Descriptors of cytoarchitecture and tissue microstructure such as average axon diameters (AAD) can provide valuable information about the functional organization of normal and pathological white matter. The linear relationship between the diameters of m...

The aging brain undergoes structural changes even in very healthy individuals. Quantifying these changes could help disentangle pathologic changes from those associated with the normal human aging process. Using longitudinal magnetic resonance imaging (MRI) data from 227 carefully selected healthy human cohort with age ranging from 50 to 80 years old at baseline scan, we quantified age-related volumetric changes in the brain of healthy human older adults. Longitudinally, the rates of tissue loss in total gray matter (GM) and white matter (WM) were 2497.5 and 2579.8 mm3 per year, respectively. Across the whole brain, the rates of GM decline varied with regions in the frontal and parietal lobes having faster rates of decline, whereas some regions in the occipital and temporal lobes appeared relatively preserved. In contrast, cross-sectional changes were mainly observed in the temporal-occipital regions. Similar longitudinal atrophic changes were also observed in subcortical regions including thalamus, hippoc...

Introduction Cerebrospinal fluid (CSF) biomarkers appear to be sensitive to the pathological status of individuals at high-risk for MCI or AD. Recent studies in such individuals have highlighted a synergistic interaction between amyloid-β and hyperphosp...

Both co-registration of the in vivo MRI to postmortem brain for MRI-pathological correlations, as well as sampling of brain tissue for stereological measures, require precisely spaced slices of the human brain. We have developed an agar-embedding method for brain-slicing that minimizes geometrical distortions from slicing and handling the fixed postmortem brain. To facilitate MRI co-registration, each hemisphere is handled separately. We embed the fixed brain hemisphere, with plastic reference markers, in agar. The block containing the brain and markers is sliced at 5 mm intervals using a rotary slicer. Each slice is photographed with a high-resolution digital camera. The digital images are reconstructed as a 3-dimensional volume via a point-based registration method for multi-slice registration. The slices of the reconstructed postmortem hemisphere are then co-registered to corresponding slices of an in vivo reference MRI-volume (3-D T1-weighted coronal SPGR, 1.4 mm slice thickness) using polynomial warpi...

Background: MRI-histology correlation studies provide unique opportunities into understanding MRI signatures of disease state, and hence predicting pathological substrates of disease progression from in-vivo imaging. Clearing methods, such as CLARITY, a...

PET imaging of nicotinic acetylcholine receptors (nAChRs) could become an effective tool for the diagnosis and therapy evaluation of neurologic diseases. Despite this, the role of nAChRs α4β2 receptors after brain diseases such as cerebral ischemia and its involvement in inflammatory reaction is still largely unknown. To investigate this, we performed in parallel in vivo magnetic resonance imaging (MRI) and positron emission tomography (PET) with 2[18F]-fluoro-A85380 and [11C]PK11195 at 1, 3, 7, 14, 21, and 28 d after middle cerebral artery occlusion (MCAO) in rats. In the ischemic territory, PET with 2[18F]-fluoro-A85380 and [11C]PK11195 showed a progressive binding increase from days 3–7, followed by a progressive decrease from days 14–28 after cerebral ischemia onset. Ex vivo immunohistochemistry for the nicotinic α4β2 receptor and the mitochondrial translocator protein (18 kDa) (TSPO) confirmed the PET findings and demonstrated the overexpression of α4β2 receptors in both microglia/macrophages and astr...

Non-human animal studies have shown that the structural development of the visual cortex critically depends on postnatal visual input. Brain-imaging studies in humans blind from birth have repeatedly reported a higher cortical thickness of early visual ...

The medial temporal lobe (MTL)—hippocampus and surrounding perirhinal, parahippocampal, and entorhinal cortical areas—has long been known to be critical for long-term memory for events. Recent functional neuroimaging and neuropsychological data in humans performing short-delay tasks suggest that the MTL also contributes to performance even when retention intervals are brief, and single-unit data in rodents reveal sustained, performance-related delay activity in the MTL during delayed-non-match-to-sample tasks. The current study used functional magnetic resonance imaging to examine the relationship between activation in human MTL subregions and performance during a delayed-match-to-sample task with repeated (non-trial-unique) stimuli. On critical trials, the presentation of two faces was followed by a 30 s delay period, after which participants performed two-alternative forced-choice recognition. Functional magnetic resonance imaging revealed significant delay period activity in anterior hippocampus, entorh...

Abstract Empathy is thought to be an advanced capability in human, which allows the individual to comprehend other’s feelings by taking a stand on others. Recently, rodents have been successfully used in studying empathy-related behavior. Since the new ...

High-resolution blood oxygenation level dependent (BOLD) based MRI studies have, recently, become a powerful tool to non-invasively probe the sub-millimeter functional organization of human cortex. However, consensus within the MRI community regarding t...