals (age range: 5-90 years; 53.59% female). The pre-trained models were tested for cross-dataset generalizability in an independent sample comprising 2101 healthy individuals (age range: 8-80 years; 55.35% female) and for longitudinal consistency in a further sample comprising 377 healthy individuals (age range: 9-25 years; 49.87% female). This empirical examination yielded the following findings: (1) the accuracy of age prediction from morphometry data was higher when no site harmonization was applied; (2) dividing the discovery sample into two age-bins (5-40 and 40-90 years) provided a better balance between model accuracy and explained age variance than other alternatives; (3) model accuracy for brain-age prediction plateaued at a sample size exceeding 1600 participants. These findings have been incorporated into CentileBrain (https://centilebrain.org/#/brainAGE2), an open-science, web-based platform for individualized neuroimaging metrics.


Asunto(s)
Envejecimiento , Encéfalo , Imagen por Resonancia Magnética , Humanos , Adolescente , Femenino , Anciano , Adulto , Niño , Adulto Joven , Masculino , Encéfalo/diagnóstico por imagen , Encéfalo/anatomía & histología , Encéfalo/crecimiento & desarrollo , Anciano de 80 o más Años , Preescolar , Persona de Mediana Edad , Envejecimiento/fisiología , Imagen por Resonancia Magnética/métodos , Neuroimagen/métodos , Neuroimagen/normas , Tamaño de la Muestra
3.
Mol Psychiatry ; 28(7): 3013-3022, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-36792654

RESUMEN

The promise of machine learning has fueled the hope for developing diagnostic tools for psychiatry. Initial studies showed high accuracy for the identification of major depressive disorder (MDD) with resting-state connectivity, but progress has been hampered by the absence of large datasets. Here we used regular machine learning and advanced deep learning algorithms to differentiate patients with MDD from healthy controls and identify neurophysiological signatures of depression in two of the largest resting-state datasets for MDD. We obtained resting-state functional magnetic resonance imaging data from the REST-meta-MDD (N = 2338) and PsyMRI (N = 1039) consortia. Classification of functional connectivity matrices was done using support vector machines (SVM) and graph convolutional neural networks (GCN), and performance was evaluated using 5-fold cross-validation. Features were visualized using GCN-Explainer, an ablation study and univariate t-testing. The results showed a mean classification accuracy of 61% for MDD versus controls. Mean accuracy for classifying (non-)medicated subgroups was 62%. Sex classification accuracy was substantially better across datasets (73-81%). Visualization of the results showed that classifications were driven by stronger thalamic connections in both datasets, while nearly all other connections were weaker with small univariate effect sizes. These results suggest that whole brain resting-state connectivity is a reliable though poor biomarker for MDD, presumably due to disease heterogeneity as further supported by the higher accuracy for sex classification using the same methods. Deep learning revealed thalamic hyperconnectivity as a prominent neurophysiological signature of depression in both multicenter studies, which may guide the development of biomarkers in future studies.


Asunto(s)
Trastorno Depresivo Mayor , Humanos , Mapeo Encefálico/métodos , Imagen por Resonancia Magnética , Vías Nerviosas , Encéfalo/patología , Neuroimagen
4.
Cereb Cortex ; 33(8): 4553-4561, 2023 04 04.
Artículo en Inglés | MEDLINE | ID: mdl-36130087

RESUMEN

Suppression of the brain's default mode network (DMN) during external goal-directed cognitive tasks has been consistently observed in neuroimaging studies. However, emerging insights suggest the DMN is not a monolithic "task-negative" network but is comprised of subsystems that show functional heterogeneity. Despite considerable research interest, no study has investigated the consistency of DMN activity suppression across multiple cognitive tasks within the same individuals. In this study, 85 healthy 15- to 25-year-olds completed three functional magnetic resonance imaging tasks that were designed to reliably map DMN suppression from a resting baseline. Our findings revealed a distinct suppression subnetwork across the three tasks that comprised traditional DMN and adjacent regions. Specifically, common suppression was observed in the medial prefrontal cortex, the dorsal-to-mid posterior cingulate cortex extending to the precuneus, and the posterior insular cortex and parietal operculum. Further, we found the magnitude of suppression of these regions were significantly correlated within participants across tasks. Overall, our findings indicate that externally oriented cognitive tasks elicit common suppression of a distinct subnetwork of the broader DMN. The consistency to which the DMN is suppressed within individuals suggests a domain-general mechanism that may reflect a stable feature of cognitive function that optimizes external goal-directed behavior.


