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
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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- "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. "
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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- ", 2001 ; Herrmann et al . , 2004 ; Javitt , 2009 ; Urgesi et al . , 2013 ) . "
ABSTRACT: Background: Body dysmorphic disorder (BDD) and anorexia nervosa (AN) share the clinical symptom of disturbed body image, which may be a function of perceptual distortions. Previous studies suggest visual or visuospatial processing abnormalities may be contributory, but have been unable to discern whether these occur early or late in the visual processing stream. We used electroencephalography (EEG) and visual event related potentials (ERP) to investigate early perceptual neural activity associated with processing visual stimuli. Methods: We performed EEG on 20 AN, 20 BDD, 20 healthy controls, all unmedicated. In order to probe configural/holistic and detailed processing, participants viewed photographs of faces and houses that were unaltered or filtered to low or high spatial frequencies, respectively. We calculated the early ERP components P100 and N170, and compared amplitudes and latencies among groups. Results: P100 amplitudes were smaller in AN than BDD and healthy controls, regardless of spatial frequency or stimulus type (faces or houses). Similarly, N170 latencies were longer in AN than healthy controls, regardless of spatial frequency or stimulus type, with a similar pattern in BDD at trend level significance. N170 amplitudes were smaller in AN than controls for high and normal spatial frequency images, and smaller in BDD than controls for normal spatial frequency images, regardless of stimulus type. Poor insight correlated with lower N170 amplitudes for normal and low spatial frequency faces in the BDD group. Conclusions: Individuals with AN exhibit abnormal early visual system activity, consistent with reduced configural processing and enhanced detailed processing. This is evident regardless of whether the stimuli are appearance-or non-appearance-related, and thus may be a reflection of general, early perceptual abnormalities. As N170 amplitude could be a marker of structural encoding of faces, lower values may be associated with perceptual distortions and could contribute to poor insight in BDD. Future studies may explore visual ERP measures as potential biomarkers of illness phenotype.Frontiers in Human Neuroscience 06/2015; 9:301. DOI:10.3389/fnhum.2015.00301 · 2.99 Impact Factor
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- "Superior temporal cortices host primary, secondary and association auditory cortices and have been implicated in the pathophysiology of 1 H MRS) is a non-invasive neuroimaging technique that can quantify in vivo neurochemical metabolites, including those related to the glutamatergic system. Glutamatergic neurotransmission is thought to be disturbed in both schizophrenia (Goff and Coyle, 2001; Paz et al., 2008; Javitt, 2009, 2010) and bipolar disorder (Sanacora et al., 2008; Machado-Vieira et al., 2012). Moreover, altered glutamatergic metabolites have been reported both in schizophrenia (Brugger et al., 2011; Marsman et al., 2013; Poels et al., 2014a,b) and bipolar disorder (Yildiz-Yesiloglu and Ankerst, 2006; Moore et al., 2007; Yuksel and Ongur, 2010; Ongur et al., 2011). "
ABSTRACT: Background: Superior temporal cortices include brain regions dedicated to auditory processing and several lines of evidence suggest structural and functional abnormalities in both schizophrenia and bipolar disorder within this brain region. However, possible glutamatergic dysfunction within this region has not been investigated in adult patients. Methods: Thirty patients with schizophrenia (38.67 ± 12.46 years of age), 28 euthymic patients with bipolar I disorder (35.32 ± 9.12 years of age), and 30 age-, gender- and education- matched healthy controls were enrolled. Proton Magnetic Resonance Spectroscopy data were acquired using a 3.0T Siemens MAGNETOM TIM Trio MR system and single voxel Point Resolved Spectroscopy Sequence (PRESS) in order to quantify brain metabolites within the left and right Heschl Gyrus and Planum Temporale of superior temporal cortices. Results: There were significant abnormalities in Glutamate (Glu) (F(2,78)=8.52, p<0.0001), n- Acetyl Aspartate (tNAA) (F(2,81)=5.73, p=0.005), Creatine (tCr) (F(2,83)=5.91, p=0.004) and Inositol (Ins) (F(2,82)=8.49, p<0.0001) concentrations in the left superior temporal cortex. In general, metabolite levels were lower for bipolar disorder patients when compared to healthy participants. Moreover, patients with bipolar disorder exhibited significantly lower tCr and Ins concentrations when compared to schizophrenia patients. In addition, we have found significant correlations between the superior temporal cortex metabolites and clinical measures. Conclusion: As the left auditory cortices are associated with language and speech, left hemisphere specific abnormalities may have clinical significance. Our findings are suggestive of shared glutamatergic abnormalities in schizophrenia and bipolar disorder.Schizophrenia Research 02/2015; 161(2-3). DOI:10.1016/j.schres.2014.11.012 · 3.92 Impact Factor
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