229 research outputs found

    Amygdala functional connectivity as a longitudinal biomarker of symptom changes in generalized anxiety

    Get PDF
    Generalized anxiety disorder (GAD) is characterized by excessive worry, autonomic dysregulation and functional amygdala dysconnectivity, yet these illness markers have rarely been considered together, nor their interrelationship tested longitudinally. We hypothesized that an individual's capacity for emotion regulation predicts longer-term changes in amygdala functional connectivity, supporting the modification of GAD core symptoms. Sixteen patients with GAD (14 women) and individually matched controls were studied at two time points separated by 1 year. Resting-state fMRI data and concurrent measurement of vagally mediated heart rate variability were obtained before and after the induction of perseverative cognition. A greater rise in levels of worry following the induction predicted a stronger reduction in connectivity between right amygdala and ventromedial prefrontal cortex, and enhanced coupling between left amygdala and ventral tegmental area at follow-up. Similarly, amplified physiological responses to the induction predicted increased connectivity between right amygdala and thalamus. Longitudinal shifts in a distinct set of functional connectivity scores were associated with concomitant changes in GAD symptomatology over the course of the year. Results highlight the prognostic value of indices of emotional dysregulation and emphasize the integral role of the amygdala as a critical hub in functional neural circuitry underlying the progression of GAD symptomatolog

    Alterations in amygdala-prefrontal functional connectivity account for excessive worry and autonomic dysregulation in generalized anxiety disorder

    Get PDF
    Background: Generalized anxiety disorder (GAD) is characterized by the core symptom of uncontrollable worry. Functional magnetic resonance imaging studies link this symptom to aberrant functional connectivity between the amygdala and prefrontal cortex. Patients with GAD also display a characteristic pattern of autonomic dysregulation. Although frontolimbic circuitry is implicated in the regulation of autonomic arousal, no previous study to our knowledge combined functional magnetic resonance imaging with peripheral physiologic monitoring in these patients to test the hypothesis that core symptoms of worry and autonomic dysregulation in GAD arise from a shared underlying neural mechanism. Methods: We used resting-state functional magnetic resonance imaging and the measurement of parasympathetic autonomic function (heart rate variability) in 19 patients with GAD and 21 control subjects to define neural correlates of autonomic and cognitive responses before and after induction of perseverative cognition. Seed-based analyses were conducted to quantify brain changes in functional connectivity with the right and left amygdala. Results: Before induction, patients showed relatively lower connectivity between the right amygdala and right superior frontal gyrus, right paracingulate/anterior cingulate cortex, and right supramarginal gyrus than control subjects. After induction, such connectivity patterns increased in patients with GAD and decreased in control subjects, and these changes tracked increases in state perseverative cognition. Moreover, decreases in functional connectivity between the left amygdala and subgenual cingulate cortex and between the right amygdala and caudate nucleus predicted the magnitude of reduction in heart rate variability after induction. Conclusions: Our results link functional brain mechanisms underlying worry and rumination to autonomic dyscontrol, highlighting overlapping neural substrates associated with cognitive and autonomic responses to the induction of perseverative cognitions in patients with GAD

    Skip Metastases in Papillary Thyroid Cancer

    Get PDF
    Papillary thyroid carcinoma (PTC) is the most common malignant thyroid disease characterized by a high rate of cervical metastases (30–80%), especially due to paratracheal lymph node involvement. »Skip metastasis« are defined as a lateral lymph node metastasis without central lymph node involvement. The aim of this prospective study was to establish the lateral nodal metastasis pattern according to neck level, general occurrence and significance of skip metastasis in PTC. Forty-two previously untreated patients who presented between 2007 and 2011 with concomitant diagnosis of papillary thyroid cancer and metastatic disease of the lateral neck, underwent total thyroidectomy and central and lateral neck dissection. Skip metastases were encountered in 8(19.5%) patients, four female and four male, with a mean age of 43.3 years. In all patients with lateral skip metastasis, level III nodes were most frequently involved (75%) followed by level IV(50%), while no metastatic disease was found in level IIb. Based on our research, skip metastasis are not uncommon (a lateral lymph node metastasis without central lymph node involvement) and present in approximately 1/5 of PTC patients with cervical lymph node metastasis

