Deconstructing emotion regulation in schizophrenia: The nature of abnormalities at the selection and implementation stages

Difficulties with emotion regulation are observed across psychiatric diagnoses, including psychotic disorders. Past studies using trait self-report indicate that people with schizophrenia (SZ) are less likely to use adaptive emotion regulation strategies and more likely to use maladaptive emotion regulation strategies than controls (CN). However, more recent evidence using ecological momentary assessment (EMA) indicates that regulation effectiveness and adaptiveness may vary across strategies. The present study aimed to systematically understand abnormalities in state-level emotion regulation strategy selection, effectiveness, and adaptiveness in SZ compared to CN using EMA. Participants (n = 50 SZ; n = 53 CN) completed 6 days of EMA surveys assessing emotional experience, emotion regulation, and symptoms. Results indicated that SZ selected interpersonal emotion regulation and avoidance more often than CN, while both groups selected reappraisal and distraction more often than avoidance and suppression. Overall, strategies were effective at reducing negative emotion and adaptive for reducing delusions over time. Reappraisal, avoidance, and suppression all significantly down-regulated delusions over time. Although some selection abnormalities were present in terms of rate of selection and effort exertion, people with SZ select strategies which are effective and adaptive in the short term. The present results have implications for how cognitive therapy for psychosis may target delusions. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The effects of the COVID-19 pandemic on hallucinations and delusions in youth at clinical high-risk for psychosis and outpatients with schizophrenia

Although the COVID-19 pandemic has had detrimental effects on mental health in the general population, the impact on those with schizophrenia-spectrum disorders has received relatively little attention. Assessing pandemic-related changes in positive symptoms is particularly critical to inform treatment protocols and determine whether fluctuations in hallucinations and delusions are related to telehealth utilization and treatment adherence. In the current longitudinal study, we evaluated changes in the frequency of hallucinations and delusions and distress resulting from them across three-time points. Participants included: (1) outpatients with chronic schizophrenia (SZ: n = 32) and healthy controls (CN: n = 31); (2) individuals at clinically high risk for psychosis (CHR: n = 25) and CN (n = 30). A series of questionnaires were administered to assess hallucination and delusion severity, medication adherence, telehealth utilization, and protective factors during the pandemic. While there were no significant increases in the frequency of hallucinations and delusions in SZ and CHR, distress increased from pre-pandemic to early pandemic in both groups and then decreased at the third time point. Additionally, changes in positive symptom severity in SZ were related to psychiatric medication adherence. Findings suggest that positive symptoms are a critical treatment target during the pandemic and that ongoing medication services will be beneficial.

Negative Symptom Inventory-Self-Report (NSI-SR): Initial development and validation

Negative symptoms (i.e., anhedonia, avolition, asociality, blunted affect, alogia) are frequently observed in the schizophrenia-spectrum (SZ) and associated with functional disability. While semi-structured interviews of negative symptoms represent a gold-standard approach, they require specialized training and may be vulnerable to rater biases. Thus, brief self-report questionnaires measuring negative symptoms may be useful. Existing negative symptom questionnaires demonstrate that this approach may be promising in schizophrenia, but no measure has been devised for use across stages of psychotic illness. The present study reports initial psychometric validation of the Negative Symptom Inventory-Self-Report (NSI-SR), the self-report counterpart of the Negative Symptom Inventory-Psychosis Risk clinical interview. The NSI-SR is a novel transphasic negative symptoms measure assessing the domains of anhedonia, avolition, and asociality. The NSI-SR and related measures were administered to two samples: 1) undergraduates (n = 335), 2) community participants, including: SZ (n = 32), clinical-high risk for psychosis (CHR, n = 25), and healthy controls matched to SZ (n = 31) and CHR (n = 30). The psychometrically trimmed 11-item NSI-SR showed good internal consistency and a three-factor solution reflecting avolition, asociality, and anhedonia. The NSI-SR demonstrated convergent validity via moderate to large correlations with clinician-rated negative symptoms and related constructs in both samples. Discriminant validity was supported by lower correlations with positive symptoms in both samples; however, correlations with positive symptoms were still significant. These initial psychometric findings suggest that the NSI-SR is a reliable and valid brief questionnaire capable of measuring negative symptoms across phases of psychotic illness.

