What Can Different Motor Circuits Tell Us About Psychosis? An RDoC Perspective

Robust Brain Correlates of Cognitive Performance in Psychosis and Its Prodrome

BACKGROUND

Neurocognitive impairment is a well-known phenomenon in schizophrenia that begins prior to psychosis onset. Connectome-wide association studies have inconsistently linked cognitive performance to resting-state functional magnetic resonance imaging. We hypothesized that a carefully selected cognitive instrument and refined population would allow identification of reliable brain-behavior associations with connectome-wide association studies. To test this hypothesis, we first identified brain-cognition correlations via a connectome-wide association study in early psychosis. We then asked, in an independent dataset, if these brain-cognition relationships would generalize to individuals who develop psychosis in the future.

METHODS

The Seidman Auditory Continuous Performance Task (ACPT) effectively differentiates healthy participants from those with psychosis. Our connectome-wide association study used the HCP-EP (Human Connectome Project for Early Psychosis) (n = 183) to identify links between connectivity and ACPT performance. We then analyzed data from the NAPLS2 (North American Prodrome Longitudinal Study 2) (n = 345), a multisite prospective study of individuals at risk for psychosis. We tested the connectome-wide association study-identified cognition-connectivity relationship in both individuals at risk for psychosis and control participants.

RESULTS

Our connectome-wide association study in early-course psychosis identified robust associations between better ACPT performance and higher prefrontal-somatomotor connectivity (p < .005). Prefrontal-somatomotor connectivity was also related to ACPT performance in at-risk individuals who would develop psychosis (n = 17). This finding was not observed in nonconverters (n = 196) or control participants (n = 132).

CONCLUSIONS

This connectome-wide association study identified reproducible links between connectivity and cognition in separate samples of individuals with psychosis and at-risk individuals who would later develop psychosis. A carefully selected task and population improves the ability of connectome-wide association studies to identify reliable brain-phenotype relationships.

Psychomotor slowing in schizophrenia is associated with aberrant postural control

Motor abnormalities, including psychomotor slowing, are prevalent in a large proportion of individuals with schizophrenia. While postural control deficits have been observed in this population, the impact of motor abnormalities on postural stability remains unclear. This study aimed to objectively evaluate postural stability in patients with and without psychomotor slowing and healthy controls. Seventy-three schizophrenia patients with psychomotor slowing (PS; Salpêtrière Retardation Rating Scale (SRRS) ≥ 15), 25 schizophrenia patients without psychomotor slowing (non-PS; SRRS < 15), and 27 healthy controls (HC) performed four conditions on the Kistler force plate: eyes open (EO), eyes closed (EC), head reclined with eyes open (EOHR), and head reclined with eyes closed (ECHR). Larger sway areas and higher Root Mean Square (RMS) values indicate lower postural stability, while a lower Complexity Index (CI) reflects reduced adaptability, flexibility, and dynamic functioning of postural control. PS exhibited larger sway areas and higher RMS compared to the other groups. Both PS and non-PS showed reduced complexity in postural control compared to healthy controls, without differences between the two patient groups. Reduced postural stability and complexity were associated with greater expert-rated motor abnormalities, as well as more severe negative symptoms. Additionally, lower complexity was linked to reduced physical activity levels. These findings suggest that psychomotor slowing is associated with lower postural stability, potentially reflecting impaired cerebellar function. Furthermore, the loss of complexity in postural control highlights reduced flexibility, adaptability, and efficiency in the postural control network of individuals with schizophrenia.

Motor actions across psychiatric disorders: A research domain criteria (RDoC) perspective

The motor system is critical for understanding the pathophysiology and treatment of mental illness. Abnormalities in the processes that allow us to plan and execute movement in a goal-directed, context-appropriate manner (i.e., motor actions) are especially central to clinical motor research. Within this context, the NIMH Research Domain Criteria (RDoC) framework now includes a Motor Actions construct within the recently incorporated Sensorimotor Systems Domain, providing a useful framework for conducting research on motor action processes. However, there is limited available resources for understanding or implementing this framework. We address this gap by providing a comprehensive critical review and conceptual integration of the current clinical literature on the subconstructs comprising the Motor Actions construct. This includes a detailed discussion of each Motor Action subconstruct (e.g., action planning/execution) and its measurement across different units of analysis (e.g., molecules to behavior), the temporal and conceptual relationships among the Motor Action subconstructs (and other relevant RDoC domain constructs), and how abnormalities in these Motor Action subconstructs manifest in mental illness. Together, the review illustrates how motor system dysfunction is implicated in the pathophysiology of many psychiatric conditions and demonstrates shared and distinct mechanisms that may account for similar manifestations of motor abnormalities across disorders.

Electrophysiological predictors of early response to antidepressants in major depressive disorder

BACKGROUND

Psychomotor retardation (PMR) is a core feature of major depressive disorder (MDD), which is characterized by abnormalities in motor control and cognitive processes. PMR in MDD can predict a poor antidepressant response, suggesting that PMR may serve as a marker of the antidepressant response. However, the neuropathological relationship between treatment outcomes and PMR remains uncertain. Thus, this study examined electrophysiological biomarkers associated with poor antidepressant response in MDD.

METHODS

A total of 142 subjects were enrolled in this study, including 49 healthy controls (HCs) and 93 MDD patients. All participants performed a simple right-hand visuomotor task during magnetoencephalography (MEG) scanning. Patients who exhibited at least a 50 % reduction in disorder severity at the endpoint (>2 weeks) were considered to be responders. Motor-related beta desynchronization (MRBD) and inter- and intra-hemispheric functional connectivity were measured in the bilateral motor network.

RESULTS

An increased MRBD and decreased inter- and intra-hemispheric functional connectivity in the motor network during movement were observed in non-responders, relative to responders and HCs. This dysregulation predicted the potential antidepressant response.

CONCLUSION

Abnormal local activity and functional connectivity in the motor network indicate poor psychomotor function, which might cause insensitivity to antidepressant treatment. This could be regarded as a potential neural mechanism for the prediction of a patient's treatment response.

Alterations of perfusion and functional connectivity of the cingulate motor area are associated with psychomotor retardation in major depressive disorder

Psychomotor retardation, characterized by slowing of speech, thoughts, and a decrease of movements, is frequent in patients with major depressive disorder (MDD). However, its neurobiological correlates are still poorly understood. This study aimed to explore if cerebral blood flow (CBF) and resting state functional connectivity (rs-FC) of the motor network are altered in patients with MDD and if these changes are associated with psychomotor retardation. Thirty-six right-handed patients with depression and 19 right-handed healthy controls (HC) that did not differ regarding age and sex underwent arterial spin labelling (ASL) and resting-state functional MRI (rs-fMRI) scans. Psychomotor retardation was assessed with the motoric items of the core assessment of psychomotor change (CORE) questionnaire. Patients with MDD had more pronounced psychomotor retardation scores than HC. Patients with MDD had reduced CBF in bilateral cingulate motor area (CMA) and increased resting-state functional connectivity (rs-FC) between the cluster in the CMA and a cluster localized in bilateral supplementary motor areas (SMA). Furthermore, increased rs-FC between the CMA and the left SMA was associated with more pronounced psychomotor retardation. Our results suggest that reduced perfusion of the CMA and increased rs-FC between the CMA and the SMA are associated with psychomotor retardation in patients with depression.

Isolation of Distinct Networks Driving Action and Cognition in Psychomotor Processes

BACKGROUND

Psychomotor disturbances are observed across psychiatric disorders and often manifest as psychomotor slowing, agitation, disorganized behavior, or catatonia. Psychomotor function includes both cognitive and motor components, but the neural circuits driving these subprocesses and how they relate to symptoms have remained elusive for centuries.

METHODS

We analyzed data from the HCP-EP (Human Connectome Project for Early Psychosis), a multisite study of 125 participants with early psychosis and 58 healthy participants with resting-state functional magnetic resonance imaging and clinical characterization. Psychomotor function was assessed using the 9-hole pegboard task, a timed motor task that engages mechanical and psychomotor components of action, and tasks assessing processing speed and task switching. We used multivariate pattern analysis of whole-connectome data to identify brain correlates of psychomotor function.

