A developmental and genetic classification for malformations of cortical development: update 2012.

Malformations of cerebral cortical development include a wide range of developmental disorders that are common causes of neurodevelopmental delay and epilepsy. In addition, study of these disorders contributes greatly to the understanding of normal brain development and its perturbations. The rapid recent evolution of molecular biology, genetics and imaging has resulted in an explosive increase in our knowledge of cerebral cortex development and in the number and types of malformations of cortical development that have been reported. These advances continue to modify our perception of these malformations. This review addresses recent changes in our perception of these disorders and proposes a modified classification based upon updates in our knowledge of cerebral cortical development

Linking Visual Cortical Development to Visual Perception

Defense Advanced Research Projects Agency and the Office of Naval Research (N00014-95-1-0409); National Science Foundation (IRI-97-20333); Office of Naval Research (N00014-95-1-0657

SnapShot: Cortical Development

Stem Cell and Regenerative Biolog

Inter-areal coordination of columnar architectures during visual cortical development

The occurrence of a critical period of plasticity in the visual cortex has long been established, yet its function in normal development is not fully understood. Here we show that as the late phase of the critical period unfolds, different areas of cat visual cortex develop in a coordinated manner. Orientation columns in areas V1 and V2 become matched in size in regions that are mutually connected. The same age trend is found for such regions in the left and right brain hemisphere. Our results indicate that a function of critical period plasticity is to progressively coordinate the functional architectures of different cortical areas - even across hemispheres.Comment: 30 pages, 1 table, 6 figure

Models for preterm cortical development using non invasive clinical EEG

The objective of this study was to evaluate the piglet and the mouse as model systems for preterm cortical development. According to the clinical context, we used non invasive EEG recordings. As a prerequisite, we developed miniaturized Ag/AgCl electrodes for full band EEG recordings in mice and verified that Urethane had no effect on EEG band power. Since mice are born with a “preterm” brain, we evaluated three age groups: P0/P1, P3/P4 and P13/P14. Our aim was to identify EEG patterns in the somatosensory cortex which are distinguishable between developmental stages and represent a physiologic brain development. In mice, we were able to find clear differences between age groups with a simple power analysis of EEG bands and also for phase locking and power spectral density. Interhemispheric coherence between corresponding regions can only be seen in two week old mice. The canolty maps for piglets as well as for mice show a clear PAC (phase amplitude coupling) pattern during development. From our data it can be concluded that analytic tools relying on network activity, as for example PAC (phase amplitude coupling) are best suited to extract basic EEG patterns of cortical development across species

Cortical development: Receiving Reelin

AbstractRecent genetic and biochemical studies indicate that lipoprotein receptors are components of the neuronal receptor for Reelin, mediating the glycoprotein’s essential function in cortical development. At least eight cadherin-related neuronal receptors may also play a part in this signalling system

Pinwheel stabilization by ocular dominance segregation

We present an analytical approach for studying the coupled development of ocular dominance and orientation preference columns. Using this approach we demonstrate that ocular dominance segregation can induce the stabilization and even the production of pinwheels by their crystallization in two types of periodic lattices. Pinwheel crystallization depends on the overall dominance of one eye over the other, a condition that is fulfilled during early cortical development. Increasing the strength of inter-map coupling induces a transition from pinwheel-free stripe solutions to intermediate and high pinwheel density states.Comment: 10 pages, 4 figure

Hippo signalling in mammalian cortical development

The cerebral cortex in humans is composed of billions of morphologically and functionally distinct neurons. Development of the neocortex requires an orchestrated succession of a series of processes, the appropriate generation, migration, and positioning of neurons, the acquisition of layer-specific transcriptional hallmarks, and the establishment of precise axonal projections. We have primarily focussed on elucidating the transcriptomic landscape of murine embryonic neural stem cells (NSCs), basal progenitors (BPs) and newborn neurons (NBNs) at the population level. I have focussed on one underexplored signalling pathway in the brain- the Hippo signalling pathway. Hippo signalling effectors are expressed dynamically during the course of development in NSCs and BPs at mRNA level. Hippo transcription factors (TFs), Tead1 and Tead3 show higher expression during gliogenesis while Tead2 is expressed at relatively higher levels during early phases of neural expansion. Known to be redundant in other biological systems, I explored different effects of three Tead TFs in NSCs using gain and loss of function. I observe reciprocal effects on neuronal migration and fate with Tead1, Tead3 and Tead2. We identified ApoE, Cyr61 and Dab2 as potential direct targets of Tead TFs in NSCs. ApoE gain of function partially recapitulates the gain of function of Tead2, reducing cell migration to the cortical plate (CP) and Dab2 gain of function recapitulates the gain of function of Tead1, an increased migration to CP. ApoE and Dab2 are involved in Reelin signalling and hence we provide the first link between Hippo and Reelin signalling pathways controlling cortical development