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Brain Structure & Function

Juri-Alexander Witt, Roland Coras, Albert J Becker, Christian E Elger, Ingmar Blümcke, Christoph Helmstaedter
Supraspan list learning tests are sensitive measures used to assess temporal lobe dysfunction. Most frequently employed is the Rey Auditory Verbal Learning and Memory Test (RAVLT). The test's structure is determined by a short- and long-term memory component. During the first of five learning trials, the short-term memory component is the highest and steadily decreases over the following trials, while the long-term memory component concurrently increases and reaches its maximum at the delayed recall after a retention interval of 30 min...
March 13, 2019: Brain Structure & Function
M F A Hauser, V Wiescholleck, J Colitti-Klausnitzer, C Bellebaum, Denise Manahan-Vaughan
In the human cortex, event-related potentials (ERPs) are triggered in response to sensory, cognitive or motor stimuli. Due to the inherent difficulties of conducting invasive mechanistic studies in human subjects, little is known as to the precise neurophysiological mechanisms that lead to their manifestation. By contrast, although much is known about synaptic and neural mechanisms that underlie information processing in rodents, very few studies have addressed to what extent ERPs are comparable in rodents and humans...
March 11, 2019: Brain Structure & Function
Isabel Tissieres, Sonia Crottaz-Herbette, Stephanie Clarke
Spatial cues contribute to the ability to segregate sound sources and thus facilitate their detection and recognition. This implicit use of spatial cues can be preserved in cases of cortical spatial deafness, suggesting that partially distinct neural networks underlie the explicit sound localization and the implicit use of spatial cues. We addressed this issue by assessing 40 patients, 20 patients with left and 20 patients with right hemispheric damage, for their ability to use auditory spatial cues implicitly in a paradigm of spatial release from masking (SRM) and explicitly in sound localization...
March 8, 2019: Brain Structure & Function
Rodrigo de Andrade Rufino, Sandra Regina Mota-Ortiz, Miguel Antonio Xavier De Lima, Marcus Vinicius C Baldo, Newton Sabino Canteras
A few studies have evaluated the behavioral roles of the periaqueductal gray (PAG) in animals facing ethologically relevant threats. Exposure to a live cat induces striking activation in the rostrodorsal and caudal ventral PAG. In the present investigation, we first showed that cytotoxic lesions of the rostrodorsal and caudal ventral PAG had similar effects on innate fear responses during cat exposure, practically abolishing freezing and increasing risk assessment responses. Conversely, rostrodorsal PAG lesions but not caudal ventral lesions disrupted learned contextual fear responses to cat exposure...
March 7, 2019: Brain Structure & Function
Silvio Sarubbo, Laurent Petit, Alessandro De Benedictis, Franco Chioffi, Maurice Ptito, Tim B Dyrby
Whether brain networks underlying the multimodal processing of language in humans are present in non-human primates is an unresolved question in primate evolution. Conceptual awareness in humans, which is the backbone of verbal and non-verbal semantic elaboration, involves intracerebral connectivity via the inferior fronto-occipital fascicle (IFOF). While non-human primates can communicate through visual information channels, there has been no formal demonstration that they possess a functional homologue of the human IFOF...
March 7, 2019: Brain Structure & Function
Eric Moulton, Florence Bouhali, Karla Monzalvo, Cyril Poupon, Hui Zhang, Stanislas Dehaene, Ghislaine Dehaene-Lambertz, Jessica Dubois
Shortly after reading instruction, a region in the ventral occipital temporal cortex (vOTC) of the left hemisphere, the Visual Word Form Area (VWFA), becomes specialized for written words. Its reproducible location across scripts suggests important anatomical constraints, such as specific patterns of connectivity, notably to spoken language areas. Here, we explored the structural connectivity of the emerging VWFA in terms of its specificity relative to other ventral visual regions and its stability throughout the process of reading instruction in ten children studied longitudinally over 2 years...
March 6, 2019: Brain Structure & Function
Giovanni Buccino, Ivan Colagè, Francesco Silipo, Paolo D'Ambrosio
This paper addresses the debated issue of abstract language in the framework of embodiment. First, we discuss the notion of abstractness in the light of the Western philosophical thought, with a focus on the English empiricist tradition. Second, we review the most relevant psychological models and neuroscientific empirical findings on abstract language. It turns out that abstract words are not such, because their meaning is "far from experience", but, because of the high complexity of the attached experiential clusters...
