Neural Substrates of Auditory Emotion Recognition Deficits in Schizophrenia

Computational Synaptic Modeling of Pitch and Duration Mismatch Negativity in First-Episode Psychosis Reveals Selective Dysfunction of the N-Methyl-D-Aspartate Receptor

Mismatch negativity (MMN) to pitch (pMMN) and to duration (dMMN) deviant stimuli is significantly more attenuated in long-term psychotic illness compared to first-episode psychosis (FEP). It was recently shown that source-modeling of magnetically recorded MMN increases the detection of left auditory cortex MMN deficits in FEP, and that computational circuit modeling of electrically recorded MMN also reveals left-hemisphere auditory cortex abnormalities. Computational modeling using dynamic causal modeling (DCM) can also be used to infer synaptic activity from EEG-based scalp recordings. We measured pMMN and dMMN with EEG from 26 FEP and 26 matched healthy controls (HCs) and used a DCM conductance-based neural mass model including α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid, N-methyl-D-Aspartate (NMDA), and Gamma-aminobutyric acid receptors to identify any changes in effective connectivity and receptor rate constants in FEP. We modeled MMN sources in bilateral A1, superior temporal gyrus, and inferior frontal gyrus (IFG). No model parameters distinguished groups for pMMN. For dMMN, reduced NMDA receptor activity in right IFG in FEP was detected. This finding is in line with literature of prefrontal NMDA receptor hypofunction in chronic schizophrenia and suggests impaired NMDA-induced synaptic plasticity may be present at psychosis onset where scalp dMMN is only moderately reduced. To the best of our knowledge, this is the first report of impaired NMDA receptor activity in FEP found through computational modeling of dMMN and shows the potential of DCM to non-invasively reveal synaptic-level abnormalities that underly subtle functional auditory processing deficits in early psychosis.

Speech Mismatch Negativity (MMN) in Schizophrenia with Auditory Verbal Hallucinations

Auditory verbal hallucinations (AVH) are experienced by many individuals with schizophrenia (SZ), a neurodevelopmental disease that encumbers the quality of life and psychosocial outcome of those afflicted by it. While many hypotheses attempt to better define the etiology of AVHs in SZ, their neural profile and its moderation by current neuroleptics remains limited. The Mismatch Negativity (MMN) is an event related potential (ERP) measured from electroencephalographic (EEG) activity during the presentation of a deviance detection auditory paradigm. The neural regions and activity underlying the generation of the MMN include the primary auditory cortex and the prefrontal cortex which are regions also found to be activated during the experience of AVHs. Decreased MMN amplitudes have been robustly noted in SZ patients during the presentation of MMN tasks using auditory tones. However, the MMN generation to speech stimuli has not been extensively examined in SZ nor in relation to AVHs. The primary objective of this study was to examine the MMN to five speech-based deviants in SZ patients and healthy controls. Second, we assessed MMN features with AVH characteristics in 19 SZ patients and 21 HC. While AVH features did not correlate with measures of MMN, we found decreased MMN amplitudes to speech-based frequency and vowel change deviants in SZ patients compared to HC potentially reflecting deficiencies in basic speech processing mechanisms.

Entrainment of neural oscillations during language processing in Early-Stage schizophrenia

BACKGROUND

Impairments in language processing in schizophrenia (ScZ) are a central aspect of the disorder but the underlying pathophysiology mechanisms are unclear. In the current study, we tested the hypothesis that neural oscillations are impaired during speech tracking in early-stage ScZ and in participants at clinical high-risk for psychosis (CHR-P).

METHOD

Magnetoencephalography (MEG) was used in combination with source reconstructed time-series to examine delta and theta-band entrainment during continuous speech. Participants were presented with a 5-minute audio recording during which they either attened to the story or word level. MEG-data were obtained from n = 22 CHR-P participants, n = 23 early-stage ScZ-patients, and n = 44 healthy controls (HC). Data were analysed with a Mutual Information (MI) approach to compute statistical dependence between the MEG and auditory signal, thus estimating individual speech-tracking ability. MEG-activity was reconstructed in a language network (bilateral inferior frontal cortex [F3T; Broca's], superior temporal areas [STS3, STS4; Wernicke's areas], and primary auditory cortex [bilateral HES; Heschl's gyrus]). MEG-data were correlated with clinical symptoms.

RESULTS

Theta-band entrainment in left Heschl's gyrus, averaged across groups, was significantly lower in the STORY compared to WORD condition (p = 0.022), and averaged over conditions, significantly lower in CHR-Ps (p = 0.045), but intact in early ScZ patients (p = 0.303), compared to controls. Correlation analyses between MEG data and symptom indicated that lower theta-band tracking in CHR-Ps was linked to the severity of perceptual abnormalities (p = 0.018).

CONCLUSION

Our results show that CHR-P participants involve impairments in theta-band entrainment during speech tracking in left primary auditory cortex while higher-order speech processing areas were intact. Moreover, the severity of aberrant perceptual experiences in CHR-P participants correlated with deficits in theta-band entrainment. Together, these findings highlight the possibility that neural oscillations during language processing could reveal fundamental abnormalities in speech processing which may constitute candidate biomarkers for early detection and diagnosis of ScZ.

The Sound of Emotional Prosody: Nearly 3 Decades of Research and Future Directions

Emotional voices attract considerable attention. A search on any browser using "emotional prosody" as a key phrase leads to more than a million entries. Such interest is evident in the scientific literature as well; readers are reminded in the introductory paragraphs of countless articles of the great importance of prosody and that listeners easily infer the emotional state of speakers through acoustic information. However, despite decades of research on this topic and important achievements, the mapping between acoustics and emotional states is still unclear. In this article, we chart the rich literature on emotional prosody for both newcomers to the field and researchers seeking updates. We also summarize problems revealed by a sample of the literature of the last decades and propose concrete research directions for addressing them, ultimately to satisfy the need for more mechanistic knowledge of emotional prosody.

The Less Things Change, the More They Remain the Same: Impaired Neural Plasticity as a Critical Target for Drug Development in Neuropsychiatry

Neuropsychiatric disability is related to reduced ability to change in response to clinical interventions, e.g., plasticity. Study of biomarkers and interventional strategies for plasticity, however, are sparse. In this chapter, we focus on the serial frequency discrimination task (SFDT), which is sensitive to impairments in early auditory processing (EAP) and auditory learning and has been most thoroughly studied in dyslexia and schizophrenia. In the SFDT, participants are presented with repeated paired tones ("reference" and "test") and indicate which tone is higher in pitch. Plasticity during the SFDT is critically dependent upon interactions between prefrontal "cognitive control" regions, and lower-level perceptual and motor regions that may be detected using both fMRI and time-frequency event-related potential (TF-ERP) approaches. Additionally, interactions between the cortex and striatum give insights into glutamate/dopamine interaction mechanisms. The SFDT task has been utilized in the development of N-methyl-D-aspartate receptor (NMDAR) targeted medications, which significantly modulate sensory and premotor neurophysiological activity. Deficits in pitch processing play a critical role in impaired neuro- and social cognitive function in schizophrenia and may contribute to similar impairments in dyslexia. Thus, the SFDT may be ideal for development of treatments aimed at amelioration of neuro- and social cognitive deficits across neuropsychiatric disorders.

Mismatch Negativity (MMN) as a Pharmacodynamic/Response Biomarker for NMDA Receptor and Excitatory/Inhibitory Imbalance-Targeted Treatments in Schizophrenia

Schizophrenia is a major mental disorder that affects approximately 0.5% of the population worldwide. Persistent negative symptoms and cognitive impairments associated with schizophrenia (CIAS) are key features of the disorder and primary predictors of long-term disability. At the neurochemical level, both CIAS and negative symptoms are potentially attributable to dysfunction or dysregulation of N-methyl-D-aspartate receptor (NMDAR)-mediated neurotransmission within cortical and subcortical brain regions. At present, there are no approved treatments for either CIAS or persistent negative symptoms. Development of novel treatments, moreover, is limited by the lack of biomarkers that can be used translationally across preclinical and early-stage clinical investigation. The present chapter describes the use of mismatch negativity (MMN) as a pharmacodynamic/response (PD/R) biomarker for early-stage clinical investigation of NMDAR targeted therapies for schizophrenia. MMN indexes dysfunction of early auditory processing (EAP) in schizophrenia. In humans, deficits in MMN generation contribute hierarchically to impaired cognition and functional outcome. Across humans, rodents, and primates, MMN has been linked to impaired NMDAR function and resultant disturbances in excitatory/inhibitory (E/I) balance involving interactions between glutamatergic (excitatory) pyramidal and GABAeric (inhibitory) local circuit neurons. In early-stage clinical trials, MMN has shown sensitivity to the acute effects of novel pharmacological treatments. These findings support use of MMN as a pharmacodynamic/response biomarker to support preclinical drug discovery and early-stage proof-of-mechanisms studies in schizophrenia and other related neuropsychiatric disorders.

