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E Saralidze, L Khuchua, I Kobaidze
The interaction between different brain structures could be crucial to predicting seizure occurrence, threshold and spread. Moreover, the sleep-wake cycle and electrical activity of brain structures in different phases of sleep could significantly affect the pattern and extent of seizure spread, and therefore the characteristics of epileptic activity. In this animal model using 15 Wistar rats, we show that the duration of hippocampal seizures, induced by electrical stimulation of the hippocampus, is significantly increased during slow sleep...
September 2016: Georgian Medical News
Benjamin Albright, Roni Dhaher, Helen Wang, Roa Harb, Tih-Shih W Lee, Hitten Zaveri, Tore Eid
Loss of glutamine synthetase (GS) in hippocampal astrocytes has been implicated in the causation of human mesial temporal lobe epilepsy (MTLE).However, the mechanism by which the deficiency in GS leads to epilepsy is incompletely understood. Here we ask how hippocampal GS inhibition affects seizure phenotype and neuronal activation during epilepsy development (epileptogenesis). Epileptogenesis was induced by infusing the irreversible GS blocker methionine sulfoximine (MSO) unilaterally into the hippocampal formation of rats...
October 18, 2016: Experimental Neurology
Yun Kyoung Ryu, Reilley P Mathena, Sanghee Lim, Minhye Kwak, Michael Xu, Cyrus D Mintz
BACKGROUND: Early postnatal exposure to general anesthetic agents causes a lasting impairment in learning and memory in animal models. One hypothesis to explain this finding is that exposure to anesthetic agents during critical points in neural development disrupts the formation of brain circuitry. Here, we explore the effects of sevoflurane on the neuronal growth cone, a specialization at the growing end of axons and dendrites that is responsible for the targeted growth that underlies connectivity between neurons...
October 2016: Journal of Neurosurgical Anesthesiology
Julie M Hall, Kaylena A Ehgoetz Martens, Courtney C Walton, Claire O'Callaghan, Peter E Keller, Simon J G Lewis, Ahmed A Moustafa
Parkinson's disease (PD) is a heterogeneous neurological disorder with a variety of motor and non-motor symptoms. The underlying mechanisms of these symptoms are not fully understood. An increased interest in structural connectivity analyses using diffusion tensor imaging (DTI) in PD has led to an expansion of our understanding of the impact of abnormalities in diffusivity on phenotype. This review outlines the contribution of these abnormalities to symptoms of PD including bradykinesia, tremor and non-tremor phenotypes, freezing of gait, cognitive impairment, mood, sleep disturbances, visual hallucinations and olfactory dysfunction...
September 28, 2016: Parkinsonism & related Disorders
Heiko Braak, Albert C Ludolph, Manuela Neumann, John Ravits, Kelly Del Tredici
Two nerve cells types, Betz cells in layer Vb of the primary motor neocortex and α-motoneurons of the lower brainstem and spinal cord, become involved at the beginning of the pathological cascade underlying sporadic amyotrophic lateral sclerosis (sALS). In both neuronal types, the cell nuclei forfeit their normal (non-phosphorylated) expression of the 43-kDa transactive response DNA-binding protein (TDP-43). Here, we present initial evidence that in α-motoneurons the loss of normal nuclear TDP-43 expression is followed by the formation of phosphorylated TDP-43 aggregates (pTDP-43) within the cytoplasm, whereas in Betz cells, by contrast, the loss of normal nuclear TDP-43 expression remains mostly unaccompanied by the development of cytoplasmic aggregations...
October 18, 2016: Acta Neuropathologica
Joshua J Emrick, Brooks A Gross, Brett T Riley, Gina R Poe
STUDY OBJECTIVES: Investigators assign sleep-waking states using brain activity collected from a single site, assuming that states occur at the same time throughout the brain. We sought to determine if sleep-waking states differ between two separate structures: the hippocampus and neocortex. METHODS: We measured electrical signals (electroencephalograms and electromyograms) during sleep from the hippocampus and neocortex of five freely behaving adult male rats. We assigned sleep-waking states in 10-sec epochs based on standard scoring criteria across a 4 h recording and analyzed and compared states and signals from simultaneous epochs between sites...
October 10, 2016: Sleep
Robert G Averkin, Viktor Szemenyei, Sándor Bordé, Gábor Tamás
Ultra-high-frequency network events in the hippocampus are instrumental in a dialogue with the neocortex during memory formation, but the existence of transient ∼200 Hz network events in the neocortex is not clear. Our recordings from neocortical layer II/III of freely behaving rats revealed field potential events at ripple and high-gamma frequencies repeatedly occurring at troughs of spindle oscillations during sleep. Juxtacellular recordings identified subpopulations of fast-spiking, parvalbumin-containing basket cells with epochs of firing at ripple (∼200 Hz) and high-gamma (∼120 Hz) frequencies detected during spindles and centered with millisecond precision at the trough of spindle waves in phase with field potential events but phase shifted relative to pyramidal cell firing...