    The verbal nature of worry in generalized anxiety: Insights from the brain

    Get PDF
    Background: The Cognitive Avoidance Theory of Worry argues that worry is a cognitive strategy adopted to control the physiological arousal associated with anxiety. According to this theory, pathological worry, as in Generalized Anxiety Disorder (GAD), is verbal in nature, negative and abstract, rather than concrete. Neuroimaging studies link the expression of worry to characteristic modes of brain functional connectivity, especially in relation to the amygdala. However, the distinctive features of worry (verbal, abstract, negative), and their relationship to physiological arousal, have not so far been mapped to brain function. Methods: We addressed this omission by undertaking a resting-state functional magnetic resonance neuroimaging study of 19 patients with GAD and 21 controls, before and after induction of perseverative cognitions, while measuring emotional bodily arousal from heart rate (HR). Seed-based analyses quantified brain changes in whole brain functional connectivity from the amygdala. Results: In GAD, the induction increased negative thoughts and their verbal content. In line with predictions, the verbal expression of worry in GAD was associated with higher HR at baseline and attenuated HR increases after induction of perseverative cognitions. Within brain, the increased use of words during worry, and the associated dampening of HR after induction were mediated by the strength of functional connectivity between the amygdala and default mode network ‘hubs’ and the opercular cortex. The negative content of worry was further related to functional communication between amygdala and cingulo-opercular and temporal cortices. Conclusions: Findings provide a neurobiological basis for the impact of verbal worry on HR in GAD

    IMMUNOLOGICAL CHARACTERISTICS OF SCHIZOPHRENIA

    Get PDF
    There are many theories about the etiology of schizophrenia. This paper presents the assumptions and latest findings about many immunological characteristics of schizophrenia. According to the neuroimunological theory, this disorder is due to neuroimunological disbalance, increased microglial activity and increased levels of proinflammatory cytokines. Studies have found that intrauterine infections in pregnant women have an effect on the fetal brain development, and that infections with rubella, measles, herpes virus, and toxoplasma are associeted with schizophrenia onset in adult life. In the first episode of schizophrenia and during exacerbation in the serum of the patient, an increased level of proinflammatory cytokines was found. Increased levels of IL-6, TNF- and IL-1, and decreased levels of anti-inflammatory cytokines, Il-10. Interleukin 6 levels increase in the psychotic phase of the disease and normalize after the antipsychotic drug treatment. Increased level of IL-6 is associated with severe cognitive impairment and it is more common with patients who had been without adequate treatment for a long time and patients with therapeutic-resistant schizophrenia. Treatment of schizophrenia could be improved by the introduction of anti-inflammatory drug in the therapy

    Epileptic Seizures are Reduced by Autonomic Biofeedback Therapy Through Enhancement of Fronto-limbic Connectivity: A Controlled Trial and Neuroimaging Study.

    Get PDF
    BACKGROUND: Thirty-percent of patients with epilepsy are drug-resistant, and might benefit from effective noninvasive therapeutic interventions. Evidence is accumulating on the efficacy of autonomic biofeedback therapy using galvanic skin response (GSR; an index of sympathetic arousal) in treating epileptic seizures. This study aimed to extend previous controlled clinical trials of autonomic biofeedback therapy with a larger homogeneous sample of patients with temporal lobe epilepsy. In addition, we used neuroimaging to characterize neural mechanisms of change in seizure frequency following the therapy. METHODS: Forty patients with drug-resistant temporal lobe epilepsy (TLE) (age: 18 to 70years old), on stable doses of anti-epileptic medication, were recruited into a controlled and parallel-group trial from three screening centers in the UK. Patients were allocated to either an active intervention group, who received therapy with GSR biofeedback, or a control group, who received treatment as usual. Allocation to the group was informed, in part, by whether patients could travel to attend repeated therapy sessions (non-randomized). Measurement of outcomes was undertaken by an assessor blinded to the patients' group membership. Resting-state functional and structural MRI data were acquired before and after one month of therapy in the therapy group, and before and after a one-month interval in the control group. The percentage change of seizure frequency was the primary outcome measure. The analysis employed an intention-to-treat principle. The secondary outcome was the change in default mode network (DMN) and limbic network functional connectivity tested for effects of therapy. The trial was registered with the National Institute for Health Research (NIHR) portfolio (ID 15967). FINDINGS: Data were acquired between May 2014 and October 2016. Twenty participants were assigned to each group. Two patients in the control group dropped out before the second scan, leaving 18 control participants. There was a significant difference in reduction of seizure frequency between the therapy and control groups (p50%. Neuroimaging analysis revealed that post-therapy seizure reduction was linearly correlated with enhanced functional connectivity between right amygdala and both the orbitofrontal cortex (OFC) and frontal pole (FP). INTERPRETATION: Our clinical study provides evidence for autonomic biofeedback therapy as an effective and potent behavioral intervention for patients with drug-resistant epilepsy. This approach is non-pharmacological, non-invasive and seemingly side-effect free

    Item-Level Analysis of Category Fluency Test Performance: A Systematic Review and Meta-Analysis of Studies of Normal and Neurologically Abnormal Ageing