Assessing Trial-to-Trial Variability in Auditory ERPs in Autism and Schizophrenia

Sensory abnormalities are characteristic of autism and schizophrenia. In autism, greater trial-to-trial variability (TTV) in sensory neural responses suggest that the system is more unstable. However, these findings have only been identified in the amplitude and not in the timing of neural responses, and have not been fully explored in schizophrenia. TTV in event-related potential amplitudes and inter-trial coherence (ITC) were assessed in the auditory mismatch negativity (MMN) in autism, schizophrenia, and controls. MMN was largest in autism and smallest in schizophrenia, and TTV was greater in autism and schizophrenia compared to controls. There were no differences in ITC. Greater TTV appears to be characteristic of both autism and schizophrenia, implicating several neural mechanisms that could underlie sensory instability.

Longitudinal Investigation of Auditory Dynamic Range Deficits in Early Psychosis and its Relationship to Negative Symptoms

BACKGROUND AND HYPOTHESIS

Despite accounting for significant disease morbidity in schizophrenia, the neuropathological basis of negative symptoms remains poorly understood and options for treatment limited. Our recent study identified robust associations between diminished auditory cortex (AC) dynamic range and social functioning impairments and negative symptoms in first episode psychosis (FESz). The current investigation examined the progression of these relationships 4-8 months from baseline testing.

STUDY DESIGN

Twenty-six FESz and 38 healthy controls (HC) were tested at baseline and follow-up. Magnetoencephalography (MEG) was recorded during binaural presentation of tones (75, 80, and 85 dB). Assessments included the MATRICS cognitive consensus battery (MCCB) and Global Functioning: Role and Social scales (GFR/GFS) and the Positive and Negative Syndrome Scale.

STUDY RESULTS

Overall, FESz exhibited a blunted response to increasing tone intensity relative to HC. While this deficit did not change over time at the group level, recovery of right hemisphere AC dynamic range (85-75 dB response) among FESz individuals was associated with reductions in negative symptoms (ρ = -0.50). Diminished dynamic range was also associated with impaired GFS (ρ = 0.65), GFR (ρ = 0.51), and MCCB (ρ = 0.49) at baseline and increased negative symptoms at baseline (ρ = -0.53) and follow-up (ρ = -0.51).

CONCLUSION

Despite persistent dynamic range impairment in FESz as a group, individual recovery of this AC response property was associated with significant reduction in negative symptoms. Identification of a functional neural deficit that tracts progression of negative symptoms during a critical period for disease modification is essential to the management of these devastating and historically treatment refractory symptoms.

Build a bridge between ECG and EEG signals for atrial fibrillation diagnosis using AI methods

Atrial fibrillation (AF) is a very common type of cardiac arrhythmia. The main characteristic of AF is an abnormally rapid and disordered atrial rhythm causing an atrial dysfunction, which can be visualized on an electrocardiograph (ECG) and distinguished by irregular fluctuations. Despite continuous and considerable efforts to analyze the pathophysiology of AF, it is challenging to determine the underlying pathogenesis of the disease in individual patients. This study aims to build a bridge between ECG and electroencephalogram (EEG) signals to probe the strong influence between human brain activity and AF by AI methods. We first found that the one-second data fragment shows the most excellent performance in our time window configuration. Secondly, in our proposed measurement, most cortical potentials were partly associated with AF. Thirdly, we found that only a few channels of data were sufficient for analysis. Finally, our experiment shows δ wave has the best performance compared to other wave bands. By AI methods, the paper contributes to concluding that δ wave band of EEG is the most associated brain wave type with AF. By EEG signals from typical regions, the central region, parietal and Occipital might be the most associated encephalic regions with AF. The clinical trial registration number for our study is ChiCTR2300068625.

Vocal emotion perception in schizophrenia and its diagnostic significance

BACKGROUND

Cognitive and emotional impairment are among the core features of schizophrenia; assessment of vocal emotion recognition may facilitate the detection of schizophrenia. We explored the differences between cognitive and social aspects of emotion using vocal emotion recognition and detailed clinical characterization.

METHODS

Clinical symptoms and social and cognitive functioning were assessed by trained clinical psychiatrists. A vocal emotion perception test, including an assessment of emotion recognition and emotional intensity, was conducted. One-hundred-six patients with schizophrenia (SCZ) and 230 healthy controls (HCs) were recruited.

RESULTS

Considering emotion recognition, scores for all emotion categories were significantly lower in SCZ compared to HC. Considering emotional intensity, scores for anger, calmness, sadness, and surprise were significantly lower in the SCZs. Vocal recognition patterns showed a trend of unification and simplification in SCZs. A direct correlation was confirmed between vocal recognition impairment and cognition. In diagnostic tests, only the total score of vocal emotion recognition was a reliable index for the presence of schizophrenia.

CONCLUSIONS

This study shows that patients with schizophrenia are characterized by impaired vocal emotion perception. Furthermore, explicit and implicit vocal emotion perception processing in individuals with schizophrenia are viewed as distinct entities. This study provides a voice recognition tool to facilitate and improve the diagnosis of schizophrenia.

Dose-Dependent Augmentation of Neuroplasticity-Based Auditory Learning in Schizophrenia: A Double-Blind, Placebo-Controlled, Randomized, Target Engagement Clinical Trial of the NMDA Glutamate Receptor Agonist d-serine

BACKGROUND

Patients with schizophrenia show reduced NMDA glutamate receptor-dependent auditory plasticity, which is rate limiting for auditory cognitive remediation (AudRem). We evaluate the utility of behavioral and neurophysiological pharmacodynamic target engagement biomarkers, using a d-serine+AudRem combination.

METHODS

Forty-five participants with schizophrenia or schizoaffective disorder were randomized to 3 once-weekly AudRem visits + double-blind d-serine (80, 100, or 120 mg/kg) or placebo in 3 dose cohorts of 12 d-serine and 3 placebo-treated participants each. In AudRem, participants indicated which paired tone was higher in pitch. The primary outcome was plasticity improvement, operationalized as change in pitch threshold between AudRem tones [(test tone Hz - reference tone Hz)/reference tone Hz] between the initial plateau pitch threshold (mean of trials 20-30 of treatment visit 1) to pitch threshold at the end of visit(s). Target engagement was assessed by electroencephalography outcomes, including mismatch negativity (pitch primary).

RESULTS

There was a significant overall treatment effect for plasticity improvement (p = .014). Plasticity improvement was largest within the 80 and 100 mg/kg groups (p < .001, d > 0.67), while 120 mg/kg and placebo-treated participants showed nonsignificant within-group changes. Plasticity improvement was seen after a single treatment and was sustained on subsequent treatments. Target engagement was demonstrated by significantly larger mismatch negativity (p = .049, d = 1.0) for the 100 mg/kg dose versus placebo.

CONCLUSIONS

Our results demonstrate sufficient proof of principle for continued development of both the d-serine+AudRem combination and our target engagement methodology. The ultimate utility is dependent on the results of an ongoing larger, longer study of the combination for clinically relevant outcomes.

Negative-emotion-induced reduction in speech-in-noise recognition is associated with source-monitoring deficits and psychiatric symptoms in mandarin-speaking patients with schizophrenia

BACKGROUND

Patients with schizophrenia (SCH) have deficits in source monitoring (SM), speech-in-noise recognition (SR), and auditory prosody recognition. This study aimed to test the covariation between SM and SR alteration induced by negative prosodies and their association with psychiatric symptoms in SCH.

METHODS

Fifty-four SCH patients and 59 healthy controls (HCs) underwent a speech SM task, an SR task, and the assessment of positive and negative syndrome scale (PANSS). We used the multivariate analyses of partial least squares (PLS) regression to explore the associations among SM (external/internal/new attribution error [AE] and response bias [RB]), SR alteration/release induced by four negative-emotion (sad, angry, fear, and disgust) prosodies of target speech, and psychiatric symptoms.

RESULTS

In SCH, but not HCs, a profile (linear combination) of SM (especially the external-source RB) was positively associated with a profile of SR reductions (induced especially by the angry prosody). Moreover, two SR reduction profiles (especially in the anger and sadness conditions) were related to two profiles of psychiatric symptoms (negative symptoms, lack of insight, and emotional disturbances). The two PLS components explained 50.4% of the total variances of the release-symptom association.

CONCLUSION

Compared to HCs, SCH is more likely to perceive the external-source speech as internal/new source speech. The SM-related SR reduction induced by the angry prosody was mainly associated with negative symptoms. These findings help understand the psychopathology of SCH and may provide a potential direction to improve negative symptoms via minimizing emotional SR reduction in schizophrenia.

