21 results found
Geranmayeh F, Wing Chau T, Wise RJS, et al., 2017, Domain-general subregions of the medial prefrontal cortex contribute to recovery of language after stroke, Brain, Vol: 140, Pages: 1947-1958, ISSN: 1460-2156
We hypothesized that the recovery of speech production after left hemisphere stroke not only depends on the integrity of language-specialized brain systems, but also on ‘domain-general’ brain systems that have much broader functional roles. The presupplementary motor area/dorsal anterior cingulate forms part of the cingular-opercular network, which has a broad role in cognition and learning. Consequently, we have previously suggested that variability in the recovery of speech production after aphasic stroke may relate in part to differences in patients’ abilities to engage this domain-general brain region. To test our hypothesis, 27 patients (aged 59 ± 11 years) with a left hemisphere stroke performed behavioural assessments and event-related functional magnetic resonance imaging tasks at two time points; first in the early phase (∼2 weeks) and then ∼4 months after the ictus. The functional magnetic resonance imaging tasks were designed to differentiate between activation related to language production (sentential overt speech production—Speech task) and activation related to cognitive processing (non-verbal decision making). Simple rest and counting conditions were also included in the design. Task-evoked regional brain activations during the early and late phases were compared with a longitudinal measure of recovery of language production. In accordance with a role in cognitive processing, substantial activity was observed within the presupplementary motor area/dorsal anterior cingulate during the decision-making task. Critically, the level of activation within this region during speech production correlated positively with the longitudinal recovery of speech production across the two time points (as measured by the in-scanner performance in the Speech task). This relationship was observed for activation in both the early phase (r = 0.363, P = 0.03 one-tailed) and the late phase (r = 0.538, P = 0.004). Furthermore, presupplem
Geranmayeh F, Leech R, Wise RJS, 2016, Network dysfunction predicts speech production after left hemisphere stroke, Neurology, Vol: 86, Pages: 1296-1305, ISSN: 0028-3878
Objective: To investigate the role of multiple distributed brain networks, including the default mode, fronto-temporo-parietal, and cingulo-opercular networks, which mediate domain-general and task-specific processes during speech production after aphasic stroke.Methods: We conducted an observational functional MRI study to investigate the effects of a previous left hemisphere stroke on functional connectivity within and between distributed networks as patients described pictures. Study design included various baseline tasks, and we compared results to those of age-matched healthy participants performing the same tasks. We used independent component and psychophysiological interaction analyses.Results: Although activity within individual networks was not predictive of speech production, relative activity between networks was a predictor of both within-scanner and out-of-scanner language performance, over and above that predicted from lesion volume, age, sex, and years of education. Specifically, robust functional imaging predictors were the differential activity between the default mode network and both the left and right fronto-temporo-parietal networks, respectively activated and deactivated during speech. We also observed altered between-network functional connectivity of these networks in patients during speech production.Conclusions: Speech production is dependent on complex interactions among widely distributed brain networks, indicating that residual speech production after stroke depends on more than the restoration of local domain-specific functions. Our understanding of the recovery of function following focal lesions is not adequately captured by consideration of ipsilesional or contralesional brain regions taking over lost domain-specific functions, but is perhaps best considered as the interaction between what remains of domain-specific networks and domain-general systems that regulate behavior.
Geranmayeh F, Wise R, 2015, NETWORK DYSFUNCTION IN POST-STROKE APHASIA, Annual Meeting of the Association-of-British-Neurologists (ABN), Publisher: BMJ PUBLISHING GROUP, ISSN: 0022-3050
Geranmayeh F, Leech R, Wise RJS, 2015, Semantic retrieval during overt picture description: Left anterior temporal or the parietal lobe?, NEUROPSYCHOLOGIA, Vol: 76, Pages: 125-135, ISSN: 0028-3932
Geranmayeh F, Wise RJS, Leech R, et al., 2015, Measuring vascular reactivity with breath-holds after stroke: a method to aid interpretation of group-level BOLD signal changes in longitudinal fMRI studies, Human Brain Mapping, Vol: 36, Pages: 1755-1771, ISSN: 1097-0193
Blood oxygenation level-dependent (BOLD) contrast functional magnetic resonance imaging (fMRI) is a widely used technique to map brain function, and to monitor its recovery after stroke. Since stroke has a vascular etiology, the neurovascular coupling between cerebral blood flow and neural activity may be altered, resulting in uncertainties when interpreting longitudinal BOLD signal changes. The purpose of this study was to demonstrate the feasibility of using a recently validated breath-hold task in patients with stroke, both to assess group level changes in cerebrovascular reactivity (CVR) and to determine if alterations in regional CVR over time will adversely affect interpretation of task-related BOLD signal changes. Three methods of analyzing the breath-hold data were evaluated. The CVR measures were compared over healthy tissue, infarcted tissue and the peri-infarct tissue, both sub-acutely (∼2 weeks) and chronically (∼4 months). In this cohort, a lack of CVR differences in healthy tissue between the patients and controls indicates that any group level BOLD signal change observed in these regions over time is unlikely to be related to vascular alterations. CVR was reduced in the peri-infarct tissue but remained unchanged over time. Therefore, although a lack of activation in this region compared with the controls may be confounded by a reduced CVR, longitudinal group-level BOLD changes may be more confidently attributed to neural activity changes in this cohort. By including this breath-hold-based CVR assessment protocol in future studies of stroke recovery, researchers can be more assured that longitudinal changes in BOLD signal reflect true alterations in neural activity.