RESULTS

We identified discrete brain circuits driving the cognitive and motor components of psychomotor function. In our combined sample of participants with psychosis (n = 89) and healthy control participants (n = 52), the strongest correlates of psychomotor function (pegboard performance) (p < .005) were between a midline cerebellar region and left frontal region and presupplementary motor area. Psychomotor function was correlated with both cerebellar-frontal connectivity (r = 0.33) and cerebellar-presupplementary motor area connectivity (r = 0.27). However, the cognitive component of psychomotor performance (task switching) was correlated only with cerebellar-frontal connectivity (r = 0.19), whereas the motor component (processing speed) was correlated only with cerebellar-presupplementary motor area connectivity (r = 0.15), suggesting distinct circuits driving unique subprocesses of psychomotor function.

CONCLUSIONS

We identified cerebellar-cortical circuits that drive distinct subprocesses of psychomotor function. Future studies should probe relationships between cerebellar connectivity and psychomotor performance using neuromodulation.

Motor precision deficits in clinical high risk for psychosis

Motor deficits appear prior to psychosis onset, provide insight into vulnerability as well as mechanisms that give rise to emerging illness, and are predictive of conversion. However, to date, the extant literature has often targeted a complex abnormality (e.g., gesture dysfunction, dyskinesia), or a single fundamental domain (e.g., accuracy) but rarely provided critical information about several of the individual components that make up more complex behaviors (or deficits). This preliminary study applies a novel implicit motor task to assess domains of motor accuracy, speed, recognition, and precision in individuals at clinical high risk for psychosis (CHR-p). Sixty participants (29 CHR-p; 31 healthy volunteers) completed clinical symptom interviews and a novel Serial Interception Sequence Learning (SISL) task that assessed implicit motor sequence accuracy, speed, precision, and explicit sequence recognition. These metrics were examined in multilevel models that enabled the examination of overall effects and changes in motor domains over blocks of trials and by positive/negative symptom severity. Implicit motor sequence accuracy, speed, and explicit sequence recognition were not detected as impacted in CHR-p. When compared to healthy controls, individuals at CHR-p were less precise in motor responses both overall (d = 0.91) and particularly in early blocks which normalized over later blocks. Within the CHR-p group, these effects were related to positive symptom levels (t = - 2.22, p = 0.036), such that individuals with higher symptom levels did not improve in motor precision over time (r's = 0.01-0.05, p's > 0.54). CHR-p individuals showed preliminary evidence of motor precision deficits but no other motor domain deficits, particularly in early performance that normalized with practice.

Crisis of objectivity: using a personalized network model to understand maladaptive sensemaking in a patient with psychotic, affective, and obsessive-compulsive symptoms

Introduction

Psychiatric comorbidities have proven a consistent challenge. Recent approaches emphasize the need to move away from categorical descriptions of symptom clusters towards a dimensional view of mental disorders. From the perspective of phenomenological psychopathology, this shift is not enough, as a more detailed understanding of patients' lived experience is necessary as well. One phenomenology-informed approach suggests that we can better understand the nature of psychiatric disorders through personalized network models, a comprehensive description of a person's lifeworld in the form of salient nodes and the relationships between them. We present a detailed case study of a patient with multiple comorbidities, maladaptive coping mechanisms, and adverse childhood experiences.

Methods

The case was followed for a period of two years, during which we collected multiple streams of data, ranging from phenomenological interviews, neuropsychological assessments, language analysis, and semi-structured interviews (Examination of Anomalous Self Experience and Examination of Anomalous World Experience). We analytically constructed a personalized network model of his lifeworld.

Results

We identified an experiential category "the crisis of objectivity" as the core psychopathological theme of his lifeworld. It refers to his persistent mistrust towards any information that he obtains that he appraises as originating in his subjectivity. We can developmentally trace the crisis of objectivity to his adverse childhood experience, as well as him experiencing a psychotic episode in earnest. He developed various maladaptive coping mechanisms in order to compensate for his psychotic symptoms. Interestingly, we found correspondence between his subjective reports and other sources of data.

Discussion

Hernan exhibits difficulties in multiple Research Domain Criteria constructs. While we can say that social sensorimotor, positive valence, and negative valence systems dysfunctions are likely associated with primary deficit (originating in his adverse childhood experience), his cognitive symptoms may be tied to his maladaptive coping mechanisms (although, they might be related to his primary disorder as well).

Cognitive functioning in adult psychiatric patients with and without attention-deficit/hyperactivity disorder

INTRODUCTION

Studies of cognitive functioning in patients with attention-deficit/hyperactivity disorder (ADHD) have often used healthy comparison groups. The present study examines cognitive profiles, including general intellectual and executive functions, in a young adult psychiatric outpatient clientele with ADHD and evaluates whether their cognitive profiles can help differentiate them from patients with non-ADHD-associated psychiatric disorders.

METHODS

The study group comprised 141 young adult psychiatric patients (age range 18-25 years) of whom 78 had ADHD. Comprehensive neuropsychological assessment included the Wechsler Adult Intelligence Scale, 4th version and subtests from Delis-Kaplan Executive Function System. Clinical psychiatric assessments and diagnostic evaluation were performed.

RESULTS

The ADHD group (including all subtypes) had significantly lower verbal comprehension and full-scale intelligence quotient than the non-ADHD group. Tests measuring working memory or executive function did not separate those with and without ADHD.

CONCLUSION

The results of our study suggest that, except for the need to establish overall cognitive performance level, the clinical implication of testing is small if the purpose is to "rule out" an ADHD diagnosis.

Early and late contingent negative variation (CNV) reflect different aspects of deficits in schizophrenia

Abnormal reward processing and psychomotor slowing are well-known in schizophrenia (SZ). As a slow frontocentral potential, contingent negative variation (CNV) is associated with anticipatory attention, motivation and motor planning. The present study aims to evaluate the early and late amplitude and latencies of CNV in patients with SZ compared to healthy controls during a reward processing task and to show its association with clinical symptoms. We recruited 21 patients with SZ and 22 healthy controls to compare early and late CNV amplitude and latency values during a Monetary Incentive Delay (MID) Task between groups. Patients' symptom severity, levels of negative symptoms and depressive symptoms were assessed. Clinical features of the patients were further examined for their relation with CNV components. In conclusion, we found decreased early CNV amplitudes in SZ during the reward condition. They also displayed diminished and shortened late CNV responses for incentive cues, specifically at the central location. Furthermore, early CNV amplitudes exhibited a significant correlation with positive symptoms. Both CNV latencies were linked with medication dosage and the behavioural outcomes of the MID task. We revealed that early and late CNV exhibit different functions in neurophysiology and correspond to various facets of the deficits observed in patients. Our findings also emphasized that slow cortical potentials are indicative of deficient motivational processes as well as impaired reaction preparation in SZ. To gain a deeper understanding of the cognitive and motor impairments associated with psychosis, future studies must compare the effects of CNV in the early and late phases.

The pathobiology of psychomotor slowing in psychosis: altered cortical excitability and connectivity

Psychomotor slowing is a frequent symptom of schizophrenia. Short-interval intracortical inhibition assessed by transcranial magnetic stimulation demonstrated inhibitory dysfunction in schizophrenia. The inhibitory deficit results from additional noise during information processing in the motor system in psychosis. Here, we tested whether cortical inhibitory dysfunction was linked to psychomotor slowing and motor network alterations. In this cross-sectional study, we included 60 patients with schizophrenia and psychomotor slowing determined by the Salpêtrière Retardation Rating Scale, 23 patients without slowing and 40 healthy control participants. We acquired single and double-pulse transcranial magnetic stimulation effects from the left primary motor cortex, resting-state functional connectivity and diffusion imaging on the same day. Groups were compared on resting motor threshold, amplitude of the motor evoked potentials, as well as short-interval intracortical inhibition. Regression analyses calculated the association between motor evoked potential amplitudes or cortical inhibition with seed-based resting-state functional connectivity from the left primary motor cortex and fractional anisotropy at whole brain level and within major motor tracts. In patients with schizophrenia and psychomotor slowing, we observed lower amplitudes of motor evoked potentials, while the short-interval intracortical inhibition/motor evoked potentials amplitude ratio was higher than in healthy controls, suggesting lower cortical inhibition in these patients. Patients without slowing also had lower amplitudes of motor evoked potentials. Across the combined patient sample, cortical inhibition deficits were linked to more motor coordination impairments. In patients with schizophrenia and psychomotor slowing, lower amplitudes of motor evoked potentials were associated with lower fractional anisotropy in motor tracts. Moreover, resting-state functional connectivity between the primary motor cortex, the anterior cingulate cortex and the cerebellum increased with stronger cortical inhibition. In contrast, in healthy controls and patients without slowing, stronger cortical inhibition was linked to lower resting-state functional connectivity between the left primary motor cortex and premotor or parietal cortices. Psychomotor slowing in psychosis is linked to less cortical inhibition and aberrant functional connectivity of the primary motor cortex. Higher neural noise in the motor system may drive psychomotor slowing and thus may become a treatment target.