Cognition, prior aggression, and psychopathic traits in relation to impaired multimodal emotion recognition in psychotic spectrum disorders

Background

Psychopathic traits have been associated with impaired emotion recognition in criminal, clinical and community samples. A recent study however, suggested that cognitive impairment reduced the relationship between psychopathy and emotion recognition. We therefore investigated if reasoning ability and psychomotor speed were impacting emotion recognition in individuals with psychotic spectrum disorders (PSD) with and without a history of aggression, as well as in healthy individuals, more than self-rated psychopathy ratings on the Triarchic Psychopathy Measure (TriPM).

Methods

Eighty individuals with PSD (schizophrenia, schizoaffective disorder, delusional disorder, other psychoses, psychotic bipolar disorder) and documented history of aggression (PSD+Agg) were compared with 54 individuals with PSD without prior aggression (PSD-Agg) and with 86 healthy individuals on the Emotion Recognition Assessment in Multiple Modalities (ERAM test). Individuals were psychiatrically stable and in remission from possible substance use disorders. Scaled scores on matrix reasoning, averages of dominant hand psychomotor speed and self-rated TriPM scores were obtained.

Results

Associations existed between low reasoning ability, low psychomotor speed, patient status and prior aggression with total accuracy on the ERAM test. PSD groups performed worse than the healthy group. Whole group correlations between total and subscale scores of TriPM to ERAM were found, but no associations with TriPM scores within each group or in general linear models when accounting for reasoning ability, psychomotor speed, understanding of emotion words and prior aggression.

Conclusion

Self-rated psychopathy was not independently linked to emotion recognition in PSD groups when considering prior aggression, patient status, reasoning ability, psychomotor speed and emotion word understanding.

Augmentation of learning in schizophrenia by D-serine is related to auditory and frontally-generated biomarkers: A randomized, double-blind, placebo-controlled study

Auditory cognition is impaired in schizophrenia, and typically engages a complex, distributed, hierarchical network, including both auditory and frontal input. We recently demonstrated proof of principle for the target engagement of an N-methyl-D-aspartate-type glutamate receptor (NMDAR) agonist + auditory targeted remediation (d-serine+AudRem) combination, showing significant improvement in auditory-learning induced plasticity and mismatch negativity. In this secondary analysis, we report on frontal EEG outcomes, assessing for both generalized effects and the mechanism of auditory plasticity. 21 schizophrenia or schizoaffective disorder participants were randomized to three 1x weekly AudRem + double-blind d-serine (100 mg/kg) visits. In AudRem, participants indicated which paired tone was higher in pitch. The focus of this secondary analysis was a frontally (premotor) mediated EEG outcome- event-related desynchronization in the b band (b-ERD), which was shown to be sensitive to AudRem in previous studies. d-Serine+AudRem led to significant improvement in b-ERD power across the retention and motor preparation intervals (F 1,18 =6.0, p=0.025) vs. AudRem alone. b-ERD was significantly related to baseline cognition, but not auditory-learning induced plasticity. The principal finding of this prespecified secondary analysis are that in addition to improving auditory based biomarkers, the d-serine+AudRem combination led to significant improvement in biomarkers thought to represent frontally mediated dysfunction, suggesting potential generalization of effects. Changes in auditory-learning induced plasticity were independent of these frontally mediated biomarkers. Ongoing work will assess whether d-serine+AudRem is sufficient to remediate cognition or whether targeting frontal NMDAR deficits with higher-level remediation may also be required. Trial Registration: NCT03711500.

Diminished Auditory Cortex Dynamic Range and its Clinical Correlates in First Episode Psychosis

BACKGROUND AND HYPOTHESIS

There is growing appreciation for the contribution of sensory disruptions to disease morbidity in psychosis. The present study examined auditory cortex (AC) dynamic range: the scaling of neurophysiological responses to stimulus intensity, among individuals with a schizophrenia spectrum illness (FESz) and its relationship to clinical outcomes at disease onset.

STUDY DESIGN

Magnetoencephalography (MEG) was recorded from 35 FESz and 40 healthy controls (HC) during binaural presentation of tones at three intensities (75 dB, 80 dB, and 85 dB). MRIs were obtained to enhance cortical localization of MEG sensor-level activity. All participants completed the MATRICS cognitive battery (MCCB) and Global Functioning: Role and Social scales (GFR/GFS). Patients were administered the Positive and Negative Syndrome Scale (PANSS).

STUDY RESULTS

FESz exhibited reduced AC response relative to HC. Enhancement of AC activity to tones of increasing intensity was blunted in FESz relative to HC. Reduced dynamic range (85-75 dB AC response) was associated with lower GFS (r = .58) and GFR (r = .45) scores, worse MCCB performance (r = .45), and increased PANSS Negative symptom subscale scores (r = -.55) among FESz, relationships not observed with AC responses to individual tones.

CONCLUSION

Beyond an impaired AC response to pure tones, FESz exhibit reduced dynamic range relative to HC. This impairment was correlated with markers of disease morbidity including poorer community functioning as well as cognitive and negative symptoms. The relationship with impaired social functioning may reflect the role of AC dynamic range in decoding the emotional content of language and highlights its importance to future therapeutic sensory remediation protocols.

Early auditory processing dysfunction in schizophrenia: Mechanisms and implications

Schizophrenia is a major mental disorder that affects approximately 1% of the population worldwide. Cognitive deficits are a key feature of the disorder and a primary cause of long-term disability. Over the past decades, significant literature has accumulated demonstrating impairments in early auditory perceptual processes in schizophrenia. In this review, we first describe early auditory dysfunction in schizophrenia from both a behavioral and neurophysiological perspective and examine their interrelationship with both higher order cognitive constructs and social cognitive processes. Then, we provide insights into underlying pathological processes, especially in relationship to glutamatergic and N-methyl-D-aspartate receptor (NMDAR) dysfunction models. Finally, we discuss the utility of early auditory measures as both treatment targets for precision intervention and as translational biomarkers for etiological investigation. Altogether, this review points out the crucial role of early auditory deficits in the pathophysiology of schizophrenia, in addition to major implications for early intervention and auditory-targeted approaches.

Basic auditory processing and its relationship with symptoms in patients with schizophrenia: A systematic review

Processing of basic auditory features, one of the earliest stages of auditory perception, has been the focus of considerable investigations in schizophrenia. Although numerous studies have shown abnormalities in pitch perception in schizophrenia, other basic auditory features such as intensity, duration, and sound localization have been less explored. Additionally, the relationship between basic auditory features and symptom severity shows inconsistent results, preventing concrete conclusions. Our aim was to present a comprehensive overview of basic auditory processing in schizophrenia and its relationship with symptoms. We conducted a systematic review according to the PRISMA guidelines. PubMed, Embase, and PsycINFO databases were searched for studies exploring auditory perception in schizophrenia compared to controls, with at least one behavioral task investigating basic auditory processing using pure tones. Forty-one studies were included. The majority investigated pitch processing while the others investigated intensity, duration and sound localization. The results revealed that patients have a significant deficit in the processing of all basic auditory features. Although the search for a relationship with symptoms was limited, auditory hallucinations experience appears to have an impact on basic auditory processing. Further research may examine correlations with clinical symptoms to explore the performance of patient subgroups and possibly implement remediation strategies.

Cognitive Impairment Associated with Schizophrenia: From Pathophysiology to Treatment

Cognitive impairment is a core feature of schizophrenia and a major contributor to poor functional outcomes. Methods for assessment of cognitive dysfunction in schizophrenia are now well established. In addition, there has been increasing appreciation in recent years of the additional role of social cognitive impairment in driving functional outcomes and of the contributions of sensory-level dysfunction to higher-order impairments. At the neurochemical level, acute administration of N-methyl-d-aspartate receptor (NMDAR) antagonists reproduces the pattern of neurocognitive dysfunction associated with schizophrenia, encouraging the development of treatments targeted at both NMDAR and its interactome. At the local-circuit level, an auditory neurophysiological measure, mismatch negativity, has emerged both as a veridical index of NMDAR dysfunction and excitatory/inhibitory imbalance in schizophrenia and as a critical biomarker for early-stage translational drug development. Although no compounds have yet been approved for treatment of cognitive impairment associated with schizophrenia, several candidates are showing promise in early-phase testing.

Unveiling the Associations between EEG Indices and Cognitive Deficits in Schizophrenia-Spectrum Disorders: A Systematic Review

Cognitive dysfunctions represent a core feature of schizophrenia-spectrum disorders due to their presence throughout different illness stages and their impact on functioning. Abnormalities in electrophysiology (EEG) measures are highly related to these impairments, but the use of EEG indices in clinical practice is still limited. A systematic review of articles using Pubmed, Scopus and PsychINFO was undertaken in November 2021 to provide an overview of the relationships between EEG indices and cognitive impairment in schizophrenia-spectrum disorders. Out of 2433 screened records, 135 studies were included in a qualitative review. Although the results were heterogeneous, some significant correlations were identified. In particular, abnormalities in alpha, theta and gamma activity, as well as in MMN and P300, were associated with impairments in cognitive domains such as attention, working memory, visual and verbal learning and executive functioning during at-risk mental states, early and chronic stages of schizophrenia-spectrum disorders. The review suggests that machine learning approaches together with a careful selection of validated EEG and cognitive indices and characterization of clinical phenotypes might contribute to increase the use of EEG-based measures in clinical settings.

