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Cortical connectivity

Tineke Grent-'t-Jong, Davide Rivolta, Joachim Gross, Ruchika Gajwani, Stephen M Lawrie, Matthias Schwannauer, Tonio Heidegger, Michael Wibral, Wolf Singer, Andreas Sauer, Bertram Scheller, Peter J Uhlhaas
Hypofunction of the N-methyl-d-aspartate receptor (NMDAR) has been implicated as a possible mechanism underlying cognitive deficits and aberrant neuronal dynamics in schizophrenia. To test this hypothesis, we first administered a sub-anaesthetic dose of S-ketamine (0.006 mg/kg/min) or saline in a single-blind crossover design in 14 participants while magnetoencephalographic data were recorded during a visual task. In addition, magnetoencephalographic data were obtained in a sample of unmedicated first-episode psychosis patients (n = 10) and in patients with chronic schizophrenia (n = 16) to allow for comparisons of neuronal dynamics in clinical populations versus NMDAR hypofunctioning...
July 17, 2018: Brain: a Journal of Neurology
Stacey A Bedwell, Chris J Tinsley
Cerebral cortex structure is crucially important for cortical organisation and function. The organisation of prefrontal cortex (PFC) is controversial and here we seek to understand it more clearly through the study of fine scale cortical connections. To determine the ordering of micro-scale input and output connections in the rat PFC we injected small volumes (20-30nl) of anterograde (Fluro-Ruby) and retrograde (Fluoro-Gold) neuroanatomical tracers into PFC. These injections revealed several connected regions of the brain but here we report findings restricted to PFC to temporal cortex and sensory-motor cortex pathways...
July 17, 2018: European Journal of Neuroscience
Wei Xu, Stuart N Baker
Primates (including humans) have a highly developed corticospinal tract, and specialised motor cortical areas which differ in key ways from rodents. Much work on motor cortex has therefore used macaque monkeys as a good animal model for human motor control. However, there is a paucity of data describing the fundamental functional architecture of primate primary motor cortex, which is best addressed with in vitro approaches. In this study we examined the cellular properties and the micro-circuitry of the adult macaque primary motor cortex by carrying out in-vitro intracellular recordings...
July 18, 2018: European Journal of Neuroscience
Joost le Feber, Anneloes Dummer, Gerco C Hassink, Michel J A M van Putten, Jeannette Hofmeijer
In the core of a brain infarct, neuronal death occurs within minutes after loss of perfusion. In the penumbra, a surrounding area with some residual perfusion, neurons initially remain structurally intact, but hypoxia-induced synaptic failure impedes neuronal activity. Penumbral activity may recover or further deteriorate, reflecting cell death. Mechanisms leading to either outcome remain ill-understood, but may involve changes in the excitation to inhibition ( E / I ) ratio. The E / I ratio is determined by structural (relative densities of excitatory and inhibitory synapses) and functional factors (synaptic strengths)...
2018: Frontiers in Cellular Neuroscience
Julius M Kernbach, Theodore D Satterthwaite, Danielle S Bassett, Jonathan Smallwood, Daniel Margulies, Sarah Krall, Philip Shaw, Gaël Varoquaux, Bertrand Thirion, Kerstin Konrad, Danilo Bzdok
Categorical diagnoses from the Diagnostic and Statistical Manual of Mental Disorders (DSM) or International Classification of Diseases (ICD) manuals are increasingly found to be incongruent with emerging neuroscientific evidence that points towards shared neurobiological dysfunction underlying attention deficit/hyperactivity disorder and autism spectrum disorder. Using resting-state functional magnetic resonance imaging data, functional connectivity of the default mode network, the dorsal attention and salience network was studied in 1305 typically developing and diagnosed participants...
July 17, 2018: Translational Psychiatry
Patricia Cowell, Jennifer Gurd
Handedness effects with respect to regional corpus callosum (CC) anatomy remain open to question. Midsagittal CC tracings were obtained from structural MRIs in 21 female monozygotic twin pairs with discordant handedness (MZHd). The CC was divided into 99 percentile widths which were grouped into seven regions based on Denenberg's (1989, 1991b) factor analysis. Results showed that left handed (LH) twins had significantly larger regional widths in CC region W22-39 compared to right handed (RH) twins, an effect present in 19/21 MZHd pairs...
