Brain circuits implicated in psychogenic paralysis in conversion disorders and hypnosis

Recent advances in understanding the neurobiology of pediatric functional neurological disorder

INTRODUCTION

Functional neurological disorder (FND) is a neuropsychiatric disorder that manifests in a broad array of functional motor, sensory, or cognitive symptoms, which arise from complex interactions between brain, mind, body, and context. Children with FND make up 10%-20% of presentations to neurology services in children's hospitals and up to 20% of adolescents admitted to hospital for the management of intractable seizures.

AREAS COVERED

The current review focuses on the neurobiology of pediatric FND. The authors present an overview of the small but growing body of research pertaining to the biological, emotion-processing, cognitive, mental health, physical health, and social system levels.

EXPERT OPINION

Emerging research suggests that pediatric FND is underpinned by aberrant changes within and between neuron-glial (brain) networks, with a variety of factors - on multiple system levels - contributing to brain network changes. In pediatric practice, adverse childhood experiences (ACEs) are commonly reported, and activation or dysregulation of stress-system components is a frequent finding. Our growing understanding of the neurobiology of pediatric FND has yielded important flow-on effects for assessing and diagnosing FND, for developing targeted treatment interventions, and for improving the treatment outcomes of children and adolescents with FND.

Transient resting-state salience-limbic co-activation patterns in functional neurological disorders

BACKGROUND

Functional neurological disorders were historically regarded as the manifestation of a dynamic brain lesion which might be linked to trauma or stress, although this association has not yet been directly tested yet. Analysing large-scale brain network dynamics at rest in relation to stress biomarkers assessed by salivary cortisol and amylase could provide new insights into the pathophysiology of functional neurological symptoms.

METHODS

Case-control resting-state functional magnetic resonance imaging study of 79 patients with mixed functional neurological disorders (i.e., functional movement disorders, functional seizures, persistent perceptual-postural dizziness) and 74 age- and sex-matched healthy controls. Using a two-step hierarchical data-driven neuroimaging approach, static functional connectivity was first computed between 17 resting-state networks. Second, dynamic alterations in these networks were examined using co-activation pattern analysis. Using a partial least squares correlation analysis, the multivariate pattern of correlation between altered temporal characteristics and stress biomarkers as well as clinical scores were evaluated.

RESULTS

Compared to healthy controls, patients presented with functional aberrancies of the salience-limbic network connectivity. Thus, the insula and amygdala were selected as seed-regions for the subsequent analyses. Insular co-(de)activation patterns related to the salience network, the somatomotor network and the default mode network were detected, which patients entered more frequently than controls. Moreover, an insular co-(de)activation pattern with subcortical regions together with a wide-spread co-(de)activation with diverse cortical networks was detected, which patients entered less frequently than controls. In patients, dynamic alterations conjointly correlated with amylase measures and duration of symptoms.

CONCLUSION

The relationship between alterations in insular co-activation patterns, stress biomarkers and clinical data proposes inter-related mechanisms involved in stress regulation and functional (network) integration. In summary, altered functional brain network dynamics were identified in patients with functional neurological disorder supporting previously raised concepts of impaired attentional and interoceptive processing.

Effectiveness and reliability of hypnosis in stereotaxy: a randomized study

BACKGROUND

Patients suffering from Parkinson's disease (PD) may experience pain during stereotactic frame (SF) fixation in deep brain stimulation (DBS). We assessed the role of hypnosis during the SF fixation in PD patients undergoing awake bilateral subthalamic nucleus (STN) DBS.

METHODS

N = 19 patients were included (N = 13 males, mean age 63 years; N = 10 allocated to the hypnosis and N = 9 allocated to the control groups). Patients were randomly assigned to the interventional (hypnosis and local anesthesia) or non-interventional (local anesthesia only) groups. The primary outcome was the pain perceived (the visual analogue scale (VAS)). Secondary outcomes were stress, anxiety, and depression, as measured by the perceived stress scale (PSS) and hospital anxiety and depression scale (HADS). Procedural distress was measured using the peritraumatic distress inventory (PDI-13).

RESULTS

In the hypnosis group, VASmean was 5.6 ± 2.1, versus 6.4 ± 1.2 in the control group (p = 0.31). Intervention and control groups reported similar VASmax scores (7.6 ± 2.1 versus 8.6 ± 1.6 (p = 0.28), respectively). Both groups had similar HADS scores (6.2 ± 4.3 versus 6.7 ± 1.92, p = 0.72 (HADSa) and 6.7 ± 4.2 versus 7.7 ± 3, p = 0.58 (HADSd)), so were the PSS scores (26.1 ± 6.3 versus 25.1 ± 7, p = 0.75). Evolutions of VASmean (R2 = 0.93, 95% CI [0.2245, 1.825], p = 0.03) and PDI-13 scores (R2 = 0.94, 95% CI [1.006, 6.279], p = 0.02) significantly differ over follow-up with patients in the hypnosis groups showing lower scores.

CONCLUSION

In this unblinded, randomized study, hypnosis does not influence pain, anxiety, and distress during awake SF fixation but modulates pain memory over time and may prevent the integration of awake painful procedures as a bad experience into the autobiographical memory of patients suffering from PD. A randomized controlled study with more data is necessary to confirm our findings.

The correlation between brain structure characteristics and emotion regulation ability in children at high risk of autism spectrum disorder

As indicated by longitudinal observation, autism has difficulty controlling emotions to a certain extent in early childhood, and most children's emotional and behavioral problems are further aggravated with the growth of age. This study aimed at exploring the correlation between white matter and white matter fiber bundle connectivity characteristics and their emotional regulation ability in children with autism using machine learning methods, which can lay an empirical basis for early clinical intervention of autism. Fifty-five high risk of autism spectrum disorder (HR-ASD) children and 52 typical development (TD) children were selected to complete the skull 3D-T1 structure and diffusion tensor imaging (DTI). The emotional regulation ability of the two groups was compared using the still-face paradigm (SFP). The classification and regression models of white matter characteristics and white matter fiber bundle connections of emotion regulation ability in the HR-ASD group were built based on the machine learning method. The volume of the right amygdala (R2 = 0.245) and the volume of the right hippocampus (R2 = 0.197) affected constructive emotion regulation strategies. FA (R2 = 0.32) and MD (R2 = 0.34) had the predictive effect on self-stimulating behaviour. White matter fiber bundle connection predicted constructive regulation strategies (positive edging R2 = 0.333, negative edging R2 = 0.334) and mother-seeking behaviors (positive edging R2 = 0.667, negative edging R2 = 0.363). The emotional regulation ability of HR-ASD children is significantly correlated with the connections of multiple white matter fiber bundles, which is a potential neuro-biomarker of emotional regulation ability.

The central role of the Thalamus in psychosis, lessons from neurodegenerative diseases and psychedelics

The PD-DLB psychosis complex found in Parkinson's disease (PD) and Dementia with Lewy Bodies (DLB) includes hallucinations, Somatic Symptom/Functional Disorders, and delusions. These disorders exhibit similar presentation patterns and progression. Mechanisms at the root of these symptoms also share similarities with processes promoting altered states of consciousness found in Rapid Eye Movement sleep, psychiatric disorders, or the intake of psychedelic compounds. We propose that these mechanisms find a crucial driver and trigger in the dysregulated activity of high-order thalamic nuclei set in motion by ThalamoCortical Dysrhythmia (TCD). TCD generates the loss of finely tuned cortico-cortical modulations promoted by the thalamus and unleashes the aberrant activity of the Default Mode Network (DMN). TCD moves in parallel with altered thalamic filtering of external and internal information. The process produces an input overload to the cortex, thereby exacerbating DMN decoupling from task-positive networks. These phenomena alter the brain metastability, creating dreamlike, dissociative, or altered states of consciousness. In support of this hypothesis, mind-altering psychedelic drugs also modulate thalamic-cortical pathways. Understanding the pathophysiological background of these conditions provides a conceptual bridge between neurology and psychiatry, thereby helping to generate a promising and converging area of investigation and therapeutic efforts.