The positivity offset theory of anhedonia in schizophrenia: evidence for a deficit in daily life using digital phenotyping

BACKGROUND

Negative symptoms of schizophrenia have recently been proposed to result from a decoupling of (intact) hedonic experience and (diminished) approach behavior. The current study challenged this view by exploring the hypothesis that negative symptoms are driven by a specific type of emotional experience abnormality, a reduction in the positivity offset (i.e. the tendency to experience greater levels of positive relative to negative emotion in low-arousal contexts), which limits the production of approach behaviors in neutral environments.

METHODS

Participants included outpatients with SZ (n = 44) and healthy controls (CN: n = 48) who completed one week of active (ecological momentary assessment surveys of emotional experience and symptoms) and passive (geolocation, accelerometry) digital phenotyping. Mathematical modeling approaches from Cacioppo's Evaluative Space Model were used to quantify the positivity offset in daily life. Negative symptoms were assessed via standard clinical ratings, as well as active (EMA surveys) and passive (geolocation, accelerometry) digital phenotyping measures.

RESULTS

Results indicated that the positivity offset was reduced in SZ and associated with more severe anhedonia and avolition measured via clinical interviews and active and passive digital phenotyping.

CONCLUSIONS

These findings suggest that current conceptual models of negative symptoms, which assume hedonic normality, may need to be revised to account for reductions in the positivity offset and its connection to diminished motivated behavior. Findings identify key real-world contexts where negative symptoms could be targeted using psychosocial treatments.

Reduced willingness to expend effort for rewards is associated with risk for conversion and negative symptom severity in youth at clinical high-risk for psychosis

BACKGROUND

Schizophrenia (SZ) is typically preceded by a prodromal (i.e. pre-illness) period characterized by attenuated positive symptoms and declining functional outcome. Negative symptoms are prominent among individuals at clinical high-risk (CHR) for psychosis (i.e. those with prodromal syndromes) and predictive of conversion to illness. Mechanisms underlying negative symptoms are unclear in the CHR population.

METHODS

The current study evaluated whether CHR participants demonstrated deficits in the willingness to expend effort for rewards and whether these impairments are associated with negative symptoms and greater risk for conversion. Participants included 44 CHR participants and 32 healthy controls (CN) who completed the Effort Expenditure for Reward Task (EEfRT).

RESULTS

Compared to CN, CHR participants displayed reduced likelihood of exerting high effort for high probability and magnitude rewards. Among CHR participants, reduced effort expenditure was associated with greater negative symptom severity and greater probability of conversion to a psychotic disorder on a cross-sectional risk calculator.

CONCLUSIONS

Findings suggest that effort-cost computation is a marker of illness liability and a transphasic mechanism underlying negative symptoms in the SZ spectrum.

Emotion regulation and social knowledge in youth at clinical high-risk for psychosis and outpatients with chronic schizophrenia: Associations with functional outcome and negative symptoms

AIM

Previous studies indicate that several aspects of social cognition are associated with poor social and vocational outcome in the chronic phase of psychosis. However, it is less clear whether specific aspects of social cognition are impaired in those at clinical high-risk (CHR) for psychosis and associated with functioning. The current study evaluated two understudied components of social cognition, emotion regulation knowledge and social knowledge, to determine whether CHR and chronic schizophrenia (SZ) samples demonstrated comparable magnitudes of impairment and associations with functioning.

METHODS

Two studies were conducted. Study 1 included n = 98 outpatients with chronic SZ and n = 88 demographically matched healthy controls (CN). Study 2 included 30 CHR and 30 matched CN participants. In both studies, participants completed the emotion management and social management subtests of the Mayer-Salovey-Caruso Emotional Intelligence Test to assess emotion regulation knowledge and social knowledge, respectively. A battery of clinical interviews was also administered, including measures of: role and social functioning, positive symptoms, negative symptoms, disorganization and general symptoms.