July 12, 2018: Neuroscience
Jed A Diekfuss, Dustin R Grooms, Weihong Yuan, Jonathan Dudley, Kim D Barber Foss, Staci Thomas, Jonathan D Ellis, Daniel K Schneider, James Leach, Scott Bonnette, Gregory D Myer
OBJECTIVES: We aimed to present a unique prospective neurological dataset for participants who experienced an ACL injury. DESIGN: Prospective longitudinal case-control. METHODS: High school female soccer athletes were evaluated using functional magnetic resonance imaging to capture resting-state brain connectivity prior to their competitive season. Two of these athletes later experienced an ACL injury (ACLI). We matched these ACLI participants with eight teammates who did not go on to sustain an ACL injury (uninjured controls, Con) based on age, grade, sex, height, and weight to examine differences in preseason connectivity...
July 10, 2018: Journal of Science and Medicine in Sport
Derek Ray Verley, Daneil Torolira, Brittany A Hessell, Richard L Sutton, Neil G Harris
Traumatic brain injury results in well-known, significant alterations in structural and functional connectivity. While this is especially likely to occur in areas of pathology, deficits in function to, and from remotely connected brain areas, or diaschisis, also occur as a consequence to local deficits. As a result, consideration of the network wiring of the brain may be required to design the most efficacious rehabilitation therapy to target specific functional networks to improve outcome. In this work, we model remote connections after controlled cortical impact injury in the rat through the effect of callosal deafferentation to the opposite, contralesional cortex...
July 17, 2018: Journal of Neurotrauma
Federica Agosta, Gorana Mandic-Stojmenovic, Elisa Canu, Tanja Stojkovic, Francesca Imperiale, Francesca Caso, Elka Stefanova, Massimiliano Copetti, Vladimir S Kostic, Massimo Filippi
This study identified structural and functional brain connectivity alterations in two independent samples of patients along the posterior cortical atrophy (PCA) disease course. Twenty-one PCA patients and 44 controls were recruited from two expert centres. Microstructural damage of white matter (WM) tracts was assessed using probabilistic tractography; resting state (RS) functional connectivity of brain networks was explored using a model free approach; grey matter (GM) atrophy was investigated using voxel-based morphometry...
2018: NeuroImage: Clinical
Justine Renard, Walter J Rushlow, Steven R Laviolette
Marijuana is the most commonly used drug of abuse among adolescents. Considerable clinical evidence supports the hypothesis that adolescent neurodevelopmental exposure to high levels of the principal psychoactive component in marijuana, -delta-9-tetrahydrocanabinol (THC), is associated with a high risk of developing psychiatric diseases, such as schizophrenia later in life. This marijuana-associated risk is believed to be related to increasing levels of THC found within commonly used marijuana strains. Adolescence is a highly vulnerable period for the development of the brain, where the inhibitory GABAergic system plays a pivotal role in the maturation of regulatory control mechanisms in the central nervous system (CNS)...
2018: Frontiers in Psychiatry
C Tur, A Eshaghi, D R Altmann, T M Jenkins, F Prados, F Grussu, T Charalambous, A Schmidt, S Ourselin, J D Clayden, C A M G Wheeler-Kingshott, A J Thompson, O Ciccarelli, A T Toosy
Brain structural covariance networks (SCNs) based on pairwise statistical associations of cortical thickness data across brain areas reflect underlying physical and functional connections between them. SCNs capture the complexity of human brain cortex structure and are disrupted in neurodegenerative conditions. However, the longitudinal assessment of SCN dynamics has not yet been explored, despite its potential to unveil mechanisms underlying neurodegeneration. Here, we evaluated the changes of SCNs over 12 months in patients with a first inflammatory-demyelinating attack of the Central Nervous System and assessed their clinical relevance by comparing SCN dynamics of patients with and without conversion to multiple sclerosis (MS) over one year...
July 16, 2018: Scientific Reports
Chi Chung Alan Fung, Tomoki Fukai
The membrane potentials of cortical neurons in vivo exhibit spontaneous fluctuations between a depolarized UP state and a resting DOWN state during the slow-wave sleeps or in the resting states. This oscillatory activity is believed to engage in memory consolidation although the underlying mechanisms remain unknown. Recently, it has been shown that UP-DOWN state transitions exhibit significantly different temporal profiles in different cortical regions, presumably reflecting differences in the underlying network structure...
July 16, 2018: Scientific Reports
Anna Wilsch, Molly J Henry, Björn Herrmann, Christoph S Herrmann, Jonas Obleser
Increased memory load is often signified by enhanced neural oscillatory power in the alpha range (8--13 Hz), taken to reflect inhibition of task-irrelevant brain regions. The corresponding neural correlates of memory decay, however, are not yet well-understood. In the current study, we investigated auditory short-term memory decay in humans (male and female) using a delayed matching-to-sample task with pure-tone sequences. First, in a behavioral experiment we modeled memory performance over six different delay-phase durations...