Asserting a Functional Neurological Symptom Disorder with a Complementary Diagnostic Approach: A Brief Report

INTRODUCTION

Functional neurological symptom disorder (FNSD) is a common diagnosis among adolescents. However, we feel it is a difficult diagnosis to assess because of the diversity of its clinical manifestations, the rapid changes in its nosography over the years, and its common imbrication with established somatic diagnoses. We would like to illustrate this hypothesis through a case presentation and the original diagnostic process that emerged from it.

METHODS

We chose to present our diagnosis approach through the case of an 11-year-old boy who showed a progressive loss of motor and sensory function to the point of total dependency, and then suddenly switched between this state and a "normal" physical presentation, while deliriously claiming to be an angel.

RESULTS

All possible infectious, autoimmune, metabolic, and toxic disorders were ruled out. After the successive therapeutic failures of antidepressants and neuroleptics, FNSD was diagnosed.

CONCLUSION

The DSM-5-TR classification was insufficient to explain the full clinical picture and a complementary approach (biblical, psychoanalytical, and historical) was used to analyze the cause of this atypical presentation.

Altered Medial Prefrontal Connectivity in Parkinson's Disease Patients with Somatic Symptoms

BACKGROUND

The high co-occurrence of somatic symptom disorder (SSD) in Parkinson's disease (PD) patients suggests overlapping pathophysiology. However, little is known about the neural correlates of SSD and their possible interactions with PD. Existing studies have shown that SSD is associated with reduced task-evoked activity in the medial prefrontal cortex (mPFC), a central node of the default-mode network (DMN). SSD is also associated with abnormal γ-aminobutyric acid (GABA) content, a marker of local inhibitory tone and regional hypoactivity, in the same area when SSD co-occurs with PD.

OBJECTIVES

To disentangle the individual and shared effects of SSD and PD on mPFC neurotransmission and connectivity patterns and help disclose the neural mechanisms of comorbidity in the PD population.

METHODS

The study cohort included 18 PD patients with SSD (PD + SSD), 18 PD patients, 13 SSD patients who did not exhibit neurologic disorders, and 17 healthy subjects (HC). Proton magnetic resonance (MR) spectroscopy evaluated GABA levels within a volume of interest centered on the mPFC. Resting-state functional MR imaging investigated the region's functional connectivity patterns.

RESULTS

Compared to HC or PD groups, the mPFC of SSD subjects exhibited higher GABA levels and connectivity. Higher mPFC connectivity involved DMN regions in SSD patients without PD and regions of the executive and attentional networks (EAN) in patients with PD comorbidity.

CONCLUSIONS

Aberrant reconfigurations of connectivity patterns between the mPFC and the EAN are distinct features of the PD + SSD comorbidity. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Repetitive transcranial magnetic stimulation for patients with functional paralysis: a randomized controlled study

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) has been proposed to treat functional neurological disorders. Here, we aim to assess the efficacy of rTMS to treat functional paralysis in a controlled randomized trial.

METHODS

Patients received 2 sessions of active or sham 0.25 Hz rTMS (60 stimuli each), with a one-day interval, applied over the motor cortex contralateral to the paralysis. The primary outcome was the number of patients with an increase in motor score between baseline and after the second rTMS session, rated by two investigators blinded to the treatment allocation. Secondary outcomes were changes in global and fine motor scores between groups after rTMS, and occurrence of adverse events.

RESULTS

Sixty-two patients (46 female; mean [SD] age, 35.2 [13.9] years) were enrolled and randomized. Thirteen out of 32 (41%) and 11/30 (37%) patients had increased motor strength after active or sham rTMS, respectively (p=0.80). Changes in both global and fine motor scores after rTMS relative to baseline were also not significantly different between treatment groups (median difference in the global motor score 0.62 [0.83] and 0.37 [0.61], and fine motor scores 0.12 [0.18] and 0.08 [0.11], in active and sham rTMS groups, respectively, p=0.14). We observed six serious adverse events, consisting of 3 cephalalgia in the active group and 2 cephalalgia and 1 asthenia in the sham group.

CONCLUSIONS

Two sessions of sham or active low frequency rTMS were effective to improve functional paralysis, suggesting a placebo effect of this non-invasive brain stimulation technique.

Management of Functional Neurological Disorders (FND): Experience from a Swiss FND Clinic

Functional neurological disorder (FND) represent a common disorder with significant socio-economic impact. In this context and alongside recent new neuroscientific insights, FND attracts a growing interest both in clinical practice and academic activities. New international recommendation and expert opinions suggest that therapy of FND should be a tailored multidisciplinary management involving the neurologist, the physiotherapist, and in most cases the psychotherapist/psychiatrist. A first decisive step is the establishment of a definitive diagnosis, based on the presence of clinical positive signs during neurological assessment together with a clear communication and explanation of the diagnosis by the neurologist. A second important step is based on individual therapeutic sessions, involving different disciplines (neurology and psychotherapy or neurology and physiotherapy). Comorbidities, such as pain or fatigue and psychiatric comorbidities (anxiety, depression, dissociation etc.) should be carefully evaluated, as they need an individualized treatment path. New FND clinics have been created worldwide over the last decades to offer such multidisciplinary settings and this article will present the experience of a first Swiss FND clinic created in 2016. The aim is to highlight in the form of a narrative review the current literature supporting the usefulness and importance of FND clinics, by reviewing the latest evidence on multidisciplinary interventions in FND.

To be, or not to be… Guillain-Barré Syndrome

Guillain-Barré Syndrome (GBS) is currently the most frequent cause of acute flaccid paralysis on a global scale, being an autoimmune disorder wherein demyelination of the peripheral nerves occurs. Its main clinical features are a symmetrical ascending muscle weakness with reduced osteotendinous reflexes and variable sensory involvement. GBS most commonly occurs after an infection, especially viral (including COVID-19), but may also transpire after immunization with certain vaccines or in the development of specific malignancies. Immunoglobulins, plasmapheresis, and glucocorticoids represent the principal treatment modalities, however patients with severe disease progression may require supportive therapy in an intensive care unit. Due to its symptomology, which overlaps with numerous neurological and infectious illnesses, the diagnosis of GBS may often be misattributed to pathologies that are essentially different from this syndrome. Moreover, many of these require specific treatment methods distinct to those recommended for GBS, in lack of which the prognosis of the patient is drastically affected. Such diseases include exposure to toxins either environmental or foodborne, central nervous system infections, metabolic or serum ion alterations, demyelinating pathologies, or even conditions amenable to neurosurgical intervention. This extensive narrative review aims to systematically and comprehensively tackle the most notable and challenging differential diagnoses of GBS, emphasizing on the clinical discrepancies between the diseases, the appropriate paraclinical investigations, and suitable management indications.