Asunto(s)
Cognición , Red en Modo Predeterminado , Adolescente , Adulto , Femenino , Humanos , Masculino , Adulto Joven , Atención/fisiología , Cognición/fisiología , Red en Modo Predeterminado/fisiología , Emociones , Expresión Facial , Objetivos , Giro del Cíngulo/fisiología , Pruebas de Inteligencia , Imagen por Resonancia Magnética , Lóbulo Parietal/fisiología , Corteza Prefrontal/fisiología , Tiempo de Reacción , Análisis y Desempeño de Tareas , Estimulación Luminosa
5.
J Neurosci ; 42(25): 5047-5057, 2022 06 22.
Artículo en Inglés | MEDLINE | ID: mdl-35577553

RESUMEN

Safety learning generates associative links between neutral stimuli and the absence of threat, promoting the inhibition of fear and security-seeking behaviors. Precisely how safety learning is mediated at the level of underlying brain systems, particularly in humans, remains unclear. Here, we integrated a novel Pavlovian conditioned inhibition task with ultra-high field (7 Tesla) fMRI to examine the neural basis of safety learning in 49 healthy participants. In our task, participants were conditioned to two safety signals: a conditioned inhibitor that predicted threat omission when paired with a known threat signal (A+/AX-), and a standard safety signal that generally predicted threat omission (BC-). Both safety signals evoked equivalent autonomic and subjective learning responses but diverged strongly in terms of underlying brain activation (PFDR whole-brain corrected). The conditioned inhibitor was characterized by more prominent activation of the dorsal striatum, anterior insular, and dorsolateral PFC compared with the standard safety signal, whereas the latter evoked greater activation of the ventromedial PFC, posterior cingulate, and hippocampus, among other regions. Further analyses of the conditioned inhibitor indicated that its initial learning was characterized by consistent engagement of dorsal striatal, midbrain, thalamic, premotor, and prefrontal subregions. These findings suggest that safety learning via conditioned inhibition involves a distributed cortico-striatal circuitry, separable from broader cortical regions involved with processing standard safety signals (e.g., CS-). This cortico-striatal system could represent a novel neural substrate of safety learning, underlying the initial generation of "stimulus-safety" associations, distinct from wider cortical correlates of safety processing, which facilitate the behavioral outcomes of learning.SIGNIFICANCE STATEMENT Identifying safety is critical for maintaining adaptive levels of anxiety, but the neural mechanisms of human safety learning remain unclear. Using 7 Tesla fMRI, we compared learning-related brain activity for a conditioned inhibitor, which actively predicted threat omission, and a standard safety signal (CS-), which was passively unpaired with threat. The inhibitor engaged an extended circuitry primarily featuring the dorsal striatum, along with thalamic, midbrain, and premotor/PFC regions. The CS- exclusively involved cortical safety-related regions observed in basic safety conditioning, such as the vmPFC. These findings extend current models to include learning-specific mechanisms for encoding stimulus-safety associations, which might be distinguished from expression-related cortical mechanisms. These insights may suggest novel avenues for targeting dysfunctional safety learning in psychopathology.


Asunto(s)
Mapeo Encefálico , Condicionamiento Clásico , Encéfalo/fisiología , Condicionamiento Clásico/fisiología , Miedo/fisiología , Humanos , Imagen por Resonancia Magnética
6.
Neuroimage ; 270: 119964, 2023 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-36822252