October 12, 2016: Neuron
David E Vance, Pariya L Fazeli, Shameka L Cody, Tyler R Bell, Caitlin Northcutt Pope
For centuries, since the advent of harnessing magnetic and electrical energies, humans have been applying such energies to various body parts, including the brain, with the goal of improving health. Advancements over the past two decades in the production and affordability of such devices that precisely deliver such energies have resulted in novel therapeutic uses. One technique in particular, transcranial Direct Current Stimulation (tDCS), uses electrodes placed on the scalp to deliver a low electrical current to various areas on the surface of the neocortex...
2016: Nursing: Research and Reviews
Naomi Onisawa, Hiroyuki Manabe, Kensaku Mori
During slow-wave sleep, inter-areal communications via coordinated slow oscillatory activities occur in the large-scale networks of the mammalian neocortex. Because olfactory cortex (OC) areas, which belong to paleocortex, show characteristic sharp-wave activity during slow-wave sleep, we examined whether OC sharp-waves in freely behaving rats occur in temporal coordination with up- and down-states of the orbitofrontal cortex (OFC) slow oscillation. Simultaneous recordings of local field potentials and spike activities in the OC and OFC showed that during the down-state in the OFC, the OC also exhibited down-state with greatly reduced neuronal activity and suppression of sharp-wave generation...
October 12, 2016: Journal of Neurophysiology
Majken Kjær, Katrine Fabricius, Rasmus Krarup Sigaard, Bente Pakkenberg
The early postnatal development of neuron and glia numbers is poorly documented in human brain. Therefore we estimated using design-based stereological methods the regional volumes of neocortex and the numbers of neocortical neurons and glial cells for 10 children (4 girls and 6 boys), ranging from neonate to 3 years of age. The 10 infants had a mean of 20.7 × 10(9) neocortical neurons (range 18.0-24.8 × 10(9)) estimated with a coefficient of variation (CV) = 0.11; this range is similar to adult neuron numbers...
October 12, 2016: Cerebral Cortex
Julian P Knopf, Patrick R Hof, Helmut H A Oelschläger
We investigated the morphology of four primary neocortical projection areas (somatomotor, somatosensory, auditory, visual) qualitatively and quantitatively in the Indian river dolphins (Platanista gangetica gangetica, P. gangetica minor) with histological and stereological methods. For comparison, we included brains of other toothed whale species. Design-based stereology was applied to the primary neocortical areas (M1, S1, A1, V1) of the Indian river dolphins and compared to those of the bottlenose dolphin with respect to layers III and V...
October 13, 2016: Brain, Behavior and Evolution
Sven Gottschalk, Thomas Felix Fehm, Xose Luís Deán-Ben, Vassiliy Tsytsarev, Daniel Razansky
Visualization of whole brain activity during epileptic seizures is essential for both fundamental research into the disease mechanisms and the development of efficient treatment strategies. It has been previously discussed that pathological synchronization originating from cortical areas may reinforce backpropagating signaling from the thalamic neurons, leading to massive seizures through enhancement of high frequency neural activity in the thalamocortical loop. However, the study of deep brain neural activity is challenging with the existing functional neuroimaging methods due to lack of adequate spatiotemporal resolution or otherwise insufficient penetration into subcortical areas...
January 2017: Neurophotonics
Zoe H Larsen, Praveen Chander, Jason A Joyner, Crina M Floruta, Tess L Demeter, Jason P Weick
BACKGROUND: Prenatal alcohol exposure (PAE) in animal models results in excitatory-inhibitory (E/I) imbalance in neocortex due to alterations in the GABAergic interneuron (IN) differentiation and migration. Thus, E/I imbalance is a potential cause for intellectual disability in individuals with fetal alcohol spectrum disorder (FASD), but whether ethanol (EtOH) changes glutamatergic and GABAergic IN specification during human development remains unknown. Here, we created a human cellular model of PAE/FASD and tested the hypothesis that EtOH exposure during differentiation of human pluripotent stem cell-derived neurons (hPSNs) would cause the aberrant production of glutamatergic and GABAergic neurons, resulting in E/I imbalance...