Functional neurological disorder and somatic symptom disorder in Parkinson's disease

The occurrence of Functional Neurological Disorder (FND) and Somatic Symptom Disorder (SSD) in PD was not commonly accepted until recently, despite some evidence that emerged in the pre and early L-Dopa era. More recently, the recognition of FND and SSD were noted to be relevant for the management of PD. FND and SSD appear early in the course of PD, often preceding motor symptoms, may interfere with treatment outcomes, often acquire psychotic features during progression, and are mixed with and often concealed by the progressive cognitive decline. We review the related features from the range of the available reports and discuss theoretical models conceived to explain the potential pathophysiological background of these disorders. Finally, we suggest that FND and SSD should be included among the non-motor symptoms of PD and be considered a prodromal feature in a subset of patients. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.

Psychedelic-assisted therapy for functional neurological disorders: A theoretical framework and review of prior reports

Functional neurological disorders (FNDs), which are sometimes also referred to as psychogenic neurological disorders or conversion disorder, are common disabling neuropsychiatric disorders with limited treatment options. FNDs can present with sensory and/or motor symptoms, and, though they may mimic other neurological conditions, they are thought to occur via mechanisms other than those related to identifiable structural neuropathology and, in many cases, appear to be triggered and sustained by recognizable psychological factors. There is intriguing preliminary evidence to support the use of psychedelic‐assisted therapy in a growing number of psychiatric illnesses, including FNDs. We review the theoretical arguments for and against exploring psychedelic‐assisted therapy as a treatment for FNDs. We also provide an in‐depth discussion of prior published cases detailing the use of psychedelics for psychosomatic conditions, analyzing therapeutic outcomes from a contemporary neuroscientific vantage as informed by several recent neuroimaging studies on psychedelics and FNDs.

Texture analysis of dorsal striatum in functional neurological (conversion) disorder

In this study, it was aimed to evaluate the dorsal striatum nuclei of patients diagnosed with Functional Neurological Disorder by texture analysis method from magnetic resonance imaging images and to compare them with healthy controls. Study groups consisted of 20 female patients and 20 healthy women. The brains of patients and controls were scanned for high-resolution images with a 1.5T scanner using the sagittal plane and 3D spiral fast spin echo sequence. Using the texture analysis method, mean, standard deviation, minimum, maximum, median, variance, entropy, size %L, size %U, size %M, kurtosis, skewness and homogeneity values of the dorsal striatum nuclei were calculated from the images. The data were compared with comparison tests according to Kolmogorov-Smirnov test results. There was no statistically significant difference between paired regions in terms of texture analysis findings in the cross-sectional images of the participants. In patients, mean, standard deviation, minimum, maximum, median, variance and entropy values for the putamen nucleus, and mean, standard deviation, minimum, maximum, median, variance, entropy and kurtosis values for the caudate nucleus were found significantly higher than controls. Additional receiver operating characteristic curve and logistic regression analyzes were performed. The implications of the results of the study are that there are significant microstructural changes in the dorsal striatum nuclei of patients and their reflection on brain images. Texture analysis is a useful technique to show tissue changes in the dorsal striatum of patients using images. It is highly recommended to use texture analysis to identify and evaluate potentially affected areas of the brain in new studies.

Improvement of functional neurological disorder after administration of esketamine nasal spray: a case report

Functional neurological disorder (FND) is a complex neuropsychiatric condition characterized by the presence of neurological symptoms and signs (either motor or sensory) that cannot be explained by any known medical or mental disease. It is frequently presented with psychiatric comorbidities, such as major depression. Its prognosis is poor, with low improvement or recovery rates at 1 year after their onset, and no particular treatment has demonstrated significant efficacy in this regard. Here, we describe the management of a patient affected by treatment-resistant depression (TRD) and FND characterized by mixed paralysis (sensory and motor) in the left arm, and who was successfully treated with esketamine nasal spray, achieving remission in both disorders. The US Food and Drug Administration and the European Medicines Agency recently approved esketamine, the S-enantiomer of ketamine, for treatment of TRD. It is a fast-acting drug that provides a rapid-onset improvement of depressive symptoms. We have presented the first case, to our knowledge, of functional neurological symptoms being successfully treated with esketamine in a patient with comorbid TRD. While the novelty of this data implies a clear need for further research, it is suggested that esketamine might be a useful tool for the treatment of FND, acting through different theorized mechanisms that are in tune with recent advances in knowledge of the etiopathology of FND.

Increased Amygdala Activity Associated With Cognitive Reappraisal Strategy in Functional Neurologic Disorder

Cognitive reappraisal is an emotion regulation strategy to reduce the impact of affective stimuli. This regulation could be incomplete in patients with functional neurologic disorder (FND) resulting in an overflowing emotional stimulation perpetuating symptoms in FND patients. Here we employed functional MRI to study cognitive reappraisal in FND. A total of 24 FND patients and 24 healthy controls employed cognitive reappraisal while seeing emotional visual stimuli in the scanner. The Symptom Checklist-90-R (SCL-90-R) was used to evaluate concomitant psychopathologies of the patients. During cognitive reappraisal of negative IAPS images FND patients show an increased activation of the right amygdala compared to normal controls. We found no evidence of downregulation in the amygdala during reappraisal neither in the patients nor in the control group. The valence and arousal ratings of the IAPS images were similar across groups. However, a subgroup of patients showed a significant higher account of extreme low ratings for arousal for negative images. These low ratings correlated inversely with the item "anxiety" of the SCL-90-R. The increased activation of the amygdala during cognitive reappraisal suggests altered processing of emotional stimuli in this region in FND patients.

Are there two different forms of functional dystonia? A multimodal brain structural MRI study

This study assessed brain structural alterations in two diverse clinical forms of functional (psychogenic) dystonia (FD) - the typical fixed dystonia (FixFD) phenotype and the "mobile" dystonia (MobFD) phenotype, which has been recently described in one study. Forty-four FD patients (13 FixFD and 31 MobFD) and 43 healthy controls were recruited. All subjects underwent 3D T1-weighted and diffusion tensor (DT) magnetic resonance imaging (MRI). Cortical thickness, volumes of gray matter (GM) structures, and white matter (WM) tract integrity were assessed. Normal cortical thickness in both FD patient groups compared with age-matched healthy controls were found. When compared with FixFD, MobFD patients showed cortical thinning of the left orbitofrontal cortex, and medial and lateral parietal and cingulate regions bilaterally. Additionally, compared with controls, MobFD patients showed reduced volumes of the left nucleus accumbens, putamen, thalamus, and bilateral caudate nuclei, whereas MobFD patients compared with FixFD demonstrated atrophy of the right hippocampus and globus pallidus. Compared with both controls and MobFD cases, FixFD patients showed a severe disruption of WM architecture along the corpus callous, corticospinal tract, anterior thalamic radiations, and major long-range tracts bilaterally. This study showed different MRI patterns in two variants of FD. MobFD had alterations in GM structures crucial for sensorimotor processing, emotional, and cognitive control. On the other hand, FixFD patients were characterized by a global WM disconnection affecting main sensorimotor and emotional control circuits. These findings may have important implications in understanding the neural substrates underlying different phenotypic FD expression levels.