March 4, 2019: Brain Structure & Function
Zikuan Chen, Qing Zhou, Vince Calhoun
A functional magnetic resonance imaging (fMRI) experiment produces complex-valued images consisting of pairwise magnitude and phase images. As different perspective on the same magnetic source, fMRI magnitude and phase data are complementary for brain function analysis. We collected 600-subject fMRI data during rest, decomposed via group-level independent component analysis (ICA) (mICA and pICA for magnitude and phase respectively), and calculated brain functional network connectivity matrices (mFC and pFC)...
March 2, 2019: Brain Structure & Function
Eunjin Hwang, Ritchie E Brown, Bernat Kocsis, Tae Kim, James T McKenna, James M McNally, Hio-Been Han, Jee Hyun Choi
High-density electroencephalographic (hdEEG) recordings are widely used in human studies to determine spatio-temporal patterns of cortical electrical activity. How these patterns of activity are modulated by subcortical arousal systems is poorly understood. Here, we couple selective optogenetic stimulation of a defined subcortical cell-type, basal forebrain (BF) parvalbumin (PV) neurons, with hdEEG recordings in mice (Opto-hdEEG). Stimulation of BF PV projection neurons preferentially generated time-locked gamma oscillations in frontal cortices...
March 2, 2019: Brain Structure & Function
Hong-Hsi Lee, Katarina Yaros, Jelle Veraart, Jasmine L Pathan, Feng-Xia Liang, Sungheon G Kim, Dmitry S Novikov, Els Fieremans
Tissue microstructure modeling of diffusion MRI signal is an active research area striving to bridge the gap between macroscopic MRI resolution and cellular-level tissue architecture. Such modeling in neuronal tissue relies on a number of assumptions about the microstructural features of axonal fiber bundles, such as the axonal shape (e.g., perfect cylinders) and the fiber orientation dispersion. However, these assumptions have not yet been validated by sufficiently high-resolution 3-dimensional histology. Here, we reconstructed sequential scanning electron microscopy images in mouse brain corpus callosum, and introduced a random-walker (RaW)-based algorithm to rapidly segment individual intra-axonal spaces and myelin sheaths of myelinated axons...
February 21, 2019: Brain Structure & Function
Ittai Shamir, Omri Tomer, Zvi Baratz, Galia Tsarfaty, Maya Faraggi, Assaf Horowitz, Yaniv Assaf
The layer composition of the cerebral cortex represents a unique anatomical fingerprint of brain development, function, connectivity, and pathology. Historically, the cortical layers were investigated solely ex-vivo using histological means, but recent magnetic resonance imaging (MRI) studies suggest that T1 relaxation images can be utilized to separate the layers. Despite technological advancements in the field of high-resolution MRI, accurate estimation of whole-brain cortical laminar composition has remained limited due to partial volume effects, leaving some layers far beyond the image resolution...
February 19, 2019: Brain Structure & Function
Martin Domin, Martin Lotze
The corpus callosum (CC) is the largest white matter structure of the brain and offers the structural basis for an intense interaction between both cerebral hemispheres. Especially with respect to the interaction of both motor cortices it shows a differentiated somatotopic organization. Neuropathological processes are often reflected in structural alterations of the CC and a spatially precise description of structures for the healthy brain is essential for further differentiation of structural damage in patients...
February 18, 2019: Brain Structure & Function
Beverly A S Reyes, Xiao-Yan Zhang, Elsa C Dufourt, Seema Bhatnagar, Rita J Valentino, Elisabeth J Van Bockstaele
Stress-related psychiatric diseases are nearly twice as prevalent in women compared to men. We recently showed in male rats that the resident-intruder model of social stress differentially engages stress-related circuitry that regulates norepinephrine-containing neurons of the locus coeruleus (LC) depending on coping strategy as determined by the latency to assume a defeat posture. Here, we determined whether this social stress had similar effects in female rats. LC afferents were retrogradely labeled with Fluorogold (FG) and rats had one or five daily exposures to an aggressive resident...
February 14, 2019: Brain Structure & Function
Alejandro Sempere-Ferràndez, Salvador Martínez, Emilio Geijo-Barrientos
In the neocortex, large layer 5B pyramidal neurons implement a high-density firing code. In contrast, other subtypes of pyramidal neurons, including those in layer 2/3, are functionally characterized by their sparse firing rate. Here, we investigate the synaptic basis of this behavior by comparing the properties of the postsynaptic responses evoked by cortical inputs in layer 5B and layer 2/3 pyramidal neurons in vitro. We demonstrate that a major determinant of the larger responsiveness of layer 5B with respect to layer 2/3 pyramidal neurons is the different properties in their inhibitory postsynaptic currents (IPSCs): layer 5B pyramidal neurons have IPSCs of lower amplitude and the temporal delay between the excitatory and inhibitory synaptic components is also larger in these cells...
