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Primary visual cortex

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https://www.readbyqxmd.com/read/28078786/v1-connections-reveal-a-series-of-elongated-higher-visual-areas-in-the-california-ground-squirrel-otospermophilus-beecheyi
#1
Moritz Negwer, Yong-Jun Liu, Dirk Schubert, David C Lyon
For studies of visual cortex organization, mouse is becoming an increasingly more often used model. In addition to its genetic tractability, the relatively small area of cortical surface devoted to visual processing simplifies efforts in relating the structure of visual cortex to visual function. However, the nature of this compact organization can make some comparisons to the much larger non-human primate visual cortex difficult. The squirrel, as a highly visual rodent offers a useful means for better understanding how mouse and monkey cortical organization compares...
January 12, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28077727/asymmetries-of-dark-and-bright-negative-afterimages-are-paralleled-by-subcortical-on-and-off-post-stimulus-responses
#2
Hui Li, Xu Liu, Xiaohong Li, Yiliang Lu, Lothar Spillmann, Ian M Andolina, Wei Wang
: Humans are more sensitive to luminance decrements than increments, as evidenced by lower thresholds and shorter latencies for dark stimuli. This asymmetry is consistent with results of neurophysiological recordings in dorsal lateral-geniculate nucleus (dLGN) and primary visual cortex (V1) of cat and monkey. Specifically, V1 population responses demonstrate that darks elicit higher levels of activation than brights, and the latency of OFF responses in dLGN and V1 is shorter than that of ON responses...
January 11, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28077720/local-circuits-of-v1-layer-4b-neurons-projecting-to-v2-thick-stripes-define-distinct-cell-classes-and-avoid-cytochrome-oxidase-blobs
#3
Jeff Yarch, Frederick Federer, Alessandra Angelucci
: Decades of anatomical studies on the primate primary visual cortex (V1) have led to a detailed diagram of V1 intrinsic circuitry, but this diagram lacks information about the output targets of V1 cells. Understanding how V1 local processing relates to downstream processing requires identification of neuronal populations defined by their output targets. In primates, V1 layers (L)2/3 and 4B send segregated projections to distinct cytochrome oxidase (CO) stripes in area V2: neurons in CO blob columns project to thin stripes while neurons outside blob columns project to thick and pale stripes, suggesting functional specialization of V1-to-V2 CO streams...
January 11, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28074441/activation-of-parvalbumin-positive-neurons-in-both-retina-and-primary-visual-cortex-improves-the-feature-selectivity-of-primary-visual-cortex-neurons
#4
Jinggang Duan, Hang Fu, Jiayi Zhang
Several recent studies using either viral or transgenic mouse models have shown different results on whether the activation of parvalbumin-positive (PV(+)) neurons expressing channelrhodopsin-2 (ChR2) in the primary visual cortex (V1) improves the orientation- and direction-selectivity of V1 neurons. Although this discrepancy was thoroughly discussed in a follow-up communication, the issue of using different models to express ChR2 in V1 was not mentioned. We found that ChR2 was expressed in retinal ganglion cells (RGCs) and V1 neurons in ChR2(fl/+); PV-Cre mice...
January 10, 2017: Neuroscience Bulletin
https://www.readbyqxmd.com/read/28071765/neural-codes-of-seeing-architectural-styles
#5
Heeyoung Choo, Jack L Nasar, Bardia Nikrahei, Dirk B Walther
Images of iconic buildings, such as the CN Tower, instantly transport us to specific places, such as Toronto. Despite the substantial impact of architectural design on people's visual experience of built environments, we know little about its neural representation in the human brain. In the present study, we have found patterns of neural activity associated with specific architectural styles in several high-level visual brain regions, but not in primary visual cortex (V1). This finding suggests that the neural correlates of the visual perception of architectural styles stem from style-specific complex visual structure beyond the simple features computed in V1...