The neural signature of psychomotor disturbance in depression

Up to 70% of patients with major depressive disorder present with psychomotor disturbance (PmD), but at the present time understanding of its pathophysiology is limited. In this study, we capitalized on a large sample of patients to examine the neural correlates of PmD in depression. This study included 820 healthy participants and 699 patients with remitted (n = 402) or current (n = 297) depression. Patients were further categorized as having psychomotor retardation, agitation, or no PmD. We compared resting-state functional connectivity (ROI-to-ROI) between nodes of the cerebral motor network between the groups, including primary motor cortex, supplementary motor area, sensory cortex, superior parietal lobe, caudate, putamen, pallidum, thalamus, and cerebellum. Additionally, we examined network topology of the motor network using graph theory. Among the currently depressed 55% had PmD (15% agitation, 29% retardation, and 11% concurrent agitation and retardation), while 16% of the remitted patients had PmD (8% retardation and 8% agitation). When compared with controls, currently depressed patients with PmD showed higher thalamo-cortical and pallido-cortical connectivity, but no network topology alterations. Currently depressed patients with retardation only had higher thalamo-cortical connectivity, while those with agitation had predominant higher pallido-cortical connectivity. Currently depressed patients without PmD showed higher thalamo-cortical, pallido-cortical, and cortico-cortical connectivity, as well as altered network topology compared to healthy controls. Remitted patients with PmD showed no differences in single connections but altered network topology, while remitted patients without PmD did not differ from healthy controls in any measure. We found evidence for compensatory increased cortico-cortical resting-state functional connectivity that may prevent psychomotor disturbance in current depression, but may perturb network topology. Agitation and retardation show specific connectivity signatures. Motor network topology is slightly altered in remitted patients arguing for persistent changes in depression. These alterations in functional connectivity may be addressed with non-invasive brain stimulation.

Spatiotemporal Psychopathology - An integrated brain-mind approach and catatonia

Catatonia is featured by complex symptoms combining motor, affective and behavioral phenomena as well as by its syndrome character with trans-diagnostic occurrence. It paradigmatically shows the limits of current forms of psychopathology like affective and cognitive approaches with respect to both clinical symptoms and brain mechanisms. We therefore suggest Spatiotemporal Psychopathology (STPP) which, as recently introduced, is here developed further following the latest findings in both clinical psychiatry and neuroscience. STPP is characterized by two core features: (i) an experience-based approach that accounts for symptoms primarily in terms of first-person experience of time-space as distinct from third-person observation of specific functions and related behavior; (ii) an integrated brain-mind approach where the brain's neural topography and dynamic, e.g., inner time and space, are shared by the mind's mental topography and dynamic, e.g., time-space experience, as their "common currency". We demonstrate how these two features can well account for both symptom complexity and trans-diagnostic nature of catatonia. In conclusion, catatonia can serve as paradigmatic example for the need to develop a more comprehensive psychopathological approach in psychiatry. This is provided by STPP that allows integrating subjective experience, clinical symptoms and the brain's neural activity in terms of their inner space-time, e.g., topography and dynamic.

Mapping Psychomotor Behavior in the Brain

This Viewpoint describes a new conception of brain regions that may be associated with abnormal psychomotor behaviors in psychotic and mood disorders.

Neuromotor dysfunction as a major outcome domain of psychotic disorders: A 21-year follow-up study

BACKGROUND

The long-term stability of neuromotor domains assessed at the first episode of psychosis (FEP) and their ability for predicting a number of outcomes remains largely unknown, and this study addressed these issues.

METHODS

This was a longitudinal study of 243 participants with FEP who were assessed at baseline for background variables and parkinsonism, dyskinesia, neurological soft signs (NSS) and catatonia, and reassessed 21 years later for the same neuromotor variables, psychopathology, functioning, personal recovery, cognitive performance and medical comorbidity. Stability of neuromotor ratings was assessed using the intraclass correlations coefficient and associations between the predictors and outcomes were examined using univariate and multivariate statistics.

RESULTS

Baseline dyskinesia and NSS ratings showed excellent stability over time whereas that for parkinsonism and catatonia was relatively low. Neuromotor dysfunction at follow-up was independently predicted by a family history of schizophrenia, obstetric complications, neurodevelopmental delay, low premorbid IQ and baseline ratings of dyskinesia and NSS. Moreover, baseline dyskinesia and NSS ratings independently predicted more positive and negative symptoms, poor functioning and less personal recovery; catatonia predicted less personal recovery and more medical comorbidity. Baseline neuromotor ratings explained between 4% (for medical comorbidity) and 34% (for neuromotor dysfunction) of the variance in the outcomes. Lastly, neuromotor dysfunction at baseline highly predicted clinical staging at follow-up.

CONCLUSION

Baseline neuromotor domains show variable stability over time and relate distinctively to very long-term outcomes. Both baseline dyskinesia and NSS are trait markers of the disease process and robust predictors of the outcomes.

Brain mechanisms underlying catatonia: A systematic review

BACKGROUND

Catatonia is a complex psychomotor disorder characterized by motor, affective, and behavioral symptoms. Despite being known for almost 150 years, its pathomechanisms are still largely unknown.

METHODS

A systematic research on PubMed, Web of Science, and Scopus was conducted to identify neuroimaging studies conducted on group or single individuals with catatonia. Overall, 33 studies employing structural magnetic resonance imaging (sMRI, n = 11), functional magnetic resonance imaging (fMRI, n = 10), sMRI and fMRI (n = 2), functional near-infrared spectroscopy (fNIRS, n = 1), single positron emission computer tomography (SPECT, n = 4), positron emission tomography (PET, n = 4), and magnetic resonance spectroscopy (MRS, n = 1), and 171 case reports were retrieved.

RESULTS

Observational sMRI studies showed numerous brain changes in catatonia, including diffuse atrophy and signal hyperintensities, while case-control studies reported alterations in fronto-parietal and limbic regions, the thalamus, and the striatum. Task-based and resting-state fMRI studies found abnormalities located primarily in the orbitofrontal, medial prefrontal, motor cortices, cerebellum, and brainstem. Lastly, metabolic and perfusion changes were observed in the basal ganglia, prefrontal, and motor areas. Most of the case-report studies described widespread white matter lesions and frontal, temporal, or basal ganglia hypoperfusion.

CONCLUSIONS

Catatonia is characterized by structural, functional, perfusion, and metabolic cortico-subcortical abnormalities. However, the majority of studies and case reports included in this systematic review are affected by considerable heterogeneity, both in terms of populations and neuroimaging techniques, which calls for a cautious interpretation. Further elucidation, through future neuroimaging research, could have great potential to improve the description of the neural motor and psychomotor mechanisms underlying catatonia.

Psychomotor slowing in schizophrenia is associated with cortical thinning of primary motor cortex: A three cohort structural magnetic resonance imaging study

Psychomotor slowing (PS) is characterized by slowed movements and lower activity levels. PS is frequently observed in schizophrenia (SZ) and distressing because it impairs performance of everyday tasks and social activities. Studying brain topography contributing to PS in SZ can help to understand the underlying neurobiological mechanisms as well as help to develop more effective treatments that specifically target affected brain areas. Here, we conducted structural magnetic resonance imaging (sMRI) of three independent cohorts of right-handed SZ patients (SZ#1: n = 72, SZ#2: n = 37, SZ#3: n = 25) and age, gender and education matched healthy controls (HC) (HC#1: n = 40, HC#2: n = 37, HC#3: n = 38). PS severity in the three SZ cohorts was determined using the Positive and Negative Syndrome Scale (PANSS) item #G7 (motor retardation) and Trail-Making-Test B (TMT-B). FreeSurfer v7.2 was used for automated parcellation and segmentation of cortical and subcortical regions. SZ#1 patients showed reduced cortical thickness in right precentral gyrus (M1; p = 0.04; Benjamini-Hochberg [BH] corr.). In SZ#1, cortical thinning in right M1 was associated with PANSS item #G7 (p = 0.04; BH corr.) and TMT-B performance (p = 0.002; BH corr.). In SZ#1, we found a significant correlation between PANSS item #G7 and TMT-B (p = 0.005, ρ=0.326). In conclusion, PANSS G#7 and TMT-B might have a surrogate value for predicting PS in SZ. Cortical thinning of M1 rather than alterations of subcortical structures may point towards cortical pathomechanism underlying PS in SZ.