RESULTS

Individuals with SZ demonstrated lower emotion management and social management scores than CN participants. CHR demonstrated lower scores in social management than CN but did not display deficits in emotion management. In both studies, reduced social knowledge was associated with worse functioning and negative symptoms.

CONCLUSIONS

Findings indicate that deficits in social knowledge are transphasic across the SZ spectrum, and are associated with clinical functioning. Social knowledge may be a novel treatment target for psychosocial interventions.

Deconstructing emotion regulation in schizophrenia: The nature and consequences of abnormalities in monitoring dynamics

Prior studies implicate abnormalities at the identification, selection, and implementation stages of Gross' extended process model of emotion regulation in schizophrenia. However, it is unclear whether monitoring dynamics (i.e., emotion regulation maintenance, switching, and stopping), another critical component of the model, are also abnormal or what predicts those abnormalities. The current study evaluated switching (i.e., switching to a different emotion regulation strategy because the initial strategy was not effective) and stopping dynamics (i.e., terminating the implementation of an emotion regulation strategy) and their associated mechanisms using 6 days of ecological momentary assessment in 47 outpatients with schizophrenia or schizoaffective disorder (SZ) and 52 healthy controls (CN). Results indicated that individuals with SZ exhibited excessive switching between emotion regulation strategies and delayed stopping compared to CN, self-efficacy moderated group differences in stopping abnormalities, and switching and stopping abnormalities were associated with different patterns of state-level positive and negative symptoms in SZ. Findings may inform psychosocial emotion regulation therapies for SZ that could incorporate elements for monitoring dynamics and associated mechanisms.

Delay discounting in youth at clinical high-risk for psychosis and adults with schizophrenia

BACKGROUND

Schizophrenia (SZ) is typically preceded by a prodromal (i.e. pre-illness) period characterized by attenuated positive symptoms and declining functional outcome. Negative symptoms are prominent among individuals at clinical high-risk (CHR) for psychosis (i.e. those with prodromal syndromes) and highly predictive of conversion to illness. Mechanisms underlying negative symptoms in the CHR population are unclear. Two studies were conducted to evaluate whether abnormalities in a reward processing mechanism thought to be core to negative symptoms in SZ, value representation, also exist in CHR individuals and whether they are associated with negative symptoms transphasically.

METHODS

Study 1 included 33 individuals in the chronic phase of illness who have been diagnosed with schizophrenia or schizoaffective disorder (SZ) and 40 healthy controls (CN). Study 2 included 37 CHR participants and 45 CN. In both studies, participants completed the delay discounting (DD) task as a measure of value representation and the Brief Negative Symptom Scale was rated to measure negative symptoms.

RESULTS

Results indicated that patients with SZ had steeper discounting rates than CN, indicating impairments in value representation. However, CHR participants were unimpaired on the DD task. In both studies, steeper discounting was associated with greater severity of negative symptoms.

CONCLUSIONS

These findings suggest that deficits in value representation are associated with negative symptoms transphasically.

Defeatist performance beliefs in individuals at clinical high-risk for psychosis and outpatients with chronic schizophrenia

AIM

Prior studies indicate that defeatist performance beliefs (DPBs) are elevated in those in the chronic phase of schizophrenia (SZ) and associated with negative symptoms, functional outcome and neurocognitive impairment. However, it is unclear whether these same patterns of results hold in participants at clinical high-risk (CHR) for psychosis.

METHODS

Two studies were conducted to determine whether prior results in SZ could be replicated and extended to CHR. Participants included 184 healthy controls (CN) and 186 outpatients with chronic SZ for Study 1, and 30 CN and 35 CHR in Study 2. In both studies, participants completed the DPB scale and measures of negative symptoms, psychosocial functioning and neurocognition.

RESULTS

Both chronic SZ and CHR participants had elevated DPBs compared to CN (p's < .01). In SZ, higher DPBs were associated with greater negative symptoms (r's = .31-.37, p's < .01), poorer social functioning and impaired social cognition (r = -.40, P < .001). In CHR, greater DPBs were associated with poorer social functioning (r = -.52, P < .05) and impairments in the neurocognitive domains of reasoning (r = -.48, P < .05) and processing speed (r = -.41, P < .05). Models testing whether DPBs mediated links between negative symptoms and functioning, negative symptoms and cognition and cognition and functioning were nonsignificant in SZ and CHR samples.