RESUMEN

Core regions of the salience network (SN), including the anterior insula (aINS) and dorsal anterior cingulate cortex (dACC), coordinate rapid adaptive changes in attentional and autonomic processes in response to negative emotional events. In doing so, the SN incorporates bottom-up signals from subcortical brain regions, such as the amygdala and periaqueductal gray (PAG). However, the precise influence of these subcortical regions is not well understood. Using ultra-high field 7-Tesla functional magnetic resonance imaging, this study investigated the bottom-up interactions of the amygdala and PAG with the SN during negative emotional salience processing. Thirty-seven healthy participants completed an emotional oddball paradigm designed to elicit a salient negative emotional response via the presentation of random, task-irrelevant negative emotional images. Negative emotional processing was associated with prominent activation in the SN, spanning the amygdala, PAG, aINS, and dACC. Consistent with previous research, analysis using dynamic causal modelling revealed an excitatory influence from the amygdala to the aINS, dACC, and PAG. In contrast, the PAG showed an inhibitory influence on amygdala, aINS and dACC activity. Our findings suggest that the amygdala may amplify the processing of negative emotional stimuli in the SN to enable upstream access to attentional resources. In comparison, the inhibitory influence of the PAG possibly reflects its involvement in modulating sympathetic-parasympathetic autonomic arousal mediated by the SN. This PAG-mediated effect may be driven by amygdala input and facilitate bottom-up processing of negative emotional stimuli. Overall, our results show that the amygdala and PAG modulate divergent functions of the SN during negative emotional processing.


Asunto(s)
Encéfalo , Emociones , Humanos , Emociones/fisiología , Giro del Cíngulo/diagnóstico por imagen , Giro del Cíngulo/fisiología , Mapeo Encefálico , Imagen por Resonancia Magnética/métodos
7.
Neurobiol Dis ; 176: 105944, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36493974

RESUMEN

Many patients with autism spectrum disorders (ASD) show disturbances in their sleep/wake cycles, and they may be particularly vulnerable to the impact of circadian disruptors. We have previously shown that a 2-weeks exposure to dim light at night (DLaN) disrupts diurnal rhythms, increases repetitive behaviors and reduces social interactions in contactin-associated protein-like 2 knock out (Cntnap2 KO) mice. The deleterious effects of DLaN may be mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment melanopsin, which is maximally sensitive to blue light (480 nm). In this study, the usage of a light-emitting diode array enabled us to shift the spectral properties of the DLaN while keeping the intensity of the illumination at 10 lx. First, we confirmed that the short-wavelength enriched lighting produced strong acute suppression of locomotor activity (masking), robust light-induced phase shifts, and cFos expression in the suprachiasmatic nucleus in wild-type (WT) mice, while the long-wavelength enriched lighting evoked much weaker responses. Opn4DTA mice, lacking the melanopsin expressing ipRGCs, were resistant to DLaN effects. Importantly, shifting the DLaN stimulus to longer wavelengths mitigated the negative impact on the activity rhythms and 'autistic' behaviors (i.e. reciprocal social interactions, repetitive grooming) in the Cntnap2 KO as well as in WT mice. The short-, but not the long-wavelength enriched, DLaN triggered cFos expression in in the basolateral amygdala (BLA) as well as in the peri-habenula region raising that possibility that these cell populations may mediate the effects. Broadly, our findings are consistent with the recommendation that spectral properties of light at night should be considered to optimize health in neurotypical as well as vulnerable populations.


Asunto(s)
Ritmo Circadiano , Células Ganglionares de la Retina , Ratones , Animales , Ritmo Circadiano/fisiología , Células Ganglionares de la Retina/metabolismo , Núcleo Supraquiasmático , Luz , Proteínas de la Membrana/metabolismo , Proteínas del Tejido Nervioso/metabolismo
8.
Hum Brain Mapp ; 44(18): 6418-6428, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-37853935

RESUMEN

Current behavioural treatment of obsessive-compulsive disorder (OCD) is informed by fear conditioning and involves iteratively re-evaluating previously threatening stimuli as safe. However, there is limited research investigating the neurobiological response to conditioning and reversal of threatening stimuli in individuals with OCD. A clinical sample of individuals with OCD (N = 45) and matched healthy controls (N = 45) underwent functional magnetic resonance imaging. While in the scanner, participants completed a well-validated fear reversal task and a resting-state scan. We found no evidence for group differences in task-evoked brain activation or functional connectivity in OCD. Multivariate analyses encompassing all participants in the clinical and control groups suggested that subjective appraisal of threatening and safe stimuli were associated with a larger difference in brain activity than the contribution of OCD symptoms. In particular, we observed a brain-behaviour continuum whereby heightened affective appraisal was related to increased bilateral insula activation during the task (r = 0.39, pFWE = .001). These findings suggest that changes in conditioned threat-related processes may not be a core neurobiological feature of OCD and encourage further research on the role of subjective experience in fear conditioning.