January 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28069921/visual-stimulus-speed-does-not-influence-the-rapid-emergence-of-direction-selectivity-in-ferret-visual-cortex
#6
Neil J Ritter, Nora M Anderson, Stephen D Van Hooser
: Sensory experience is necessary for the development of some receptive field properties of neurons in primary sensory cortical areas. However, it remains unclear whether the parameters of an individual animal's experience play an instructive role and influence the tuning parameters of cortical sensory neurons as selectivity emerges, or rather if experience merely permits the completion of processes that are fully seeded at the onset of experience. Here we have examined whether the speed of visual stimuli that are presented to visually naïve ferrets can influence the parameters of speed tuning and direction selectivity in cortical neurons...
January 9, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28068565/retinal-thinning-is-uniquely-associated-with-medial-temporal-lobe-atrophy-in-neurologically-normal-older-adults
#7
Kaitlin B Casaletto, Michael E Ward, Nicholas S Baker, Brianne M Bettcher, Jeffrey M Gelfand, Yaqiao Li, Robert Chen, Shubir Dutt, Bruce Miller, Joel H Kramer, Ari J Green
Given the converging pathologic and epidemiologic data indicating a relationship between retinal integrity and neurodegeneration, including Alzheimer's disease (AD), we aimed to determine if retinal structure correlates with medial temporal lobe (MTL) structure and function in neurologically normal older adults. Spectral-domain optical coherence tomography, verbal and visual memory testing, and 3T-magnetic resonance imaging of the brain were performed in 79 neurologically normal adults enrolled in a healthy aging cohort study...
December 21, 2016: Neurobiology of Aging
https://www.readbyqxmd.com/read/28062251/opioid-suppression-of-conditioned-anticipatory-brain-responses-to-breathlessness
#8
Anja Hayen, Vishvarani Wanigasekera, Olivia K Faull, Stewart F Campbell, Payashi S Garry, Simon J M Raby, Josephine Robertson, Ruth Webster, Richard G Wise, Mari Herigstad, Kyle T S Pattinson
Opioid painkillers are a promising treatment for chronic breathlessness, but are associated with potentially fatal side effects. In the treatment of breathlessness, their mechanisms of action are unclear. A better understanding might help to identify safer alternatives. Learned associations between previously neutral stimuli (e.g. stairs) and repeated breathlessness induce an anticipatory threat response that may worsen breathlessness, contributing to the downward spiral of decline seen in clinical populations...
January 3, 2017: NeuroImage
https://www.readbyqxmd.com/read/28060929/a-single-vector-platform-for-high-level-gene-transduction-of-central-neurons-adeno-associated-virus-vector-equipped-with-the-tet-off-system
#9
Jaerin Sohn, Megumu Takahashi, Shinichiro Okamoto, Yoko Ishida, Takahiro Furuta, Hiroyuki Hioki
Visualization of neurons is indispensable for the investigation of neuronal circuits in the central nervous system. Virus vectors have been widely used for labeling particular subsets of neurons, and the adeno-associated virus (AAV) vector has gained popularity as a tool for gene transfer. Here, we developed a single AAV vector Tet-Off platform, AAV-SynTetOff, to improve the gene-transduction efficiency, specifically in neurons. The platform is composed of regulator and response elements in a single AAV genome...
2017: PloS One
https://www.readbyqxmd.com/read/28054544/layer-specificity-in-the-effects-of-attention-and-working-memory-on-activity-in-primary-visual-cortex
#10
Timo van Kerkoerle, Matthew W Self, Pieter R Roelfsema
Neuronal activity in early visual cortex depends on attention shifts but the contribution to working memory has remained unclear. Here, we examine neuronal activity in the different layers of the primary visual cortex (V1) in an attention-demanding and a working memory task. A current-source density analysis reveales top-down inputs in the superficial layers and layer 5, and an increase in neuronal firing rates most pronounced in the superficial and deep layers and weaker in input layer 4. This increased activity is strongest in the attention task but it is also highly reliable during working memory delays...
