When Doors of Perception Close: Bottom-up Models of Disrupted Cognition in Schizophrenia

Schizophrenia Research Center, Nathan Kline Institute for Psychiatric Research/New York University School of Medicine, Orangeburg, NY 10962, USA.
Annual Review of Clinical Psychology (Impact Factor: 12.67). 02/2009; 5(1):249-75. DOI: 10.1146/annurev.clinpsy.032408.153502
Source: PubMed


Schizophrenia is a major mental disorder that affects approximately 1% of the population worldwide. Cognitive deficits are a key feature of schizophrenia and a primary cause of long-term disability. Current neurophysiological models of schizophrenia focus on distributed brain dysfunction with bottom-up as well as top-down components. Bottom-up deficits in cognitive processing are driven by impairments in basic perceptual processes that localize to primary sensory brain regions. Within the auditory system, deficits are apparent in elemental sensory processing, such as tone matching following brief delay. Such deficits lead to impairments in higher-order processes such as phonological processing and auditory emotion recognition. Within the visual system, deficits are apparent in functioning of the magnocellular visual pathway, leading to higher-order deficits in processes such as perceptual closure, object recognition, and reading. In both auditory and visual systems, patterns of deficit are consistent with underlying impairment of brain N-methyl-d-aspartate receptor systems.

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    • "The highlighting of sensorimotor systems is in contrast to the frequent emphasis on dysfunction of executive and highlevel association areas, which intuitively may be more related to cardinal symptoms of the disease. Sensory and motor impairments are nevertheless indicated by multiple lines of research (Butler et al., 2008; Javitt, 2009; Walther and Strik, 2012). Motor cortex, like prefrontal cortex, has lower neuronal density in schizophrenia when measured post-mortem (Benes et al., 1986) and imaging studies have shown alterations in cortical and subcortical motor areas (Dazzan et al., 2004; Honey et al., 2005). "
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    ABSTRACT: Schizophrenia is increasingly recognized as a neurodevelopmental disorder with altered connectivity among brain networks. In the current study we examined large-scale network interactions in childhood-onset schizophrenia, a severe form of the disease with salient genetic and neurobiological abnormalities. Using a data-driven analysis of resting-state functional magnetic resonance imaging fluctuations, we characterized data from 19 patients with schizophrenia and 26 typically developing controls, group matched for age, sex, handedness, and magnitude of head motion during scanning. This approach identified 26 regions with decreased functional correlations in schizophrenia compared to controls. These regions were found to organize into two function-related networks, the first with regions associated with social and higher-level cognitive processing, and the second with regions involved in somatosensory and motor processing. Analyses of across- and within-network regional interactions revealed pronounced across-network decreases in functional connectivity in the schizophrenia group, as well as a set of across-network relationships with overall negative coupling indicating competitive or opponent network dynamics. Critically, across-network decreases in functional connectivity in schizophrenia predicted the severity of positive symptoms in the disorder, such as hallucinations and delusions. By contrast, decreases in functional connectivity within the social-cognitive network of regions predicted the severity of negative symptoms, such as impoverished speech and flattened affect. These results point toward the role that abnormal integration of sensorimotor and social-cognitive processing may play in the pathophysiology and symptomatology of schizophrenia.
    Brain 10/2015; DOI:10.1093/brain/awv306 · 9.20 Impact Factor
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    • "Therefore, based on this prior work, in the current investigation we sought to test whether the function of this parietal–frontal network is (1) altered and (2) predictive of abnormalities in personal space in schizophrenia. Also, since abnormalities in schizophrenia in lowerlevel visual areas (Javitt, 2009), such as those dedicated to face perception or motion processing, could theoretically influence the function of this near space–monitoring sensory–motor pathway, in another cohort of schizophrenic patients and demographically-matched healthy subjects, we conducted additional control experiments measuring the function of lower-level visual areas in schizophrenia. "
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    ABSTRACT: Schizophrenia is associated with subtle abnormalities in day-to-day social behaviors, including a tendency in some patients to “keep their distance” from others in physical space. The neural basis of this abnormality, and related changes in social functioning, is unknown. Here we examined, in schizophrenic patients and healthy control subjects, the functioning of a parietal–frontal network involved in monitoring the space immediately surrounding the body (“personal space”). Using fMRI, we found that one region of this network, the dorsal intraparietal sulcus (DIPS), was hyper-responsive in schizophrenic patients to face stimuli appearing to move towards the subjects, intruding into personal space. This hyper-responsivity was predicted both by the size of personal space (which was abnormally elevated in the schizophrenia group) and the severity of negative symptoms. In contrast, in a second study, the activity of two lower-level visual areas that send information to DIPS (the fusiform face area and middle temporal area) was normal in schizophrenia. Together, these findings suggest that changes in parietal–frontal networks that support the sensory-guided initiation of behavior, including actions occurring in the space surrounding the body, contribute to social dysfunction and negative symptoms in schizophrenia.
    • "Basic deficits in visual motion processing have also been identified (Chen, 2011). Historically, this area of research has framed sensory deficits as a consequence of mental illness in a top-down approach; however, recent research is beginning to refute this trend, arguing that sensory disturbances may be risk factors in the onset of schizophrenia (Javitt, 2009). Accordingly, an expanded understanding is needed of how sensory perturbations in everyday life affect mental health. "
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    ABSTRACT: In occupational therapy, research has studied sensory function predominantly in relation to sensory disorders. There is a gap in the literature exploring how sensory experiences affect mental health. This study sought to provide a phenomenological understanding of how people relate experiences of sensory dissonance to their mental health. Ten immigrants from Latin America participated in semistructured interviews and video observations of their occupational behavior. Participants' experiences of sensory dissonance provoked negative mental states and distress. Participants reported poor mental health following sensory experiences that were incongruent with their habits of sensing. They also intentionally used sensory anchors to induce positive mental states and connect with past occupational experiences. Occupational therapy practitioners should be mindful of how sensory environments can facilitate or impede intervention. Practitioners are encouraged to harness clients' sensory habits and use sensory anchors as a form of sensory scaffolding to facilitate therapeutic gains. Copyright © 2015 by the American Occupational Therapy Association, Inc.
    07/2015; 69(4):6904250020p1-6904250020p8. DOI:10.5014/ajot.2015.014977
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