An event-related functional magnetic resonance imaging study of prefrontal cortex was conducted during which subjects performed a visual “oddball” target detection task. Exemplars of three stimulus categories were presented at a rate of one per 1.5 sec for 10 runs, each consisting of 132 trials. Standards were color squares of varying sizes that were presented on ∼92% of trials. Targets were color circles of varying sizes presented irregularly on ∼4% of trials. Novels were pictures of everyday objects that were also presented irregularly on ∼4% of trials. Ten subjects participated in two separate sessions in which they were required to count mentally or to push a button whenever a target appeared. Targets evoked activation within prefrontal cortex, primarily within the middle frontal gyri (MFG). This MFG activation did not differ as a function of the required response. Novels did not evoke significant activity within this region despite evidence from a separate behavioral and event-related potential study ...

Cardiovascular exercise (CE) is a promising intervention strategy to facilitate cognition and motor learning in healthy and diseased populations of all ages. CE elevates humoral parameters, such as growth factors, and stimulates brain changes potentially relevant for learning and behavioral adaptations. However, the causal relationship between CE-induced brain changes and human's ability to learn remains unclear. We tested the hypothesis that CE elicits a positive effect on learning via alterations in brain structure (morphological changes of gray and white matter) and function (functional connectivity and cerebral blood flow in resting state). We conducted a randomized controlled trial with healthy male and female human participants to compare the effects of a 2 week CE intervention against a non-CE control group on subsequent learning of a challenging new motor task (dynamic balancing; DBT) over 6 consecutive weeks. We used multimodal neuroimaging [T1-weighted magnetic resonance imaging (MRI), diffusion-...

Restoration of functional connectivity is a major contributor to functional recovery after stroke. We investigated the role of reactive astrocytes in functional connectivity and recovery after photothrombotic stroke in mice with attenuated reactive glio...

Functional magnetic resonance imaging (fMRI) combined with population receptive field (pRF) mapping allows for associating positions on the visual cortex to areas on the visual field. Apart from applications in healthy subjects, this method can also be used to examine dysfunctions in patients suffering from partial visual field losses. While such objective measurement of visual deficits (scotoma) is of great importance for, e.g., longitudinal studies addressing treatment effects, it requires a thorough assessment of accuracy and reproducibility of the results obtained. In this study, we quantified the reproducibility of pRF mapping results within and across sessions in case of central visual field loss in a group of 15 human subjects. We simulated scotoma by masking a central area of 2° radius from stimulation to establish ground-truth conditions. This study was performed on a 7T ultra-high field MRI scanner for increased sensitivity. We found excellent intrasession and intersession reproducibility for the...

Background: American-style football players are likely to have experienced exposure to repetitive head impacts. Several studies suggested an association between traumatic brain injury (TBI) and risk of developing misfolded p-Tau protein identified in ch...

The prevalence of overweight and obesity, insulin resistance, hyperglycemia, dyslipidemia and type 2 diabetes mellitus (T2DM) are increasing in children, with epidemic rates reported in children in the United States. Increased adiposity and related reductions in insulin sensitivity are major risk factors for the development of hyperglycemia, dyslipidemia, and cardiovascular disease. Antipsychotic medications are extensively used in children, with certain agents producing greater increases in weight and adiposity than other commonly used drugs in this age group. However, no study in children has sensitively quantified the metabolic effects of widely used atypical antipsychotics. Adiposity can be directly measured using whole-body glucose and lipid kinetics measured with stable isotope tracer methodology during hyperinsulinemic-euglycemic clamp conditions, whole body dual energy x-ray absorptiometry (DEXA), and abdominal magnetic resonance imaging (MRI). These sensitive methods can be used to measure tissue-...

Discoveries in the study of vascular dementia could lead to earlier diagnoses and new treatments for patients with Alzheimer’s disease.

Enlarged perivascular spaces (EPVS) have been recently proposed as a means to investigate abnormalities of the brain glymphatic system, which is considered to have a role in the clearance of neurotoxic metabolites. Multiple Sclerosis (MS) patients showe...

Primary and nonprimary cerebral cortex mature along different timescales; however, the differences between the rates of maturation of primary and nonprimary cortex are unclear. Cortical maturation can be measured through changes in tissue microstructure detectable by diffusion magnetic resonance imaging (MRI). In this study, diffusion tensor imaging (DTI) was used to characterize the maturation of Heschl’s gyrus (HG), which contains both primary auditory cortex (pAC) and nonprimary auditory cortex (nAC), in 90 preterm infants between 26 and 42 weeks postmenstrual age (PMA). The preterm infants were in different acoustical environments during their hospitalization: 46 in open ward beds and 44 in single rooms. A control group consisted of 15 term-born infants. Diffusion parameters revealed that (1) changes in cortical microstructure that accompany cortical maturation had largely already occurred in pAC by 28 weeks PMA, and (2) rapid changes were taking place in nAC between 26 and 42 weeks PMA. At term equiva...

While the effects of diabetes upon the brain are well known, the pathophysiology underlying these pathological and functional changes is not understood. Human diabetes is associated with cognitive decline, stroke, cerebral atrophy and white matter abnormalities (WMA). One potential mechanism is the deposition of advanced glycosylation end products (AGEs) and their interaction with receptors for AGEs (RAGE). We studied an in vivo model of streptozotocin-induced chronic long term (8-9) experimental diabetes in mice and littermate age- and sex-matched controls. Immunohistochemical expression of RAGE was detected over multiple cerebral cell types, including neurons, astrocytes, oligodendrocytes, and microglia, as well as over white matter pathways. RAGE expression was significantly greater over regions of identified magnetic resonance imaging (MRI) T2 multi-echo image abnormalities and within regions of myelination deficit. Quantitative real-time polymerase chain reaction detected a 160 fold elevations in the ...