25 research outputs found

    Anxiety and amygdala connectivity during movie-watching

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    Rodent and human studies have implicated an amygdala-prefrontal circuit during threat processing. One possibility is that while amygdala activity underlies core features of anxiety (e.g. detection of salient information), prefrontal cortices (i.e. dorsomedial prefrontal/anterior cingulate cortex) entrain its responsiveness. To date, this has been established in tightly controlled paradigms (predominantly using static face perception tasks) but has not been extended to more naturalistic settings. Consequently, using ‘movie fMRI’—in which participants watch ecologically-rich movie stimuli rather than constrained cognitive tasks—we sought to test whether individual differences in anxiety correlate with the degree of face-dependent amygdala-prefrontal coupling in two independent samples. Analyses suggested increased face-dependent superior parietal activation and decreased speech-dependent auditory cortex activation as a function of anxiety. However, we failed to find evidence for anxiety-dependent connectivity, neither in our stimulus-dependent or -independent analyses. Our findings suggest that work using experimentally constrained tasks may not replicate in more ecologically valid settings and, moreover, highlight the importance of testing the generalizability of neuroimaging findings outside of the original context

    Anxiety Shapes Amygdala-Prefrontal Dynamics During Movie Watching

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    Background: A well-characterized amygdala–dorsomedial prefrontal circuit is thought to be crucial for threat vigilance during anxiety. However, engagement of this circuitry within relatively naturalistic paradigms remains unresolved. // Methods: Using an open functional magnetic resonance imaging dataset (Cambridge Centre for Ageing Neuroscience; n = 630), we sought to investigate whether anxiety correlates with dynamic connectivity between the amygdala and dorsomedial prefrontal cortex during movie watching. // Results: Using an intersubject representational similarity approach, we saw no effect of anxiety when comparing pairwise similarities of dynamic connectivity across the entire movie. However, preregistered analyses demonstrated a relationship between anxiety, amygdala-prefrontal dynamics, and anxiogenic features of the movie (canonical suspense ratings). Our results indicated that amygdala-prefrontal circuitry was modulated by suspense in low-anxiety individuals but was less sensitive to suspense in high-anxiety individuals. We suggest that this could also be related to slowed habituation or amplified anticipation. Moreover, a measure of threat-relevant attentional bias (accuracy/reaction time to fearful faces) demonstrated an association with connectivity and suspense. // Conclusions: Overall, this study demonstrated the presence of anxiety-relevant differences in connectivity during movie watching, varying with anxiogenic features of the movie. Mechanistically, exactly how and when these differences arise remains an opportunity for future research

    Dissociable neural systems for unconditioned acute and sustained fear

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    Fear protects organisms by increasing vigilance and preparedness, and by coordinating survival responses during life-threatening encounters. The fear circuit must thus operate on multiple timescales ranging from preparatory sustained alertness to acute fight-or-flight responses. Here we studied the brain basis of sustained and acute fear using naturalistic functional magnetic resonance imaging (fMRI) enabling analysis of different time-scales of fear responses. Subjects (N ​= ​37) watched feature-length horror movies while their hemodynamic brain activity was measured with fMRI. Time-variable intersubject correlation (ISC) was used to quantify the reliability of brain activity across participants, and seed-based phase synchronization was used for characterizing dynamic connectivity. Subjective ratings of fear were used to assess how synchronization and functional connectivity varied with emotional intensity. These data suggest that acute and sustained fear are supported by distinct neural pathways, with sustained fear amplifying mainly sensory responses, and acute fear increasing activity in brainstem, thalamus, amygdala and cingulate cortices. Sustained fear increased ISC in regions associated with acute fear, and also amplified functional connectivity within this network. The results were replicated in an independent experiment with a different subject sample and stimulus movie. The functional interplay between cortical networks involved in sustained anticipation of, and acute response to, threat involves a complex and dynamic interaction that depends on the proximity of threat, and the need to employ threat appraisals and vigilance for decision making and response selection

    Dissociable neural systems for unconditioned acute and sustained fear

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    Fear protects organisms by increasing vigilance and preparedness, and by coordinating survival responses during life-threatening encounters. The fear circuit must thus operate on multiple timescales ranging from preparatory sustained alertness to acute fight-or-flight responses. Here we studied the brain basis of sustained and acute fear using naturalistic functional magnetic resonance imaging (fMRI) enabling analysis of different time-scales of fear responses. Subjects (N ​= ​37) watched feature-length horror movies while their hemodynamic brain activity was measured with fMRI. Time-variable intersubject correlation (ISC) was used to quantify the reliability of brain activity across participants, and seed-based phase synchronization was used for characterizing dynamic connectivity. Subjective ratings of fear were used to assess how synchronization and functional connectivity varied with emotional intensity. These data suggest that acute and sustained fear are supported by distinct neural pathways, with sustained fear amplifying mainly sensory responses, and acute fear increasing activity in brainstem, thalamus, amygdala and cingulate cortices. Sustained fear increased ISC in regions associated with acute fear, and also amplified functional connectivity within this network. The results were replicated in an independent experiment with a different subject sample and stimulus movie. The functional interplay between cortical networks involved in sustained anticipation of, and acute response to, threat involves a complex and dynamic interaction that depends on the proximity of threat, and the need to employ threat appraisals and vigilance for decision making and response selection.</p