CONCLUSIONS

Findings generally provide support for the cognitive model of negative symptoms and functioning and suggest that DPBs are an important clinical target across phases of psychotic illness.

Avolition as the core negative symptom in schizophrenia: relevance to pharmacological treatment development

Negative symptoms have long been considered a core component of schizophrenia. Modern conceptualizations of the structure of negative symptoms posit that there are at least two broad dimensions (motivation and pleasure and diminished expression) or perhaps five separable domains (avolition, anhedonia, asociality, blunted affect, alogia). The current review synthesizes a body of emerging research indicating that avolition may have a special place among these dimensions, as it is generally associated with poorer outcomes and may have distinct neurobiological mechanisms. Network analytic findings also indicate that avolition is highly central and interconnected with the other negative symptom domains in schizophrenia, and successfully remediating avolition results in global improvement in the entire constellation of negative symptoms. Avolition may therefore reflect the most critical treatment target within the negative symptom construct. Implications for targeted treatment development and clinical trial design are discussed.

Mathematically Modeling Anhedonia in Schizophrenia: A Stochastic Dynamical Systems Approach

OBJECTIVE

Anhedonia, traditionally defined as a diminished capacity for pleasure, is a core symptom of schizophrenia (SZ). However, modern empirical evidence indicates that hedonic capacity may be intact in SZ and anhedonia may be better conceptualized as an abnormality in the temporal dynamics of emotion.

METHOD

To test this theory, the current study used ecological momentary assessment (EMA) to examine whether abnormalities in one aspect of the temporal dynamics of emotion, sustained reward responsiveness, were associated with anhedonia. Two experiments were conducted in outpatients diagnosed with SZ (n = 28; n = 102) and healthy controls (n = 28; n = 71) who completed EMA reports of emotional experience at multiple time points in the day over the course of several days. Markov chain analyses were applied to the EMA data to evaluate stochastic dynamic changes in emotional states to determine processes underlying failures in sustained reward responsiveness.

RESULTS

In both studies, Markov models indicated that SZ had deficits in the ability to sustain positive emotion over time, which resulted from failures in augmentation (ie, the ability to maintain or increase the intensity of positive emotion from time t to t+1) and diminution (ie, when emotions at time t+1 are opposite in valence from emotions at time t, resulting in a decrease in the intensity of positive emotion over time). Furthermore, in both studies, augmentation deficits were associated with anhedonia.

CONCLUSIONS

These computational findings clarify how abnormalities in the temporal dynamics of emotion contribute to anhedonia.

Prism Adaptation Deficits in Schizophrenia

Recent clinical and neurobehavioral evidence suggests cerebellar dysfunction in schizophrenia (SZ). We used the prism adaptation motor task (PAT) to probe specific cerebellar circuits in the disorder. PAT requires cerebellum-dependent motor adaptation, perceptual remapping, and strategic control. A failure to engage in early corrective processes may indicate impairment within either the cerebellum or regions contributing to strategic components, such as the parietal lobe, while an inability to develop and retain a visuomotor shift with time strongly suggests cerebellar impairment. Thirty-one individuals with SZ and 31 individuals without a history of psychological disorders completed PAT. Subjects reached to a target before, during, and following prism exposure, while their movements were recorded using motion-sensing technology. The SZ group performed worse on conditions consisting of adaptation, post-adaptation, aftereffects, and reorientation, thereby demonstrating a failure to adapt to the same degree as healthy controls. SZ performance remained impaired even with visual feedback and did not differ from controls at baseline, suggesting the observed deficit is specific to adaptation. Results indicate that sensorimotor adaptation is impaired in SZ and implicate disturbances in cerebellar circuits.