Asunto(s)
Trastorno Obsesivo Compulsivo , Humanos , Miedo/fisiología , Encéfalo/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Corteza Insular , Mapeo Encefálico
9.
Psychol Med ; 53(8): 3387-3395, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35916600

RESUMEN

BACKGROUND: Cognitive-behavior therapy (CBT) is a well-established first-line intervention for anxiety-related disorders, including specific phobia, social anxiety disorder, panic disorder/agoraphobia, generalized anxiety disorder, obsessive-compulsive disorder, and posttraumatic stress disorder. Several neural predictors of CBT outcome for anxiety-related disorders have been proposed, but previous results are inconsistent. METHODS: We conducted a systematic review and meta-analysis of task-based functional magnetic resonance imaging (fMRI) studies investigating whole-brain predictors of CBT outcome in anxiety-related disorders (17 studies, n = 442). RESULTS: Across different tasks, we observed that brain response in a network of regions involved in salience and interoception processing, encompassing fronto-insular (the right inferior frontal gyrus-anterior insular cortex) and fronto-limbic (the dorsomedial prefrontal cortex-dorsal anterior cingulate cortex) cortices was strongly associated with a positive CBT outcome. CONCLUSIONS: Our results suggest that there are robust neural predictors of CBT outcome in anxiety-related disorders that may eventually lead (probably in combination with other data) to develop personalized approaches for the treatment of these mental disorders.


Asunto(s)
Terapia Cognitivo-Conductual , Imagen por Resonancia Magnética , Humanos , Trastornos de Ansiedad/diagnóstico por imagen , Trastornos de Ansiedad/terapia , Terapia Cognitivo-Conductual/métodos , Ansiedad , Cognición
10.
Mol Psychiatry ; 27(3): 1611-1617, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-34974523

RESUMEN

Negative self-beliefs are a core feature of psychopathology. Despite this, we have a limited understanding of the brain mechanisms by which negative self-beliefs are cognitively restructured. Using a novel paradigm, we had participants use Socratic questioning techniques to restructure negative beliefs during ultra-high resolution 7-Tesla functional magnetic resonance imaging (UHF 7 T fMRI) scanning. Cognitive restructuring elicited prominent activation in a fronto-striato-thalamic circuit, including the mediodorsal thalamus (MD), a group of deep subcortical nuclei believed to synchronize and integrate prefrontal cortex activity, but which has seldom been directly examined with fMRI due to its small size. Increased activity was also identified in the medial prefrontal cortex (MPFC), a region consistently activated by internally focused mental processing, as well as in lateral prefrontal regions associated with regulating emotional reactivity. Using Dynamic Causal Modelling (DCM), evidence was found to support the MD as having a strong excitatory effect on the activity of regions within the broader network mediating cognitive restructuring. Moreover, the degree to which participants modulated MPFC-to-MD effective connectivity during cognitive restructuring predicted their individual tendency to engage in repetitive negative thinking. Our findings represent a major shift from a cortico-centric framework of cognition and provide important mechanistic insights into how the MD facilitates key processes in cognitive interventions for common psychiatric disorders. In addition to relaying integrative information across basal ganglia and the cortex, we propose a multifaceted role for the MD whose broad excitatory pathways act to increase synchrony between cortical regions to sustain complex mental representations, including the self.


Asunto(s)
Corteza Prefrontal , Tálamo , Ganglios Basales , Cognición/fisiología , Humanos , Imagen por Resonancia Magnética/métodos , Vías Nerviosas
11.
Mol Psychiatry ; 27(11): 4550-4560, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36071108