Network-level mechanisms underlying effects of transcranial direct current stimulation (tDCS) on visuomotor learning in schizophrenia

Motor learning is a fundamental skill to our daily lives. Dysfunction in motor performance in schizophrenia (Sz) has been associated with poor social and functional outcomes. Transcranial direct current stimulation (tDCS), a non-invasive electrical brain stimulation approach, can influence underlying brain function with potential for improving motor learning in Sz. We used a well-established Serial Reaction Time Task (SRTT) to study motor learning, in combination with simultaneous tDCS and EEG recording, to investigate mechanisms of motor and procedural learning deficits in Sz, and to develop refined non-invasive brain stimulation approaches to improve neurocognitive dysfunction. We recruited 27 individuals with Sz and 21 healthy controls (HC). Individuals performed the SRTT task as they received sham and active tDCS with simultaneous EEG recording. Reaction time (RT), neuropsychological, and measures of global functioning were assessed. SRTT performance was significantly impaired in Sz and showed significant correlations with motor-related and working memory measures as well as global function. Source-space time-frequency decomposition of EEG showed beta-band coherence across supplementary-motor, primary-motor and visual cortex forming a network involved in SRTT performance. Motor-cathodal and visual-cathodal stimulations resulted in significant modulation in coherence particularly across the motor-visual nodes of the network accompanied by significant improvement in motor learning in both controls and patients. Here, we confirm earlier reports of SRTT impairment in Sz and demonstrate significant reversal of the deficits with tDCS. The findings support continued development of tDCS for enhancement of plasticity-based interventions in Sz, as well as source-space EEG analytic approaches for evaluating underlying neural mechanisms.

Speech characteristics yield important clues about motor function: Speech variability in individuals at clinical high-risk for psychosis

BACKGROUND AND HYPOTHESIS

Motor abnormalities are predictive of psychosis onset in individuals at clinical high risk (CHR) for psychosis and are tied to its progression. We hypothesize that these motor abnormalities also disrupt their speech production (a highly complex motor behavior) and predict CHR individuals will produce more variable speech than healthy controls, and that this variability will relate to symptom severity, motor measures, and psychosis-risk calculator risk scores.

STUDY DESIGN

We measure variability in speech production (variability in consonants, vowels, speech rate, and pausing/timing) in N = 58 CHR participants and N = 67 healthy controls. Three different tasks are used to elicit speech: diadochokinetic speech (rapidly-repeated syllables e.g., papapa…, pataka…), read speech, and spontaneously-generated speech.

STUDY RESULTS

Individuals in the CHR group produced more variable consonants and exhibited greater speech rate variability than healthy controls in two of the three speech tasks (diadochokinetic and read speech). While there were no significant correlations between speech measures and remotely-obtained motor measures, symptom severity, or conversion risk scores, these comparisons may be under-powered (in part due to challenges of remote data collection during the COVID-19 pandemic).

CONCLUSION

This study provides a thorough and theory-driven first look at how speech production is affected in this at-risk population and speaks to the promise and challenges facing this approach moving forward.

Facial and upper-limb movement abnormalities in individuals with psychotic-like experiences: a motion analysis study

Slow movements and irregular muscle contraction have been reported separately in different studies targeting individuals with psychotic-like experiences (PLEs). To date, it remains unknown whether these two movement abnormalities, possibly associated with hypo- and hyper-dopaminergia, respectively, co-existed in one sample with PLEs and interrelated in the early stage of psychotic progression. Therefore, this study was to examine if facial and upper-limb slow movements and irregular muscle contraction co-existed in individuals with PLEs, interrelated, and were associated with PLEs. A total of 26 individuals with PLEs, who were identified using the 16-item Prodromal Questionnaire, and 26 age- and gender-matched healthy controls received the facial and upper-limb movement measurement. A motion capture system was used to record the movement procedure and thus calculate kinematic variables that represented severity of slow movements and irregular muscle contraction. Results showed that facial and upper-limb slow movements and facial irregular muscle contraction existed in individuals with PLEs. For the total sample, slower facial movements were associated with less regular facial muscle contraction; slower upper-limb movements were associated with less regular upper-limb muscle contraction. Slower and less regular facial and upper-limb movements were associated with more severe PLEs. Compensatory changes in dopaminergic neural pathways in response to elevated dopamine might explain connection between slow movements and irregular muscle contraction. Because of the ability to detect facial and upper-limb movement abnormalities objectively and sensitively, motion analysis has great applicability to sensorimotor studies for people in the psychosis continuum.

The Effect of Physical Exercise on People with Psychosis: A Qualitative Critical Review of Neuroimaging Findings

Recently, genuine motor abnormalities have been recognized as prodromal and predictive signs of psychosis onset and progression. Therefore, physical exercise could represent a potentially relevant clinical tool in promoting the reshaping of neural connections in motor circuitry. The aim of this review is to provide an overview of the literature on neuroimaging findings as a result of physical treatment in psychosis cohorts. Twenty-one studies, all research articles, were included and discussed in this narrative review. Here, we first outlined how the psychotic brain is susceptible to structural plastic changes after aerobic physical training in pathognomic brain areas (i.e., temporal, hippocampal and parahippocampal regions). Secondly, we focused on functional changes, both region-specific and in terms of connections, to gain insights into the involvement of distant but inter-related neural regions in the plastic process occurring after treatment. Third, we attempted to bridge neural plastic changes occurring after physical interventions with clinical and cognitive outcomes of psychotic patients in order to assess the relevance of such neural reshaping in the psychiatric rehabilitation field. In conclusion, we suggest that the current state of the art is presenting physical intervention as effective in promoting neural changes for patients with psychosis; it is not only useful at the onset of the pathology but also in improving the course of the illness and its functional outcome. However, more evidence is needed to improve our knowledge of the efficacy of physical exercise in plastically reorganizing the psychotic brain in the long term, especially within regions lacking specific investigations, such as motor circuitry.

Attenuated post-movement beta rebound reflects psychomotor alterations in major depressive disorder during a simple visuomotor task: a MEG study

BACKGROUND

Psychomotor alterations are a common symptom in patients with major depressive disorder (MDD). The primary motor cortex (M1) plays a vital role in the mechanism of psychomotor alterations. Post-movement beta rebound (PMBR) in the sensorimotor cortex is abnormal in patients with motor abnormalities. However, the changes in M1 beta rebound in patients with MDD remain unclear. This study aimed to primarily explore the relationship between psychomotor alterations and PMBR in MDD.

METHODS

One hundred thirty-two subjects were enrolled in the study, comprising 65 healthy controls (HCs) and 67 MDD patients. All participants performed a simple right-hand visuomotor task during MEG scanning. PMBR was measured in the left M1 at the source reconstruction level with the time-frequency analysis method. Retardation factor scores and neurocognitive test performance, including the Digit Symbol Substitution Test (DSST), the Making Test Part A (TMT-A), and the Verbal Fluency Test (VFT), were used to measure psychomotor functions. Pearson correlation analyses were used to assess relationships between PMBR and psychomotor alterations in MDD.

RESULTS

The MDD group showed worse neurocognitive performance than the HC group in all three neurocognitive tests. The PMBR was diminished in patients with MDD compared to HCs. In a group of MDD patients, the reduced PMBR was negatively correlated with retardation factor scores. Further, there was a positive correlation between the PMBR and DSST scores. PMBR is negatively associated with the TMT-A scores.

CONCLUSION

Our findings suggested that the attenuated PMBR in M1 could illustrate the psychomotor disturbance in MDD, possibly contributing to clinical psychomotor symptoms and deficits of cognitive functions.

The reliability and validity of the revised Green et al. paranoid thoughts scale in individuals at clinical high-risk for psychosis

INTRODUCTION

Paranoia is a common and impairing psychosis symptom, which exists along a severity continuum that extends into the general population. Individuals at clinical high-risk for psychosis (CHR) frequently experience paranoia and this may elevate their risk for developing full psychosis. Nonetheless, limited work has examined the efficient measurement of paranoia in CHR individuals. The present study aimed to validate an often-used self-report measure, the revised green paranoid thoughts scale (RGPTS), in this critical population.