Relationship of Metacognition and Insight to Neural Synchronization and Cognitive Function in Early Phase Psychosis

Metacognition is the process of thinking about one's own mental states. It involves a range of faculties that allow an individual to integrate information and form understanding of self and others, and use this understanding to respond to life challenges. Clinical insight is the awareness of one's mental illness, its consequences, and the need for treatment. Persons with psychotic disorders show impaired metacognition and insight, but the neurobiological bases for these impairments are not well characterized. We hypothesized that metacognition and insight may depend on capacity of neural circuits to synchronize at gamma frequencies, as well as the integrity of underlying cognitive processes. In order to test these hypotheses, 17 adults with early phase psychosis were evaluated. Metacognition was assessed with the Metacognition Assessment Scale-Abbreviated, and insight was assessed with the Scale of Unawareness of Illness-Abbreviated. The auditory steady state response (ASSR) to gamma range stimulation (40 Hz) was used as an index of neural synchronization. Cognitive function was assessed using the Brief Assessment of Cognition in Schizophrenia. Increases in ASSR power were associated with poorer metacognition and insight. Higher cognitive performance was associated with higher levels of metacognitive function and insight. These findings suggest that altered neural synchronization and constituent cognitive processes affect both metacognition and insight in early phase psychosis and may offer targets for both pharmacological and psychotherapeutic interventions.

Neurophysiological evidence for emotion regulation impairment in schizophrenia: The role of visual attention and cognitive effort

Prior research indicates that individuals with schizophrenia (SZ) display emotion regulation abnormalities that are critically linked to increased symptom severity and poor functional outcome. However, processes contributing to the aberrant implementation of various strategies are unclear. The current study took a multimodal approach to identifying mechanisms underlying the impaired implementation of 2 strategies: reappraisal and distraction. Participants included 25 individuals with SZ and 25 healthy controls (CN) who completed separate event-related potential and eye-tracking/pupil dilation tasks. On each task, participants were required to either passively view unpleasant or neutral stimuli or reduce negative affect using reappraisal or distraction emotion regulation strategies. The late positive potential (LPP) event related potential component was used as an objective neurophysiological indicator of emotion regulation effectiveness. Eye tracking and pupil dilation were used to determine whether the implementation of reappraisal and distraction were associated with abnormal patterns of visual attention and reduced cognitive effort, respectively. Results indicated that CN could effectively decrease the amplitude of the LPP for both reappraisal and distraction compared with unpleasant passive viewing; however, individuals with SZ showed comparable LPP amplitude among conditions, indicating a failure to effectively implement these strategies. In CN, successful down-regulation of negative affect was associated with different patterns of visual attention across regulation strategies. During reappraisal, there was an increase in fixations to arousing scene regions, whereas distraction was associated with reduced attention to arousing interest areas. In contrast, individuals with SZ made fewer fixations to arousing interest areas during reappraisal and more fixations to arousing interest areas during distraction. Furthermore, pupil dilation results suggested that individuals with SZ failed to exert adequate effort while implementing reappraisal. Collectively, these findings suggest that individuals with SZ are ineffective at implementing reappraisal and distraction; dysfunctional patterns of visual attention and low cognitive effort may contribute to these difficulties. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Long-Term Aberrations To Cerebellar Endocannabinoids Induced By Early-Life Stress

Emerging evidence points to the role of the endocannabinoid system in long-term stress-induced neural remodeling with studies on stress-induced endocannabinoid dysregulation focusing on cerebral changes that are temporally proximal to stressors. Little is known about temporally distal and sex-specific effects, especially in cerebellum, which is vulnerable to early developmental stress and is dense with cannabinoid receptors. Following limited bedding at postnatal days 2-9, adult (postnatal day 70) cerebellar and hippocampal endocannabinoids, related lipids, and mRNA were assessed, and behavioral performance evaluated. Regional and sex-specific effects were present at baseline and following early-life stress. Limited bedding impaired peripherally-measured basal corticosterone in adult males only. In the CNS, early-life stress (1) decreased 2-arachidonoyl glycerol and arachidonic acid in the cerebellar interpositus nucleus in males only; (2) decreased 2-arachidonoyl glycerol in females only in cerebellar Crus I; and (3) increased dorsal hippocampus prostaglandins in males only. Cerebellar interpositus transcriptomics revealed substantial sex effects, with minimal stress effects. Stress did impair novel object recognition in both sexes and social preference in females. Accordingly, the cerebellar endocannabinoid system exhibits robust sex-specific differences, malleable through early-life stress, suggesting the role of endocannabinoids and stress to sexual differentiation of the brain and cerebellar-related dysfunctions.