Neural correlates of perceived emotions in human insula and amygdala for auditory emotion recognition

The emotional status of a speaker is an important non-linguistic cue carried by human voice and can be perceived by a listener in vocal communication. Understanding the neural circuits involved in processing emotions carried by human voice is crucial for understanding the neural basis of social interaction. Previous studies have shown that human insula and amygdala responded more selectively to emotional sounds than non-emotional sounds. However, it is not clear whether the neural selectivity to emotional sounds in these brain structures is determined by the emotion presented by a speaker which is associated with the acoustic properties of the sounds or by the emotion perceived by a listener. In this study, we recorded intracranial electroencephalography (iEEG) responses to emotional human voices while subjects performed emotion recognition tasks. We found that the iEEG responses of Heschl's gyrus (HG) and posterior insula were determined by the presented emotion, whereas the iEEG responses of anterior insula and amygdala were driven by the perceived emotion. These results suggest that the anterior insula and amygdala play a crucial role in conscious perception of emotions carried by human voice.

Automatic auditory processing features in distinct subtypes of patients at clinical high risk for psychosis: Forecasting remission with mismatch negativity

Individuals at clinical high risk (CHR) for psychosis exhibit a compromised mismatch negativity (MMN) response, which indicates dysfunction of pre-attentive deviance processing. Event-related potential and time-frequency (TF) information, in combination with clinical and cognitive profiles, may provide insight into the pathophysiology and psychopathology of the CHR stage and predict the prognosis of CHR individuals. A total of 92 individuals with CHR were recruited and followed up regularly for up to 3 years. Individuals with CHR were classified into three clinical subtypes demonstrated previously, specifically 28 from Cluster 1 (characterized by extensive negative symptoms and cognitive deficits), 31 from Cluster 2 (characterized by thought and behavioral disorganization, with moderate cognitive impairment), and 33 from Cluster 3 (characterized by the mildest symptoms and cognitive deficits). Auditory MMN to frequency and duration deviants was assessed. The event-related spectral perturbation (ERSP) and inter-trial coherence (ITC) were acquired using TF analysis. Predictive indices for remission were identified using logistic regression analyses. As expected, reduced frequency MMN (fMMN) and duration MMN (dMMN) responses were noted in Cluster 1 relative to the other two clusters. In the TF analysis, Cluster 1 showed decreased theta and alpha ITC in response to deviant stimuli. The regression analyses revealed that dMMN latency and alpha ERSP to duration deviants, theta ITC to frequency deviants and alpha ERSP to frequency deviants, and fMMN latency were significant MMN predictors of remission for the three clusters. MMN variables outperformed behavioral variables in predicting remission of Clusters 1 and 2. Our findings indicate relatively disrupted automatic auditory processing in a certain CHR subtype and a close affinity between these electrophysiological indexes and clinical profiles within different clusters. Furthermore, MMN indexes may serve as predictors of subsequent remission from the CHR state. These findings suggest that the auditory MMN response is a potential neurophysiological marker for distinct clinical subtypes of CHR.

Mismatch negativity as an index of target engagement for excitation/inhibition-based treatment development: a double-blind, placebo-controlled, randomized, single-dose cross-over study of the serotonin type-3 receptor antagonist CVN058

Serotonin type-3 receptor (5-HT₃R) antagonists show potential as a treatment for cognitive deficits in schizophrenia. CVN058, a brain-penetrant, potent and selective 5-HT₃R antagonist, shows efficacy in rodent models of cognition and was well-tolerated in Phase-1 studies. We evaluated the target engagement of CVN058 using mismatch negativity (MMN) in a randomized, double-blind, placebo-controlled, cross-over study. Subjects were stable outpatients with schizophrenia or schizoaffective disorder treated with antipsychotics. Subjects were not permitted to use other 5-HT₃R modulators or serotonin reuptake inhibitors. Each subject received a high (150 mg) and low (15 mg or 75 mg) oral dose of CVN058 and placebo in a randomized order across 3 single-day treatment visits separated by at least 1 week. The primary pre-registered outcome was amplitude of duration MMN. Amplitude of other MMN deviants (frequency, intensity, frequency modulation, and location), P50, P300 and auditory steady-state response (ASSR) were exploratory endpoints. 19 of 22 randomized subjects (86.4%) completed the study. Baseline PANSS scores indicated moderate impairment. CVN058 150 mg led to significant improvement vs. placebo on the primary outcome of duration MMN (p = 0.02, Cohen's d = 0.48). A significant treatment effect was also seen in a combined analysis across all MMN deviants (p < 0.001, d = 0.57). Effects on location MMN were independently significant (p < 0.007, d = 0.46). No other significant effects were seen for other deviants, doses or EEG measures. There were no clinically significant treatment related adverse effects. These results show MMN to be a sensitive target engagement biomarker for 5-HT₃R, and support the potential utility of CVN058 in correcting the excitatory/inhibitory imbalance in schizophrenia.

Relationships between Diffusion Tensor Imaging and Resting State Functional Connectivity in Patients with Schizophrenia and Healthy Controls: A Preliminary Study

Schizophrenia is widely seen as a disorder of dysconnectivity. Neuroimaging studies have examined both structural and functional connectivity in the disorder, but these modalities have rarely been integrated directly. We scanned 29 patients with schizophrenia and 25 healthy control subjects, and we acquired resting state fMRI and diffusion tensor imaging. We used the Functional and Tractographic Connectivity Analysis Toolbox (FATCAT) to estimate functional and structural connectivity of the default mode network. Correlations between modalities were investigated, and multimodal connectivity scores (MCS) were created using principal component analysis. Of the 28 possible region pairs, 9 showed consistent (>80%) tracts across participants. Correlations between modalities were found among those with schizophrenia for the prefrontal cortex, posterior cingulate, and lateral temporal lobes, with frontal and parietal regions, consistent with frontotemporoparietal network involvement in the disorder. In patients, MCS correlated with several aspects of the Positive and Negative Syndrome Scale, with higher multimodal connectivity associated with outward-directed (externalizing) behavior and lower multimodal connectivity related to psychosis per se. In this preliminary sample, we found FATCAT to be a useful toolbox to directly integrate and examine connectivity between imaging modalities. A consideration of conjoint structural and functional connectivity can provide important information about the network mechanisms of schizophrenia.

A hippocampus dependent neural circuit loop underlying the generation of auditory mismatch negativity

Extracting relevant information and transforming it into appropriate behavior, is a fundamental brain function, and requires the coordination between the sensory and cognitive systems, however, the underlying mechanisms of interplay between sensory and cognition systems remain largely unknown. Here, we developed a mouse model for mimicking human auditory mismatch negativity (MMN), a well-characterized translational biomarker for schizophrenia, and an index of early auditory information processing. We found that a subanesthetic dose of ketamine decreased the amplitude of MMN in adult mice. Using pharmacological and chemogenetic approaches, we identified an auditory cortex-entorhinal cortex-hippocampus neural circuit loop that is required for the generation of MMN. In addition, we found that inhibition of dCA1→MEC circuit impaired the auditory related fear discrimination. Moreover, we found that ketamine induced MMN deficiency by inhibition of long-range GABAergic projection from the CA1 region of the dorsal hippocampus to the medial entorhinal cortex. These results provided circuit insights for ketamine effects and early auditory information processing. As the entorhinal cortex is the interface between the neocortex and hippocampus, and the hippocampus is critical for the formation, consolidation, and retrieval of episodic memories and other cognition, our results provide a neural mechanism for the interplay between the sensory and cognition systems.

Auditory emotion recognition deficits in schizophrenia: A systematic review and meta-analysis

BACKGROUND

Auditory emotion recognition (AER) deficits refer to the abnormal identification and interpretation of tonal or prosodic features that transmit emotional information in sounds or speech. Evidence suggests that AER deficits are related to the pathology of schizophrenia. However, the effect size of the deficit in specific emotional category recognition in schizophrenia and its association with psychotic symptoms have never been evaluated through a meta-analysis.

METHODS

A systematic search for literature published in English or Chinese until November 30, 2020 was conducted in PubMed, Embase, Web of Science, PsychINFO, and China National Knowledge Infrastructure (CNKI), WanFang and Weip Databases. AER differences between patients and healthy controls (HCs) were assessed by the standardized mean differences (SMDs). Subgroup analyses were conducted for the type of emotional stimuli and the diagnosis of schizophrenia or schizoaffective disorders (Sch/SchA). Meta-regression analyses were performed to assess the influence of patients' age, sex, illness duration, antipsychotic dose, positive and negative symptoms on the study SMDs.