METHOD

Participants were CHR individuals (n = 103), mixed clinical controls (n = 80), and healthy controls (n = 71) who completed self-report and interview measures. Confirmatory factor analysis (CFA), psychometric indices, group differences, and relations to external measures were used to evaluate the reliability and validity of the RGPTS.

RESULTS

CFA replicated a two-factor structure for the RGPTS and the associated reference and persecution scales were reliable. CHR individuals scored significantly higher on both reference and persecution, relative to both healthy (ds = 1.03, 0.86) and clinical controls (ds = 0.64, 0.73). In CHR participants, correlations between reference and persecution and external measures were smaller than expected, though showed evidence of discriminant validity (e.g., interviewer-rated paranoia, r = 0.24). When examined in the full sample, correlation magnitude was larger and follow-up analyses indicated that reference related most specifically to paranoia (β = 0.32), whereas persecution uniquely related to poor social functioning (β = -0.29).

CONCLUSION

These results demonstrate the reliability and validity of the RGPTS, though its scales related more weakly to severity in CHR individuals. The RGPTS may be useful in future work aiming to develop symptom-specific models of emerging paranoia in CHR individuals.

Spontaneous beta power, motor-related beta power and cortical thickness in major depressive disorder with psychomotor disturbance

INTRODUCTION

The psychomotor disturbance is a common symptom in patients with major depressive disorder (MDD). The neurological mechanisms of psychomotor disturbance are intricate, involving alterations in the structure and function of motor-related regions. However, the relationship among changes in the spontaneous activity, motor-related activity, local cortical thickness, and psychomotor function remains unclear.

METHOD

A total of 140 patients with MDD and 68 healthy controls performed a simple right-hand visuomotor task during magnetoencephalography (MEG) scanning. All patients were divided into two groups according to the presence of psychomotor slowing. Spontaneous beta power, movement-related beta desynchronization (MRBD), absolute beta power during movement and cortical characteristics in the bilateral primary motor cortex were compared using general linear models with the group as a fixed effect and age as a covariate. Finally, the moderated mediation model was tested to examine the relationship between brain metrics with group differences and psychomotor performance.

RESULTS

The patients with psychomotor slowing showed higher spontaneous beta power, movement-related beta desynchronization and absolute beta power during movement than patients without psychomotor slowing. Compared with the other two groups, significant decreases were found in cortical thickness of the left primary motor cortex in patients with psychomotor slowing. Our moderated mediation model showed that the increased spontaneous beta power indirectly affected impaired psychomotor performance by abnormal MRBD, and the indirect effects were moderated by cortical thickness.

CONCLUSION

These results suggest that patients with MDD have aberrant cortical beta activity at rest and during movement, combined with abnormal cortical thickness, contributing to the psychomotor disturbance observed in this patient population.

Biotypes of major depressive disorder identified by a multiview clustering framework

BACKGROUND

The advances in resting-state functional magnetic resonance imaging techniques motivate parsing heterogeneity in major depressive disorder (MDD) through neurophysiological subtypes (i.e., biotypes). Based on graph theories, researchers have observed the functional organization of the human brain as a complex system with modular structures and have found wide-spread but variable MDD-related abnormality regarding the modules. The evidence implies the possibility of identifying biotypes using high-dimensional functional connectivity (FC) data in ways that suit the potentially multifaceted biotypes taxonomy.

METHODS

We proposed a multiview biotype discovery framework that involves theory-driven feature subspace partition (i.e., "view") and independent subspace clustering. Six views were defined using intra- and intermodule FC regarding three MDD focal modules (i.e., the sensory-motor system, default mode network, and subcortical network). For robust biotypes, the framework was applied to a large multisite sample (805 MDD participants and 738 healthy controls).

RESULTS

Two biotypes were stably obtained in each view, respectively characterized by significantly increased and decreased FC compared to healthy controls. These view-specific biotypes promoted the diagnosis of MDD and showed different symptom profiles. By integrating the view-specific biotypes into biotype profiles, a broad spectrum in the neural heterogeneity of MDD and its separation from symptom-based subtypes was further revealed.

LIMITATIONS

The power of clinical effects is limited and the cross-sectional nature cannot predict the treatment effects of the biotypes.

CONCLUSIONS

Our findings not only contribute to the understanding of heterogeneity in MDD, but also provide a novel subtyping framework that could transcend current diagnostic boundaries and data modality.

Network-level mechanisms underlying effects of transcranial direct current stimulation (tDCS) on visuomotor learning impairments in schizophrenia

Motor learning is a fundamental skill to our daily lives. Dysfunction in motor performance in schizophrenia (Sz) is associated with poor social and functional outcomes, but nevertheless remains understudied relative to other neurocognitive domains. Moreover, transcranial direct current stimulation (tDCS) can influence underlying brain function in Sz and may be especially useful in enhancing local cortical plasticity, but underlying neural mechanisms remain incompletely understood. Here, we evaluated performance of Sz individuals on the Serial Reaction Time Task (SRTT), which has been extensively used in prior tDCS research, in combination with concurrent tDCS and EEG source localization first to evaluate the integrity of visuomotor learning in Sz relative to other cognitive domains and second to investigate underlying neural mechanisms. Twenty-seven individuals with Sz and 21 healthy controls (HC) performed the SRTT task as they received sham or active tDCS and simultaneous EEG recording. Measures of motor, neuropsychological and global functioning were also assessed. Impaired SRTT performance correlated significantly with deficits in motor performance, working memory, and global functioning. Time-frequency ("Beamformer") EEG source localization showed beta-band coherence across supplementary-motor, primary-motor and visual cortex regions, with reduced visuomotor coherence in Sz relative to HC. Cathodal tDCS targeting both visual and motor regions resulted in significant modulation in coherence particularly across the motor-visual nodes of the network accompanied by significant improvement in motor learning in both controls and patients. Overall, these findings demonstrate the utility of the SRTT to study mechanisms of visuomotor impairment in Sz and demonstrate significant tDCS effects on both learning and connectivity when applied over either visual or motor regions. The findings support continued study of dysfunctional dorsal-stream visual connectivity and motor plasticity as components of cognitive impairment in Sz, of local tDCS administration for enhancement of plasticity, and of source-space EEG-based biomarkers for evaluation of underlying neural mechanisms.

Structural network alterations and their association with neurological soft signs in schizophrenia: Evidence from clinical patients and unaffected siblings

BACKGROUND

Grey matter abnormalities and neurological soft signs (NSS) have been found in schizophrenia patients and their unaffected relatives. Evidence suggested that NSS are associated with grey matter morphometrical alterations in multiple regions in schizophrenia. However, the association between NSS and structural abnormalities at network level remains largely unexplored, especially in the schizophrenia and unaffected siblings.

METHOD

We used source-based morphometry (SBM) to examine the association of structural brain network characteristics with NSS in 62 schizophrenia patients, 25 unaffected siblings, and 60 healthy controls.

RESULTS

Two components, namely the IC-5 (superior temporal gyrus, inferior frontal gyrus and insula network) and the IC-10 (parahippocampal gyrus, fusiform, thalamus and insula network) showed significant grey matter reductions in schizophrenia patients compared to healthy controls and unaffected siblings. Further association analysis demonstrated separate NSS-related grey matter covarying patterns in schizophrenia, unaffected siblings and healthy controls. Specifically, NSS were negatively associated with IC-1 (hippocampus, caudate and thalamus network) and IC-5 in schizophrenia, but with IC-3 (caudate, superior and middle frontal cortices network) in unaffected siblings and with IC-5 in healthy controls.

CONCLUSION

Our results confirmed the key cortical and subcortical network abnormalities and NSS-related grey matter covarying patterns in the schizophrenia and unaffected siblings. Our findings suggest that brain regions implicating genetic liability to schizophrenia are partly separated from brain regions implicating neural abnormalities.

Depression and Psychosis Risk Shared Vulnerability for Motor Signs Across Development, Symptom Dimensions, and Familial Risk

BACKGROUND

Motor abnormalities are strong transdiagnostic indicators of psychopathology risk that reflect emerging neural network abnormalities. Indeed, motor signs, such as motor slowing and agitation, are widely recognized as core features of both psychosis and depression. However, it is unclear whether these reflect shared or distinct etiology.

METHODS

A sample of 11 878 adolescents completed self-reported clinical measures of rated psychotic-like experiences (PLEs) and depression. Familial risk for psychopathology and the presence of motor signs were drawn from parental reports, including developmental motor delays (eg, sitting, walking), and adolescent motor signs (eg, dyscoordination, psychomotor retardation, and psychomotor agitation). Finally, motor network connectivity in theoretically relevant networks (cortico-striatal, cortico-thalamic, and cortico-cerebellar) were related to symptoms and familial risk for psychopathology.

