Impaired Fixation-Related Theta Modulation Predicts Reduced Visual Span and Guided Search Deficits in Schizophrenia.

During normal visual behavior, individuals scan the environment through a series of saccades and fixations. At each fixation, the phase of ongoing rhythmic neural oscillations is reset, thereby increasing efficiency of subsequent visual processing. This phase-reset is reflected in the generation of a fixation-related potential (FRP). Here, we evaluate the integrity of theta phase-reset/FRP generation and Guided Visual Search task in schizophrenia. Subjects performed serial and parallel versions of the task. An initial study (15 healthy controls (HC)/15 schizophrenia patients (SCZ)) investigated behavioral performance parametrically across stimulus features and set-sizes. A subsequent study (25-HC/25-SCZ) evaluated integrity of search-related FRP generation relative to search performance and evaluated visual span size as an index of parafoveal processing. Search times were significantly increased for patients versus controls across all conditions. Furthermore, significantly, deficits were observed for fixation-related theta phase-reset across conditions, that fully predicted impaired reduced visual span and search performance and correlated with impaired visual components of neurocognitive processing. By contrast, overall search strategy was similar between groups. Deficits in theta phase-reset mechanisms are increasingly documented across sensory modalities in schizophrenia. Here, we demonstrate that deficits in fixation-related theta phase-reset during naturalistic visual processing underlie impaired efficiency of early visual function in schizophrenia.

Exploring the Relationship of Transdiagnostic Mood and Psychosis Symptom Domains with Motor Dysfunction.

BACKGROUND: A number of motor abnormalities have been reported in psychotic disorders, including dyskinesia and psychomotor slowing. There is also evidence for many of the same motor abnormalities in biological first-degree relatives and accruing evidence for motor abnormalities in bipolar disorder. In addition to motor dysfunction, there are also shared symptom domains amongst these populations. OBJECTIVES: We explored the associations of (1) current and lifetime psychosis and mood symptom domains and (2) domains of psychosis proneness with various domains of motor function in a transdiagnostic sample (n = 149). METHOD: Individuals with schizophrenia, schizoaffective disorder, or bipolar disorder, biological first-degree relatives of individuals with a psychotic disorder, and controls completed measures of psychomotor speed and movement fluidity, and neural activity related to motor preparation (stimulus-locked lateralized readiness potential, S-LRP) and execution (response-locked LRP) was assessed using EEG. All participants completed the Brief Psychiatric Rating Scale; patients were additionally assessed for lifetime psychosis and mood episode symptoms, and relatives and controls completed the Chapman psychosis proneness scales. RESULTS: Multiple regression revealed levels of current negative symptoms and mania were significantly positively associated with psychomotor slowing even after accounting for current antipsychotic medication dosage and duration of illness. S-LRP onset latency was significantly positively associated with magical ideation. CONCLUSION: Domains of motor function are associated with various mood and psychosis symptom domains in a transdiagnostic sample, which may provide insight into brain abnormalities relevant to the expression of symptoms across disorders.

Abnormal neural functions associated with motor inhibition deficits in schizophrenia and bipolar disorder.

Deficits in response inhibition have been observed in schizophrenia and bipolar disorder; however, the neural origins of the abnormalities and their relevance to genetic liability for psychosis are unknown. We used a stop-signal task to examine motor inhibition and associated neural processes in schizophrenia patients (n = 57), bipolar disorder patients (n = 21), first-degree biological relatives of patients with schizophrenia (n = 34), and healthy controls (n = 56). Schizophrenia patients demonstrated motor control deficits reflected in longer stop-signal reaction times and elongated reaction times. With the possibility of needing to inhibit a button press, both schizophrenia and bipolar disorder patients showed diminished reductions of the P300 brain response and only the healthy controls demonstrated adjustments in response execution time, as measured by response-locked lateralized readiness potentials. Schizotypal traits in the biological relatives were associated with less P300 modulation consistent with the motor-related anomalies being associated with subtle schizophrenia-spectrum symptomatology in family members. The two patient groups had elongated response selection processes as manifest in the delayed onset of the stimulus-locked lateralized readiness potential. The bipolar disorder group was unique in showing significantly diminished neural responses to the stop-signal to inhibit a response. Antipsychotic medication dosage was related to worse motor inhibition, thus motor inhibition deficits in schizophrenia may be partially explained by the effect of pharmacological agents. Failed modulation of brain processes in relation to response inhibition probability and the lengthening of motor response selection appear to be transdiagnostic abnormalities spanning schizophrenia and bipolar disorder.

Neurophysiological correlates of cognitive control and approach motivation abnormalities in adolescent bipolar disorders.

