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The human brain is often considered to be the most cognitively capable among mammalian brains and to be much larger than expected for a mammal of our body size. Although the number of neurons is generally assumed to be a determinant of computational power, and despite the widespread quotes that the human brain contains 100 billion neurons and ten times more(More)
Callosal dysgenesis (CD) is observed in many neurodevelopmental conditions, but its subjacent mechanisms are unknown, despite extensive research on animals. Here we employ magnetic resonance diffusion tensor imaging and tractography in human CD to reveal the aberrant circuitry of these brains. We searched particularly for evidence of plasticity. Four main(More)
The rat brain increases >6x in mass from birth to adulthood, presumably through the addition of glial cells and increasing neuronal size, without the addition of neurons. To test this hypothesis, here we investigate quantitatively the postnatal changes in the total number of neuronal and non-neuronal cells in the developing rat brain, and examine how these(More)
How do cell number and size determine brain size? Here, we show that, in the order Rodentia, increased size of the cerebral cortex, cerebellum, and remaining areas across six species is achieved through greater numbers of neurons of larger size, and much greater numbers of nonneuronal cells of roughly invariant size, such that the ratio between total(More)
Stereological techniques that estimate cell numbers must be restricted to well defined structures of isotropic architecture and therefore do not apply to the whole brain or to large neural regions. We developed a novel, fast, and inexpensive method to quantify total numbers of neuronal and non-neuronal cells in the brain or any dissectable regions thereof.(More)
Glial cells and extracellular matrix (ECM) molecules surround developing fiber tracts and are implicated in axonal pathfinding. These and other molecules are produced by these strategically located glial cells and have been shown to influence axonal growth across the midline in rodents. We searched for similar cellular and molecular structures surrounding(More)
Chondroitin sulfate (CS) carrying proteoglycans (PGs) are widely expressed in the nervous system, and there is increasing evidence that they regulate developmental mechanisms like neurite outgrowth, axonal guidance and neuronal migration. Moreover, they can also act indirectly by organizing and/or modulating growth factors and guidance molecules. We found(More)
Previous studies have indicated that amputation or deafferentation of a limb induces functional changes in sensory (S1) and motor (M1) cortices, related to phantom limb pain. However, the extent of cortical reorganization after lower limb amputation in patients with nonpainful phantom phenomena remains uncertain. In this study, we combined functional(More)
In the human brain, the transformation of radial glial cells (RGC) into astrocytes has been studied only rarely. In this work, we were interested in studying the morphologic aspects underlying this transformation during the fetal/perinatal period, particularly emphasizing the region-specific glial fiber anatomy in the medial cortex. We have used(More)
Alzheimer’s disease (AD) is a major public health problem, and there is currently no clinically accepted treatment to cure it or to stop its progression. Fibrillar aggregates of the β−amyloid peptide (Aβ) are major constituents of the senile plaques found in the brains of AD patients and have been related to AD neurotoxicity. Here it is shown that(More)