RESULTS

Developmental motor delays related to increased PLEs, increased depression symptoms, and greater familial risk. Familial risk for both PLEs and depression showed higher rates of developmental motor delays than all other groups. Adolescent motor signs, however, showed unique patterns of relationships to symptoms and familial risk such that dyscoordination reflected risk for PLEs, both psychomotor agitation and retardation reflected depression risk, and psychomotor agitation reflected transdiagnostic risk. Cortico-striatal connectivity was related to depression and PLEs, but cortico-cerebellar connectivity was linked to PLEs only.

CONCLUSIONS

Motor signs may be a transdiagnostic marker of vulnerability for psychopathology. Early developmental motor delays could belie pluripotent, familial risk features. Unique items, eg, dyscoordination specifically related to PLEs, possibly reflecting processes inherent in distinct emerging forms of psychopathology.

Neural mechanisms of motor dysfunction in individuals at clinical high-risk for psychosis: Evidence for impairments in motor activation

Motor abnormalities are a core feature of psychotic disorders observed from the premorbid period through chronic illness, suggesting motor dysfunction may reflect the pathophysiology of psychosis. Electrophysiology research in schizophrenia suggests impaired motor activation and preparation may underlie these motor abnormalities. Despite behavioral studies suggesting similar motor dysfunction in those at clinical high-risk (CHR) for psychosis, there have been no studies examining neural mechanisms of motor dysfunction in the CHR period, where research can inform pathophysiological and risk models. The present study used the lateralized readiness potential (LRP), an event-related potential index of motor activation and preparation, to examine mechanisms of motor dysfunction in 42 CHR and 41 control participants (N = 83, 56% female). Response competition was manipulated to determine whether deficits are secondary to cognitive control impairments or reflect primary motor deficits. Behaviorally, CHR participants exhibited overall slower responses than controls. Further, relative to controls, CHR participants showed reduced activation of correct but not incorrect responses, reflected in blunted LRP amplitude under weak response competition and no difference in amplitude associated with the incorrect response under strong response competition. This pattern of results suggests individuals at CHR for psychosis exhibit primary motor deficits in activating and preparing behavioral responses and are contrary to a deficit in cognitive control. Further, blunted LRP amplitude was associated with worsening of negative symptoms at 12-month follow-up. Together, these findings are consistent with LRP studies in psychosis and implicate motor activation deficits as potential mechanisms of motor dysfunction in the high-risk period. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Impaired Sensorimotor Adaption in Schizophrenia in Comparison to Age-Matched and Elderly Controls

BACKGROUND

The "cognitive dysmetria hypothesis" of schizophrenia proposes a disrupted communication between the cerebellum and cerebral cortex, resulting in sensorimotor and cognitive symptoms. Sensorimotor adaptation relies strongly on the function of the cerebellum.

OBJECTIVES

This study investigated whether sensorimotor adaptation is reduced in schizophrenia compared with age-matched and elderly healthy controls.

METHODS

Twenty-nine stably treated patients with schizophrenia, 30 age-matched, and 30 elderly controls were tested in three motor adaptation tasks in which visual movement feedback was unexpectedly altered. In the "rotation adaptation task" the perturbation consisted of a rotation (30° clockwise), in the "gain adaptation task" the extent of the movement feedback was reduced (by a factor of 0.7) and in the "vertical reversal task," up- and downward pen movements were reversed by 180°.

RESULTS

Patients with schizophrenia adapted to the perturbations, but their movement times and errors were substantially larger than controls. Unexpectedly, the magnitude of adaptation was significantly smaller in schizophrenia than elderly participants. The impairment already occurred during the first adaptation trials, pointing to a decline in explicit strategy use. Additionally, post-adaptation aftereffects provided strong evidence for impaired implicit adaptation learning. Both negative and positive schizophrenia symptom severities were correlated with indices of the amount of adaptation and its aftereffects.

CONCLUSIONS

Both explicit and implicit components of sensorimotor adaptation learning were reduced in patients with schizophrenia, adding to the evidence for a role of the cerebellum in the pathophysiology of schizophrenia. Elderly individuals outperformed schizophrenia patients in the adaptation learning tasks.

The polysemous concepts of psychomotricity and catatonia: A European multi-consensus perspective

Current classification systems use the terms "catatonia" and "psychomotor phenomena" as mere a-theoretical descriptors, forgetting about their theoretical embedment. This was the source of misunderstandings among clinicians and researchers of the European collaboration on movement and sensorimotor/psychomotor functioning in schizophrenia and other psychoses or ECSP. Here, we review the different perspectives, their historical roots and highlight discrepancies. In 1844, Wilhelm Griesinger coined the term "psychic-motor" to name the physiological process accounting for volition. While deriving from this idea, the term "psychomotor" actually refers to systems that receive miscellaneous intrapsychic inputs, convert them into coherent behavioral outputs send to the motor systems. More recently, the sensorimotor approach has drawn on neuroscience to redefine the motor signs and symptoms observed in psychoses. In 1874, Karl Kahlbaum conceived catatonia as a brain disease emphasizing its somatic - particularly motor - features. In conceptualizing dementia praecox Emil Kraepelin rephrased catatonic phenomena in purely mental terms, putting aside motor signs which could not be explained in this way. Conversely, the Wernicke-Kleist-Leonhard school pursued Kahlbaum's neuropsychiatric approach and described many new psychomotor signs, e.g. parakinesias, Gegenhalten. They distinguished 8 psychomotor phenotypes of which only 7 are catatonias. These barely overlap with consensus classifications, raising the risk of misunderstanding. Although coming from different traditions, the authors agreed that their differences could be a source of mutual enrichment, but that an important effort of conceptual clarification remained to be made. This narrative review is a first step in this direction.

Handwriting Kinematics in Patients with Schizophrenia Treated with Long-Acting Injectable Atypical Antipsychotics: Results From the ALPINE Study

Handwriting kinematics (HWKs) were assessed in the randomized controlled ALPINE study of 2 long-acting injectable antipsychotics started during an acute exacerbation of schizophrenia. This exploratory analysis examined the relationship between baseline HWKs and response to acute antipsychotic treatment. Adults with acute schizophrenia were assigned to aripiprazole lauroxil or paliperidone palmitate (groups combined for this analysis). Treatment response was defined as ≥20% reduction from baseline in Positive and Negative Syndrome Scale (PANSS) total score at week 4. Two HWK measures, peak velocity (decreases with greater dysfunction) and percentage of nonballistic movements (%NBM; increases with greater dysfunction), were captured in 4 handwriting tasks (complex loops, maximum speed circles, overlay circles, and left-right loops). Peak velocity and %NBM at baseline were compared between responders and nonresponders. The analysis included 143 patients (mean baseline PANSS total score, 94.5). PANSS responders (n = 67 [46.9%]) had a lower mean peak velocity (i.e., slower pen movements) on all HWK tasks at baseline compared with nonresponders (n = 76): complex loops, 8.8 versus 12.1 cm/s; maximum speed circles, 18.0 versus 23.7 cm/s; overlay circles, 12.6 versus 17.2 cm/s; and left-right loops, 11.2 versus 14.6 cm/s. PANSS responders had a greater %NBM on 3 tasks compared with nonresponders: complex loops, 57.1% versus 47.4%; overlay circles, 30.6% versus 24.3%; and left-right loops, 58.7% versus 47.0%. In this exploratory analysis, PANSS responders to aripiprazole lauroxil or paliperidone palmitate treatment at week 4 had lower baseline HWK movement velocities and greater baseline %NBM versus nonresponders, suggesting that baseline HWKs might predict response to these antipsychotic drugs.

Motor abnormalities, depression risk, and clinical course in adolescence

Background

Motor abnormalities, such as psychomotor agitation and retardation, are widely recognized as core features of depression. However, it is not currently known if motor abnormalities connote risk for depression.

Methods

Using data from the Adolescent Brain Cognitive Development (ABCD) Study, a nationally representative sample of youth (n=10,835, 9-11 years old), the present paper examines whether motor abnormalities are associated with (a) depression symptoms in early adolescence, (b) familial risk for depression (familial risk loading), and (c) future depression symptoms. Motor abnormalities measures included traditional (DSM) motor signs such as psychomotor agitation and retardation as well as other motor domains such as developmental motor delays and dyscoordination.