The chronnectome as a model for Charcot's 'dynamic lesion' in functional movement disorders

This exploratory study set out to investigate dynamic functional connectivity (dFC) in patients with jerky and tremulous functional movement disorders (JT-FMD). The focus in this work is on dynamic brain states, which represent distinct dFC patterns that reoccur in time and across subjects. Resting-state fMRI data were collected from 17 patients with JT-FMD and 17 healthy controls (HC). Symptom severity was measured using the Clinical Global Impression-Severity scale. Depression and anxiety were measured using the Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI), respectively. Independent component analysis was used to extract functional brain components. After computing dFC, dynamic brain states were determined for every subject using k-means clustering. Compared to HC, patients with JT-FMD spent more time in a state that was characterized predominantly by increasing medial prefrontal, and decreasing posterior midline connectivity over time. They also tended to visit this state more frequently. In addition, patients with JT-FMD transitioned significantly more often between different states compared to HC, and incorporated a state with decreasing medial prefrontal, and increasing posterior midline connectivity in their attractor, i.e., the cyclic patterns of state transitions. Altogether, this is the first study that demonstrates altered functional brain network dynamics in JT-FMD that may support concepts of increased self-reflective processes and impaired sense of agency as driving factors in FMD.

Psychological comorbidities and functional neurological disorders in women with idiopathic urinary retention: International Consultation on Incontinence Research Society (ICI-RS) 2019

AIMS

Chronic urinary retention occurring in young women is poorly understood and a cause may not be found in a majority of cases. Different psychological comorbidities and functional neurological symptom disorders (FNDs) have been reported; however, these have been poorly explored.

METHODS

At the International Consultation on Incontinence Research Society meeting in 2019, a panel of clinicians generated a proposal to explore the relationship between psychological comorbidities, FNDs, and urinary retention in women with chronic idiopathic urinary retention.

RESULTS

Psychological comorbidities such as depression and anxiety, and FNDs such as leg weakness and loss of consciousness, have been reported in women with idiopathic urinary retention. Individuals react differently to physical and emotional stressors, and experimental models have demonstrated a relationship between the stress response and developing urinary retention. Trauma, particularly sexual trauma, may be a shared risk factor for developing psychological comorbidities and urinary retention. Children with voiding postponement often suffer from psychological comorbidities and behavioral disturbances; however, there is no evidence to suggest that this progresses to urinary retention in adulthood. "Psychogenic urinary retention" has been described in the urology and psychiatry literature in the past, and anecdotal cases of successful voiding following psychotherapy have been reported, though the true pathophysiology of this entity is uncertain.

CONCLUSION

Psychological and functional disorder comorbidities are reported in women with chronic urinary retention. The nature of the association between urinary retention and functional neurological disorder comorbidities needs to be further explored in terms of a disorder of bladder-brain interaction.

Modification of both functional neurological symptoms and neuroimaging patterns with a good anatomoclinical concordance: a case report

Background

In the nineteenth century, Jean Martin Charcot explained functional neurological disorder (formerly called conversion disorder) as a “psychodynamic” lesion. Numerous advances in neuroimaging have permitted identification of the neural underpinnings of this disorder.

Case presentation

Herein we describe a case of functional neurological disorder (FND) with initial left sensorimotor deficit, in-coordinated limb movements, neglect, clouded consciousness, slurred speech and a semiology of visual impairment. A single photon emission computed tomography (SPECT) showed a right thalamic hypoperfusion, which is rather concordant with the initial semiology. Later, the semiology changed, presenting with a predominantly neurovisual complex presentation. The second SPECT showed no more thalamic abnormalities but an hypoperfusion in the right temporo-occipital junction, right inferior parietal lobe and left superior frontal lobe, which is also rather concordant with the changing semiology.

Conclusions

This case illustrates the evolving neuroimaging patterns of FND but also the concordance between semiology and neuroimaging findings in FND supporting Charcot's theory of “dynamic lesion”.

Impaired Action Control in Patients With Functional Movement Disorders

OBJECTIVE

Despite being a major cause of neurological disability, the neural mechanisms of functional movement disorders (FMDs) remain poorly understood. Recent studies suggest that FMD is linked to dysfunctional motor and prefrontal regions that could lead to motor and cognitive impairments. The aim of this study was to investigate different components of action control in FMD by using choice-reaction, stop-signal, and Simon tasks.

METHODS

Thirty patients with an FMD were prospectively recruited from the University of Louisville Movement Disorders Clinic and compared with 53 healthy control subjects, recruited from the Vanderbilt University Medical Center Movement Disorders Clinic. FMD motor symptom severity was rated with the Simplified Functional Movement Disorder Rating Scale (S-FMDRS). By using a computer and handheld response grips, participants completed three action-control tasks (choice-reaction task, stop-signal task, and Simon task) that tested action initiation, action cancelation, and interference control over actions. Action-control measures were compared between groups with analyses of variance.

RESULTS

Patients with FMD were less proficient in suppressing incorrect response impulses on the Simon task and were slower to stop on the stop-signal task compared with healthy control subjects. No significant correlation with neuropsychological measurements, S-FMDRS scores, and action-control measurements was observed.

CONCLUSIONS

These results suggest that two forms of inhibitory control, selective impulse inhibition and global action cancelation, are impaired in patients with FMD, independent of slowing on go reaction times. Improved understanding of action control in FMD may help in the development of new diagnostic and therapeutic strategies.

Hallucinations, somatic-functional disorders of PD-DLB as expressions of thalamic dysfunction

Hallucinations, delusions, and functional neurological manifestations (conversion and somatic symptom disorders) of Parkinson's disease (PD) and dementia with Lewy bodies increase in frequency with disease progression, predict the onset of cognitive decline, and eventually blend with and are concealed by dementia. These symptoms share the absence of reality constraints and can be considered comparable elements of the PD-dementia with Lewy bodies psychosis. We propose that PD-dementia with Lewy bodies psychotic disorders depend on thalamic dysfunction promoting a theta burst mode and subsequent thalamocortical dysrhythmia with focal cortical coherence to theta electroencephalogram rhythms. This theta electroencephalogram activity, also called fast-theta or pre-alpha, has been shown to predict cognitive decline and fluctuations in Parkinson's disease with dementia and dementia with Lewy bodies. These electroencephalogram alterations are now considered a predictive marker for progression to dementia. The resulting thalamocortical dysrhythmia inhibits the frontal attentional network and favors the decoupling of the default mode network. As the default mode network is involved in integration of self-referential information into conscious perception, unconstrained default mode network activity, as revealed by recent imaging studies, leads to random formation of connections that link strong autobiographical correlates to trivial stimuli, thereby producing hallucinations, delusions, and functional neurological disorders. The thalamocortical dysrhythmia default mode network decoupling hypothesis provides the rationale for the design and testing of novel therapeutic pharmacological and nonpharmacological interventions in the context of PD, PD with dementia, and dementia with Lewy bodies. © 2019 International Parkinson and Movement Disorder Society.