Geranmayeh F, Brownsett SLE, Wise RJS, 2014, Task-induced brain activity in aphasic stroke patients: what is driving recovery?, BRAIN, Vol: 137, Pages: 2632-2648, ISSN: 0006-8950
Geranmayeh F, Wise RJS, Mehta A, et al., 2014, Overlapping Networks Engaged during Spoken Language Production and Its Cognitive Control, JOURNAL OF NEUROSCIENCE, Vol: 34, Pages: 8728-8740, ISSN: 0270-6474
Brownsett SLE, Warren JE, Geranmayeh F, et al., 2014, Cognitive control and its impact on recovery from aphasic stroke, BRAIN, Vol: 137, Pages: 242-254, ISSN: 0006-8950
Dassan P, Geranmayeh F, Davies N, et al., 2012, INPATIENT OBSTETRIC REFERRALS TO NEUROLOGY SERVICES: A CROSS-SECTIONAL SURVEY, Annual Meeting of the Association-of-British-Neurologists, Publisher: BMJ PUBLISHING GROUP, ISSN: 0022-3050
Geranmayeh F, Pritchard J, Janssen JC, 2012, Recurrent sensory and motor neuropathy., Pract Neurol, Vol: 12, Pages: 253-256
Geranmayeh F, Brownsett SLE, Leech R, et al., 2012, The contribution of the inferior parietal cortex to spoken language production, BRAIN AND LANGUAGE, Vol: 121, Pages: 47-57, ISSN: 0093-934X
Lyons OTA, Smith C, Winston JS, et al., 2010, Impact of UK academic foundation programmes on aspirations to pursue a career in academia, MEDICAL EDUCATION, Vol: 44, Pages: 996-1005, ISSN: 0308-0110
Geranmayeh F, Clement E, Feng LH, et al., 2010, Genotype-phenotype correlation in a large population of muscular dystrophy patients with LAMA2 mutations, NEUROMUSCULAR DISORDERS, Vol: 20, Pages: 241-250, ISSN: 0960-8966
Geranmayeh F, Waters K, Takon I, et al., 2008, Chromosome 10q26.3 deletion associated with neurodevelopmental impairment and dysmorphic features, British Human Genetics Conference, Publisher: B M J PUBLISHING GROUP, Pages: S61-S61, ISSN: 0022-2593
Geranmayeh F, Usman S, Bhutiani R, 2008, Jejunal ischaemia - rare aetiologies and a surgical dilemma, ACTA GASTRO-ENTEROLOGICA BELGICA, Vol: 71, Pages: 263-266, ISSN: 1784-3227
Geranmayeh F, Ashkan K, 2008, Mind on canvas: anatomy, signs and neurosurgery in art, BRITISH JOURNAL OF NEUROSURGERY, Vol: 22, Pages: 1-12, ISSN: 0268-8697
Geranmayeh F, Christian L, Turkheimer FE, et al., 2005, A need to clarify the role of apolipoprotein E in peripheral nerve injury and repair, JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Vol: 10, Pages: 344-345, ISSN: 1085-9489
Geranmayeh F, Scheithauer BW, Graeber MB, 2005, Microglia in gemistocytic astrocytomas, 2nd Quadrennial Meeting of the World-Federation-of-Neuro-Oncology/6th Meeting of the European-Association-for-Neur-Oncology, Publisher: DUKE UNIV PRESS, Pages: 328-328, ISSN: 1522-8517
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