July 16, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Simone S Nascimento, Larissa R Oliveira, Josimari M DeSantana
BACKGROUND: There are different ways of dealing with pain and cognitive and meditative therapies (CMT) are alternative ways to regulate the emotions associated with pain. Current studies apply neuroimaging techniques trying to elucidate the neural mechanisms of cognitive strategies for pain. This systematic review aimed to summarize the evidence on brain activity changes after CMT, which include cognitive behavioral therapy, mindfulness and/or meditation, for pain management as well as to evaluate clinical pain outcomes...
August 2018: Complementary Therapies in Medicine
I V Talalay, A V Kurgansky, R I Machinskaya
The anticipation of future events based on a background experience is one of the main components of any goal-directed behavior. Anticipatory attention can be either voluntary (explicit) or involuntary (implicit). We presumed that these two types of anticipatory attention differed in terms of cortical functional organization. We examined this assumption with an experimental model consisting of three experimental sessions (cued attention, implicit learning, and baseline) that were equal in terms of stimuli, motor responses, and cognitive task...
July 16, 2018: Psychophysiology
Guy Eyal, Matthijs B Verhoog, Guilherme Testa-Silva, Yair Deitcher, Ruth Benavides-Piccione, Javier DeFelipe, Christiaan P J de Kock, Huibert D Mansvelder, Idan Segev
We present detailed models of pyramidal cells from human neocortex, including models on their excitatory synapses, dendritic spines, dendritic NMDA- and somatic/axonal Na + spikes that provided new insights into signal processing and computational capabilities of these principal cells. Six human layer 2 and layer 3 pyramidal cells (HL2/L3 PCs) were modeled, integrating detailed anatomical and physiological data from both fresh and postmortem tissues from human temporal cortex. The models predicted particularly large AMPA- and NMDA-conductances per synaptic contact (0...
2018: Frontiers in Cellular Neuroscience
Eduardo Bellomo, Andrew Cooke, James Hardy
This study was designed to test the theorized link between reinvestment, motor chunks, and conscious processing, to provide a thorough examination of reinvestment theory. The authors measured electroencephalographic power and connectivity alongside self-reported conscious processing and behavioral indices of chunking in a 2 (group) × 5 (block) mixed-model design. A total of 55 individuals acquired a motor sequence (blocks A1, A2, A3, and A4) by relatively explicit (errorful) or implicit (errorless) paradigms...
July 14, 2018: Journal of Sport & Exercise Psychology
Hime Suzuki, Rei Enatsu, Aya Kanno, Yuto Suzuki, Rintaro Yokoyama, Satoshi Ookawa, Satoko Ochi, Nobuhiro Mikuni
OBJECTIVE: The present study aimed to investigate the threshold and distribution of afterdischarges (ADs) with cortical electrical stimulation for functional brain mapping. METHOD: We retrospectively analyzed data from 11 patients with medically intractable epilepsy who underwent 50-Hz cortical electrical stimulation for functional mapping followed by resection. These patients became seizure free for more than six months. The threshold and distribution of ADs induced by the stimulation were evaluated...
July 11, 2018: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
Kurt G Schilling, Yurui Gao, Matthew Christian, Vaibhav Janve, Iwona Stepniewska, Bennett A Landman, Adam W Anderson
The squirrel monkey (Saimiri sciureus) is a commonly-used surrogate for humans in biomedical research. In the neuroimaging community, MRI and histological atlases serve as valuable resources for anatomical, physiological, and functional studies of the brain; however, no digital MRI/histology atlas is currently available for the squirrel monkey. This paper describes the construction of a web-based multi-modal atlas of the squirrel monkey brain. The MRI-derived information includes anatomical MRI contrast (i...
July 13, 2018: Neuroinformatics
Thomas Reed, Roi Cohen Kadosh
In this review, we describe transcranial electrical stimulation (tES) techniques currently being used in neuroscientific research, including transcranial direct current (tDCS), alternating current (tACS) and random noise (tRNS) stimulation techniques. We explain how these techniques are used and summarise the proposed mechanisms of action for each technique. We continue by describing how each method has been used to alter endogenous neuronal oscillations and connectivity between brain regions, and we conclude by highlighting the varying effects of stimulation and discussing the future direction of these stimulation techniques in research...
July 13, 2018: Journal of Inherited Metabolic Disease
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