Emotional processing in functional neurological disorder: a review, biopsychosocial model and research agenda

Functional neurological disorder (FND) is a common and highly disabling disorder, but its aetiology remains enigmatic. Conceptually, there has been reduced emphasis on the role of psychosocial stressors in recent years, with a corresponding increase in neurobiological explanations. However, a wealth of evidence supports the role of psychosocial adversities (eg, stressful life events, interpersonal difficulties) as important risk factors for FND. Therefore, there is a need to integrate psychosocial (environmental) and neurobiological factors (eg, sensorimotor and cognitive functions) in contemporary models of FND. Altered emotional processing may represent a key link between psychosocial risk factors and core features of FND. Here, we summarise and critically appraise experimental studies of emotional processing in FND using behavioural, psychophysiological and/or neuroimaging measures in conjunction with affective processing tasks. We propose that enhanced preconscious (implicit) processing of emotionally salient stimuli, associated with elevated limbic reactivity (eg, amygdala), may contribute to the initiation of basic affective/defensive responses via hypothalamic and brainstem pathways (eg, periaqueductal grey). In parallel, affect-related brain areas may simultaneously exert a disruptive influence on neurocircuits involved in voluntary motor control, awareness and emotional regulation (eg, sensorimotor, salience, central executive networks). Limbic-paralimbic disturbances in patients with FND may represent one of several neurobiological adaptations linked to early, severe and/or prolonged psychosocial adversity. This perspective integrates neurobiological and psychosocial factors in FND and proposes a research agenda, highlighting the need for replication of existing findings, multimodal sampling across emotional response domains and further examination of emotional influences on sensorimotor and cognitive functions in FND populations.

Structural alterations in functional neurological disorder and related conditions: a software and hardware problem?

Functional neurological (conversion) disorder (FND) is a condition at the interface of neurology and psychiatry. A "software" vs. "hardware" analogy describes abnormal neurobiological mechanisms occurring in the context of intact macroscopic brain structure. While useful for explanatory and treatment models, this framework may require more nuanced considerations in the context of quantitative structural neuroimaging findings in FND. Moreover, high co-occurrence of FND and somatic symptom disorders (SSD) as defined in DSM-IV (somatization disorder, somatoform pain disorder, and undifferentiated somatoform disorder; referred to as SSD for brevity in this article) raises the possibility of a partially overlapping pathophysiology. In this systematic review, we use a transdiagnostic approach to review and appraise the structural neuroimaging literature in FND and SSD. While larger sample size studies are needed for definitive characterization, this article highlights that individuals with FND and SSD may exhibit sensorimotor, prefrontal, striatal-thalamic, paralimbic, and limbic structural alterations. The structural neuroimaging literature is contextualized within the neurobiology of stress-related neuroplasticity, gender differences, psychiatric comorbidities, and the greater spectrum of functional somatic disorders. Future directions that could accelerate the characterization of the pathophysiology of FND and DSM-5 SSD are outlined, including "disease staging" discussions to contextualize subgroups with or without structural changes. Emerging neuroimaging evidence suggests that some individuals with FND and SSD may have a "software" and "hardware" problem, although if structural alterations are present the neural mechanisms of functional disorders remain distinct from lesional neurological conditions. Furthermore, it remains unclear whether structural alterations relate to predisposing vulnerabilities or consequences of the disorder.

Abnormal postural behavior in patients with functional movement disorders during exposure to stress

BACKGROUND

Patients affected by functional (psychogenic) movement disorders (FMD) have abnormal processing of stress responses. However, little is known about the influence of this abnormal stress processing on automatic motor defense behavior, such as freeze response. Our aim was thus to investigate stress-induced postural motor responses in FMD.

METHODS

Nine FMD patients and thirteen healthy controls were engaged in the Trier Social Stress Test, while we measured the movement of their body by means of accelerometers and gyroscopes attached to the thorax. Standard deviation of thorax acceleration, reflecting the variability of movement amplitude (body sway), was compared across groups over time in a 2 × 2 ANOVA design. Higuchi's fractal dimension (HFD), reflecting the complexity of movement pattern over time, was also analyzed. Salivary cortisol and α-amylase samples were collected before and after the experiment, as stress biomarkers. Pearson's correlation coefficients were calculated between these biomarkers and movement parameters.

RESULTS

A significant interaction effect was found, showing that healthy controls reduced their thorax sway over time during exposure to stress (from 0.027 ± 0.010 m/s² to 0.023 ± 0.008 m/s², effect size of Cohen's d = 0.95), whereas patients with FMD did not. This change in body sway in controls over time negatively correlated with salivary cortisol values (ρ = -0.67, p = 0.012). A significant group effect revealed that FMD patients had an overall larger body sway (0.038 ± 0.013 m/s²) compared to controls (0.025 ± 0.009 m/s² - effect size of Cohen's d = 1.29) and a lower HFD (1.602 ± 0.071) than controls (1.710 ± 0.078 - Cohen's d = 1.43).

CONCLUSIONS

Patients with FMD failed to show a reduction of body sway over time, i.e., freeze response observed in the controls, thus suggesting an impairment in the automatic defense behavior. Moreover, our analysis found a lower complexity of movement (HFD) in FMD, which deserves future research in order to verify whether this could represent a characteristic trait of the disorder.

Pathogenesis and pathophysiology of functional (psychogenic) movement disorders

Functional movement disorders (FMDs), known over time as "hysteria", "dissociative", "conversion", "somatoform", "non-organic" and "psychogenic" disorders, are characterized by having a voluntary quality, being modifiable by attention and distraction but perceived by the patient as involuntary. Although a high prevalence of depression and anxiety is observed in these patients, a definitive role of psychiatric disorders in FMDs has not been proven, and many patients do not endorse such manifestations. Stressful events, social influences and minor trauma may precede the onset of FMDs, but their pathogenic mechanisms are unclear. Patients with FMDs have several abnormalities in their neurobiology including strengthened connectivity between the limbic and motor networks. Additionally, there is altered top-down regulation of motor activities and increased activation of areas implicated in self-awareness, self-monitoring, and active motor inhibition such as the cingulate and insular cortex. Decreased activation of the supplementary motor area (SMA) and pre-SMA, implicated in motor control and preparation, is another finding. The sense of agency defined as the feeling of controlling external events through one's own action also seems to be impaired in individuals with FMDs. Correlating with this is a loss of intentional binding, a subjective time compression between intentional action and its sensory consequences. Organic and functional dystonia may be difficult to differentiate since they share diverse neurophysiological features including decreased cortical inhibition, and similar local field potentials in the globus pallidus and thalamus; although increased cortical plasticity is observed only in patients with organic dystonia. Advances in the pathogenesis and pathophysiology of FMDs may be helpful to understand the nature of these disorders and plan further treatment strategies.

Modality-specific effects of aversive expectancy in the anterior insula and medial prefrontal cortex

Expectations modulate the subjective experience of pain by increasing sensitivity to nociceptive inputs, an effect mediated by brain regions such as the insula. However, it is still unknown whether the neural structures underlying pain expectancy hold sensory-specific information or, alternatively, code for modality-independent features (eg, unpleasantness), potentially common with other negative experiences. We used functional magnetic resonance imaging to investigate neural activity underlying the expectation of different, but comparably unpleasant, pain and disgust. We presented participants with visual cues predicting either a painful heat or disgusting odor, and assessed how they affected the subsequent subjective experience of stimuli from the same (within-modality) or opposite (cross-modal) modality. We found a reliable influence of expectancy on the subjective experience of stimuli whose modality matched that of the previous cue. At the brain level, this effect was mediated by the intermediate dysgranular section of the insula, whereas it was suppressed by more anterior agranular portions of the same region. Instead, no expectancy modulation was observed when the modality of the cue differed from that of the subsequent stimulus. Our data suggest that the insular cortex encodes prospective aversive events in terms of their modality-specific features, and whether they match with subsequent stimulations.