FRONTAL ALPHA ASYMMETRY IN YOUTH AT CLINICAL HIGH-RISK FOR PSYCHOSIS

PURPOSE OF THE REVIEW

Negative symptoms are highly predictive of whether individuals at clinical high-risk (CHR) develop a psychotic disorder. However, little is known about pathophysiological mechanisms underlying negative symptoms during this period. The current study examined neurophysiological mechanisms underlying negative symptoms in CHR individuals using electroencephalography frontal alpha asymmetry power, a biomarker of approach and avoidance motivation.

RECENT FINDINGS

People with schizophrenia display abnormal patterns of frontal alpha asymmetry indicative of reduced approach motivation. However, It is unknown whether similar abnormalities occur in CHR youth that predict negative symptoms.

SUMMARY

Results indicated that CHR and healthy controls did not differ in frontal alpha asymmetry scores. However, in CHR youth, frontal alpha asymmetry was inversely correlated with the motivation and pleasure dimension of negative symptoms, which was accounted for by mood symptoms. Findings suggest that depression contributes to reduced approach motivation in CHR youth that manifests clinically as negative symptoms.

Relationship of auditory electrophysiological responses to magnetic resonance spectroscopy metabolites in Early Phase Psychosis

Both auditory evoked responses and metabolites measured by magnetic resonance spectroscopy (MRS) are altered in schizophrenia and other psychotic disorders, but the relationship between electrophysiological and metabolic changes are not well characterized. We examined the relation of MRS metabolites to cognitive and electrophysiological measures in individuals during the early phase of psychosis (EPP) and in healthy control subjects. The mismatch negativity (MMN) of the auditory event-related potential to duration deviant tones and the auditory steady response (ASSR) to 40 Hz stimulation were assessed. MRS was used to quantify glutamate+glutamine (Glx), N-Acetylasparate (NAA), creatine (Cre), myo-inositol (Ins) and choline (Cho) at a voxel placed medially in the frontal cortex. MMN amplitude and ASSR power did not differ between groups. The MRS metabolites Glx, Cre and Cho were elevated in the psychosis group. Partial least squares analysis in the patient group indicated that elevated levels of MRS metabolites were associated with reduced MMN amplitude and increased 40 Hz ASSR power. There were no correlations between the neurobiological measures and clinical measures. These data suggest that elevated neurometabolites early in psychosis are accompanied by altered auditory neurotransmission, possibly indicative of a neuroinflammatory or excitotoxic disturbance which disrupts a wide range of metabolic processes in the cortex.

A comprehensive review of psychophysiological applications for ecological momentary assessment in psychiatric populations

Psychophysiological assessment is a core method used in psychopathology research that has led to important insights in relation to the etiology and maintenance of many disorders. However, laboratory psychophysiology has limited ecological validity. This limitation has resulted in the field moving toward ambulatory recordings of psychophysiology paired with ecological momentary assessment (EMA). This review uses the results of a comprehensive review of EMA psychophysiology studies to discuss applications, advantages, limitations, and future use of this methodology, including electrocardiography, blood pressure, electroencephalography, and more. Mobile psychophysiology has several advantages, including ecological validity, temporal precision, and concurrent evaluation of internally and externally generated contexts that influence physiological response. However, it is limited by the difficulty of conducting such studies and reduced experimental control. Future research using EMA psychophysiology should aim to record over longer periods, better integrate with everyday life, determine the utility of ecological momentary interventions based on psychophysiology, create guidelines for standardization, and aim to establish reliability and validity. EMA psychophysiology is a promising direction for the field and provides novel avenues for research and treatment of psychopathology, although methodological shortcomings must be addressed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Postural Sway Abnormalities in Schizotypal Personality Disorder