RESUMEN

Identifying brain alterations associated with suicidal thoughts and behaviors (STBs) in young people is critical to understanding their development and improving early intervention and prevention. The ENIGMA Suicidal Thoughts and Behaviours (ENIGMA-STB) consortium analyzed neuroimaging data harmonized across sites to examine brain morphology associated with STBs in youth. We performed analyses in three separate stages, in samples ranging from most to least homogeneous in terms of suicide assessment instrument and mental disorder. First, in a sample of 577 young people with mood disorders, in which STBs were assessed with the Columbia Suicide Severity Rating Scale (C-SSRS). Second, in a sample of young people with mood disorders, in which STB were assessed using different instruments, MRI metrics were compared among healthy controls without STBs (HC; N = 519), clinical controls with a mood disorder but without STBs (CC; N = 246) and young people with current suicidal ideation (N = 223). In separate analyses, MRI metrics were compared among HCs (N = 253), CCs (N = 217), and suicide attempters (N = 64). Third, in a larger transdiagnostic sample with various assessment instruments (HC = 606; CC = 419; Ideation = 289; HC = 253; CC = 432; Attempt=91). In the homogeneous C-SSRS sample, surface area of the frontal pole was lower in young people with mood disorders and a history of actual suicide attempts (N = 163) than those without a lifetime suicide attempt (N = 323; FDR-p = 0.035, Cohen's d = 0.34). No associations with suicidal ideation were found. When examining more heterogeneous samples, we did not observe significant associations. Lower frontal pole surface area may represent a vulnerability for a (non-interrupted and non-aborted) suicide attempt; however, more research is needed to understand the nature of its relationship to suicide risk.


Asunto(s)
Ideación Suicida , Intento de Suicidio , Adolescente , Humanos , Encéfalo , Neuroimagen/métodos , Trastornos del Humor
12.
Cereb Cortex ; 32(19): 4345-4355, 2022 09 19.
Artículo en Inglés | MEDLINE | ID: mdl-34974620

RESUMEN

The brain's "default mode network" (DMN) enables flexible switching between internally and externally focused cognition. Precisely how this modulation occurs is not well understood, although it may involve key subcortical mechanisms, including hypothesized influences from the basal forebrain (BF) and mediodorsal thalamus (MD). Here, we used ultra-high field (7 T) functional magnetic resonance imaging to examine the involvement of the BF and MD across states of task-induced DMN activity modulation. Specifically, we mapped DMN activity suppression ("deactivation") when participants transitioned between rest and externally focused task performance, as well as DMN activity engagement ("activation") when task performance was internally (i.e., self) focused. Consistent with recent rodent studies, the BF showed overall activity suppression with DMN cortical regions when comparing the rest to external task conditions. Further analyses, including dynamic causal modeling, confirmed that the BF drove changes in DMN cortical activity during these rest-to-task transitions. The MD, by comparison, was specifically engaged during internally focused cognition and demonstrated a broad excitatory influence on DMN cortical activation. These results provide the first direct evidence in humans of distinct BF and thalamic circuit influences on the control of DMN function and suggest novel mechanistic avenues for ongoing translational research.


Asunto(s)
Mapeo Encefálico , Red Nerviosa , Mapeo Encefálico/métodos , Cognición/fisiología , Humanos , Imagen por Resonancia Magnética , Red Nerviosa/fisiología , Descanso
13.
Vascular ; : 17085381231174726, 2023 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-37249070

RESUMEN

OBJECTIVES: To demonstrate the ease with which steerable sheaths, designed for cardiac electrophysiological applications, can be used to aid endovascular treatment of a wide range of non-cardiac vascular disease and to assist with target vessel cannulation in branched and fenestrated aortic grafts. METHODS: A retrospective medical chart review was carried out to identify cases from a single vascular surgery unit (2019-2022) where the HeartSpan Steerable Sheath (HSS) (Merit Medical, South Jordan, UT, USA) was utilised to enable endovascular management of complex vascular pathology. A case presentation of branch graft insertion performed entirely via distal access is described and used to help identify pertinent sheath characteristics and technical considerations, and to illustrate the advantages and disadvantages of the design for modified use in target vessel cannulation. RESULTS: The HSS was used in the endovascular treatment of different vascular pathologies in 15 patients (23 target vessels) where access to the vessels using standard catheters and approaches was not possible. Cannulation and subsequent stenting were successful for 21 of the 23 target vessels in total. Of these cases, the HSS was used as an adjunct for deployment of fenestrated endovascular graft systems when conventional techniques for canulation of target vessels had failed on five occasions. On another four occasions, the HSS enabled full deployment of the entire Zenith® t-Branch™ Thoracoabdominal Endovascular Graft system from an exclusively femoral approach. An additional three cases involved use of the HSS for superior mesenteric artery cannulation in patients with mesenteric ischaemia. The device was also used once in each of the following cases: contralateral common iliac cannulation, cannulation of contralateral internal iliac artery for coil embolisation, and access of a contralateral iliac branched device. There were no stent dislocations and all aortic branches that were patent at the completion of each case remained so 1-year post procedure. CONCLUSION: Steerable sheaths designed for cardiac electrophysical applications, like the HSS Introducer, can be successfully utilised for cannulation of challenging target vessels in a wide range of aortic endovascular procedures. This modified approach may salvage cases that would otherwise be considered inoperable in regions of the world where steerable sheaths designed for aortic use are not readily available.

