Article

Spatial working memory in individuals at high risk for psychosis: Longitudinal fMRI study

Institute of Psychiatry, King's Health Partners, King's College London, UK.
Schizophrenia Research (Impact Factor: 4.43). 10/2010; 123(1):45-52. DOI: 10.1016/j.schres.2010.06.008
Source: PubMed

ABSTRACT Neurocognitive impairments in executive and mnemonic domains are already evident in the pre-psychotic phases. The longitudinal dynamic course of the neurofunctional abnormalities underlying liability to psychosis and their relation to clinical outcomes is unknown.
In this study we used functional magnetic resonance imaging (fMRI) in a cohort of subjects at ultra high clinical risk for psychosis (with an "At Risk Mental State", ARMS) and in healthy controls. Images were acquired at baseline and again after one year on a 1.5 Tesla Signa, while patients were performing a visuospatial working memory task. Psychopathological assessment of the prodromal symptoms was conducted at the same time points by using the CAARMS and the PANSS instruments.
There were no significant differences between the ARMS and control groups with respect to age or IQ. Although both groups performed the PAL task with a high degree of accuracy, the ARMS showed an increased latency in answers during the most demanding level of the task. At baseline, such cognitive impairment was associated with reduced activation in the left precuneus, left superior parietal lobule, right middle temporal gyrus in the ARMS as compared to controls. In addition, the ARMS failed to activate parietal areas with increasing difficulty of the task. Between presentation and follow-up the overall clinical status of the ARMS sample improved, despite 2 out of the 15 subjects having developed a full-blown psychosis: the CAARMS (perceptual disorder and thought disorder subscales) and the PANNS general scores decreased, while the GAF score increased. Such clinical amelioration was associated with a longitudinal compensatory increase in occipitoparietal regions.
The prodromal phase of psychosis is associated with functional alterations in parietal and temporal networks subserving visuospatial working memory which are more evident under high cognitive loads. The clinical improvement at one year is associated with a compensatory increase in occipitoparietal regions.

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    • "Recognition of real faces vs. Darker image identification 11. Fusar-poli et al. (2010) fMRI 15 Visuospatial working memory task n Hard vs. intermediate level of difficulty 12. Broome, Matthiasson, Woolley, Valmaggia, and Johns (2009) fMRI 15 Object-location memory task with manipulation of the mnemonic load n Hard vs. intermediate level of difficulty 13. Hirano, Obata, Kashikura, and Nonaka (2008) fMRI 33 N-back N-back vs. zero-back 14. "
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    ABSTRACT: journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit:-analysis of functional neuroimaging studies indicates that an increase of cognitive difficulty during executive tasks engages brain regions associated with time perception a b s t r a c t Objectives: We hypothesize that time perception and executive functions are interrelated and share neuroanatomical basis, and that fluctuations in levels of cognitive effort play a role in mediating that relation. The main goal of this study was to identify brain structures activated both by increases in cognitive activity and during time perception tasks. Methods: We performed a multimodal meta-analysis to identify common brain regions in the findings of (a) an SDM meta-analysis of neuroimaging studies assessing the brain response to increasing levels of cognitive difficulty, and (b) an ALE meta-analysis on neuroimaging of time perception (Ortuño,. Results and conclusions: Consistent with results of previous, separate meta-analyses, the current study supports the hypothesis that there exists a group of brain regions engaged both in time perception tasks and during tasks requiring cognitive effort. Thus, brain regions associated with working memory and executive functions were found to be engaged during time estimation tasks, and regions associated with time perception were found to be engaged by an increase in the difficulty of non-temporal tasks. The implication is that temporal perception and cognitive processes demanding cognitive control become interlinked when there is an increase in the level of cognitive effort demanded.
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    • "Recognition of real faces vs. Darker image identification 11. Fusar-poli et al. (2010) fMRI 15 Visuospatial working memory task n Hard vs. intermediate level of difficulty 12. Broome, Matthiasson, Woolley, Valmaggia, and Johns (2009) fMRI 15 Object-location memory task with manipulation of the mnemonic load n Hard vs. intermediate level of difficulty 13. Hirano, Obata, Kashikura, and Nonaka (2008) fMRI 33 N-back N-back vs. zero-back 14. "
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    ABSTRACT: Objectives We hypothesize that time perception and executive functions are interrelated and share neuroanatomical basis, and that fluctuations in levels of cognitive effort play a role in mediating that relation. The main goal of this study was to identify brain structures activated both by increases in cognitive activity and during time perception tasks. Methods We performed a multimodal meta-analysis to identify common brain regions in the findings of (a) an SDM meta-analysis of neuroimaging studies assessing the brain response to increasing levels of cognitive difficulty, and (b) an ALE meta-analysis on neuroimaging of time perception (Ortuño, Guillén-Grima, López-García, Gómez, & Pla, 2011). Results and conclusions Consistent with results of previous, separate meta-analyses, the current study supports the hypothesis that there exists a group of brain regions engaged both in time perception tasks and during tasks requiring cognitive effort. Thus, brain regions associated with working memory and executive functions were found to be engaged during time estimation tasks, and regions associated with time perception were found to be engaged by an increase in the difficulty of non-temporal tasks. The implication is that temporal perception and cognitive processes demanding cognitive control become interlinked when there is an increase in the level of cognitive effort demanded.
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    • "WMem-associated activation continues to change across adolescence (Schweinsburg et al., 2005), which suggests maturational changes that are likely to reflect refinement of the dorsolateral prefrontal cortical (DLPFC) contribution to WMem across adolescence (Geier et al., 2009). CHR individuals have shown abnormalities in fMRI activation during WMem (Broome et al., 2009; Choi et al., 2011; Fusar-Poli et al., 2010; Morey et al., 2005) but it is not clear how these differences may vary with age during adolescence. The goals of this study were to determine whether CHR youth show a differential association between age and functional activation during adolescence compared with typically developing controls (TDC), and to clarify whether such a putative differential association is limited to adolescents who convert to psychosis. "
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    10/2013; 221(1). DOI:10.1016/j.pscychresns.2013.08.004
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