Results

Traditional motor abnormalities were less prevalent (agitation=3.2%, retardation=0.3%) than non-traditional domains (delays=13.79%, coordination=35.5%) among adolescents. Motor dysfunction was associated with depression symptoms (Cohen's ds=0.02 to 0.12). Familial risk for depression was related to motor abnormalities (Cohen's ds=0.08 to 0.27), with the exception of motor retardation. Family vulnerability varied in sensitivity to depression risk (e.g., retardation: .53%; dyscoordination: 32.05%). Baseline endorsement of motor abnormalities predicted future depression symptoms at one-year follow-up.

Conclusions

These findings suggest that motor signs reflect a novel, promising future direction for examining vulnerability to depression risk in early adolescence.

Progress in sensorimotor neuroscience of schizophrenia spectrum disorders: Lessons learned and future directions

The number of neuroimaging studies on movement disorders, sensorimotor, and psychomotor functioning in schizophrenia spectrum disorders (SSD) has steadily increased over the last two decades. Accelerated by the addition of the "sensorimotor domain" to the Research Domain Criteria (RDoC) framework in January 2019, neuroscience research on the role of sensorimotor dysfunction in SSD has gained greater scientific and clinical relevance. To draw attention to recent rapid progress in the field, we performed a triennial systematic review (PubMed search from January 1st^, 2018 through December 31st^, 2020), in which we highlight recent neuroimaging findings and discuss methodological pitfalls as well as challenges for future research. The identified magnetic resonance imaging (MRI) studies suggest that sensorimotor abnormalities in SSD are related to cerebello-thalamo-cortico-cerebellar network dysfunction. Longitudinal and interventional studies highlight the translational potential of the sensorimotor domain as putative biomarkers for treatment response and as targets for non-invasive neurostimulation techniques in SSD.

Repetitive transcranial magnetic stimulation modulates cortical-subcortical connectivity in sensorimotor network

Repetitive transcranial magnetic stimulation (rTMS) holds the ability to modulate the connectivity within the stimulated network. However, whether and how the rTMS targeted over the primary motor cortex (M1) could affect the connectivity within the sensorimotor network (SMN) is not fully elucidated. Hence, in this study, we investigated the after-effects of rTMS over left M1 at different frequencies on connectivity within SMN. Forty-five healthy participants were recruited and randomly divided into three groups according to rTMS frequencies (high-frequency [HF], 3 Hz; low-frequency [LF], 1 Hz; and SHAM). Participants received 1-Hz, 3-Hz or sham stimulation and underwent two functional magnetic resonance imaging (fMRI) scanning sessions before and after rTMS intervention. Using resting-state functional connectivity (FC) approach, we found that high- and low-frequency rTMS had opposing effects on FC within the SMN, especially for connectivity with subcortical regions (i.e., putamen, thalamus and cerebellum). Specifically, the reductions in connectivity between cortical and subcortical regions within cortico-basal ganglia thalamo-cortical circuits and the cognitive loop of cerebellum, and increased connectivity between cortical and subdivisions within the sensorimotor loop of cerebellum were observed after high-frequency rTMS intervention, whereas the thalamus and cognitive cerebellum subdivisions exhibited increased connectivity, and sensorimotor cerebellum subdivisions showed decreased connectivity with stimulated target after low-frequency stimulation. Collectively, these findings demonstrated the alterations of connectivity within SMN after rTMS intervention at different frequencies and may help to understand the mechanisms of rTMS treatment for movement disorders associated with deficits in subcortical regions such as Parkinson's disease, Huntington's disease and Tourette's syndrome.

Effects of rhythmic auditory stimulation on upper-limb movement speed in patients with schizophrenia spectrum disorders

Movement slowness, linked to dysfunctional basal ganglia and cerebellum, is prevalent but lacks effective therapy in patients with schizophrenia spectrum disorders. This study was to examine immediate effects of rhythmic auditory stimulation (RAS) on upper-limb movement speed in patients. Thirty patients and 30 psychiatrically healthy people executed the right-hand task and the both-hand task of the Purdue Pegboard Test when listening to RAS with two tempi: normal (equal to the fastest movement tempo for each participant without RAS) and fast (120% of the normal tempo). The testing order of the RAS tempi for each participant was randomized. Patients had lower scores of right-hand and both-hand tasks than did psychiatrically healthy people. Scores of right-hand and both-hand tasks were higher in the fast-RAS condition than the normal-RAS condition in participants. This is the first study to explore the possibility of applying RAS to movement therapy for patients with schizophrenia spectrum disorders. The results demonstrated that faster RAS was effective in inducing faster upper-limb movements in patients and psychiatrically healthy people, suggesting that manipulating RAS may be a feasible therapeutic strategy utilized to regulate movement speed. The RAS may involve alternative neural pathways to modulate movement speed and thus to compensate for impaired function of basal ganglia and cerebellum in patients.

Investigation of structural brain correlates of neurological soft signs in individuals at ultra-high risk for psychosis

Increased severity of neurological soft signs (NSS) in schizophrenia have been associated with abnormal brain morphology in cerebello-thalamo-cortical structures, but it is unclear whether similar structures underlie NSS prior to the onset of psychosis. The present study investigated the relationship between severity of NSS and grey matter volume (GMV) in individuals at ultra-high risk for psychosis (UHR) stratified for later conversion to psychosis. Structural T1-weighted MRI scans were obtained from 56 antipsychotic-naïve UHR individuals and 35 healthy controls (HC). The UHR individuals had follow-up data (mean follow-up: 5.2 years) to ascertain clinical outcome. Using whole-brain voxel-based morphometry, the relationship between NSS and GMV at baseline was assessed in UHR, HC, as well as individuals who later transitioned (UHR-P, n = 25) and did not transition (UHR-NP, n = 31) to psychosis. NSS total and subscale scores except motor coordination were significantly higher in UHR compared to HC. Higher signs were also found in UHR-P, but not UHR-NP. Total NSS was not associated with GMV in the whole sample or in each group. However, in UHR-P individuals, greater deficits in sensory integration was associated with lower GMV in the left cerebellum, right insula, and right middle frontal gyrus. In conclusion, NSS are present in UHR individuals, particularly those who later transitioned to a psychotic disorder. While these signs show little overall variation with GMV, the association of sensory integration deficits with lower GMV in UHR-P suggests that certain brain areas may be implicated in the development of specific neurological abnormalities in the psychosis prodrome.

A systematic review of the prognostic value of motor abnormalities on clinical outcome in psychosis

Schizophrenia spectrum disorders have heterogeneous outcomes and currently no marker predicts the course of illness. Motor abnormalities (MAs) are inherent to psychosis, the risk of psychosis, symptom severity, and brain alterations. However, the prognostic value of MAs is still unresolved. Here, we provide a systematic review of longitudinal studies on the prognostic role of MAs spanning individuals at clinical high risk for psychosis (CHR), patients with first-episode psychosis (FEP), and chronic schizophrenia. We included 68 studies for a total of 23,630 subjects that assessed neurological soft signs (NSS), hypo- or hyperkinetic movement disorders and/or catatonia as a prognostic factor on clinical and functional outcomes. We found increased levels of MAs, in particular NSS, parkinsonism, and dyskinesia, were related to deteriorating symptomatic and poor functional outcome over time. Collectively, the findings emphasize the clinical, prognostic and scientific relevance of MA assessment and detection in individuals with or at risk of psychosis. In the future, instrumental measures of MA are expected to further augment detection, early intervention and treatment strategies in psychosis.

Catatonia: Clinical Overview of the Diagnosis, Treatment, and Clinical Challenges

Catatonia is a syndrome that has been associated with several mental illness disorders but that has also presented as a result of other medical conditions. Schizophrenia and other psychiatric disorders such as mania and depression are known to be associated with catatonia; however, several case reports have been published of certain medical conditions inducing catatonia, including hyponatremia, cerebral venous sinus thrombosis, and liver transplantation. Neuroleptic Malignant Syndrome and anti-NMDA receptor encephalitis are also prominent causes of catatonia. Patients taking benzodiazepines or clozapine are also at risk of developing catatonia following the withdrawal of these medications—it is speculated that the prolonged use of these medications increases gamma-aminobutyric acid (GABA) activity and that discontinuation may increase excitatory neurotransmission, leading to catatonia. The treatment of catatonia often involves the use of benzodiazepines, such as lorazepam, that can be used in combination therapy with antipsychotics. Definitive treatment may be found with electroconvulsive therapy (ECT). Aberrant neuronal activity in different motor pathways, defective neurotransmitter regulation, and impaired oligodendrocyte function have all been proposed as the pathophysiology behind catatonia. There are many clinical challenges that come with catatonia and, as early treatment is associated with better outcomes, it becomes imperative to understand these challenges. The purpose of this manuscript is to provide an overview of these challenges and to look at clinical studies regarding the pathophysiology, diagnosis, and treatment of as well as the complications and risk factors associated with catatonia.

