It has long been established that individuals with anxiety disorders tend to overgeneralize attributes of fearful stimuli to nonfearful stimuli, but there is little mechanistic understanding of the neural system that supports overgeneralization. To address this gap in our knowledge, this study examined effect of experimentally induced anxiety in humans on generalization using the behavioral pattern separation (BPS) paradigm. Healthy subjects of both sexes encoded and retrieved novel objects during periods of safety and threat of unpredictable shocks while we recorded brain activity with fMRI. During retrieval, subjects were instructed to differentiate among new, old, and altered images. We hypothesized that the hippocampus and dorsolateral prefrontal cortex (dlPFC) would play a key role in the effect of anxiety on BPS. The dlPFC, but not the hippocampus, showed increased activity for altered images compared with old images when retrieval occurred during periods of threat compared with safety. In addition, accuracy for altered items retrieved during threat was correlated with dlPFC activity. Together, these results suggest that overgeneralization in anxiety patients may be mediated by an inability to recruit the dlPFC, which mediates the cognitive control needed to overcome anxiety and differentiate between old and altered items during periods of threat. Anxiety and posttraumatic stress disorder patients generalize fear to nonfearful fear stimuli, making it difficult to regulate anxiety. Understanding how anxiety affects generalization is key to understanding the overgeneralization experienced by these patients. We examined this relationship in healthy subjects by studying how threat of shock affects neural responses to previously encountered stimuli. Although previous studies point to hippocampal involvement, we found that threat affected activity in the dorsolateral prefrontal cortex (dlPFC), rather than the hippocampus, when subjects encountered slightly altered versions of the previously encountered items. Importantly, this dlPFC activity predicted performance for these items. Together, these results suggest that the dlPFC is important for discrimination during elevated anxiety and that overgeneralization may reflect a deficit in dlPFC-mediated cognitive control.
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http://dx.doi.org/10.1523/JNEUROSCI.0717-17.2017 | DOI Listing |
Neuropsychopharmacology
January 2025
Neurocognition and Emotion in Affective Disorders (NEAD) Centre, Psychiatric Centre Copenhagen, Mental Health Services, Capital Region of Denmark, Frederiksberg, Denmark.
Individuals with bipolar disorder (BD) show heterogeneity in clinical, cognitive, and daily functioning characteristics, which challenges accurate diagnostics and optimal treatment. A key goal is to identify brain-based biomarkers that inform patient stratification and serve as treatment targets. The objective of the present study was to apply a data-driven, multivariate approach to quantify the relationship between multimodal imaging features and behavioral phenotypes in BD.
View Article and Find Full Text PDFNeuroimage
January 2025
Department of Radiology, First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.. Electronic address:
The human cerebral cortex is known for its hemispheric specialization, which underpins a variety of functions and activities. However, it is not well understood if similar lateralization exists within the deep gray matter nuclei, such as the basal ganglia (BG) and thalamus, and their associated arteries, including the lenticulostriate arteries (LSAs). To explore this, we analyzed images from 7T MRI scans of 40 healthy young individuals.
View Article and Find Full Text PDFBrain
December 2024
Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.
Chronic pain and fatigue in musculoskeletal disease contribute significantly to disability, and recent studies suggest an association with reduced motivation and excessive fear avoidance. In this behavioural neuroimaging study, we aimed to identify the specific behavioral and neural changes associated with musculoskeletal pain and fatigue during reward and loss decision-making. Twenty-nine participants with chronic inflammatory arthritis and 28 healthy controls performed an instrumental learning task (4-armed bandit) during 3T brain fMRI.
View Article and Find Full Text PDFHum Brain Mapp
January 2025
The Mind Research Network/Lovelace Biomedical Research Institute, Albuquerque, New Mexico, USA.
Evaluation of mechanisms of action of EEG neurofeedback (EEG-nf) using simultaneous fMRI is highly desirable to ensure its effective application for clinical rehabilitation and therapy. Counterbalancing training runs with active neurofeedback and sham (neuro)feedback for each participant is a promising approach to demonstrate specificity of training effects to the active neurofeedback. We report the first study in which EEG-nf procedure is both evaluated using simultaneous fMRI and controlled via the counterbalanced active-sham study design.
View Article and Find Full Text PDFMed Sci Sports Exerc
January 2025
Guangdong Provincial Key Laboratory of Physical Activity and Health Promotion, Guangzhou Sport University, Guangzhou, Guangdong, CHINA.
Purpose: The present study aimed to compare the impacts of different exercise types on cardiovascular health and executive function in sedentary young individuals, and to determine the associations between cardiovascular function and executive function (EF) after exercise.
Methods: Sixty-three sedentary participants were randomly divided into high-intensity interval training (HIIT), moderate-intensity continuous training (MICT), resistance exercise (RE), and control groups. Macro- and microvascular endothelial function were assessed using brachial artery flow-mediated dilation and fingertip reactive hyperemia index, respectively.
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