Resting-state functional connectivity-based parcellation of the human dentate nucleus: new findings and clinical relevance.

For years, the cerebellum was left out of functional magnetic resonance imaging (fMRI) studies due to technological limitations. The advent of novel data acquisition and reconstruction strategies (e.g.

Theories of psychopathology: Introduction to a special section.

This special section on theories of psychopathology provides an opportunity to collect the emergent, cross-cutting scholarship that is challenging traditional approaches to understanding mental illness. Here, we appraise the state of theory in the field and emphasize the pitfalls of working in the context of overly flexible, unchallenged, and essentially unchallengeable theoretic models, such as the biopsychosocial model, which we argue has become the de facto theoretic model for our field. We further posit that theoretic shortcomings are contributing to the often-referenced pessimism regarding our progress in understanding and treating mental illness, and introduce the charge of the authors of the papers in this section to articulate novel, falsifiable theories of psychopathology.

Cerebellar Activation Deficits in Schizophrenia During an Eyeblink Conditioning Task.

The cognitive dysmetria theory of psychotic disorders posits that cerebellar circuit abnormalities give rise to difficulties coordinating motor and cognitive functions. However, brain activation during cerebellar-mediated tasks is understudied in schizophrenia. Accordingly, this study examined whether individuals with schizophrenia have diminished neural activation compared to controls in key regions of the delay eyeblink conditioning (dEBC) cerebellar circuit (eg, lobule VI) and cerebellar regions associated with cognition (eg, Crus I).

Investigating cerebellar neural function in schizophrenia using delay eyeblink conditioning: A pilot fMRI study.

There is accruing evidence of cerebellar abnormalities in individuals with schizophrenia as measured by performance on a variety of tasks believed to be dependent on cerebellar integrity, including delay eyeblink conditioning. There is also evidence of cerebellar dysfunction on a neural level in schizophrenia from both task-based and resting state neuroimaging studies, however few studies have examined cerebellar neural function while the cerebellum is directly recruited in individuals with schizophrenia. In the current pilot study, we examined neural activity during an explicitly cerebellar task in individuals with schizophrenia or schizoaffective disorder and non-psychiatric controls.

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.

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.

Instrument-based assessment of motor function yields no evidence of dyskinesia in adult first-degree biological relatives of individuals with schizophrenia and schizoaffective disorder.

There is accruing evidence of spontaneous dyskinesia in individuals with schizophrenia that is independent of medication exposure. Dyskinetic motor behavior is also present in individuals who are at high risk of schizophrenia and appears to have prognostic value for the development of psychosis. Nonetheless, it remains unclear whether dyskinesia is present in first-degree relatives of individuals with schizophrenia and thus associated with genetic liability for schizophrenia (i.

The clinical and prognostic value of motor abnormalities in psychosis, and the importance of instrumental assessment.

Motor abnormalities comprise several clinical signs intrinsic to psychosis. Critically, these features are of prognostic value in individuals at-risk for psychosis, and for those in early stages of psychotic disorders. Motor abnormalities such as tremor, rigidity, and neurological soft signs often go unrecognized.

New Insights into the Nature of Cerebellar-Dependent Eyeblink Conditioning Deficits in Schizophrenia: A Hierarchical Linear Modeling Approach.

Evidence of cerebellar dysfunction in schizophrenia has mounted over the past several decades, emerging from neuroimaging, neuropathological, and behavioral studies. Consistent with these findings, cerebellar-dependent delay eyeblink conditioning (dEBC) deficits have been identified in schizophrenia. While repeated-measures analysis of variance is traditionally used to analyze dEBC data, hierarchical linear modeling (HLM) more reliably describes change over time by accounting for the dependence in repeated-measures data.

Eyeblink Conditioning in Schizophrenia: A Critical Review.

There is accruing evidence of cerebellar abnormalities in schizophrenia. The theory of cognitive dysmetria considers cerebellar dysfunction a key component of schizophrenia. Delay eyeblink conditioning (EBC), a cerebellar-dependent translational probe, is a behavioral index of cerebellar integrity.

Nodal centrality of functional network in the differentiation of schizophrenia.

A disturbance in the integration of information during mental processing has been implicated in schizophrenia, possibly due to faulty communication within and between brain regions. Graph theoretic measures allow quantification of functional brain networks. Functional networks are derived from correlations between time courses of brain regions.

Increased postural sway predicts negative symptom progression in youth at ultrahigh risk for psychosis.

Impaired ability to maintain an upright posture may reflect impairment in the cerebellum, a critical structure for the fluid coordination of neural information, thought to be disrupted in psychosis. The current study utilized an instrumental measure of posture in individuals at ultrahigh risk (UHR) for psychosis (n=43) and healthy controls (n=44). Positive and negative symptoms were assessed twice over 12months.