What's in a word? How instructions, suggestions, and social information change pain and emotion

Instructions, suggestions, and other types of social information can have powerful effects on pain and emotion. Prominent examples include observational learning, social influence, placebo, and hypnosis. These different phenomena and their underlying brain mechanisms have been studied in partially separate literatures, which we discuss, compare, and integrate in this review. Converging findings from these literatures suggest that (1) instructions and social information affect brain systems associated with the generation of pain and emotion, and with reinforcement learning, and that (2) these changes are mediated by alterations in prefrontal systems responsible for top-down control and the generation of affective meaning. We argue that changes in expectation and appraisal, a process of assessing personal meaning and implications for wellbeing, are two potential key mediators of the effects of instructions and social information on affective experience. Finally, we propose a tentative model of how prefrontal regions, especially dorsolateral and ventromedial prefrontal cortex may regulate affective processing based on instructions and socially transmitted expectations more broadly.

Metacognition of visuomotor decisions in conversion disorder

Motor conversion disorder (CD) entails genuine disturbances in the subjective experience of patients who maintain they are unable to perform a motor function, despite lack of apparent neurological damage. Abilities by which individuals assess their own capacities during performance in a task are called metacognitive, and distinctive impairment of such abilities is observed in several disorders of self-awareness such as blindsight and anosognosia. In CD, previous research has focused on the recruitment of motor and emotional brain systems, generally linking symptoms to altered limbic-motor interactions; however, metacognitive function has not been studied to our knowledge. Here we tested ten CD patients and ten age-gender matched controls during a visually-guided motor paradigm, previously employed in healthy controls (HC), allowing us to probe for motor awareness and metacognition. Participants had to draw straight trajectories towards a visual target while, unbeknownst to them, deviations were occasionally introduced in the reaching trajectory seen on the screen. Participants then reported both awareness of deviations and confidence in their response. Activity in premotor and cingulate cortex distinguished between conscious and unconscious movement corrections in controls better than patients. Critically, whereas controls engaged the left superior precuneus and middle temporal region during confidence judgments, CD patients recruited bilateral parahippocampal and amygdalo-hippocampal regions instead. These results reveal that distinct brain regions subserve metacognitive monitoring for HC and CD, pointing to different mechanisms and sources of information used to monitor and form confidence judgments of motor performance. While brain systems involved in sensory-motor integration and vision are more engaged in controls, CD patients may preferentially rely on memory and contextual associative processing, possibly accounting for how affect and memories can imbue current motor experience in these patients.

"Motoring in idle": The default mode and somatomotor networks are overactive in children and adolescents with functional neurological symptoms

Objective

Children and adolescents with functional neurological symptom disorder (FND) present with diverse neurological symptoms not explained by a disease process. Functional neurological symptoms have been conceptualized as somatoform dissociation, a disruption of the brain's intrinsic organization and reversion to a more primitive level of function. We used EEG to investigate neural function and functional brain organization in children/adolescents with FND.

Method

EEG was recorded in the resting eyes-open condition in 57 patients (aged 8.5-18 years) and 57 age- and sex-matched healthy controls. Using a topographical map, EEG power data were quantified for regions of interest that define the default mode network (DMN), salience network, and somatomotor network. Source localization was examined using low-resolution brain electromagnetic tomography (LORETA). The contributions of chronic pain and arousal as moderators of differences in EEG power were also examined.

Results

Children/adolescents with FND had excessive theta and delta power in electrode clusters corresponding to the DMN-both anteriorly (dorsomedial prefrontal cortex [dmFPC]) and posteriorly (posterior cingulate cortex [PCC], precuneus, and lateral parietal cortex)-and in the premotor/supplementary motor area (SMA) region. There was a trend toward increased theta and delta power in the salience network. LORETA showed activation across all three networks in all power bands and localized neural sources to the dorsal anterior cingulate cortex/dmPFC, mid cingulate cortex, PCC/precuneus, and SMA. Pain and arousal contributed to slow wave power increases in all three networks.

Conclusions

These findings suggest that children and adolescents with FND are characterized by overactivation of intrinsic resting brain networks involved in threat detection, energy regulation, and preparation for action.

The imaginative mind

The astounding capacity for the human imagination to be engaged across a wide range of contexts is limitless and fundamental to our day-to-day experiences. Although processes of imagination are central to human psychological function, they rarely occupy center stage in academic discourse or empirical study within psychological and neuroscientific realms. The aim of this paper is to tackle this imbalance by drawing together the multitudinous facets of imagination within a common framework. The processes fall into one of five categories depending on whether they are characterized as involving perceptual/motor related mental imagery, intentionality or recollective processing, novel combinatorial or generative processing, exceptional phenomenology in the aesthetic response, or altered psychological states which range from commonplace to dysfunctional. These proposed categories are defined on the basis of theoretical ideas from philosophy as well as empirical evidence from neuroscience. By synthesizing the findings across these domains of imagination, this novel five-part or quinquepartite classification of the human imagination aids in systematizing, and thereby abets, our understanding of the workings and neural foundations of the human imagination. It would serve as a blueprint to direct further advances in the field of imagination while also promoting crosstalk with reference to stimulus-oriented facets of information processing. A biologically and ecologically valid psychology is one that seeks to explain fundamental aspects of human nature. Given the ubiquitous nature of the imaginative operations in our daily lives, there can be little doubt that these quintessential aspects of the mind should be central to the discussion. Hum Brain Mapp 37:4197-4211, 2016. © 2016 Wiley Periodicals, Inc.

An Emotional Call to Action: Integrating Affective Neuroscience in Models of Motor Control

Intimate relationships between emotion and action have long been acknowledged, yet contemporary theories and experimental research within affective and movement neuroscience have not been linked into a coherent framework bridging these two fields. Accumulating psychological and neuroimaging evidence has, however, brought new insights regarding how emotions affect the preparation, execution, and control of voluntary movement. Here we review main approaches and findings on such emotion–action interactions. To assimilate key emotion concepts of action tendencies and motive states with fundamental constructs of the motor system, we underscore the need for integrating an information-processing approach of motor control into affective neuroscience. This should provide a rich foundation to bridge the two fields, allowing further refinement and empirical testing of emotion theories and better understanding of affective influences in movement disorders.

Impact of Transcranial Magnetic Stimulation on Functional Movement Disorders: Cortical Modulation or a Behavioral Effect?

Introduction

Recent studies suggest that repeated transcranial magnetic stimulation (TMS) improves functional movement disorders (FMDs), but the underlying mechanisms are unclear. The objective was to determine whether the beneficial action of TMS in patients with FMDs is due to cortical neuromodulation or rather to a cognitive-behavioral effect.

Method

Consecutive patients with FMDs underwent repeated low-frequency (0.25 Hz) magnetic stimulation over the cortex contralateral to the symptoms or over the spinal roots [root magnetic stimulation (RMS)] homolateral to the symptoms. The patients were randomized into two groups: group 1 received RMS on day 1 and TMS on day 2, while group 2 received the same treatments in reverse order. We blindly assessed the severity of movement disorders before and after each stimulation session.

Results

We studied 33 patients with FMDs (dystonia, tremor, myoclonus, Parkinsonism, or stereotypies). The median symptom duration was 2.9 years. The magnetic stimulation sessions led to a significant improvement (>50%) in 22 patients (66%). We found no difference between TMS and RMS.

Conclusion

We suggest that the therapeutic benefit of TMS in patients with FMDs is due more to a cognitive-behavioral effect than to cortical neuromodulation.