RESULTS

Eighteen studies containing 615 psychosis (Sch/SchA) and 488 HCs were included in the meta-analysis. Patients exhibited moderate deficits in recognizing the neutral, happy, sad, angry, fear, disgust, and surprising emotion. Neither the semantic information in the auditory stimuli nor the diagnosis subtype affected AER deficits in schizophrenia. Sadness, anger, and disgust AER deficits were each positively associated with negative symptoms in schizophrenia.

CONCLUSIONS

Patients with schizophrenia have moderate AER deficits, which were associated with negative symptoms. Rehabilitation focusing on improving AER abilities may help improve negative symptoms and the long-term prognosis of schizophrenia.

A bottom-up model of functional outcome in schizophrenia

Schizophrenia results in poor functional outcomes owing to numerous factors. This study provides the first test of a bottom-up causal model of functional outcome in schizophrenia, using neurocognition, vocal emotional cognition, alexithymia, and negative symptoms as predictors of functional outcome. We investigated a cross-sectional sample of 135 individuals with schizophrenia and 78 controls. Using a series of structural equation modelling analyses, a single pathway was generated among scores from the MATRICS Consensus Cognitive Battery (MCCB), vocal emotion recognition test, Toronto Alexithymia Scale (TAS), Brief Negative Symptom Scale, and the Personal and Social Performance Scale. The scores for each dimension of the MCCB in the schizophrenia group were significantly lower than that in the control group. The recognition accuracy for different emotions (anger, disgust, fear, sadness, surprise, and satire, but not calm was significantly lower in the schizophrenia group than in the control group. Moreover, the scores on the three dimensions of TAS were significantly higher in the schizophrenia group than in the control group. On path analysis modelling, the proposed bottom-up causal model showed a strong fit with the data and formed a single pathway, from neurocognition to vocal emotional cognition, to alexithymia, to negative symptoms, and to poor functional outcomes. The study results strongly support the proposed bottom-up causal model of functional outcome in schizophrenia. The model could be used to better understand the causal factors related to the functional outcome, as well as for the development of intervention strategies to improve functional outcomes in schizophrenia.

Deficits in Pre-attentive Processing of Spatial Location and Negative Symptoms in Subjects at Clinical High Risk for Schizophrenia

Deficits in mismatch negativity (MMN) generation are among the best-established biomarkers for cognitive dysfunction in schizophrenia and predict conversion to schizophrenia (Sz) among individuals at symptomatic clinical high risk (CHR). Impairments in MMN index dysfunction at both subcortical and cortical components of the early auditory system. To date, the large majority of studies have been conducted using deviants that differ from preceding standards in either tonal frequency (pitch) or duration. By contrast, MMN to sound location deviation has been studied to only a limited degree in Sz and has not previously been examined in CHR populations. Here, we evaluated location MMN across Sz and CHR using an optimized, multi-deviant pattern that included a location-deviant, as defined using interaural time delay (ITD) stimuli along with pitch, duration, frequency modulation (FM) and intensity deviants in a sample of 42 Sz, 33 CHR and 28 healthy control (HC) subjects. In addition, we obtained resting state functional connectivity (rsfMRI) on CHR subjects. Sz showed impaired MMN performance across all deviant types, along with strong correlation between MMN deficits and impaired neurocognitive function. In this sample of largely non-converting CHR subjects, no deficits were observed in either pitch or duration MMN. By contrast, CHR subjects showed significant impairments in location MMN generation particularly over right hemisphere and significant correlation between impaired location MMN and negative symptoms including deterioration of role function. In addition, significant correlations were observed between location MMN and rsfMRI involving brainstem circuits. In general, location detection using ITD stimuli depends upon precise processing within midbrain regions and provides a rapid and robust reorientation of attention. Present findings reinforce the utility of MMN as a pre-attentive index of auditory cognitive dysfunction in Sz and suggest that location MMN may index brain circuits distinct from those indexed by other deviant types.

CDP-choline and galantamine, a personalized α7 nicotinic acetylcholine receptor targeted treatment for the modulation of speech MMN indexed deviance detection in healthy volunteers: a pilot study

RATIONALE

The combination of CDP-choline, an α7 nicotinic acetylcholine receptor (α7 nAChR) agonist, with galantamine, a positive allosteric modulator of nAChRs, is believed to counter the fast desensitization rate of the α7 nAChRs and may be of interest for schizophrenia (SCZ) patients. Beyond the positive and negative clinical symptoms, deficits in early auditory prediction-error processes are also observed in SCZ. Regularity violations activate these mechanisms that are indexed by electroencephalography-derived mismatch negativity (MMN) event-related potentials (ERPs) in response to auditory deviance.

OBJECTIVES/METHODS

This pilot study in thirty-three healthy humans assessed the effects of an optimized α7 nAChR strategy combining CDP-choline (500 mg) with galantamine (16 mg) on speech-elicited MMN amplitude and latency measures. The randomized, double-blinded, placebo-controlled, and counterbalanced design with a baseline stratification method allowed for assessment of individual response differences.

RESULTS

Increases in MMN generation mediated by the acute CDP-choline/galantamine treatment in individuals with low baseline MMN amplitude for frequency, intensity, duration, and vowel deviants were revealed.

CONCLUSIONS

These results, observed primarily at temporal recording sites overlying the auditory cortex, implicate α7 nAChRs in the enhancement of speech deviance detection and warrant further examination with respect to dysfunctional auditory deviance processing in individuals with SCZ.

Multisensory Integration of Emotion in Schizophrenic Patients

Multisensory integration (MSI) of emotion has been increasingly recognized as an essential element of schizophrenic patients' impairments, leading to the breakdown of their interpersonal functioning. The present review provides an updated synopsis of schizophrenics' MSI abilities in emotion processing by examining relevant behavioral and neurological research. Existing behavioral studies have adopted well-established experimental paradigms to investigate how participants understand multisensory emotion stimuli, and interpret their reciprocal interactions. Yet it remains controversial with regard to congruence-induced facilitation effects, modality dominance effects, and generalized vs specific impairment hypotheses. Such inconsistencies are likely due to differences and variations in experimental manipulations, participants' clinical symptomatology, and cognitive abilities. Recent electrophysiological and neuroimaging research has revealed aberrant indices in event-related potential (ERP) and brain activation patterns, further suggesting impaired temporal processing and dysfunctional brain regions, connectivity and circuities at different stages of MSI in emotion processing. The limitations of existing studies and implications for future MSI work are discussed in light of research designs and techniques, study samples and stimuli, and clinical applications.

Targeting Serotonin 5-HT2A Receptors to Better Treat Schizophrenia: Rationale and Current Approaches

Schizophrenia is a major mental illness associated with profound disability. Current treatments for schizophrenia (antipsychotics) all have a similar mechanism of action and are primarily dopamine type 2 receptor (D₂R) antagonists. Antipsychotics are not fully effective for the majority of schizophrenia patients, suggesting the need for alternative approaches. The primary focus of this review is to assess the evidence for the role of the serotonin type 2A receptor (5-HT_2AR) in schizophrenia. Topics include an overview of 5-HT_2AR physiology and pathophysiology in schizophrenia, 5-HT_2AR interaction with other neurotransmitter systems, including the glutamatergic system, a review of the 5-HT_2AR/d-lysergic acid diethylamide (LSD) model of schizophrenia, a contrast of the 5-HT_2AR and glutamatergic models of schizophrenia, and finally, a review of Food and Drug Administration (FDA)-approved and investigational 5-HT_2AR-modulating compounds. Recent studies with lumeteperone, pimavanserin, and roluperidone are highlighted.

Auditory versus visual neuroscience-informed cognitive training in schizophrenia: Effects on cognition, symptoms and quality of life

BACKGROUND

Cognitive impairments are related to deficits in primary auditory and visual sensory processes in schizophrenia. These impairments can be remediated by neuroscience-informed computerized cognitive trainings that target auditory and visual processes. However, it is not clear which modality results in greater improvements in cognition, symptoms and quality of life. We aimed to investigate the impact of training auditory versus visual cognitive processes in global cognition in patients with schizophrenia.

METHODS

Seventy-nine schizophrenia participants were randomly assigned to either 40 h of auditory or visual computerized training. Auditory and visual exercises were chosen to be dynamically equivalent and difficulties increased progressively during the training. We evaluated cognition, symptoms and quality of life before, after 20 h, and after 40 h of training. ClinicalTrials.gov (1R03TW009002-01).

RESULTS

Participants who received the visual training showed significant improvements in global cognition compared to the auditory training group. The visual training significantly improved attention and reasoning and problem-solving, while the auditory training improved reasoning and problem-solving only. Schizophrenia symptoms improved after training in both groups, whereas quality of life remained unchanged. Interestingly, there was a significant and positive correlation between improvements in attention and symptoms in the visual training group.

CONCLUSIONS

We conclude that the visual training and the auditory training are differentially efficient at remediating cognitive deficits and symptoms of clinically stable schizophrenia patients. Ongoing follow-up of participants will evaluate the durability of training effects on cognition and symptoms, as well as the potential impact on quality of life over time.

