RESUMO
Cross-modal plasticity in blind individuals has been reported over the past decades showing that nonvisual information is carried and processed by "visual" brain structures. However, despite multiple efforts, the structural underpinnings of cross-modal plasticity in congenitally blind individuals remain unclear. We mapped thalamocortical connectivity and assessed the integrity of white matter of 10 congenitally blind individuals and 10 sighted controls. We hypothesized an aberrant thalamocortical pattern of connectivity taking place in the absence of visual stimuli from birth as a potential mechanism of cross-modal plasticity. In addition to the impaired microstructure of visual white matter bundles, we observed structural connectivity changes between the thalamus and occipital and temporal cortices. Specifically, the thalamic territory dedicated to connections with the occipital cortex was smaller and displayed weaker connectivity in congenitally blind individuals, whereas those connecting with the temporal cortex showed greater volume and increased connectivity. The abnormal pattern of thalamocortical connectivity included the lateral and medial geniculate nuclei and the pulvinar nucleus. For the first time in humans, a remapping of structural thalamocortical connections involving both unimodal and multimodal thalamic nuclei has been demonstrated, shedding light on the possible mechanisms of cross-modal plasticity in humans. The present findings may help understand the functional adaptations commonly observed in congenitally blind individuals.
Assuntos
Cegueira , Lobo Occipital , Humanos , Cegueira/diagnóstico por imagem , Tálamo/diagnóstico por imagem , Lobo Temporal , Corpos GeniculadosRESUMO
BACKGROUND: Overgeneralised self-blame and worthlessness are key symptoms of major depressive disorder (MDD) and have previously been associated with self-blame-selective changes in connectivity between right superior anterior temporal lobe (rSATL) and subgenual frontal cortices. Another study showed that remitted MDD patients were able to modulate this neural signature using functional magnetic resonance imaging (fMRI) neurofeedback training, thereby increasing their self-esteem. The feasibility and potential of using this approach in symptomatic MDD were unknown. METHOD: This single-blind pre-registered randomised controlled pilot trial probed a novel self-guided psychological intervention with and without additional rSATL-posterior subgenual cortex (BA25) fMRI neurofeedback, targeting self-blaming emotions in people with insufficiently recovered MDD and early treatment-resistance (n = 43, n = 35 completers). Participants completed three weekly self-guided sessions to rebalance self-blaming biases. RESULTS: As predicted, neurofeedback led to a training-induced reduction in rSATL-BA25 connectivity for self-blame v. other-blame. Both interventions were safe and resulted in a 46% reduction on the Beck Depression Inventory-II, our primary outcome, with no group differences. Secondary analyses, however, revealed that patients without DSM-5-defined anxious distress showed a superior response to neurofeedback compared with the psychological intervention, and the opposite pattern in anxious MDD. As predicted, symptom remission was associated with increases in self-esteem and this correlated with the frequency with which participants employed the psychological strategies in daily life. CONCLUSIONS: These findings suggest that self-blame-rebalance neurofeedback may be superior over a solely psychological intervention in non-anxious MDD, although further confirmatory studies are needed. Simple self-guided strategies tackling self-blame were beneficial, but need to be compared against treatment-as-usual in further trials. https://doi.org/10.1186/ISRCTN10526888.
Assuntos
Transtorno Depressivo Maior , Neurorretroalimentação , Humanos , Transtorno Depressivo Maior/diagnóstico por imagem , Transtorno Depressivo Maior/terapia , Transtorno Depressivo Maior/patologia , Projetos Piloto , Neurorretroalimentação/métodos , Depressão , Imageamento por Ressonância Magnética , Método Simples-CegoRESUMO
Moral motivations drive humans to sacrifice selfish needs to serve the needs of others and internalized sociocultural norms. Over the past two decades, several brain regions have been associated with different aspects of moral cognition and behaviour. Only more recently, however, investigations have highlighted the importance of the basal forebrain for moral motivation. This includes the septo-hypothalamic region, implicated in kinship bonding across mammal species, and the closely connected subgenual frontal cortex. Understanding the neuroanatomy of moral motivation and its impairments will be fundamental for future research aiming to promote prosocial behaviour and mental health.