January 5, 2017: Nature Communications
https://www.readbyqxmd.com/read/28054126/longitudinal-multi-modal-neuroimaging-in-opsoclonus-myoclonus-syndrome
#11
Sun-Young Oh, Rainer Boegle, Peter Zu Eulenburg, Matthias Ertl, Ji-Soo Kim, Marianne Dieterich
To investigate structural, metabolic, and functional connectivity changes in visual and oculomotor structures in a patient with paraneoplastic opsoclonus-myoclonus syndrome, serial resting-state functional and structural MRI, and FDG-PET data were collected during the acute stage and later on when the opsoclonus had resolved. In the acute stage, an FDG-PET scan demonstrated a substantially increased metabolism in structures around the deep cerebellar nuclei [e.g., fastigial nucleus (FN)] and a relatively reduced metabolism in the bilateral occipital lobes which normalized over 12 months...
January 4, 2017: Journal of Neurology
https://www.readbyqxmd.com/read/28053246/orientation-selectivity-in-the-visual-cortex-of-the-nine-banded-armadillo
#12
Benjamin Scholl, Johnathan Rylee, Jeffrey J Luci, Nicholas J Priebe, Jeff Padberg
Orientation selectivity in primary visual cortex (V1) has been proposed to reflect a canonical computation performed by the neocortical circuitry.  While orientation selectivity has been reported in all mammals examined to date, the degree of selectivity and the functional organization of selectivity varies across clades. The differences in degree of orientation selectivity are large from reports in marsupials that only a small subset of neurons are selective to studies in carnivores in which it is rare to find a neuron lacking selectivity...
January 4, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28048887/su-f-i-18-altered-visual-cortex-responses-by-wide-view-fmri-in-primary-open-angle-glaucoma-patients
#13
W Zhou, E Muir, S Chalfin, K Nagi, G Clarke, T Duong
PURPOSE: Primary open-angle glaucoma (POAG) is a common ocular disorder with progressive retinal ganglion cell loss. This study explored the application of wide view fMRI to evaluate neural activity of the whole visual cortex and its relation with visual field functions in POAG patients. METHODS: Nine subjects with diagnosed POAG (age: 59.9±10.9 y.o., 4 males) and nine age-matched healthy volunteers (age: 58.0±4.6 y.o., 6 males) were scanned on a 3T Siemens scanner...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28044015/contextual-modulation-of-primary-visual-cortex-by-auditory-signals
#14
REVIEW
L S Petro, A T Paton, L Muckli
Early visual cortex receives non-feedforward input from lateral and top-down connections (Muckli & Petro 2013 Curr. Opin. Neurobiol. 23, 195-201. (doi:10.1016/j.conb.2013.01.020)), including long-range projections from auditory areas. Early visual cortex can code for high-level auditory information, with neural patterns representing natural sound stimulation (Vetter et al. 2014 Curr. Biol. 24, 1256-1262. (doi:10.1016/j.cub.2014.04.020)). We discuss a number of questions arising from these findings. What is the adaptive function of bimodal representations in visual cortex? What type of information projects from auditory to visual cortex? What are the anatomical constraints of auditory information in V1, for example, periphery versus fovea, superficial versus deep cortical layers? Is there a putative neural mechanism we can infer from human neuroimaging data and recent theoretical accounts of cortex? We also present data showing we can read out high-level auditory information from the activation patterns of early visual cortex even when visual cortex receives simple visual stimulation, suggesting independent channels for visual and auditory signals in V1...
February 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28039551/single-session-transcranial-direct-current-stimulation-induces-enduring-enhancement-of-visual-processing-speed-in-patients-with-major-depression
#15
Nadine Gögler, Lina Willacker, Johanna Funk, Wolfgang Strube, Simon Langgartner, Natan Napiórkowski, Alkomiet Hasan, Kathrin Finke
Attentional deficits are considered key cognitive symptoms in major depressive disorder (MDD) arising from abnormal activation patterns within dorsolateral prefrontal cortex (dlPFC) alertness networks. Altering these activity patterns with transcranial direct current stimulation (tDCS) might thus ameliorate alertness-dependent cognitive deficits in MDD patients. In a double-blind, randomized, sham-controlled study, we investigated the effect of a single session of anodal tDCS (2 mA) applied to the left dlPFC on different parameters of visual attention based on Bundesen's theory of visual attention (Psychol Rev 97(4):523-547, 1990) in a group of 20 patients with MDD and a control group of 20 healthy participants...