    Using Movies to Probe the Neurobiology of Anxiety

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    Over the past century, research has helped us build a fundamental understanding of the neurobiological underpinnings of anxiety. Specifically, anxiety engages a broad range of cortico-subcortical neural circuitry. Core to this is a ‘defensive response network’ which includes an amygdala-prefrontal circuit that is hypothesized to drive attentional amplification of threat-relevant stimuli in the environment. In order to help prepare the body for defensive behaviors to threat, anxiety also engages peripheral physiological systems. However, our theoretical frameworks of the neurobiology of anxiety are built mostly on the foundations of tightly-controlled experiments, such as task-based fMRI. Whether these findings generalize to more naturalistic settings is unknown. To address this shortcoming, movie-watching paradigms offer an effective tool at the intersection of tightly controlled and entirely naturalistic experiments. Particularly, using suspenseful movies presents a novel and effective means to induce and study anxiety. In this thesis, I demonstrate the potential of movie-watching paradigms in the study of how trait and state anxiety impact the ‘defensive response network’ in the brain, as well as peripheral physiology. The key findings reveal that trait anxiety is associated with differing amygdala-prefrontal responses to suspenseful movies; specific trait anxiety symptoms are linked to altered states of anxiety during suspenseful movies; and states of anxiety during movies impact brain-body communication. Notably, my results frequently diverged from those of conventional task-based experiments. Taken together, the insights gathered from this thesis underscore the utility of movie-watching paradigms for a more nuanced understanding of how anxiety impacts the brain and peripheral physiology. These outcomes provide compelling evidence that further integration of naturalistic methods will be beneficial in the study of the neurobiology of anxiety

    Brain structural connectivity and neuroticism in healthy adults

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    Understanding the neural correlates of the neurotic brain is important because neuroticism is a risk factor for the development of psychopathology. We examined the correlation between brain structural networks and neuroticism based on NEO Five-Factor Inventory (NEO-FFI) scores. Fifty-one healthy participants (female, n = 18; male, n = 33; mean age, 38.5 ± 11.7 years) underwent the NEO-FFI test and magnetic resonance imaging (MRI), including diffusion tensor imaging and 3D T1WI. Using MRI data, for each participant, we constructed whole-brain interregional connectivity matrices by deterministic tractography and calculated the graph theoretical network measures, including the characteristic path length, global clustering coefficient, small-worldness, and betweenness centrality (BET) in 83 brain regions from the Desikan-Killiany atlas with subcortical segmentation using FreeSurfer. In relation to the BET, neuroticism score had a negative correlation in the left isthmus cingulate cortex, left superior parietal, left superior temporal, right caudal middle frontal, and right entorhinal cortices, and a positive correlation in the bilateral frontal pole, left caudal anterior cingulate cortex, and left fusiform gyrus. No other measurements showed significant correlations. Our results imply that the brain regions related to neuroticism exist in various regions, and that the neuroticism trait is likely formed as a result of interactions among these regions. This work was supported by a Grant-in-Aid for Scientific Research on Innovative Areas (Comprehensive Brain Science Network) from the Ministry of Education, Science, Sports and Culture of Japan

    Neurobiology, empathy and social cognition: the potential benefits of theatre in traumatised communities

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    Includes abstract.Includes bibliographical references.The ubiquity of technology enables unprecedented contact between people, yet it neglects essential face-to-face communion; e-mail, text-messaging and even social media strip away the metadata of our interpersonal communications; the emotional cues and clues that are a necessary part of everyday social interaction. At the same time, the relentless densification of urban populations enforces proximity among strangers, with routine encounters increasingly bereft of emotional nourishment. The affective numbing that ensues shares many characteristics of post-traumatic stress disorder. The current study explores how exposure to theatre may help to maintain the emotional health of individuals alienated by the stresses of 21st century urban living; moreover, it examines how performance is able to facilitate emotional and social healing in post-conflict communities

    Neuroethological studies of primate social perception

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    The neuroethological basis of social signals was investigated using a multidisciplinary approach, involving connectional and comparative analysis of anatomical data, single cell recording and behavioural techniques. Previous literature implicates the amygdala, anterior temporal and prefrontal cortex in primate social functions. Non-metric multidimensional scaling (NMDS) and cluster analysis were used to analyse the connectional relatedness of macaque cortico-cortical and amygdalo-cortical connections. This objective analysis separated the amygdala nuclei into two groups, the basolateral (BL) and centromedial (CM) complexes. A comparative analysis was made of the possible functions of the amygdala nuclei by correlating amygdala nuclear volume with 5 socio-ecological indices, across 44 primate species. The lateral basal (LB) nucleus and BL size was found to correlate positively with social complexity. CM size correlated negatively. The LB nucleus receives information from the STS, which contains visual neurons responsive to eyes, heads and bodies. These cells were assessed for coding of socially relevant information. Single cell recording localised within the macaque superior temporal sulcus (STS) revealed neurons responsive to specific views, elevations and orientations of the head, eye position, and specific views of bodies walking in specific directions and reaching to objects. The tuning of these neurons could therefore support the function of recognition of another's purposive behaviour (e.g. direction of attention or intention). Visually responsive neurons in the STS also differentiated faces of different species (i.e. monkeys, humans and other animals). Behavioural studies suggest that monkeys do not follow the direction of attention of humans, yet monkeys appear to have the neural capacity. A behavioural study using video stimuli, revealed that monkeys spontaneously follow other monkeys' gaze onto an object or point in space. It is concluded that the amygdala and STS are part of a neural system which enable monkeys to interpret another's gaze and actions within a purposive behavioural framework
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