February 12, 2019: Brain Structure & Function
Hilary R Smith, Thomas J R Beveridge, Susan H Nader, Michael A Nader, Linda J Porrino
It has been shown that exposure to cocaine can result in neuroinflammatory responses. Microglia, the resident CNS immune cells, undergo a transition to an activated state when challenged. In rodents, and possibly humans, cocaine exposure activates microglia. The goal of this study was to assess the extent and magnitude of microglial activation in rhesus monkeys with an extensive history of cocaine self-administration. Male rhesus monkeys (N = 4/group) were trained to respond on a fixed-interval 3-min schedule of food or 0...
February 12, 2019: Brain Structure & Function
Miguel Ángel García-Cabezas, Basilis Zikopoulos, Helen Barbas
The classical theory of cortical systematic variation has been independently described in reptiles, monotremes, marsupials and placental mammals, including primates, suggesting a common bauplan in the evolution of the cortex. The Structural Model is based on the systematic variation of the cortex and is a platform for advancing testable hypotheses about cortical organization and function across species, including humans. The Structural Model captures the overall laminar structure of areas by dividing the cortical architectonic continuum into discrete categories (cortical types), which can be used to test hypotheses about cortical organization...
February 9, 2019: Brain Structure & Function
Kaoru Amemiya, Tomoyo Morita, Daisuke N Saito, Midori Ban, Koji Shimada, Yuko Okamoto, Hirotaka Kosaka, Hidehiko Okazawa, Minoru Asada, Eiichi Naito
Sensorimotor function is a fundamental brain function in humans, and the cerebrocerebellar circuit is essential to this function. In this study, we demonstrate how the cerebrocerebellar circuit develops both functionally and anatomically from childhood to adulthood in the typically developing human brain. We measured brain activity using functional magnetic resonance imaging while a total of 57 right-handed, blindfolded, healthy children (aged 8-11 years), adolescents (aged 12-15 years), and young adults (aged 18-23 years) (n = 19 per group) performed alternating extension-flexion movements of their right wrists in precise synchronization with 1-Hz audio tones...
February 7, 2019: Brain Structure & Function
Marcel Adam Just, Timothy A Keller
The critical role of the hippocampus in human learning has been illuminated by neuroimaging studies that increasingly improve the detail with which hippocampal function is understood. However, the hippocampal information developed with different types of imaging technologies is seldom integrated within a single investigation of the neural changes that occur during learning. Here, we show three different ways in which a small hippocampal region changes as the structures and names of a set of organic compounds are being learned, reflecting changes at the microstructural, informational, and cortical network levels...
February 6, 2019: Brain Structure & Function
Linda A Antonucci, Pasquale Di Carlo, Roberta Passiatore, Marco Papalino, Anna Monda, Nicola Amoroso, Sabina Tangaro, Paolo Taurisano, Antonio Rampino, Fabio Sambataro, Teresa Popolizio, Alessandro Bertolino, Giulio Pergola, Giuseppe Blasi
The functional connectivity between thalamic medio-dorsal nucleus (MD) and cortical regions, especially the dorsolateral prefrontal cortex (DLPFC), is implicated in attentional processing and is anomalous in schizophrenia, a brain disease associated with polygenic risk and attentional deficits. However, the molecular and genetic underpinnings of thalamic connectivity anomalies are unclear. Given that gene co-expression across brain areas promotes synchronous interregional activity, our aim was to investigate whether coordinated expression of genes relevant to schizophrenia in MD and DLPFC may reflect thalamic connectivity anomalies in an attention-related network including the DLPFC...
February 6, 2019: Brain Structure & Function
Md Mamun Al-Amin, Robert K P Sullivan, Nyoman D Kurniawan, Thomas H J Burne
Converging evidence from human and animal studies support an association between vitamin D deficiency and cognitive impairment. Previous studies have shown that hippocampal volume is reduced in adults with vitamin D deficiency as well as in a range of disorders, such as schizophrenia. The aim of the current study was to examine the effect of adult vitamin D (AVD) deficiency on hippocampal-dependent spatial learning, and hippocampal volume and connectivity in healthy adult mice. Ten-week-old male BALB/c mice were fed a control (vitamin D 1500 IU/kg) or vitamin D-depleted (vitamin D 0 IU/kg) diet for a minimum of 10 weeks...
February 2, 2019: Brain Structure & Function
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