Assuntos
Prosencéfalo Basal/fisiologia , Giro do Cíngulo/fisiologia , Hipotálamo/fisiologia , Princípios Morais , Motivação/fisiologia , Apego ao Objeto , Cognição Social , HumanosRESUMO
Previously, using fMRI, we demonstrated lower connectivity between right anterior superior temporal (ATL) and anterior subgenual cingulate (SCC) regions while patients with major depressive disorder (MDD) experience guilt. This neural signature was detected despite symptomatic remission which suggested a putative role in vulnerability. This randomised controlled double-blind parallel group clinical trial investigated whether patients with MDD are able to voluntarily modulate this neural signature. To this end, we developed a fMRI neurofeedback software (FRIEND), which measures ATL-SCC coupling and displays its levels in real time. Twenty-eight patients with remitted MDD were randomised to two groups, each receiving one session of fMRI neurofeedback whilst retrieving guilt and indignation/anger-related autobiographical memories. They were instructed to feel the emotion whilst trying to increase the level of a thermometer-like display on a screen. Active intervention group: The thermometer levels increased with increasing levels of ATL-SCC correlations in the guilt condition. Control intervention group: The thermometer levels decreased when correlation levels deviated from the previous baseline level in the guilt condition, thus reinforcing stable correlations. Both groups also received feedback during the indignation condition reinforcing stable correlations. We confirmed our predictions that patients in the active intervention group were indeed able to increase levels of ATL-SCC correlations for guilt vs. indignation and their self-esteem after training compared to before training and that this differed significantly from the control intervention group. These data provide proof-of-concept for a novel treatment target for MDD patients and are in keeping with the hypothesis that ATL-SCC connectivity plays a key role in self-worth. https://clinicaltrials.gov/ct2/show/results/NCT01920490.
Assuntos
Transtorno Depressivo Maior/fisiopatologia , Neuroimagem Funcional , Culpa , Giro do Cíngulo/fisiopatologia , Neurorretroalimentação/fisiologia , Autoimagem , Lobo Temporal/fisiopatologia , Adulto , Transtorno Depressivo Maior/diagnóstico por imagem , Método Duplo-Cego , Feminino , Giro do Cíngulo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estudo de Prova de Conceito , Lobo Temporal/diagnóstico por imagemRESUMO
Encoding models can reveal and decode neural representations in the visual and semantic domains. However, a thorough understanding of how distributed information in auditory cortices and temporal evolution of music contribute to model performance is still lacking in the musical domain. We measured fMRI responses during naturalistic music listening and constructed a two-stage approach that first mapped musical features in auditory cortices and then decoded novel musical pieces. We then probed the influence of stimuli duration (number of time points) and spatial extent (number of voxels) on decoding accuracy. Our approach revealed a linear increase in accuracy with duration and a point of optimal model performance for the spatial extent. We further showed that Shannon entropy is a driving factor, boosting accuracy up to 95% for music with highest information content. These findings provide key insights for future decoding and reconstruction algorithms and open new venues for possible clinical applications.
Assuntos
Estimulação Acústica , Córtex Auditivo/fisiologia , Imageamento por Ressonância Magnética , Música , Adulto , Feminino , Voluntários Saudáveis , Humanos , Masculino , Modelos Neurológicos , Análise Espaço-Temporal , Adulto JovemRESUMO
In Ridley Scott's film "Blade Runner", empathy-detection devices are employed to measure affiliative emotions. Despite recent neurocomputational advances, it is unknown whether brain signatures of affiliative emotions, such as tenderness/affection, can be decoded and voluntarily modulated. Here, we employed multivariate voxel pattern analysis and real-time fMRI to address this question. We found that participants were able to use visual feedback based on decoded fMRI patterns as a neurofeedback signal to increase brain activation characteristic of tenderness/affection relative to pride, an equally complex control emotion. Such improvement was not observed in a control group performing the same fMRI task without neurofeedback. Furthermore, the neurofeedback-driven enhancement of tenderness/affection-related distributed patterns was associated with local fMRI responses in the septohypothalamic area and frontopolar cortex, regions previously implicated in affiliative emotion. This demonstrates that humans can voluntarily enhance brain signatures of tenderness/affection, unlocking new possibilities for promoting prosocial emotions and countering antisocial behavior.