Motor abnormalities are among the most robust findings in schizophrenia, and increasing evidence suggests they are a core feature of the disorder. Postural sway during balance tasks is a highly sensitive probe of sensorimotor systems including the cerebellum, basal ganglia, and motor cortices. Postural sway deficits are present in schizophrenia as well as groups at high risk for psychosis, suggesting altered postural control may be sensitive to the pathophysiological processes associated with risk and expression of schizophrenia spectrum disorders. This study examined postural sway performance in schizotypal personality disorder (SPD). Individuals with SPD have attenuated psychotic symptoms and share genetic risk with schizophrenia but are usually free from antipsychotic medication and other illness confounds, making SPD useful for assessing candidate biomarkers. We measured postural sway using force plates in 27 individuals with SPD, 27 carefully matched controls, and 27 matched patients with schizophrenia. It was predicted that postural sway in the SPD group would fall intermediate to schizophrenia and controls. In all conditions (eyes open and closed, with feet together or apart), the SPD group swayed significantly more than the controls, as measured by path length and sway area. Moreover, the magnitude of the sway deficit was comparable in the SPD and schizophrenia groups. These findings suggest that postural sway measures may represent a sensorimotor biomarker of schizophrenia spectrum disorders.

Impaired Effective Connectivity During a Cerebellar-Mediated Sensorimotor Synchronization Task in Schizophrenia

Prominent conceptual models characterize schizophrenia as a dysconnectivity syndrome, with recent research focusing on the contributions of the cerebellum in this framework. The present study examined the role of the cerebellum and its effective connectivity to the cerebrum during sensorimotor synchronization in schizophrenia. Specifically, the role of the cerebellum in temporally coordinating cerebral motor activity was examined through path analysis. Thirty-one individuals diagnosed with schizophrenia and 40 healthy controls completed a finger-tapping fMRI task including tone-paced synchronization and self-paced continuation tapping at a 500 ms intertap interval (ITI). Behavioral data revealed shorter and more variable ITIs during self-paced continuation, greater clock (vs motor) variance, and greater force of tapping in the schizophrenia group. In a whole-brain analysis, groups showed robust activation of the cerebellum during self-paced continuation but not during tone-paced synchronization. However, effective connectivity analysis revealed decreased connectivity in individuals with schizophrenia between the cerebellum and primary motor cortex but increased connectivity between cerebellum and thalamus during self-paced continuation compared with healthy controls. These findings in schizophrenia indicate diminished temporal coordination of cerebral motor activity by cerebellum during the continuation tapping portion of sensorimotor synchronization. Taken together with the behavioral finding of greater temporal variability in schizophrenia, these effective connectivity results are consistent with structural and temporal models of dysconnectivity in the disorder.

Reduced electroencephalogram responses to standard and target auditory stimuli in bipolar disorder and the impact of psychotic features: Analysis of event-related potentials, spectral power, and inter-trial coherence

BACKGROUND

Bipolar disorder (BD) is associated with reductions in the P3b event-related potential (ERP) response to target auditory stimuli, which suggests deficits in context updating. Previous studies have typically examined these responses in the temporal domain, which may not capture alterations in specific frequencies of phase-locked or induced electrophysiological activity. Therefore, the present study examined early and late ERPs in temporal and frequency domains in a bipolar sample with and without current psychotic features.

METHODS

The electroencephalogram (EEG) was recorded during an auditory oddball task. Seventy-five BD patients and 98 healthy controls (HCs) discriminated between standard and target tones. N1 ERPs to standards and P3b ERPs to targets were analyzed in the temporal domain. Event-related spectral perturbation (ERSP) and inter-trial coherence (ITC) were analyzed in the frequency domain.

RESULTS

The early N1 response to standard tones was not significantly different between the total HC and BD samples irrespective of psychotic features. However, N1 amplitude was reduced in BD patients with psychotic features (BDP) compared to HCs and BD patients without psychotic features. P3b was reduced in BD patients versus HCs, with the BDP sample having the most reduced amplitude. In the time-frequency analysis, delta and theta ERSP and ITC were reduced across the time window for both standard and target stimuli in BD patients compared to HCs, but did not differ in the psychotic features analysis.

CONCLUSIONS

The results provide neural evidence that BD is associated with disrupted sensory, attentional, and cognitive processing of auditory stimuli, which may be worsened with the presence of psychotic features.