Grant Report on d-Serine Augmentation of Neuroplasticity-Based Auditory Learning in Schizophrenia †

We report on the rationale and design of an ongoing NIMH sponsored R61-R33 project in schizophrenia/schizoaffective disorder. This project studies augmenting the efficacy of auditory neuroplasticity cognitive remediation (AudRem) with d-serine, an N-methyl-d-aspartate-type glutamate receptor (NMDAR) glycine-site agonist. We operationalize improved (smaller) thresholds in pitch (frequency) between successive auditory stimuli after AudRem as improved plasticity, and mismatch negativity (MMN) and auditory θ as measures of functional target engagement of both NMDAR agonism and plasticity. Previous studies showed that AudRem alone produces significant, but small cognitive improvements, while d-serine alone improves symptoms and MMN. However, the strongest results for plasticity outcomes (improved pitch thresholds, auditory MMN and θ) were found when combining d-serine and AudRem. AudRem improvements correlated with reading and other auditory cognitive tasks, suggesting plasticity improvements are predictive of functionally relevant outcomes. While d-serine appears to be efficacious for acute AudRem enhancement, the optimal dose remains an open question, as does the ability of combined d-serine + AudRem to produce sustained improvement. In the ongoing R61, 45 schizophrenia patients will be randomized to receive three placebo-controlled, double-blind d-serine + AudRem sessions across three separate 15 subject dose cohorts (80/100/120 mg/kg). Successful completion of the R61 is defined by ≥moderate effect size changes in target engagement and correlation with function, without safety issues. During the three-year R33, we will assess the sustained effects of d-serine + AudRem. In addition to testing a potentially viable treatment, this project will develop a methodology to assess the efficacy of novel NMDAR modulators, using d-serine as a "gold-standard".

Neural and functional correlates of impaired reading ability in schizophrenia

Deficits in early auditory processing (EAP) are a core component of schizophrenia (SZ) and contribute significantly to impaired overall function. Here, we evaluate the potential contributions of EAP-related impairments in reading to functional capacity and outcome, relative to effects of auditory social cognitive and general neurocognitive dysfunction. Participants included 30-SZ and 28-controls of similar age, sex, and educational achievement. EAP was assessed using an auditory working memory (tone-matching) task. Phonological processing and reading Fluency were assessed using the Comprehensive Test of Phonological Processing and Woodcock-Johnson reading batteries, respectively. Auditory-related social cognition was assessed using measures of emotion/sarcasm recognition. Functional capacity and outcome were assessed using the UCSD Performance-based Skills Assessment and Specific Level of Functioning scale, respectively. fMRI resting-state functional-connectivity (rsFC) was used to evaluate potential underlying substrates. As predicted, SZ patients showed significant and interrelated deficits in both phonological processing (d = 0.74, p = 0.009) and reading fluency (d = 1.24, p < 0.00005). By contrast, single word reading (d = 0.35, p = 0.31) was intact. In SZ, deficits in EAP and phonological reading ability significantly predicted reduced functional capacity, but not functional outcome. By contrast, deficits in reading fluency significantly predicted impairments in both functional capacity and functional outcome. Moreover, deficits in reading fluency correlated with rsFC alterations among auditory thalamus, early auditory and auditory association regions. These findings indicate significant contributions of EAP deficits and functional connectivity changes in subcortical and early auditory regions to reductions in reading fluency, and of impaired reading ability to impaired functional outcome in SZ.

Bimodal distribution of tone-matching deficits indicates discrete pathophysiological entities within the syndrome of schizophrenia

To date, no measures are available that permit differentiation of discrete, clinically distinct subtypes of schizophrenia (SZ) with potential differential underlying pathophysiologies. Over recent years, there has been increasing recognition that SZ is heterogeneously associated with deficits in early auditory processing (EAP), as demonstrated using clinically applicable tasks such as tone-matching task (TMT). Here, we pooled TMT performances across 310 SZ individuals and 219 healthy controls (HC), along with clinical, cognitive, and resting-state functional-connectivity MRI (rsFC-MRI) measures. In addition, TMT was measured in a group of 24 patients at symptomatic clinical high risk (CHR) for SZ and 24 age-matched HC (age range 7-27 years). We provide the first demonstration that the EAP deficits are bimodally distributed across SZ subjects (P < 0.0001 vs. unimodal distribution), with one group showing entirely unimpaired TMT performance (SZ-EAP+), and a second showing an extremely large TMT impairment (SZ-EAP-), relative to both controls (d = 2.1) and SZ-EAP+ patients (d = 3.4). The SZ-EAP- group predominated among samples drawn from inpatient sites, showed higher levels of cognitive symptoms (PANSS), worse social cognition and a differential deficit in neurocognition (MATRICS battery), and reduced functional capacity. rsFC-MRI analyses showed significant reduction in SZ-EAP- relative to controls between subcortical and cortical auditory regions. As opposed to SZ, CHR patients showed intact EAP function. In HC age-matched to CHR, EAP ability was shown to increase across the age range of vulnerability preceding SZ onset. These results indicate that EAP measure segregates between discrete SZ subgroups. As TMT can be readily implemented within routine clinical settings, its use may be critical to account for the heterogeneity of clinical outcomes currently observed across SZ patients, as well as for pre-clinical detection and efficacious treatment selection.

Significant improvement in treatment resistant auditory verbal hallucinations after 5 days of double-blind, randomized, sham controlled, fronto-temporal, transcranial direct current stimulation (tDCS): A replication/extension study

BACKGROUND

Transcranial direct current stimulation (tDCS) is a potentially novel treatment for antipsychotic-resistant auditory verbal hallucinations (AVH) in schizophrenia. Nevertheless, results have been mixed across studies.

METHODS

89 schizophrenia/schizoaffective subjects (active: 47; Sham: 42) were randomized to five days of twice-daily 20-min active tDCS vs. sham treatments across two recruitment sites. AVH severity was assessed using the Auditory Hallucination Rating Scale (AHRS) total score. To assess target engagement, MRI was obtained in a sub sample.

RESULTS

We observed a statistically significant, moderate effect-size change in AHRS total score across one-week and one-month favoring active treatment following covariation for baseline symptoms and antipsychotic dose (p = 0.036; d = 0.48). Greatest change was observed on the AHRS loudness item (p = 0.003; d = 0.69). In exploratory analyses, greatest effects on AHRS were observed in patients with lower cognitive symptoms (d = 0.61). In target engagement analysis, suprathreshold mean field-strength (>0.2 V/m) was seen within language-sensitive regions. However, off-target field-strength, which correlated significantly with less robust clinical response, was observed in anterior regions.

CONCLUSIONS

This is the largest study of tDCS for persistent AVH conducted to date. We replicate previous reports of significant therapeutic benefit, but only if medication dosage is considered, with patients receiving lowest medication dosage showing greatest effect. Response was also greatest in patients with lowest levels of cognitive symptoms. Overall, these findings support continued development of tDCS for persistent AVH, but also suggest that response may be influenced by specific patient and treatment characteristics. CLINICALTRIALS.GOV: NCT01898299.

NMDA Receptor Antagonist Effects on Speech-Related Mismatch Negativity and Its Underlying Oscillatory and Source Activity in Healthy Humans

Background: Previous studies in schizophrenia have consistently shown that deficits in the generation of the auditory mismatch negativity (MMN) – a pre-attentive, event-related potential (ERP) typically elicited by changes to simple sound features – are linked to N-methyl-D-aspartate (NMDA) receptor hypofunction. Concomitant with extensive language dysfunction in schizophrenia, patients also exhibit MMN deficits to changes in speech but their relationship to NMDA-mediated neurotransmission is not clear. Accordingly, our study aimed to investigate speech MMNs in healthy humans and their underlying electrophysiological mechanisms in response to NMDA antagonist treatment. We also evaluated the relationship between baseline MMN/electrocortical activity and emergent schizophrenia-like symptoms associated with NMDA receptor blockade.

Methods: In a sample of 18 healthy volunteers, a multi-feature Finnish language paradigm incorporating changes in syllables, vowels and consonant stimuli was used to assess the acute effects of the NMDA receptor antagonist ketamine and placebo on the MMN. Further, measures of underlying neural activity, including evoked theta power, theta phase locking and source-localized current density in cortical regions of interest were assessed. Subjective symptoms were assessed with the Clinician Administered Dissociative States Scale (CADSS).

Results: Participants exhibited significant ketamine-induced increases in psychosis-like symptoms and depending on temporal or frontal recording region, co-occurred with reductions in MMN generation in response to syllable frequency/intensity, vowel duration, across vowel and consonant deviants. MMN attenuation was associated with decreases in evoked theta power, theta phase locking and diminished current density in auditory and inferior frontal (language-related cortical) regions. Baseline (placebo) MMN and underlying electrophysiological features associated with the processing of changes in syllable intensity correlated with the degree of psychotomimetic response to ketamine.