Hypersensitivity to reward-relevant stimuli is theorized to be a core etiological factor in bipolar disorders (BDs). However, little is known about the role of cognitive control dysregulation within reward contexts in BDs, particularly during adolescence. Using electroencephalography (EEG), we explored alterations in cognitive control processes and approach motivation in 99 adolescents with (n=53) and without (n=46) BD during reward striving (target anticipation) and reward attainment (feedback) phases of a monetary incentive delay (MID) task. Time-frequency analysis yielded frontal theta and frontal alpha asymmetry as indices of cognitive control and approach motivation, respectively. Multilevel mixed models examined group differences, as well as age, sex, and other effects, on frontal theta and frontal alpha asymmetry during both phases of the task and on performance accuracy and reaction times. Healthy adolescent girls exhibited lower frontal theta than both adolescent girls with BD and adolescent boys with and without BD during reward anticipation and feedback. Across groups, adolescent boys displayed greater relative left frontal alpha activity than adolescent girls during reward anticipation and feedback. Behaviorally, adolescents with BD exhibited faster responses on both positively and negatively motivated trials versus neutral trials, whereas healthy adolescents had faster responses only on positively motivated trials; adolescents with BD were less accurate in responding to neutral trials compared to healthy controls. These findings shed light on normative and BD-specific involvement of approach motivation and cognitive control during different stages of reward processing in adolescence and, further, provide evidence of adolescent sex differences in these processes.

Neural abnormalities of reward processing in adolescents with bipolar disorders: An ERP study.

Adolescent onset is common in bipolar disorders (BDs) and is associated with a worse illness course in adulthood. A model of BDs suggests that a dysregulated behavioral approach system (BAS), a neural system that mobilizes reward-seeking behavior, is at the root of BDs. Normative adolescence is often accompanied by dynamic changes to neural structures underlying the BAS and related cognitive processes. It is possible that adolescent-onset BDs is associated with abnormal BAS neurodevelopment. Consistently, the present study is the first to compare specific BAS-relevant anticipatory and consummatory reward processes as indexed by event-related potentials (ERPs) in adolescents with BDs and typically developing peers. Using a sample of 43 adolescents with BDs and 56 without psychopathology, we analyzed N1 and P3 responses to anticipatory cues and feedback-related negativity (FRN) and P3 responses to feedback stimuli during a monetary incentive delay (MID) task. Hierarchical linear models examined relationships between ERP amplitudes and diagnostic group, MID condition, sex, and age. During anticipation phase, adolescent boys with BDs exhibited significantly larger N1 amplitudes in loss than even or gain trials. During feedback phase, compared to their healthy peers, adolescents with BDs had smaller FRN amplitudes across all conditions. Additional effects involving age, sex and trial type were observed. The findings indicate subtle, non-ubiquitous BAS-relevant neural abnormalities involving early attentional processes during reward anticipation and reward learning following feedback in adolescents with BDs. Adolescents with BDs did not show overall hypersensitive neural responses to monetary reward anticipation or feedback observed in adults with BDs.

Transcendental meditation for veterans with post-traumatic stress disorder.

OBJECTIVE: Transcendental Meditation (TM) is a mental technique using a mantra to facilitate meditation. TM has a potential for treating symptoms of posttraumatic stress disorder (PTSD), but its clinical efficacy remains to be clarified. This pilot study evaluated the acceptability, preliminary effectiveness, and neurophysiology of TM for veterans with PTSD. METHOD: Twenty-nine veterans (20.7% female) were recruited from a major medical center and enrolled in the study. TM instruction was provided by certified TM teachers from the Maharishi Foundation and consisted of 8 weeks of individual and group-based meditation instruction and practice. Outcomes were assessed at baseline, during treatment, posttreatment, and at 2-month follow-up, and included clinical interviews, self-report questionnaires, and electroencephalography (EEG) recorded during resting and meditation states. RESULTS: From baseline to posttreatment, participants reported reductions in PTSD symptoms, experiential avoidance, and depressive and somatic symptoms, as well as increases on measures of mindfulness and quality of life. Gains were either maintained or continued to improve through the 2-month follow-up. Compared to baseline, EEG spectral power increased in low-frequency bands (1-7 Hz) at posttreatment and follow-up and only during meditation states suggesting TM-specific changes in brain state associated with the intervention. CONCLUSIONS: TM appears to be an acceptable and effective treatment for veterans with PTSD that warrants further study regarding specific outcomes and beneficial changes in brain function. (PsycINFO Database Record (c) 2018 APA, all rights reserved).