White matter abnormalities of microstructure and physiological noise in schizophrenia.

White matter abnormalities in schizophrenia have been revealed by many imaging techniques and analysis methods. One of the findings by diffusion tensor imaging is a decrease in fractional anisotropy (FA), which is an indicator of white matter integrity. On the other hand, elevation of metabolic rate in white matter was observed from positron emission tomography (PET) studies.

Deficits in metacognitive capacity distinguish patients with schizophrenia from those with prolonged medical adversity.

Research has suggested that many with schizophrenia experience decrements in synthetic metacognition, or the abilities to form integrated representations of oneself and others and then utilize that knowledge to respond to problems. Although such deficits have been linked with functional impairments even after controlling for symptoms and neurocognition, it is unclear to what extent these deficits can distinguish persons with schizophrenia from others experiencing significant life adversity but without psychosis. To explore this issue we conducted logistic regression analysis to determine whether assessment of metacognition could distinguish between 166 participants with schizophrenia and 51 adults with HIV after controlling for social cognition and education.

Disrupted modular architecture of cerebellum in schizophrenia: a graph theoretic analysis.

Recent studies of schizophrenia have revealed cognitive and memory deficits that are accompanied by disruptions of neuronal connectivity in cortical and subcortical brain regions. More recently, alterations of topological organization of structural networks in schizophrenia are also being identified using graph theoretical analysis. However, the role of the cerebellum in this network structure remains largely unknown.

Cerebellar networks in individuals at ultra high-risk of psychosis: impact on postural sway and symptom severity.

Despite known deficits in postural control in patients with schizophrenia, this domain has not been investigated in youth at ultra high-risk (UHR) for psychosis. This is particularly relevant as postural control implicates dysfunction in the cerebellum-a region implicated in cognitive dysmetria conceptions of schizophrenia but poorly understood in the prodrome. Here, we extended our understanding of movement abnormalities in UHR individuals to include postural control, and have linked these deficits to both symptom severity and cerebello-cortical network connectivity.

Impaired cerebellar-dependent eyeblink conditioning in first-degree relatives of individuals with schizophrenia.

Consistent with reports of cerebellar structural, functional, and neurochemical anomalies in schizophrenia, robust cerebellar-dependent delay eyeblink conditioning (dEBC) deficits have been observed in the disorder. Impaired dEBC is also present in schizotypal personality disorder, an intermediate phenotype of schizophrenia. The present work sought to determine whether dEBC deficits exist in nonpsychotic first-degree relatives of individuals with schizophrenia.

A magnetic resonance imaging-safe method for the study of human eyeblink conditioning.

Eyeblink conditioning (EBC) is a widely used translational probe of cerebellar function in both humans and non-human animals. Decades of animal research have identified the cerebellum as critical for EBC. While there is evidence for the involvement of the cerebellum in human EBC, the neural circuitry of EBC in healthy humans has yet to be fully elucidated.

Self perception of empathy in schizophrenia: emotion recognition, insight, and symptoms predict degree of self and interviewer agreement.

Many with schizophrenia have been found to experience difficulties recognizing a range of their own mental states including memories and emotions. While there is some evidence that the self perception of empathy in schizophrenia is often at odds with objective observations, little is known about the correlates of rates of concordance between self and rater assessments of empathy for this group. To explore this issue we gathered self and rater assessments of empathy in addition to assessments of emotion recognition using the Bell Lysaker Emotion Recognition Task, insight using the Scale to Assess Unawareness of Mental Disorder, and symptoms using the Positive and Negative Syndrome Scale from 91 adults diagnosed with schizophrenia spectrum disorders.

Motor deficits in schizophrenia quantified by nonlinear analysis of postural sway.

Motor dysfunction is a consistently reported but understudied aspect of schizophrenia. Postural sway area was examined in individuals with schizophrenia under four conditions with different amounts of visual and proprioceptive feedback: eyes open or closed and feet together or shoulder width apart. The nonlinear complexity of postural sway was assessed by detrended fluctuation analysis (DFA).

Postural control in bipolar disorder: increased sway area and decreased dynamical complexity.

Structural, neurochemical, and functional abnormalities have been identified in the brains of individuals with bipolar disorder, including in key brain structures implicated in postural control, i.e. the cerebellum, brainstem, and basal ganglia.

Paced finger-tapping abnormalities in bipolar disorder indicate timing dysfunction.

Objectives: Theoretical and empirical evidence suggests that impaired time perception and the neural circuitry contributing to internal timing mechanisms may contribute to severe psychiatric disorders, including mood disorders. The structures that are involved in subsecond timing, i.e.