14.
Neuroimage ; 251: 118980, 2022 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-35143976

RESUMEN

The 'core' regions of the default mode network (DMN) - the medial prefrontal cortex (MPFC), the posterior cingulate cortex (PCC), and inferior parietal lobules (IPL) - show consistent engagement across mental states that involve self-oriented processing. Precisely how these regions interact in support of such processes remains an important unanswered question. In the current functional magnetic resonance imaging (fMRI) study, we examined dynamic interactions of the 'core-self' DMN regions during two forms of self-referential cognition: direct self-appraisal (thinking about oneself) and reflected self-appraisal (thinking about oneself from a third-person perspective). One-hundred and eleven participants completed our dual self-appraisal task during fMRI, and general linear models were used to characterize common and distinct neural responses to these conditions. Informed by these results, we then applied dynamic causal modelling to examine causal interactions among the 'core-self' regions, and how they were specifically modulated under the influence of direct and reflected self-appraisal. As a primary observation, this network modelling revealed a distinct inhibitory influence of the left IPL on the PCC during reflected compared to direct self-appraisal, which was accompanied by evidence of greater activation in both regions during the reflected self-appraisal condition. We suggest that the greater engagement of posterior DMN regions during reflected self-appraisal is a function of the higher-order processing needed for this form of self-appraisal, with the left IPL supporting abstract self-related processes including episodic memory retrieval and shifts of perspective. Overall, we show that core DMN regions interact in functionally unique ways in support of self-referential processes, even when these processes are inter-related. Further characterization of DMN functional interactions across self-related mental states is likely to inform a deeper understanding of how this brain network orchestrates the self.


Asunto(s)
Autoevaluación Diagnóstica , Memoria Episódica , Encéfalo/fisiología , Mapeo Encefálico/métodos , Humanos , Imagen por Resonancia Magnética , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/fisiología
15.
Hum Brain Mapp ; 43(2): 733-749, 2022 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-34811847

RESUMEN

There is growing recognition that the composition of the gut microbiota influences behaviour, including responses to threat. The cognitive-interoceptive appraisal of threat-related stimuli relies on dynamic neural computations between the anterior insular (AIC) and the dorsal anterior cingulate (dACC) cortices. If, to what extent, and how microbial consortia influence the activity of this cortical threat processing circuitry is unclear. We addressed this question by combining a threat processing task, neuroimaging, 16S rRNA profiling and computational modelling in healthy participants. Results showed interactions between high-level ecological indices with threat-related AIC-dACC neural dynamics. At finer taxonomic resolutions, the abundance of Ruminococcus was differentially linked to connectivity between, and activity within the AIC and dACC during threat updating. Functional inference analysis provides a strong rationale to motivate future investigations of microbiota-derived metabolites in the observed relationship with threat-related brain processes.


Asunto(s)
Conectoma , Miedo/fisiología , Microbioma Gastrointestinal/fisiología , Giro del Cíngulo/fisiología , Corteza Insular/fisiología , Red Nerviosa/fisiología , Adulto , Condicionamiento Clásico/fisiología , Femenino , Giro del Cíngulo/diagnóstico por imagen , Humanos , Corteza Insular/diagnóstico por imagen , Imagen por Resonancia Magnética , Masculino , Modelos Teóricos , Red Nerviosa/diagnóstico por imagen , ARN Ribosómico 16S , Adulto Joven
16.
Mol Psychiatry ; 26(9): 5124-5139, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-32424236