Symptom-specific amygdala hyperactivity modulates motor control network in conversion disorder

Initial historical accounts as well as recent data suggest that emotion processing is dysfunctional in conversion disorder patients and that this alteration may be the pathomechanistic neurocognitive basis for symptoms in conversion disorder. However, to date evidence of direct interaction of altered negative emotion processing with motor control networks in conversion disorder is still lacking. To specifically study the neural correlates of emotion processing interacting with motor networks we used a task combining emotional and sensorimotor stimuli both separately as well as simultaneously during functional magnetic resonance imaging in a well characterized group of 13 conversion disorder patients with functional hemiparesis and 19 demographically matched healthy controls. We performed voxelwise statistical parametrical mapping for a priori regions of interest within emotion processing and motor control networks. Psychophysiological interaction (PPI) was used to test altered functional connectivity of emotion and motor control networks. Only during simultaneous emotional stimulation and passive movement of the affected hand patients displayed left amygdala hyperactivity. PPI revealed increased functional connectivity in patients between the left amygdala and the (pre-)supplemental motor area and the subthalamic nucleus, key regions within the motor control network. These findings suggest a novel mechanistic direct link between dysregulated emotion processing and motor control circuitry in conversion disorder.

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We studied emotion processing effects on motor networks in conversion disorder (CD).

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Simultaneous motor and emotional stimulation resulted in enhanced amygdala activation.

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Left amygdala showed increased functional connectivity with an inhibitory motor loop.

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This suggests a direct link of impaired emotion processing and motor networks in CD.

New directions in hypnosis research: strategies for advancing the cognitive and clinical neuroscience of hypnosis

This article summarizes key advances in hypnosis research during the past two decades, including (i) clinical research supporting the efficacy of hypnosis for managing a number of clinical symptoms and conditions, (ii) research supporting the role of various divisions in the anterior cingulate and prefrontal cortices in hypnotic responding, and (iii) an emerging finding that high hypnotic suggestibility is associated with atypical brain connectivity profiles. Key recommendations for a research agenda for the next decade include the recommendations that (i) laboratory hypnosis researchers should strongly consider how they assess hypnotic suggestibility in their studies, (ii) inclusion of study participants who score in the middle range of hypnotic suggestibility, and (iii) use of expanding research designs that more clearly delineate the roles of inductions and specific suggestions. Finally, we make two specific suggestions for helping to move the field forward including (i) the use of data sharing and (ii) redirecting resources away from contrasting state and nonstate positions toward studying (a) the efficacy of hypnotic treatments for clinical conditions influenced by central nervous system processes and (b) the neurophysiological underpinnings of hypnotic phenomena. As we learn more about the neurophysiological mechanisms underlying hypnosis and suggestion, we will strengthen our knowledge of both basic brain functions and a host of different psychological functions.

5-HT2A Agonists: A Novel Therapy for Functional Neurological Disorders?

Functional neurological disorders are frequently encountered in clinical practice. They have a poor prognosis and treatment options are limited. Their etiology is unknown, but leading theories propose a disturbance of somatic self-representation: the mind perceives dysfunction of a body region despite intact motor and sensory pathways. Central to this model is the concept of an abnormal top-down cognitive influence upon sensorimotor function. There is growing interest in the use of 5-HT2A agonists in the management of neuropsychiatric conditions. Recent studies have shown that these agents induce changes in neural activity that disrupt hierarchical brain dynamics and modulate networks subserving self-related processing. Converging evidence suggests they may hold unique therapeutic potential in functional neurological disorders. This is of importance given the considerable personal and societal burden of this condition and we argue a clinical trial to test this hypothesis is warranted.

Functional neurological symptoms modulate processing of emotionally salient stimuli

OBJECTIVE

Dysfunctional emotion processing has been discussed as a contributing factor to functional neurological symptoms (FNS) in the context of conversion disorder, and refers to blunted recognition and the expression of one's own feelings. However, the emotion processing components characteristic for FNS and/or relevant for conversion remain to be specified. With this goal, the present study targeted the initial, automatic discrimination of emotionally salient stimuli.

METHODS

The magnetoencephalogram (MEG) was monitored in 21 patients with functional weakness and/or sensory disturbance subtypes of FNS and 21 healthy comparison participants (HC) while they passively watched 600 emotionally arousing, pleasant, unpleasant or neutral stimuli in a rapid serial visual presentation (RSVP) design. Neuromagnetic activity was analyzed 110-330ms following picture onset in source space for prior defined posterior and central regions of interest.

RESULTS

As early as 110ms and across presentation interval, posterior neural activity modulation by picture category was similar in both groups, despite smaller initial (110-150ms) overall and posterior power in patients with FNS. The initial activity modulation by picture category was also evident in the left sensorimotor area in patients with FNS, but not significant in HC.

CONCLUSIONS

Similar activity modulation by emotional picture category in patients with FNS and HC suggests that the fast, automatic detection of emotional salience is unchanged in patients with FNS, but involves an emotion-processing network spanning posterior and sensorimotor areas.

Aversive stimuli exacerbate defensive motor behaviour in motor conversion disorder

Conversion disorder or functional neurological symptom disorder (FND) can affect the voluntary motor system, without an organic cause. Functional symptoms are thought to be generated unconsciously, arising from underlying psychological stressors. However, attempts to demonstrate a direct relationship between the limbic system and disrupted motor function in FND are lacking. We tested whether negative affect would exacerbate alterations of motor control and corresponding brain activations in individuals with FND. Ten patients and ten healthy controls produced an isometric precision-grip contraction at 10% of maximum force while either viewing visual feedback of their force output, or unpleasant or pleasant emotional images (without feedback). Force magnitude was continuously recorded together with change in brain activity using fMRI. For controls, force output decayed from the target level while viewing pleasant and unpleasant images. Patients however, maintained force at the target level without decay while viewing unpleasant images, indicating a pronounced effect of negative affect on force output in FND. This emotional modulation of force control was associated with different brain activation patterns between groups. Contrasting the unpleasant with the pleasant condition, controls showed increased activity in the inferior frontal cortex and pre-supplementary motor area, whereas patients had greater activity in the cerebellum (vermis), posterior cingulate cortex, and hippocampus. Engagement of a cerebellar-limbic network in patients is consistent with heightened processing of emotional salience, and supports the role of the cerebellum in freezing responses in the presence of aversive events. These data highlight a possible neural circuit through which psychological stressors elicit defensive behaviour and modulate motor function in FND.

Can motor imagery and hypnotic susceptibility explain Conversion Disorder with motor symptoms?

Marked distortions in sense of agency can be induced by hypnosis in susceptible individuals, including alterations in subjective awareness of movement initiation and control. These distortions, with associated disability, are similar to those experienced with Conversion Disorder (CD), an observation that has led to the hypothesis that hypnosis and CD share causal mechanisms. The purpose of this review is to explore the relationships among motor imagery (MI), hypnotic susceptibility, and CD, then to propose how MI ability may contribute to hypnotic responding and CD. Studies employing subjective assessments of mental imagery have found little association between imagery abilities and hypnotic susceptibility. A positive association between imagery abilities and hypnotic susceptibility becomes apparent when objective measures of imagery ability are employed. A candidate mechanism to explain motor responses during hypnosis is kinaesthetic MI, which engages a strategy that involves proprioception or the "feel" of movement when no movement occurs. Motor suppression imagery (MSI), a strategy involving inhibition of movement, may provide an alternate objective measurable phenomenon that underlies both hypnotic susceptibility and CD. Evidence to date supports the idea that there may be a positive association between kinaesthetic MI ability and hypnotic susceptibility. Additional evidence supports a positive association between hypnotic susceptibility and CD. Disturbances in kinaesthetic MI performance in CD patients indicate that MI mechanisms may also underlie CD symptoms. Further investigation of the above relationships is warranted to explain these phenomena, and establish theoretical explanations underlying sense of agency.