Conclusion: Ketamine-induced impairments in healthy human speech MMNs and their underlying electrocortical mechanisms closely resemble those observed in schizophrenia and support a model of dysfunctional NMDA receptor-mediated neurotransmission of language processing deficits in schizophrenia.

N-methyl-d-aspartate-type glutamate receptor modulators and related medications for the enhancement of auditory system plasticity in schizophrenia

Deficits in N-methyl-d-aspartate-type (NMDAR) function contribute to cognitive deficits in schizophrenia, particularly dysfunction in neuroplasticity, defined as reduced learning during training on exercises that place implicit, increasing demands on early sensory (auditory and visual) information processing. Auditory mismatch negativity (MMN) can be both a target engagement biomarker for the NMDAR and a proxy measure of neurophysiological plasticity. This review covers the evidence for using NMDAR modulator and related compounds for enhancement of cognition, with a particular focus on early auditory processing/plasticity. Compounds covered include glycine site agonists, glycine and system A-type transporter inhibitors, d-amino acid oxidase inhibitors, memantine and nicotinic alpha-7 acetylcholine receptor agonists. As opposed to daily treatment studies focusing on schizophrenia in general, intermittent, non-daily treatment combining NMDAR modulators with neuroplasticity-based paradigms, using MMN as target-engagement biomarkers show promise as treatments to both remediate plasticity deficits and overall functional deficits.

Hierarchical deficits in auditory information processing in schizophrenia

Deficits in auditory processing contribute significantly to impaired functional outcome in schizophrenia (SZ), but mediating factors remain under investigation. Here we evaluated two hierarchical components of early auditory processing: pitch-change detection (i.e. identifying if 2 tones have "same" or "different" pitch), which is preferentially associated with early auditory cortex, and serial pitch-pattern detection (i.e. identifying if 3 tones have "same" or "different" pitch, and, if "different", which one differed from the others), which depends also on auditory association regions. Deficits in pitch-change detection deficits in SZ have been widely reported and correlated with higher auditory disturbances such as Auditory Emotion Recognition (AER). Deficits in serial pitch-pattern discrimination have been less studied. Here, we investigated both pitch perception components, along with integrity of AER in SZ patients vs. controls using behavioral paradigms. We hypothesized that the deficits could be viewed as hierarchically organized in SZ, with deficits in low-level function propagating sequentially through subsequent levels of processing. Participants included 27 SZ and 40 controls. The magnitude of the deficits in SZ participants was large in both the pitch-change (d = 1.15) and serial pitch-pattern tasks (d = 1.21) with no significant differential task effect. The effect size of the AER deficits was extremely large (d = 2.82). In the SZ group, performance in both pitch tasks correlated significantly with impaired AER performance. However, a mediation analysis showed that serial pitch-pattern detection mediated the relationship between simpler pitch-change detection and AER in patients. Findings are consistent with hierarchical models of cognitive dysfunction in SZ with deficits in early information processing contributing to higher level impairments. Furthermore, findings are consistent with recent neurophysiological results suggesting similar level impairments for processing of simple vs. more complex tonal dysfunction in SZ.

Altered attentional processing of happy prosody in schizophrenia

BACKGROUND

Abnormalities in emotional prosody processing have been consistently reported in schizophrenia. Emotionally salient changes in vocal expressions attract attention in social interactions. However, it remains to be clarified how attention and emotion interact during voice processing in schizophrenia. The current study addressed this question by examining the P3b event-related potential (ERP) component.

METHOD

The P3b was elicited with a modified oddball task, in which frequent (p = .84) neutral stimuli were intermixed with infrequent (p = .16) task-relevant emotional (happy or angry) targets. Prosodic speech was presented in two conditions - with intelligible (semantic content condition - SCC) or unintelligible semantic content (prosody-only condition - POC). Fifteen chronic schizophrenia patients and 15 healthy controls were instructed to silently count the target vocal sounds.

RESULTS

Compared to controls, P3b amplitude was specifically reduced for happy prosodic stimuli in schizophrenia, irrespective of semantic status. Groups did not differ in the processing of neutral standards or angry targets.

DISCUSSION

The selectively reduced P3b for happy prosody in schizophrenia suggests top-down attentional resources were less strongly engaged by positive relative to negative prosody, reflecting alterations in the evaluation of the emotional salience of the voice. These results highlight the role played by higher-order processes in emotional prosody dysfunction in schizophrenia.

Sensory-targeted cognitive training for schizophrenia

INTRODUCTION

Auditory and visual dysfunctions are key pathophysiological features of schizophrenia (Sz). Therefore, remedial interventions that directly target such impairments could potentially drive gains in higher-order cognition (e.g., memory, executive functions, emotion processing), symptoms and functional outcome, in addition to improving sensory abilities in this population. Here, we reviewed available sensory-targeted cognitive training (S-TCT) programs that were investigated so far in Sz patients. Area covered: A systematic review of the literature was conducted following PRISMA guidelines. Twenty-seven relevant records were included. The superiority of S-TCT over control conditions on higher-order cognition measures was repeatedly demonstrated, but mostly lost significance at later endpoints of evaluation. Clinical symptoms and functional outcome were improved in a minority of studies. S-TCT interventions were associated with the relative normalization of several neurobiological biomarkers of neuroplasticity and sensory mechanisms. Expert commentary: S-TCT, although time-intensive, is a cost-efficient, safe and promising technique for Sz treatment. Its efficacy on higher-order cognition opens a critical window for clinical and functional improvement. The biological impact of S-TCT may allow for the identification of therapeutic biomarkers to further precision-medicine. Additional research is required to investigate the long-term effects of S-TCT, optimal training parameters and potential confounding factors associated with the illness.

Basic auditory processing deficits and their association with auditory emotion recognition in schizophrenia

BACKGROUND

Individuals with schizophrenia are impaired in their ability to recognize emotions based on vocal cues and these impairments are associated with poor global outcome. Basic perceptual processes, such as auditory pitch processing, are impaired in schizophrenia and contribute to difficulty identifying emotions. However, previous work has focused on a relatively narrow assessment of auditory deficits and their relation to emotion recognition impairment in schizophrenia.

METHODS

We have assessed 87 patients with schizophrenia and 73 healthy controls on a comprehensive battery of tasks spanning the five empirically derived domains of auditory function. We also explored the relationship between basic auditory processing and auditory emotion recognition within the patient group using correlational analysis.

RESULTS

Patients exhibited widespread auditory impairments across multiple domains of auditory function, with mostly medium effect sizes. Performance on all of the basic auditory tests correlated with auditory emotion recognition at the p < .01 level in the patient group, with 9 out of 13 tests correlating with emotion recognition at r = 0.40 or greater. After controlling for cognition, many of the largest correlations involved spectral processing within the phase-locking range and discrimination of vocally based stimuli.

CONCLUSIONS

While many auditory skills contribute to this impairment, deficient formant discrimination appears to be a key skill contributing to impaired emotion recognition as this was the only basic auditory skill to enter a step-wise multiple regression after first entering a measure of cognitive impairment, and formant discrimination accounted for significant unique variance in emotion recognition performance after accounting for deficits in pitch processing.

Improving emotion recognition in schizophrenia with "VOICES": An on-line prosodic self-training

Introduction

Emotion recognition (ER) deficits have been extensively demonstrated in schizophrenia. These deficiencies are not only restricted to facial emotion recognition but also include emotional prosody (tone of the voice) recognition deficits. They have been significantly associated with symptom severity and poor social functioning. The aim of this study was to test the efficacy, in real clinical conditions, of an online self-training prosodic game included in the Social Cognition rehabilitation program e-Motional Training.

Method

A randomized, single-blind multicenter clinical trial was conducted with 50 outpatients with schizophrenia or schizoaffective disorder. The control group was treated with Treatment-as-usual (TAU), based on drug therapy, case management and individual and group psychotherapy (not focused on Social Cognition). The intervention group was treated with TAU plus the employment of Voices, an online self-training program devised for prosodic rehabilitation.

Statistical analysis

Linear regression was used to evaluate the effectiveness of the intervention in emotion recognition measured with the Reading the Mind in the Voice–Spanish Version (RMV-SV).

Results

There were statistically significant differences between the intervention and control group measured with RMV-SV (β = 3,6[IC 95%], p<0.001), with a response variable in RMV post R² = 0,617.

Discussion

Voices, a prosodic rehabilitation game included in e-Motional Training, seems to be a promising tool for improving emotional voice recognition deficits in schizophrenia, filling the need for such interventions.