December 30, 2016: European Archives of Psychiatry and Clinical Neuroscience
https://www.readbyqxmd.com/read/28031455/independent-effects-of-motivation-and-spatial-attention-in-the-human-visual-cortex
#16
Mareike Bayer, Valentina Rossi, Naomi Vanlessen, Annika Grass, Annekathrin Schacht, Gilles Pourtois
Motivation and attention constitute major determinants of human perception and action. Nonetheless, it remains a matter of debate whether motivation effects on the visual cortex depend on the spatial attention system, or rely on independent pathways. This study investigated the impact of motivation and spatial attention on the activity of the human primary and extrastriate visual cortex by employing a factorial manipulation of the two factors in a cued pattern discrimination task. During stimulus presentation, we recorded event-related potentials and pupillary responses...
December 28, 2016: Social Cognitive and Affective Neuroscience
https://www.readbyqxmd.com/read/28030774/local-and-global-gestalt-laws-a-neurally-based-spectral-approach
#17
Marta Favali, Giovanna Citti, Alessandro Sarti
This letter presents a mathematical model of figure-ground articulation that takes into account both local and global gestalt laws and is compatible with the functional architecture of the primary visual cortex (V1). The local gestalt law of good continuation is described by means of suitable connectivity kernels that are derived from Lie group theory and quantitatively compared with long-range connectivity in V1. Global gestalt constraints are then introduced in terms of spectral analysis of a connectivity matrix derived from these kernels...
December 28, 2016: Neural Computation
https://www.readbyqxmd.com/read/28029725/epicenters-of-dynamic-connectivity-in-the-adaptation-of-the-ventral-visual-system
#18
Vesna Prčkovska, Willem Huijbers, Aaron Schultz, Laura Ortiz-Teran, Cleofe Peña-Gomez, Pablo Villoslada, Keith Johnson, Reisa Sperling, Jorge Sepulcre
OBJECTIVES AND DESIGN: Neuronal responses adapt to familiar and repeated sensory stimuli. Enhanced synchrony across wide brain systems has been postulated as a potential mechanism for this adaptation phenomenon. Here, we used recently developed graph theory methods to investigate hidden connectivity features of dynamic synchrony changes during a visual repetition paradigm. Particularly, we focused on strength connectivity changes occurring at local and distant brain neighborhoods. PRINCIPAL OBSERVATIONS: We found that connectivity reorganization in visual modal cortex-such as local suppressed connectivity in primary visual areas and distant suppressed connectivity in fusiform areas-is accompanied by enhanced local and distant connectivity in higher cognitive processing areas in multimodal and association cortex...
December 28, 2016: Human Brain Mapping
https://www.readbyqxmd.com/read/28029594/priming-hand-motor-training-with-repetitive-stimulation-of-the-fingertips-performance-gain-and-functional-imaging-of-training-effects
#19
Martin Lotze, Aija Marie Ladda, Sybille Roschka, Thomas Platz, Hubert R Dinse
BACKGROUND: Application of repetitive electrical stimulation (rES) of the fingers has been shown to improve tactile perception and sensorimotor performance in healthy individuals. OBJECTIVE: To increase motor performance by priming the effects of active motor training (arm ability training; AAT) using rES. METHODS: We compared the performance gain for the training increase of the averaged AAT tasks of both hands in two groups of strongly right-handed healthy volunteers...
October 6, 2016: Brain Stimulation
https://www.readbyqxmd.com/read/28027309/novel-models-of-visual-topographic-map-alignment-in-the-superior-colliculus
#20
Ruben A Tikidji-Hamburyan, Tarek A El-Ghazawi, Jason W Triplett
The establishment of precise neuronal connectivity during development is critical for sensing the external environment and informing appropriate behavioral responses. In the visual system, many connections are organized topographically, which preserves the spatial order of the visual scene. The superior colliculus (SC) is a midbrain nucleus that integrates visual inputs from the retina and primary visual cortex (V1) to regulate goal-directed eye movements. In the SC, topographically organized inputs from the retina and V1 must be aligned to facilitate integration...
December 2016: PLoS Computational Biology
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