September 26, 2016: Alcoholism, Clinical and Experimental Research
Johannes Brettschneider, David J Irwin, Susana Boluda, Matthew D Byrne, Lubin Fang, Edward B Lee, John L Robinson, EunRan Suh, Vivianna M Van Deerlin, Jon B Toledo, Murray Grossman, Howard Hurtig, Reinhard Dengler, Susanne Petri, Virginia M-Y Lee, John Q Trojanowski
AIMS: To identify early foci of α-synuclein (α-syn pathology) accumulation, subsequent progression and neurodegeneration in multiple system atrophy of the cerebellar type (MSA-C). METHODS: We analyzed 70 μm thick sections of 10 cases with MSA-C and 24 normal controls. RESULTS: MSA-C cases with the lowest burden of pathology showed α-syn glial cytoplasmic inclusions (GCIs) in the cerebellum as well as in medullary and pontine cerebellar projections...
September 22, 2016: Neuropathology and Applied Neurobiology
Guy Eyal, Matthijs B Verhoog, Guilherme Testa-Silva, Yair Deitcher, Johannes C Lodder, Ruth Benavides-Piccione, Juan Morales, Javier DeFelipe, Christiaan Pj de Kock, Huibert D Mansvelder, Idan Segev
The advanced cognitive capabilities of the human brain are often attributed to our recently evolved neocortex. However, it is not known whether the basic building blocks of human neocortex, the pyramidal neurons, possess unique biophysical properties that might impact on cortical computations. Here we show that layer 2/3 pyramidal neurons from human temporal cortex (HL2/3 PCs) have a specific membrane capacitance (Cm) of ~0.5 µF/cm(2), half of the commonly accepted 'universal' value (~1 µF/cm(2)) for biological membranes...
October 6, 2016: ELife
Prabhuanand Selvaraj, Lan Xiao, Cheol Lee, Saravana R K Murthy, Niamh X Cawley, Malcolm Lane, Istvan Merchenthaler, Sohyun Ahn, Y Peng Loh
Embryonic neurodevelopment involves inhibition of proliferation of multipotent neural stem cells followed by differentiation into neurons, astrocytes and oligodendrocytes to form the brain. We have identified a new neurotrophic factor, NF-α1, which inhibits proliferation and promotes differentiation of neural stem cell/progenitors derived from E13.5 mouse cortex. Inhibition of proliferation of these cells was mediated through negatively regulating the Wnt pathway and decreasing β-catenin. NF-α1 induced differentiation of neural stem cells to astrocytes by enhancing Glial Fibrillary Acidic Protein (GFAP) expression through activating the ERK1/2-Sox9 signaling pathway...
October 6, 2016: Stem Cells
Simon Früh, Jennifer Romanos, Patrizia Panzanelli, Daniela Bürgisser, Shiva K Tyagarajan, Kevin P Campbell, Mirko Santello, Jean-Marc Fritschy
: Distinct types of GABAergic interneurons target different subcellular domains of pyramidal cells, thereby shaping pyramidal cell activity patterns. Whether the presynaptic heterogeneity of GABAergic innervation is mirrored by specific postsynaptic factors is largely unexplored. Here we show that dystroglycan, a protein responsible for the majority of congenital muscular dystrophies when dysfunctional, has a function at postsynaptic sites restricted to a subset of GABAergic interneurons...
October 5, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Atahualpa Castillo-Morales, Jimena Monzón-Sandoval, Alexandra A de Sousa, Araxi O Urrutia, Humberto Gutierrez
Increased brain size is thought to have played an important role in the evolution of mammals and is a highly variable trait across lineages. Variations in brain size are closely linked to corresponding variations in the size of the neocortex, a distinct mammalian evolutionary innovation. The genomic features that explain and/or accompany variations in the relative size of the neocortex remain unknown. By comparing the genomes of 28 mammalian species, we show that neocortical expansion relative to the rest of the brain is associated with variations in gene family size (GFS) of gene families that are significantly enriched in biological functions associated with chemotaxis, cell-cell signalling and immune response...
October 2016: Open Biology
Akiya Watakabe, Osamu Sadakane, Katsusuke Hata, Masanari Ohtsuka, Masafumi Takaji, Tetsuo Yamamori
It is important to study the neural connectivities and functions in primates. For this purpose, it is critical to be able to transfer genes to certain neurons in the primate brain so that we can image the neuronal signals and analyze the function of the transferred gene. Toward this end, our team has been developing gene transfer systems using viral vectors. In this review, we summarize our current achievements as follows. 1) We compared the features of gene transfer using five different AAV serotypes in combination with three different promoters, namely, CMV, mouse CaMKII (CaMKII), and human synapsin 1 (hSyn1), in the marmoset cortex with those in the mouse and macaque cortices...
October 5, 2016: Developmental Neurobiology
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