Potential Role of Antipsychotic-Galantamine-Memantine Combination in the Treatment of Positive, Cognitive, and Negative Symptoms of Schizophrenia

Schizophrenia is, in part, a cognitive illness. There are no approved medications for cognitive impairments associated with schizophrenia (CIAS) and primary negative symptoms. Cholinergic and glutamatergic systems, alpha-7 nicotinic acetylcholine (α-7nACh) and N-methyl-D-aspartate (NMDA) receptors, kynurenic acid (KYNA), and mismatch negativity have been implicated in the pathophysiology of CIAS and negative symptoms. Galantamine is an acetylcholinesterase inhibitor that is also a positive allosteric modulator at the α4β2 and α7nACh receptors. Memantine is a noncompetitive NMDA receptor antagonist. Galantamine and memantine alone and in combination were effective for cognition in animals and people with Alzheimer's disease. The objective of this article is to critically dissect the published randomized controlled trials with galantamine and memantine for CIAS to highlight the efficacy signal. These studies may have failed to detect a clinically meaningful efficacy signal due to limitations, methodological issues, and possible medication nonadherence. There is evidence from a small open-label study that the galantamine-memantine combination may be effective for CIAS with kynurenine pathway metabolites as biomarkers to detect the severity of cognitive impairments. Given that there are no available treatments for cognitive impairments and primary negative symptoms in schizophrenia, testing of this "five-pronged strategy" (quintuple hypotheses: dopamine, nicotinic-cholinergic, glutamatergic/NMDA, GABA, and KYNA) is a "low-risk high-gain" approach that could be a major breakthrough in the field. The galantamine-memantine combination has the potential to treat positive, cognitive, and negative symptoms, and targeting the quintuple hypotheses concurrently may lead to a major scientific advancement - from antipsychotic treatment to antischizophrenia treatment.

The relationship of IQ and emotional processing with insula volume in schizophrenia

OBJECTIVE

The insula is involved in general and social cognition, in particular emotion regulation. Aim of this study is to investigate whether insula volume is associated with Intelligence Quotient (IQ) and emotional processing in schizophrenia patients versus healthy controls (HC).

METHODS

Magnetic resonance imaging (MRI) brain scans, IQ and emotional processing tests (Benton Facial Recognition Test [BFRT], Degraded Facial Affect Recognition Task [DFAR], Emotional Mentalizing Task [EMT]) were administered in 246 subjects (133 schizophrenia patients and 113 controls). First order linear regression analyses were performed with group as independent variable and IQ/emotional processing test scores as dependent variables. Second order stepwise linear regression analyses were performed with IQ/emotional processing test scores as independent variables (as well as intracranial volumes, age, gender and cannabis abuse) and right/left insula volumes as dependent ones. A final mediation analysis (Sobel test) was performed to verify if IQ or emotional processing test scores could explain the eventual differences in insula volumes between the two groups.

RESULTS

Schizophrenia patients presented lower insula volumes (left: F = 9.72, p < 0.01; right: F = 10.93, p < 0.01) as compared with healthy controls. Smaller insula volumes in schizophrenia patients are mediated by lower IQ scores (Sobel tests: 3.07, p < 0.01 for right insula; 2.72, p < 0.01 for left insula), but not by impairments in emotion processing.

CONCLUSIONS

IQ, but not emotional processing mediates smaller insula volumes in schizophrenia patients.

Neurobiological correlates of emotional intelligence in voice and face perception networks

Facial expressions and voice modulations are among the most important communicational signals to convey emotional information. The ability to correctly interpret this information is highly relevant for successful social interaction and represents an integral component of emotional competencies that have been conceptualized under the term emotional intelligence. Here, we investigated the relationship of emotional intelligence as measured with the Salovey-Caruso-Emotional-Intelligence-Test (MSCEIT) with cerebral voice and face processing using functional and structural magnetic resonance imaging. MSCEIT scores were positively correlated with increased voice-sensitivity and gray matter volume of the insula accompanied by voice-sensitivity enhanced connectivity between the insula and the temporal voice area, indicating generally increased salience of voices. Conversely, in the face processing system, higher MSCEIT scores were associated with decreased face-sensitivity and gray matter volume of the fusiform face area. Taken together, these findings point to an alteration in the balance of cerebral voice and face processing systems in the form of an attenuated face-vs-voice bias as one potential factor underpinning emotional intelligence.

Deep neural network predicts emotional responses of the human brain from functional magnetic resonance imaging

An artificial neural network with multiple hidden layers (known as a deep neural network, or DNN) was employed as a predictive model (DNN_p) for the first time to predict emotional responses using whole-brain functional magnetic resonance imaging (fMRI) data from individual subjects. During fMRI data acquisition, 10 healthy participants listened to 80 International Affective Digital Sound stimuli and rated their own emotions generated by each sound stimulus in terms of the arousal, dominance, and valence dimensions. The whole-brain spatial patterns from a general linear model (i.e., beta-valued maps) for each sound stimulus and the emotional response ratings were used as the input and output for the DNN_P, respectively. Based on a nested five-fold cross-validation scheme, the paired input and output data were divided into training (three-fold), validation (one-fold), and test (one-fold) data. The DNN_P was trained and optimized using the training and validation data and was tested using the test data. The Pearson's correlation coefficients between the rated and predicted emotional responses from our DNN_P model with weight sparsity optimization (mean ± standard error 0.52 ± 0.02 for arousal, 0.51 ± 0.03 for dominance, and 0.51 ± 0.03 for valence, with an input denoising level of 0.3 and a mini-batch size of 1) were significantly greater than those of DNN models with conventional regularization schemes including elastic net regularization (0.15 ± 0.05, 0.15 ± 0.06, and 0.21 ± 0.04 for arousal, dominance, and valence, respectively), those of shallow models including logistic regression (0.11 ± 0.04, 0.10 ± 0.05, and 0.17 ± 0.04 for arousal, dominance, and valence, respectively; average of logistic regression and sparse logistic regression), and those of support vector machine-based predictive models (SVM_ps; 0.12 ± 0.06, 0.06 ± 0.06, and 0.10 ± 0.06 for arousal, dominance, and valence, respectively; average of linear and non-linear SVM_ps). This difference was confirmed to be significant with a Bonferroni-corrected p-value of less than 0.001 from a one-way analysis of variance (ANOVA) and subsequent paired t-test. The weights of the trained DNN_Ps were interpreted and input patterns that maximized or minimized the output of the DNN_Ps (i.e., the emotional responses) were estimated. Based on a binary classification of each emotion category (e.g., high arousal vs. low arousal), the error rates for the DNN_P (31.2% ± 1.3% for arousal, 29.0% ± 1.7% for dominance, and 28.6% ± 3.0% for valence) were significantly lower than those for the linear SVM_P (44.7% ± 2.0%, 50.7% ± 1.7%, and 47.4% ± 1.9% for arousal, dominance, and valence, respectively) and the non-linear SVM_P (48.8% ± 2.3%, 52.2% ± 1.9%, and 46.4% ± 1.3% for arousal, dominance, and valence, respectively), as confirmed by the Bonferroni-corrected p < 0.001 from the one-way ANOVA. Our study demonstrates that the DNN_p model is able to reveal neuronal circuitry associated with human emotional processing - including structures in the limbic and paralimbic areas, which include the amygdala, prefrontal areas, anterior cingulate cortex, insula, and caudate. Our DNN_p model was also able to use activation patterns in these structures to predict and classify emotional responses to stimuli.

Emotional Prosody Processing in Schizophrenic Patients: A Selective Review and Meta-Analysis

Emotional prosody (EP) has been increasingly recognized as an important area of schizophrenic patients’ dysfunctions in their language use and social communication. The present review aims to provide an updated synopsis on emotional prosody processing (EPP) in schizophrenic disorders, with a specific focus on performance characteristics, the influential factors and underlying neural mechanisms. A literature search up to 2018 was conducted with online databases, and final selections were limited to empirical studies which investigated the prosodic processing of at least one of the six basic emotions in patients with a clear diagnosis of schizophrenia without co-morbid diseases. A narrative synthesis was performed, covering the range of research topics, task paradigms, stimulus presentation, study populations and statistical power with a quantitative meta-analytic approach in Comprehensive Meta-Analysis Version 2.0. Study outcomes indicated that schizophrenic patients’ EPP deficits were consistently observed across studies (d = −0.92, 95% CI = −1.06 < δ < −0.78), with identification tasks (d = −0.95, 95% CI = −1.11 < δ < −0.80) being more difficult to process than discrimination tasks (d = −0.74, 95% CI = −1.03 < δ < −0.44) and emotional stimuli being more difficult than neutral stimuli. Patients’ performance was influenced by both participant- and experiment-related factors. Their social cognitive deficits in EP could be further explained by right-lateralized impairments and abnormalities in primary auditory cortex, medial prefrontal cortex and auditory-insula connectivity. The data pointed to impaired pre-attentive and attentive processes, both of which played important roles in the abnormal EPP in the schizophrenic population. The current selective review and meta-analysis support the clinical advocacy of including EP in early diagnosis and rehabilitation in the general framework of social cognition and neurocognition deficits in schizophrenic disorders. Future cross-sectional and longitudinal studies are further suggested to investigate schizophrenic patients’ perception and production of EP in different languages and cultures, modality forms and neuro-cognitive domains.