    Get PDF
    \ua9 The Author(s) 2025.While Category Fluency (CF) is widely used to help profile semantic memory, item-level scoring (ILS) approaches to this test have been proposed to obtain indices that are less influenced by non-semantic supportive functions. We systematically reviewed the literature to test the hypotheses that (1) compared with healthy adults, individuals with a clinical diagnosis suggestive of neurodegeneration generate words of lower semantic complexity; (2) compared with young adults, older adults generate words of higher semantic complexity. We searched six databases (date of search: 8 December 2023) for studies that relied on CF and ILS methods, in normal ageing and in age-associated neurodegeneration. Thirty-four studies were shortlisted: 27 on neurodegenerative conditions; 7 on normal ageing. Risk of bias was evaluated via a published checklist. Data were presented via qualitative synthesis. Most studies reported words of lower semantic complexity in relation to at least one item-level feature in individuals with mild cognitive impairment (MCI), Alzheimer’s dementia (AD), and other neurodegenerative diseases. Post-hoc meta-analyses focussing on the MCI/AD continuum confirmed an effect on words’ frequency (385 MCI/AD individuals and 350 controls; Hedges’s G = 0.59) and age-of-acquisition (193 MCI/AD individuals and 161 controls; Hedges’s G = − 1.51). Studies on normal ageing, conversely, failed to demonstrate any overall effect. Most studies on MCI and AD have not relied on neurobiological diagnostic criteria. Moreover, only a small number of studies analysed ILS controlling for quantitative CF performance. Despite these two limitations, this study suggests that ILS can contribute to an in-depth characterisation of semantic memory in neurological ageing

    Audio-visual interactions in manual and saccadic responses

    Get PDF
    Chapter 1 introduces the notions of multisensory integration (the binding of information coming from different modalities into a unitary percept) and multisensory response enhancement (the improvement of the response to multisensory stimuli, relative to the response to the most efficient unisensory stimulus), as well as the general goal of the present thesis, which is to investigate different aspects of the multisensory integration of auditory and visual stimuli in manual and saccadic responses. The subsequent chapters report experimental evidence of different factors affecting the multisensory response: spatial discrepancy, stimulus salience, congruency between cross-modal attributes, and the inhibitory influence of concurring distractors. Chapter 2 reports three experiments on the role of the superior colliculus (SC) in multisensory integration. In order to achieve this, the absence of S-cone input to the SC has been exploited, following the method introduced by Sumner, Adamjee, and Mollon (2002). I found evidence that the spatial rule of multisensory integration (Meredith & Stein, 1983) applies only to SC-effective (luminance-channel) stimuli, and does not apply to SC-ineffective (S-cone) stimuli. The same results were obtained with an alternative method for the creation of S-cone stimuli: the tritanopic technique (Cavanagh, MacLeod, & Anstis, 1987; Stiles, 1959; Wald, 1966). In both cases significant multisensory response enhancements were obtained using a focused attention paradigm, in which the participants had to focus their attention on the visual modality and to inhibit responses to auditory stimuli. Chapter 3 reports two experiments showing the influence of shape congruency between auditory and visual stimuli on multisensory integration; i.e. the correspondence between structural aspects of visual and auditory stimuli (e.g., spiky shape and “spiky” sounds). Detection of audio-visual events was faster for congruent than incongruent pairs, and this congruency effect occurred also in a focused attention task, where participants were required to respond only to visual targets and could ignore irrelevant auditory stimuli. This particular type of cross-modal congruency was been evaluated in relation to the inverse effectiveness rule of multisensory integration (Meredith & Stein, 1983). In Chapter 4, the locus of the cross-modal shape congruency was evaluated applying the race model analysis (Miller, 1982). The results showed that the violation of the model is stronger for some congruent pairings in comparison to incongruent pairings. Evidence of multisensory depression was found for some pairs of incongruent stimuli. These data imply a perceptual locus for the cross-modal shape congruency effect. Moreover, it is evident that multisensoriality does not always induce an enhancement, and in some cases, when the attributes of the stimuli are particularly incompatible, a unisensory response may be more effective that the multisensory one. Chapter 5 reports experiments centred on saccadic generation mechanisms. Specifically, the multisensoriality of the saccadic inhibition (SI; Reingold&Stampe, 2002) phenomenon is investigated. Saccadic inhibition refers to a characteristic inhibitory dip in saccadic frequency beginning 60-70 ms after onset of a distractor. The very short latency of SI suggests that the distractor interferes directly with subcortical target selection processes in the SC. The impact of multisensory stimulation on SI was studied in four experiments. In Experiments 7 and 8, a visual target was presented with a concurrent audio, visual or audio-visual distractor. Multisensory audio-visual distractors induced stronger SI than did unisensory distractors, but there was no evidence of multisensory integration (as assessed by a race model analysis). In Experiments 9 and 10, visual, auditory or audio-visual targets were accompanied by a visual distractor. When there was no distractor, multisensory integration was observed for multisensory targets. However, this multisensory integration effect disappeared in the presence of a visual distractor. As a general conclusion, the results from Chapter 5 results indicate that multisensory integration occurs for target stimuli, but not for distracting stimuli, and that the process of audio-visual integration is itself sensitive to disruption by distractors
    corecore