Revisiting lorazepam challenge test: Clinical response with dose variations and utility for catatonia in a psychiatric emergency setting

OBJECTIVE

Catatonia can be life-threatening unless timely identified and treated. Lorazepam's ubiquitous response has led to its universal acceptance as being the first-line management of catatonia and alludes to catatonia's neurobiological underpinnings. Lorazepam challenge test (LCT) is widely used to either confirm a catatonia diagnosis or determine lorazepam sensitivity. It has a proposed schedule for administering lorazepam. However, efficacy of recommended LCT doses lack systematic evidence, resulting in variable LCT doses used in clinical and research settings contributing to findings that are challenging to generalize or assist with developing standardized lorazepam treatment protocols for catatonia. Given the same, this study aimed to objectively compare the response between two groups receiving different LCT doses and factors influencing the same.

METHODS

The 6-month study in a psychiatric emergency setting at a tertiary neuropsychiatric center in India evaluated 57 catatonia patients, before and after administration of single 2 mg (n = 37; LCT-2) or 4 mg (n = 20; LCT-4) lorazepam dose, applying Bush Francis Catatonia Rating Scale (BFCRS), Mini International Neuropsychiatric Interview (MINI 5.0) and obtaining sociodemographic, clinical data.

RESULTS

No between-group differences (LCT-2 vs LCT-4) for sociodemographic, clinical profiles or BFCRS severity score changes to lorazepam on Mann-Whitney U test were noted. Applying Wilcoxon signed rank test comparing individual sign severity demonstrated response variability, with significant response noted to both doses (stupor, mutism, staring, posturing, withdrawal, ambitendency, automatic obedience) and others selectively to 2 mg (echolalia, rigidity, negativism, mitgehen). Notably, sign resolution (present/absent) only to 2 mg was significant for stupor, mutism, staring, posturing, echolalia, rigidity, negativism and mitgehen.

CONCLUSION

This study suggests 2 mg lorazepam may be an optimal LCT dose, given significant response to most catatonic signs thereby ensuring accurate detection and preventing misinterpretation of response. It offers future studies direction for standardizing lorazepam dosing schedules for catatonia management and exploring neurobiological underpinnings for individual catatonic signs that may be potentially different, given these findings.

White matter microstructure alterations in cortico-striatal networks are associated with parkinsonism in schizophrenia spectrum disorders

The specific role of white matter (WM) microstructure in parkinsonism among patients with schizophrenia spectrum disorders (SSD) is largely unknown. To determine whether topographical alterations of WM microstructure contribute to parkinsonism in SSD patients, we examined healthy controls (HC, n=16) and SSD patients with and without parkinsonism, as defined by Simpson-Angus Scale total score of ≥4 (SSD-P, n=33) or <4 (SSD-nonP, n=62). We used whole brain tract-based spatial statistics (TBSS), tractometry (along tract statistics using TractSeg) and graph analytics (clustering coefficient (CCO), local betweenness centrality (BC)) to provide a framework of specific WM microstructural changes underlying parkinsonism in SSD. Using these methods, post hoc analyses showed (a) decreased fractional anisotrophy (FA), as measured via tractometry, in the corpus callosum, corticospinal tract and striato-fronto-orbital tract, and (b) increased CCO, as derived by graph analytics, in the left orbitofrontal cortex (OFC) and left superior frontal gyrus (SFG), in SSD-P patients when compared to SSD-nonP patients. Increased CCO in the left OFC and SFG was associated with SAS scores. These findings indicate the prominence of OFC alterations and aberrant connectivity with fronto-parietal regions and striatum in the pathogenesis of parkinsonism in SSD. This study further supports the notion of altered "bottom-up modulation" between basal ganglia and fronto-parietal regions in the pathobiology of parkinsonism, which may reflect an interaction between movement disorder intrinsic to SSD and antipsychotic drug-induced sensorimotor dysfunction.

[Twelve years of research domain criteria in psychiatric research and practice: claim and reality]

The research domain criteria (RDoC) initiative of the National Institute of Mental Health (NIMH) was presented 12 years ago. The RDoC provides a matrix for the systematic, dimensional and domain-based study of mental disorders that is not based on established disease entities as defined by the Diagnostic and Statistical Manual of Mental Disorders (DSM) or the International Classification of Diseases (ICD). The primary aim of RDoC is to understand the nature of mental health and illness in terms of different extents of dysfunction in psychological/biological systems with interconnected diagnoses. This selective review article aims to provide a comprehensive overview of RDoC-based studies that have contributed to a better conceptual organization of mental disorders. Numerous promising and methodologically sophisticated studies on RDoC were identified. The number of scientific studies increased over time, indicating that dimensional research is increasingly being pursued in psychiatry. In summary, the RDoC initiative has a considerable potential to more precisely define the complexity of pathomechanisms underlying mental disorders; however, major challenges (e.g. small and heterogeneous study samples, unclear biomarker definitions and lack of replication studies) remain to be overcome in the future. Furthermore, it is plausible that a diagnostic system of the future will integrate categorical and dimensional approaches to arrive at a stratification that can underpin a precision medical approach in psychiatry.

A Network of Psychopathological, Cognitive, and Motor Symptoms in Schizophrenia Spectrum Disorders

Schizophrenia spectrum disorders (SSDs) are complex syndromes involving psychopathological, cognitive, and also motor symptoms as core features. A better understanding of how these symptoms mutually impact each other could translate into diagnostic, prognostic, and, eventually, treatment advancements. The present study aimed to: (1) estimate a network model of psychopathological, cognitive, and motor symptoms in SSD; (2) detect communities and explore the connectivity and relative importance of variables within the network; and (3) explore differences in subsample networks according to remission status. A sample of 1007 patients from a multisite cohort study was included in the analysis. We estimated a network of 43 nodes, including all the items from the Positive and Negative Syndrome Scale, a cognitive assessment battery and clinical ratings of extrapyramidal symptoms. Methodologies specific to network analysis were employed to address the study's aims. The estimated network for the total sample was densely interconnected and organized into 7 communities. Nodes related to insight, abstraction capacity, attention, and suspiciousness were the main bridges between network communities. The estimated network for the subgroup of patients in remission showed a sparser density and a different structure compared to the network of nonremitted patients. In conclusion, the present study conveys a detailed characterization of the interrelations between a set of core clinical elements of SSD. These results provide potential novel clues for clinical assessment and intervention.

Motor abnormalities and basal ganglia in first-episode psychosis (FEP)

BACKGROUND

Motor abnormalities (MAs) are the primary manifestations of schizophrenia. However, the extent to which MAs are related to alterations of subcortical structures remains understudied.

METHODS

We aimed to investigate the associations of MAs and basal ganglia abnormalities in first-episode psychosis (FEP) and healthy controls. Magnetic resonance imaging was performed on 48 right-handed FEP and 23 age-, gender-, handedness-, and educational attainment-matched controls, to obtain basal ganglia shape analysis, diffusion tensor imaging techniques (fractional anisotropy and mean diffusivity), and relaxometry (R2*) to estimate iron load. A comprehensive motor battery was applied including the assessment of parkinsonism, catatonic signs, and neurological soft signs (NSS). A fully automated model-based segmentation algorithm on 1.5T MRI anatomical images and accurate corregistration of diffusion and T2* volumes and R2* was used.

RESULTS

FEP patients showed significant local atrophic changes in left globus pallidus nucleus regarding controls. Hypertrophic changes in left-side caudate were associated with higher scores in sensory integration, and in right accumbens with tremor subscale. FEP patients showed lower fractional anisotropy measures than controls but no significant differences regarding mean diffusivity and iron load of basal ganglia. However, iron load in left basal ganglia and right accumbens correlated significantly with higher extrapyramidal and motor coordination signs in FEP patients.

CONCLUSIONS

Taken together, iron load in left basal ganglia may have a role in the emergence of extrapyramidal signs and NSS of FEP patients and in consequence in the pathophysiology of psychosis.