RESUMEN

Major depressive disorder (MDD) is associated with an increased risk of brain atrophy, aging-related diseases, and mortality. We examined potential advanced brain aging in adult MDD patients, and whether this process is associated with clinical characteristics in a large multicenter international dataset. We performed a mega-analysis by pooling brain measures derived from T1-weighted MRI scans from 19 samples worldwide. Healthy brain aging was estimated by predicting chronological age (18-75 years) from 7 subcortical volumes, 34 cortical thickness and 34 surface area, lateral ventricles and total intracranial volume measures separately in 952 male and 1236 female controls from the ENIGMA MDD working group. The learned model coefficients were applied to 927 male controls and 986 depressed males, and 1199 female controls and 1689 depressed females to obtain independent unbiased brain-based age predictions. The difference between predicted "brain age" and chronological age was calculated to indicate brain-predicted age difference (brain-PAD). On average, MDD patients showed a higher brain-PAD of +1.08 (SE 0.22) years (Cohen's d = 0.14, 95% CI: 0.08-0.20) compared with controls. However, this difference did not seem to be driven by specific clinical characteristics (recurrent status, remission status, antidepressant medication use, age of onset, or symptom severity). This highly powered collaborative effort showed subtle patterns of age-related structural brain abnormalities in MDD. Substantial within-group variance and overlap between groups were observed. Longitudinal studies of MDD and somatic health outcomes are needed to further assess the clinical value of these brain-PAD estimates.


Asunto(s)
Trastorno Depresivo Mayor , Adolescente , Adulto , Anciano , Envejecimiento , Encéfalo/diagnóstico por imagen , Femenino , Humanos , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Adulto Joven
17.
Mol Psychiatry ; 26(9): 4839-4852, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-32467648

RESUMEN

Emerging evidence suggests that obesity impacts brain physiology at multiple levels. Here we aimed to clarify the relationship between obesity and brain structure using structural MRI (n = 6420) and genetic data (n = 3907) from the ENIGMA Major Depressive Disorder (MDD) working group. Obesity (BMI > 30) was significantly associated with cortical and subcortical abnormalities in both mass-univariate and multivariate pattern recognition analyses independent of MDD diagnosis. The most pronounced effects were found for associations between obesity and lower temporo-frontal cortical thickness (maximum Cohen´s d (left fusiform gyrus) = -0.33). The observed regional distribution and effect size of cortical thickness reductions in obesity revealed considerable similarities with corresponding patterns of lower cortical thickness in previously published studies of neuropsychiatric disorders. A higher polygenic risk score for obesity significantly correlated with lower occipital surface area. In addition, a significant age-by-obesity interaction on cortical thickness emerged driven by lower thickness in older participants. Our findings suggest a neurobiological interaction between obesity and brain structure under physiological and pathological brain conditions.


Asunto(s)
Trastorno Depresivo Mayor , Anciano , Encéfalo/diagnóstico por imagen , Corteza Cerebral , Trastorno Depresivo Mayor/genética , Humanos , Imagen por Resonancia Magnética , Obesidad/genética , Factores de Riesgo
18.
Cereb Cortex ; 31(2): 961-973, 2021 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-32960214

RESUMEN

The cognitive reappraisal of emotion is hypothesized to involve frontal regions modulating the activity of subcortical regions such as the amygdala. However, the pathways by which structurally disparate frontal regions interact with the amygdala remains unclear. In this study, 104 healthy young people completed a cognitive reappraisal task. Dynamic causal modeling (DCM) was used to map functional interactions within a frontoamygdalar network engaged during emotion regulation. Five regions were identified to form the network: the amygdala, the presupplementary motor area (preSMA), the ventrolateral prefrontal cortex (vlPFC), dorsolateral prefrontal cortex (dlPFC), and ventromedial prefrontal cortex (vmPFC). Bayesian Model Selection was used to compare 256 candidate models, with our winning model featuring modulations of vmPFC-to-amygdala and amygdala-to-preSMA pathways during reappraisal. Moreover, the strength of amygdala-to-preSMA modulation was associated with the habitual use of cognitive reappraisal. Our findings support the vmPFC serving as the primary conduit through which prefrontal regions directly modulate amygdala activity, with amygdala-to-preSMA connectivity potentially acting to shape ongoing affective motor responses. We propose that these two frontoamygdalar pathways constitute a recursive feedback loop, which computes the effectiveness of emotion-regulatory actions and drives model-based behavior.