Metacognition of intentions in mindfulness and hypnosis

In a famous series of experiments, Libet investigated the subjective timing of awareness of an intention to move, a task that can be considered a metacognitive judgement. The ability to strategically produce inaccurate metacognitions about intentions has been postulated to be central to the changes in judgements of agency common to all hypnotic responding. Therefore, differences in hypnotisability may be reflected in Libet’s measure. Specifically, the ability to sustain inaccurate judgements of agency displayed by highly hypnotisable people may result from their having coarser higher order representations of intentions. They, therefore, should report a delayed time of intention relative to less hypnotisable individuals. Conversely, mindfulness practice aims at accurate metacognition, including of intentions, and may lead to the development of finer grained higher order representations of intending. Thus, the long-term practice of mindfulness may produce an earlier judgement of the time of an intention. We tested these groups using Libet’s task, and found that, consistent with predictions, highly hypnotisable people reported a later time of intention than less hypnotisable people and meditators an earlier time than non-meditators. In a further two studies, we replicated the finding that hypnotisable people report later awareness of a motor intention and additionally found a negative relationship between trait mindfulness and this measure. Based on these findings, we argue that hypnotic response and meditation involve opposite processes.

Freud's "Project": The Mind-Brain Connection Revisited

Freud's "Project for a Scientific Psychology" (1895) reflected his attempt to explain psychic phenomena in neurobiological terms. The recent discovery of the neuron motivated him to embark on this endeavor. His basic hypothesis was that neurons were vehicles for the conduction of "currents" or "excitations," and that they were connected to one another. Using this model, Freud attempted to describe a number of mental phenomena, including: consciousness, perception, affect, self, cognition, dreaming, memory, and symptom formation. However, he was unable to complete his exploration of these mental processes because he lacked the information and technology that became available over the following century. Subsequent discoveries, including fMRIs, PET scans, EEGs, synapses, neural networks, genetic factors, neurotransmitters, and discrete brain circuits facilitated a significant expansion of our knowledge of mind-brain phenomena. As a result, effective pharmacological treatments have been developed for schizophrenia, mood and anxiety disorders. Moreover, changes in brain function can be measured that reflect successful pharmacologic and psychotherapeutic treatment. Despite these advances, there remain limitations in our understanding of the relationship between mind and brain functions. More than a century after Freud began the "Project," the neurobiology underlying the phenomena of consciousness, unconsciousness, qualities of subjective feelings, thoughts, and memories is still not fully understood. Can we expect to reach a more comprehensive integration of mind and its neurobiological substrate a century from now? The purpose of this article is to update our knowledge of the neurobiology associated with the specific mental functions that Freud examined in the "Project," and to pose questions concerning mind-brain phenomena that will hopefully be answered in the future.

Emotion and dissociative seizures: A phenomenological analysis of patients' perspectives

Quantitative research has indicated that patients with dissociative seizures (DS) show altered responses to emotional stimuli, in addition to considerable emotional distress and dysregulation. The present study sought to further explore emotional processes in this population, to extend previous findings, and to provide a phenomenological insight into patients' perspectives on these issues. Semistructured interviews were carried out with 15 patients with DS, and the principles of interpretative phenomenological analysis (IPA) were adopted in data analysis. Key themes elicited included: i) general emotional functioning; ii) adverse (stressful/traumatic) life experiences; iii) the role of emotions in DS; iv) relating to others; and v) resilience, protective factors, and coping mechanisms. The clinical and theoretical implications of the findings are discussed.

Resignation Syndrome: Catatonia? Culture-Bound?

Resignation syndrome (RS) designates a long-standing disorder predominately affecting psychologically traumatized children and adolescents in the midst of a strenuous and lengthy migration process. Typically a depressive onset is followed by gradual withdrawal progressing via stupor into a state that prompts tube feeding and is characterized by failure to respond even to painful stimuli. The patient is seemingly unconscious. Recovery ensues within months to years and is claimed to be dependent on the restoration of hope to the family. Descriptions of disorders resembling RS can be found in the literature and the condition is unlikely novel. Nevertheless, the magnitude and geographical distribution stand out. Several hundred cases have been reported exclusively in Sweden in the past decade prompting the Swedish National Board of Health and Welfare to recognize RS as a separate diagnostic entity. The currently prevailing stress hypothesis fails to account for the regional distribution and contributes little to treatment. Consequently, a re-evaluation of diagnostics and treatment is required. Psychogenic catatonia is proposed to supply the best fit with the clinical presentation. Treatment response, altered brain metabolism or preserved awareness would support this hypothesis. Epidemiological data suggests culture-bound beliefs and expectations to generate and direct symptom expression and we argue that culture-bound psychogenesis can accommodate the endemic distribution. Last, we review recent models of predictive coding indicating how expectation processes are crucially involved in the placebo and nocebo effect, delusions and conversion disorders. Building on this theoretical framework we propose a neurobiological model of RS in which the impact of overwhelming negative expectations are directly causative of the down-regulation of higher order and lower order behavioral systems in particularly vulnerable individuals.

Imaging studies of functional neurologic disorders

Brain imaging techniques provide unprecedented opportunities to study the neural mechanisms underlying functional neurologic disorder (FND, or conversion disorder), which have long remained a mystery and clinical challenge for physicians, as they arise with no apparent underlying organic disease. One of the first questions addressed by imaging studies concerned whether motor conversion deficits (e.g., hysteric paralysis) represent a form of (perhaps unconscious) simulation, a mere absence of voluntary movement, or more specific disturbances in motor control (such as abnormal inhibition). Converging evidence from several studies using different techniques and paradigms has now demonstrated distinctive brain activation patterns associated with functional deficits, unlike those seen in actors simulating similar deficits. Thus, patients with motor FND show consistent hypoactivation of both cortical and subcortical motor pathways, with frequent increases in other brain areas within the limbic system, but no recruitment of prefrontal regions usually associated with voluntary motor inhibition. Other studies point to a dysfunction in sensorimotor integration and agency - related to parietal dysfunction - and abnormal motor planning related to supplementary motor area and prefrontal areas. These findings not only suggest that functional symptoms reflect a genuine brain dysfunction, but also give new insights into how they are produced. However, fewer studies attempted to understand why these symptoms are produced and linked to potential psychologic or emotional risk/triggering factors. Results from such studies point towards abnormal limbic regulation with heightened emotional arousal and amygdalar activity, potentially related to engagement of defense systems and stereotyped motor behaviors, mediated by medial prefrontal cortex and subcortical structures, including the periaqueductal gray area and basal ganglia. In addition, across different symptom domains, several studies reported abnormal recruitment of ventromedial prefrontal cortex (vmPFC), a region known to regulate emotion appraisal, memory retrieval, and self-reflective representations. The vmPFC might provide important modulatory signals to both cortical and subcortical sensorimotor, visual, and even memory circuits, promoting maladaptive self-protective behaviors based on personal affective appraisals of particular events. A better understanding of such a role of vmPFC in FND may help link how and why these symptoms are produced. Further research is also needed to determine brain activation patterns associated with FND across different types of deficits and different evolution stages (e.g., acute vs. chronic vs. recovered).