Assuntos
Empatia/fisiologia , Lobo Frontal/fisiologia , Região Hipotalâmica Lateral/fisiologia , Neurorretroalimentação/métodos , Adulto , Mapeamento Encefálico , Feminino , Lobo Frontal/anatomia & histologia , Humanos , Região Hipotalâmica Lateral/anatomia & histologia , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Análise Multivariada , Neurorretroalimentação/instrumentação , Máquina de Vetores de SuporteRESUMO
The demonstration that humans can learn to modulate their own brain activity based on feedback of neurophysiological signals opened up exciting opportunities for fundamental and applied neuroscience. Although EEG-based neurofeedback has been long employed both in experimental and clinical investigation, functional MRI (fMRI)-based neurofeedback emerged as a promising method, given its superior spatial resolution and ability to gauge deep cortical and subcortical brain regions. In combination with improved computational approaches, such as pattern recognition analysis (e.g., Support Vector Machines, SVM), fMRI neurofeedback and brain decoding represent key innovations in the field of neuromodulation and functional plasticity. Expansion in this field and its applications critically depend on the existence of freely available, integrated and user-friendly tools for the neuroimaging research community. Here, we introduce FRIEND, a graphic-oriented user-friendly interface package for fMRI neurofeedback and real-time multivoxel pattern decoding. The package integrates routines for image preprocessing in real-time, ROI-based feedback (single-ROI BOLD level and functional connectivity) and brain decoding-based feedback using SVM. FRIEND delivers an intuitive graphic interface with flexible processing pipelines involving optimized procedures embedding widely validated packages, such as FSL and libSVM. In addition, a user-defined visual neurofeedback module allows users to easily design and run fMRI neurofeedback experiments using ROI-based or multivariate classification approaches. FRIEND is open-source and free for non-commercial use. Processing tutorials and extensive documentation are available.
Assuntos
Interfaces Cérebro-Computador , Gráficos por Computador , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética , Neurorretroalimentação/métodos , Interface Usuário-Computador , Adulto , Mapeamento Encefálico , Emoções , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Atividade Motora , Análise Multivariada , Máquina de Vetores de Suporte , Fatores de TempoRESUMO
CONTEXT: Proneness to overgeneralization of self-blame is a core part of cognitive vulnerability to major depressive disorder (MDD) and remains dormant after remission of symptoms. Current neuroanatomical models of MDD, however, assume general increases of negative emotions and are unable to explain biases toward emotions entailing self-blame (eg, guilt) relative to those associated with blaming others (eg, indignation). Recent functional magnetic resonance imaging (fMRI) studies in healthy participants have shown that moral feelings such as guilt activate representations of social meaning within the right superior anterior temporal lobe (ATL). Furthermore, this area was selectively coupled with the subgenual cingulate cortex and adjacent septal region (SCSR) during the experience of guilt compared with indignation. Despite its psychopathological importance, the functional neuroanatomy of guilt in MDD is unknown. OBJECTIVE: To use fMRI to test the hypothesis that, in comparison with control individuals, participants with remitted MDD exhibit guilt-selective SCSR-ATL decoupling as a marker of deficient functional integration. DESIGN: Case-control study from May 1, 2008, to June 1, 2010. SETTING: Clinical research facility. PARTICIPANTS: Twenty-five patients with remitted MDD (no medication in 16 patients) with no current comorbid Axis I disorders and 22 controls with no personal or family history of MDD. MAIN OUTCOME MEASURES: Between-group difference of ATL coupling with a priori SCSR region of interest for guilt vs indignation. RESULTS: We corroborated the prediction of a guilt-selective reduction in ATL-SCSR coupling in MDD vs controls (familywise error-corrected P=.001 over the region of interest) and revealed additional medial frontopolar, right hippocampal, and lateral hypothalamic areas of decoupling while controlling for medication status and intensity of negative emotions. Lower levels of ATL-SCSR coupling were associated with higher scores on a validated measure of overgeneralized self-blame (67-item Interpersonal Guilt Questionnaire). CONCLUSIONS: Vulnerability to MDD is associated with temporofrontolimbic decoupling that is selective for self-blaming feelings. This provides the first neural mechanism ofMDD vulnerability that accounts for self-blaming biases.