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- Lycke Brandt, Christine, et al.
(author)
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Working memory networks and activation patterns in schizophrenia and bipolar disorder : comparison with healthy controls
- 2014
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In: British Journal of Psychiatry. - 0007-1250 .- 1472-1465. ; 204:4, s. 290-298
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Journal article (peer-reviewed)abstract
- BACKGROUND: Schizophrenia and bipolar disorder are severe mental disorders with overlapping genetic and clinical characteristics, including cognitive impairments. An important question is whether these disorders also have overlapping neuronal deficits.AIMS: To determine whether large-scale brain networks associated with working memory, as measured with functional magnetic resonance imaging (fMRI), are the same in both schizophrenia and bipolar disorder, and how they differ from those in healthy individuals.METHOD: Patients with schizophrenia (n = 100) and bipolar disorder (n = 100) and a healthy control group (n = 100) performed a 2-back working memory task while fMRI data were acquired. The imaging data were analysed using independent component analysis to extract large-scale networks of task-related activations.RESULTS: Similar working memory networks were activated in all groups. However, in three out of nine networks related to the experimental task there was a graded response difference in fMRI signal amplitudes, where patients with schizophrenia showed greater activation than those with bipolar disorder, who in turn showed more activation than healthy controls. Secondary analysis of the patient groups showed that these activation patterns were associated with history of psychosis and current elevated mood in bipolar disorder.CONCLUSIONS: The same brain networks were related to working memory in schizophrenia, bipolar disorder and controls. However, some key networks showed a graded hyperactivation in the two patient groups, in line with a continuum of neuronal abnormalities across psychotic disorders.
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| 2. |
- Beniczky, Sándor, et al.
(author)
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Standardized computer-based organized reporting of EEG : SCORE - Second version
- 2017
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In: Clinical Neurophysiology. - : Elsevier BV. - 1388-2457. ; 128:11, s. 2334-2346
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Journal article (peer-reviewed)abstract
- Standardized terminology for computer-based assessment and reporting of EEG has been previously developed in Europe. The International Federation of Clinical Neurophysiology established a taskforce in 2013 to develop this further, and to reach international consensus. This work resulted in the second, revised version of SCORE (Standardized Computer-based Organized Reporting of EEG), which is presented in this paper. The revised terminology was implemented in a software package (SCORE EEG), which was tested in clinical practice on 12,160 EEG recordings. Standardized terms implemented in SCORE are used to report the features of clinical relevance, extracted while assessing the EEGs. Selection of the terms is context sensitive: initial choices determine the subsequently presented sets of additional choices. This process automatically generates a report and feeds these features into a database. In the end, the diagnostic significance is scored, using a standardized list of terms. SCORE has specific modules for scoring seizures (including seizure semiology and ictal EEG patterns), neonatal recordings (including features specific for this age group), and for Critical Care EEG Terminology. SCORE is a useful clinical tool, with potential impact on clinical care, quality assurance, data-sharing, research and education.
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| 3. |
- Kompus, Kristiina, 1983-, et al.
(author)
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Early analysis of retrieval cues guides selection of retrieval processing
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Other publication (other academic/artistic)abstract
- Human long-term memory holds semantic and episodic memories. Retrieval from these two memory systems occurs independently. As required information may be held in either of these systems, the question arises how and when is the choice of retrieval processing (episodic/semantic) determined. Here we report results from an ERP study on healthy young adults during a forced-choice associative recognition task, designed to test the hypothesis that early processing of retrieval cues influences subsequent retrieval processing. The test items had previously been encoded repeatedly (6x) or only once (1x) during pre-experimental training period, thereby influencing the reliance on semantic or episodic retrieval processes. Differences between the two conditions were observed for the familiarity-sensitive FN400 component as well as for a late (>1000 ms) component indexing post-retrieval processing. Most critically, we found that a difference between successfully retrieved 6x and 1x items emerged already during the 100-140 ms time window. These results indicate that choice of retrieval processes (episodic/semantic) depends on early matching between retrieval cues and memory traces.
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| 4. |
- Kompus, Kristiina, 1983-, et al.
(author)
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Multimodal imaging of incidental retrieval : the low route to memory
- 2011
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In: Journal of cognitive neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 23:4, s. 947-960
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Journal article (peer-reviewed)abstract
- Memories of past episodes frequently come to mind incidentally, without directed search. It has remained unclear how incidental retrieval processes are initiated in the brain. Here we used fMRI and ERP recordings to find brain activity that specifically correlates with incidental retrieval, as compared to intentional retrieval. Intentional retrieval was associated with increased activation in the dorsolateral prefrontal cortex. By contrast, incidental retrieval was associated with a reduced fMRI signal in posterior brain regions, including extrastriate and parahippocampal cortex, and a modulation of a posterior ERP component 170 ms after the onset of visual retrieval cues. Successful retrieval under both intentional and incidental conditions was associated with increased activation in hippocampus, precuneus and ventrolateral prefrontal cortex, as well as increased amplitude of the P600 ERP component. These results demonstrate how early bottom-up signals from the posterior cortex can lead to reactivation of episodic memories in the absence of strategic retrieval attempts.
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