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Dr. Ansaam Abdul Salam Ahmadi :: Theses : |
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| Title | Cognitive/Neural Compensatory Mechanisms in Schizophrenia: Reaction Times-Brain Activity Correlates |
| Type | PhD |
| Supervisors | Angus Macdonald |
| Year | 2021 |
| Abstract | Cognitive deficiency in schizophrenia (SZ) was found to be associated with decreased PFC activity compared to healthy controls (HC). Other studies referred to increased / intact patterns of PFC activity. Parallel to those inconsistent neuroimaging findings, schizophrenia patients also showed increased intra-individual reaction times variability (RT_IIV). In the current work, we suggested that inconsistent findings in schizophrenia neuroimaging literature are driven by their increased RT-IIV. We hypothesized that performance with increased reaction times in SZ patients reflects compensatory cognitive/neural mechanisms. To address that general hypothesis, we conducted three studies as follow: 1. Activation likelihood Estimation (ALE) meta analysis of (90 fMRI studies in SZ); In that study we were first concerned with extracting the most consistent neuroimaging findings in the previous SZ literature. Second, we conducted ALE analyses within two categories: experiment with impaired RT (effect sizes > 0.3) vs. experiments with unimpaired RT (effect sizes |
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| University | university of minnesota |
| Country | USA |
| Full Paper | - |
| Title | Spatial Attentional Control Is Not Impaired In Schizophrenia: Dissociating Specific Deficits From Generalized Impairments |
| Type | PhD |
| Supervisors | Angus Macdonald |
| Year | 2013 |
| Abstract | A large literature has established that people with schizophrenia are impaired on tasks that require attentional control. However, evidence is mixed as to whether these impairments are specific deficits (Oltmanns & Neale, 1975) or merely reflect a generalized impairment (Dickinson & Harvey, 2009). Recent evidence also suggests visual attentional control for encoding into working memory may be selectively spared in people with schizophrenia (Gold et al., 2006). The current study used a cued backward masking task to investigate 23 people with schizophrenia and 27 healthy controls. People with schizophrenia were hypothesized to perform better on invalidly cued trials when making a simple identification or location judgment. However, we found schizophrenia impaired performance on both valid and invalid cues to the same degree whether the cue was a stored representation (top-down) or presented at the location of the stimulus (bottom-up). In contrast to a large neuropsychological literature, these findings suggest that people with schizophrenia show no specific spatial attentional control deficit. The errors that they make on such task may be consistent with a generalized impairment. |
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| University | university of minnesota |
| Country | USA |
| Full Paper | - |
| Title | الفروق في المؤشرات النيوروسيكولوجية و الكيماوية العصبية بين مرضي الفصام و مرضي الوسواس القهري |
| Type | MSc |
| Supervisors | السيد ابو شعيشع ، عبد العزيز باتع |
| Year | 2006 |
| Abstract | |
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| University | benha university |
| Country | egypt |
| Full Paper | - |
