Background: Extremely preterm (EPT)/extremely low-birth-weight (ELBW) children attaining school age and adolescence often have problems with executive functions such as working memory and selective attention. Our aim was to investigate a hypothesized difference in blood oxygen level-dependent (BOLD) activation during a selective attention-working memory task in EPT/ELBW children as compared with term-born controls.
Methods: A regional cohort of 28 EPT/ELBW children and 28 term-born controls underwent functional magnetic resonance imaging (fMRI) scanning at 11 y of age while performing a combined Stroop n-back task. Group differences in BOLD activation were analyzed with Statistical Parametric Mapping 8 analysis software package, and reaction times (RTs) and response accuracy (RA) were compared in a multifactorial ANOVA test.
Results: The BOLD activation pattern in the preterm group involved the same areas (cingulate, prefrontal, and parietal cortexes), but all areas displayed significantly less activation than those in the control group, particularly when the cognitive load was increased. The RA results corresponded with the activation data in that the preterm group had significantly fewer correct responses. No group difference was found regarding RTs.
Conclusion: Children born EPT/ELBW displayed reduced working memory and selective attention capacity as compared with term-born controls. These impairments had neuronal correlates with reduced BOLD activation in areas responsible for online stimulus monitoring, working memory, and cognitive control.
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http://dx.doi.org/10.1038/pr.2013.79 | DOI Listing |
Cerebrospinal fluid (CSF) dynamics, driven by sensory stimulation-induced neuronal activity, is crucial for maintaining homeostasis and clearing metabolic waste. However, it remains unclear whether such CSF flow is impaired in age-related neurodegenerative diseases of the visual system. This study addresses this gap by examining CSF flow during visual stimulation in glaucoma patients and healthy older adults using functional magnetic resonance imaging.
View Article and Find Full Text PDFThe complementary strengths of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) have driven extensive research into integrating these two noninvasive modalities to better understand the neural mechanisms underlying cognitive, sensory, and motor functions. However, the precise neural patterns associated with motor functions, especially imagined movements, remain unclear. Specifically, the correlations between electrophysiological responses and hemodynamic activations during executed and imagined movements have not been fully elucidated at a whole-brain level.
View Article and Find Full Text PDFNeuroimaging methods rely on models of neurovascular coupling that assume hemodynamic responses evolve seconds after changes in neural activity. However, emerging evidence reveals noncanonical BOLD (blood oxygen level dependent) responses that are delayed under stress and aberrant in neuropsychiatric conditions. To investigate BOLD coupling to resting-state fluctuations in neural activity, we simultaneously recorded EEG and fMRI in people with schizophrenia and psychiatrically unaffected participants.
View Article and Find Full Text PDFBackground: Writer's cramp (WC) dystonia is an involuntary movement disorder with distributed abnormalities in the brain's motor network. Prior studies established the potential for repetitive transcranial magnetic stimulation (rTMS) to either premotor cortex (PMC) or primary somatosensory cortex (PSC) to modify symptoms. However, clinical effects have been modest with limited understanding of the neural mechanisms hindering therapeutic advancement of this promising approach.
View Article and Find Full Text PDFJ Cereb Blood Flow Metab
January 2025
Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Hyperpolarized-C magnetic resonance imaging (HP-C MRI) was used to image changes in C-lactate signal during a visual stimulus condition in comparison to an eyes-closed control condition. Whole-brain C-pyruvate, C-lactate and C-bicarbonate production was imaged in healthy volunteers (N = 6, ages 24-33) for the two conditions using two separate hyperpolarized C-pyruvate injections. BOLD-fMRI scans were used to delineate regions of functional activation.
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