Asunto(s)
Cognición/fisiología , Emociones/fisiología , Afecto , Amígdala del Cerebelo/fisiología , Teorema de Bayes , Encéfalo/fisiología , Mapeo Encefálico , Corteza Prefontal Dorsolateral , Retroalimentación Psicológica/fisiología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/fisiología , Corteza Prefrontal/fisiología , Adulto Joven
19.
Neuroimage ; 245: 118643, 2021 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-34699966

RESUMEN

Threat learning elicits robust changes across multiple affective domains, including changes in autonomic indices and subjective reports of fear and anxiety. It has been argued that the underlying causes of such changes may be dissociable at a neural level, but there is currently limited evidence to support this notion. To address this, we examined the neural mediators of trial-by-trial skin conductance responses (SCR), and subjective reports of anxious arousal and valence in participants (n = 27; 17 females) performing a threat reversal task during ultra-high field functional magnetic resonance imaging. This allowed us to identify brain mediators during initial threat learning and subsequent threat reversal. Significant neural mediators of anxious arousal during threat learning included the dorsal anterior cingulate, anterior insula cortex (AIC), and ventromedial prefrontal cortex (vmPFC), subcortical regions including the amygdala, ventral striatum, caudate and putamen, and brain-stem regions including the pons and midbrain. By comparison, autonomic changes (SCR) were mediated by a subset of regions embedded within this broader circuitry that included the caudate, putamen and thalamus, and two distinct clusters within the vmPFC. The neural mediators of subjective negative valence showed prominent effects in posterior cortical regions and, with the exception of the AIC, did not overlap with threat learning task effects. During threat reversal, positive mediators of both subjective anxious arousal and valence mapped to the default mode network; this included the vmPFC, posterior cingulate, temporoparietal junction, and angular gyrus. Decreased SCR during threat reversal was positively mediated by regions including the mid cingulate, AIC, two sub-regions of vmPFC, the thalamus, and the hippocampus. Our findings add novel evidence to support distinct underlying neural processes facilitating autonomic and subjective responding during threat learning and threat reversal. The results suggest that the brain systems engaged in threat learning mostly capture the subjective (anxious arousal) nature of the learning process, and that appropriate responding during threat reversal is facilitated by participants engaging self- and valence-based processes. Autonomic changes (SCR) appear to involve distinct facilitatory and regulatory contributions of vmPFC sub-regions.


Asunto(s)
Sistema Nervioso Autónomo/fisiología , Mapeo Encefálico/métodos , Miedo/fisiología , Aprendizaje/fisiología , Imagen por Resonancia Magnética/métodos , Adolescente , Adulto , Ansiedad/fisiopatología , Nivel de Alerta/fisiología , Femenino , Respuesta Galvánica de la Piel , Humanos , Masculino
20.
Psychol Med ; : 1-8, 2021 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-36762975

RESUMEN

BACKGROUND: Suppression of the rostral anterior cingulate cortex (rACC) has shown promise as a prognostic biomarker for depression. We aimed to use machine learning to characterise its ability to predict depression remission. METHODS: Data were obtained from 81 15- to 25-year-olds with a major depressive disorder who had participated in the YoDA-C trial, in which they had been randomised to receive cognitive behavioural therapy plus either fluoxetine or placebo. Prior to commencing treatment patients performed a functional magnetic resonance imaging (fMRI) task to assess rACC suppression. Support vector machines were trained on the fMRI data using nested cross-validation, and were similarly trained on clinical data. We further tested our fMRI model on data from the YoDA-A trial, in which participants had completed the same fMRI paradigm. RESULTS: Thirty-six of 81 (44%) participants in the YoDA-C trial achieved remission. Our fMRI model was able to predict remission status (AUC = 0.777 [95% confidence interval (CI) 0.638-0.916], balanced accuracy = 67%, negative predictive value = 74%, p < 0.0001). Clinical models failed to predict remission status at better than chance levels. Testing the model on the alternative YoDA-A dataset confirmed its ability to predict remission (AUC = 0.776, balanced accuracy = 64%, negative predictive value = 70%, p < 0.0001). CONCLUSIONS: We confirm that rACC activity acts as a prognostic biomarker for depression. The machine learning model can identify patients who are likely to have difficult-to-treat depression, which might direct the earlier provision of enhanced support and more intensive therapies.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA