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Primary visual cortex

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https://www.readbyqxmd.com/read/28227739/cortical-responses-following-simultaneous-and-sequential-retinal-neurostimulation-with-different-return-configurations
#1
Alejandro Barriga-Rivera, John W Morley, Nigel H Lovell, Gregg J Suaning, Alejandro Barriga-Rivera, John W Morley, Nigel H Lovell, Gregg J Suaning, Alejandro Barriga-Rivera, Gregg J Suaning, John W Morley, Nigel H Lovell
Researchers continue to develop visual prostheses towards safer and more efficacious systems. However limitations still exist in the number of stimulating channels that can be integrated. Therefore there is a need for spatial and time multiplexing techniques to provide improved performance of the current technology. In particular, bright and high-contrast visual scenes may require simultaneous activation of several electrodes. In this research, a 24-electrode array was suprachoroidally implanted in three normally-sighted cats...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227165/reward-value-is-encoded-in-primary-somatosensory-cortex-and-can-be-decoded-from-neural-activity-during-performance-of-a-psychophysical-task
#2
David B McNiel, John S Choi, John P Hessburg, Joseph T Francis, David B McNiel, John S Choi, John P Hessburg, Joseph T Francis, John P Hessburg, Joseph T Francis, John S Choi, David B McNiel
Encoding of reward valence has been shown in various brain regions, including deep structures such as the substantia nigra as well as cortical structures such as the orbitofrontal cortex. While the correlation between these signals and reward valence have been shown in aggregated data comprised of many trials, little work has been done investigating the feasibility of decoding reward valence on a single trial basis. Towards this goal, one non-human primate (macaca radiata) was trained to grip and hold a target level of force in order to earn zero, one, two, or three juice rewards...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28223914/decoding-lower-limb-muscle-activity-and-kinematics-from-cortical-neural-spike-trains-during-monkey-performing-stand-and-squat-movements
#3
Xuan Ma, Chaolin Ma, Jian Huang, Peng Zhang, Jiang Xu, Jiping He
Extensive literatures have shown approaches for decoding upper limb kinematics or muscle activity using multichannel cortical spike recordings toward brain machine interface (BMI) applications. However, similar topics regarding lower limb remain relatively scarce. We previously reported a system for training monkeys to perform visually guided stand and squat tasks. The current study, as a follow-up extension, investigates whether lower limb kinematics and muscle activity characterized by electromyography (EMG) signals during monkey performing stand/squat movements can be accurately decoded from neural spike trains in primary motor cortex (M1)...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28221328/retinotopic-fmri-reveals-visual-dysfunction-and-functional-reorganization-in-the-visual-cortex-of-mild-to-moderate-glaucoma-patients
#4
Wei Zhou, Eric R Muir, Kundandeep S Nagi, Steven Chalfin, Pavel Rodriguez, Timothy Q Duong
PURPOSE: To investigate retinotopic functional representation in the visual cortex of mild to moderate primary open-angle glaucoma (POAG) participants and age-matched normal volunteers using high-resolution retinotopic blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI). METHODS: fMRI was performed on 9 POAG participants (61±11 y old) and 9 age-matched controls (58±5 y old) were studied. A wide-view visual presentation (±55 degrees) was used to evaluate central and peripheral vision...
February 17, 2017: Journal of Glaucoma
https://www.readbyqxmd.com/read/28220070/neural-correlates-of-mirror-visual-feedback-induced-performance-improvements-a-resting-state-fmri-study
#5
Viola Rjosk, Jöran Lepsien, Elisabeth Kaminski, Maike Hoff, Bernhard Sehm, Christopher J Steele, Arno Villringer, Patrick Ragert
Mirror visual feedback (MVF) is a promising approach to enhance motor performance without training in healthy adults as well as in patients with focal brain lesions. There is preliminary evidence that a functional modulation within and between primary motor cortices as assessed with transcranial magnetic stimulation (TMS) might be one candidate mechanism mediating the observed behavioral effects. Recently, studies using task-based functional magnetic resonance imaging (fMRI) have indicated that MVF-induced functional changes might not be restricted to the primary motor cortex (M1) but also include higher order regions responsible for perceptual-motor coordination and visual attention...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28219983/neural-representation-and-causal-models-in-motor-cortex
#6
Kris S Chaisanguanthum, Helen H Shen, Philip N Sabes
Dorsal premotor (PMd) and primary motor (M1) cortex play a central role in mapping sensation to movement. Many studies of these areas have focused on correlation-based tuning curves relating neural activity to task or movement parameters, but the link between tuning and movement generation is unclear. We recorded motor preparatory activity from populations of neurons in PMd/M1 as macaque monkeys performed a visually guided reaching task and show that tuning curves for sensory inputs (reach target direction) and motor outputs (initial movement direction) are not typically aligned...
February 20, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28217713/catching-the-voltage-gradient-asymmetric-boost-of-cortical-spread-generates-motion-signals-across-visual-cortex-a-brief-review-with-special-thanks-to-amiram-grinvald
#7
REVIEW
Dirk Jancke
Wide-field voltage imaging is unique in its capability to capture snapshots of activity-across the full gradient of average changes in membrane potentials from subthreshold to suprathreshold levels-of hundreds of thousands of superficial cortical neurons that are simultaneously active. Here, I highlight two examples where voltage-sensitive dye imaging (VSDI) was exploited to track gradual space-time changes of activity within milliseconds across several millimeters of cortex at submillimeter resolution: the line-motion condition, measured in Amiram Grinvald's Laboratory more than 10 years ago and-coming full circle running VSDI in my laboratory-another motion-inducing condition, in which two neighboring stimuli counterchange luminance simultaneously...
July 2017: Neurophotonics
https://www.readbyqxmd.com/read/28213112/laminar-imaging-of-positive-and-negative-bold-in-human-visual-cortex-at-7t
#8
Alessio Fracasso, Peter R Luijten, Serge O Dumoulin, Natalia Petridou
Deciphering the direction of information flow is critical to understand the brain. Data from non-human primate histology shows that connections between lower to higher areas (e.g. retina→V1), and between higher to lower areas (e.g. V1←V2) can be dissociated based upon the distribution of afferent synapses at the laminar level. Ultra-high field scanners opened up the possibility to image brain structure and function at an unprecedented level of detail. Taking advantage of the increased spatial resolution available, it could theoretically be possible to disentangle activity from different cortical depths from human cerebral cortex, separately studying different compartments across depth...
February 14, 2017: NeuroImage
https://www.readbyqxmd.com/read/28209521/impaired-visual-competition-in-patients-with-homonymous-visual-field-defects
#9
A C Geuzebroek, A V van den Berg
Intense visual training can lead to partial recovery of visual field defects caused by lesions of the primary visual cortex. However, the standard visual detection and discrimination tasks, used to assess this recovery process tend to ignore the complexity of the natural visual environment, where multiple stimuli continuously interact. Visual competition is an essential component for natural search tasks and detecting unexpected events. Our study focused on visual decision-making and to what extent the recovered visual field can compete for attention with the 'intact' visual field...
February 13, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/28203148/dopamine-d1-receptor-immunoreactivity-on-fine-processes-of-gfap-positive-astrocytes-in-the-substantia-nigra-pars-reticulata-of-adult-mouse
#10
Katsuhiro Nagatomo, Sechiko Suga, Masato Saitoh, Masahito Kogawa, Kazuto Kobayashi, Yoshio Yamamoto, Katsuya Yamada
Substantia nigra pars reticulata (SNr), the major output nucleus of the basal ganglia, receives dopamine from dendrites extending from dopaminergic neurons of the adjacent nucleus pars compacta (SNc), which is known for its selective degeneration in Parkinson's disease. As a recipient for dendritically released dopamine, the dopamine D1 receptor (D1R) is a primary candidate due to its very dense immunoreactivity in the SNr. However, the precise location of D1R remains unclear at the cellular level in the SNr except for that reported on axons/axon terminals of presumably striatal GABAergic neurons...
2017: Frontiers in Neuroanatomy
https://www.readbyqxmd.com/read/28194098/spatiotemporal-profiles-of-proprioception-processed-by-the-masseter-muscle-spindles-in-rat-cerebral-cortex-an-optical-imaging-study
#11
Satoshi Fujita, Mari Kaneko, Hiroko Nakamura, Masayuki Kobayashi
Muscle spindles in the jaw-closing muscles, which are innervated by trigeminal mesencephalic neurons (MesV neurons), control the strength of occlusion and the position of the mandible. The mechanisms underlying cortical processing of proprioceptive information are critical to understanding how sensory information from the masticatory muscles regulates orofacial motor function. However, these mechanisms are mostly unknown. The present study aimed to identify the regions that process proprioception of the jaw-closing muscles using in vivo optical imaging with a voltage-sensitive dye in rats under urethane anesthesia...
2017: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/28194008/genetic-otx2-mis-localization-delays-critical-period-plasticity-across-brain-regions
#12
H H C Lee, C Bernard, Z Ye, D Acampora, A Simeone, A Prochiantz, A A Di Nardo, T K Hensch
Accumulation of non-cell autonomous Otx2 homeoprotein in postnatal mouse visual cortex (V1) has been implicated in both the onset and closure of critical period (CP) plasticity. Here, we show that a genetic point mutation in the glycosaminoglycan recognition motif of Otx2 broadly delays the maturation of pivotal parvalbumin-positive (PV+) interneurons not only in V1 but also in the primary auditory (A1) and medial prefrontal cortex (mPFC). Consequently, not only visual, but also auditory plasticity is delayed, including the experience-dependent expansion of tonotopic maps in A1 and the acquisition of acoustic preferences in mPFC, which mitigates anxious behavior...
February 14, 2017: Molecular Psychiatry
https://www.readbyqxmd.com/read/28192130/ielvis-an-open-source-matlab-toolbox-for-localizing-and-visualizing-human-intracranial-electrode-data
#13
David M Groppe, Stephan Bickel, Andrew R Dykstra, Xiuyuan Wang, Pierre Mégevand, Manuel R Mercier, Fred A Lado, Ashesh D Mehta, Christopher J Honey
BACKGROUND: Intracranial electrical recordings (iEEG) and brain stimulation (iEBS) are invaluable human neuroscience methodologies. However, the value of such data is often unrealized as many laboratories lack tools for localizing electrodes relative to anatomy. To remedy this, we have developed a MATLAB toolbox for intracranial electrode localization and visualization, iELVis. NEW METHOD: iELVis uses existing tools (BioImage Suite, FSL, and FreeSurfer) for preimplant magnetic resonance imaging (MRI) segmentation, neuroimaging coregistration, and manual identification of electrodes in postimplant neuroimaging...
February 9, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28188622/the-optic-nerve-superior-colliculus-visual-thalamus-and-primary-visual-cortex-of-the-northern-elephant-seal-mirounga-angustirostris-and-california-sea-lion-zalophus-californianus
#14
Emily C Turner, Eva K Sawyer, Jon H Kaas
The northern elephant seal (Mirounga angustirostris) and California sea lion (Zalophus californianus) are members of a diverse clade of carnivorous mammals known as pinnipeds. Pinnipeds are notable for their large, ape-sized brains, yet little is known about their central nervous system. Both the northern elephant seal and California sea lion spend most of their lives at sea, but each also spends time on land to breed and give birth. These unique coastal niches may be reflected in specific evolutionary adaptations to their sensory systems...
February 11, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28165427/developing-and-evaluating-a-flexible-wireless-microcoil-array-based-integrated-interface-for-epidural-cortical-stimulation
#15
Xing Wang, Sharjeel A Chaudhry, Wensheng Hou, Xiaofeng Jia
Stroke leads to serious long-term disability. Electrical epidural cortical stimulation has made significant improvements in stroke rehabilitation therapy. We developed a preliminary wireless implantable passive interface, which consists of a stimulating surface electrode, receiving coil, and single flexible passive demodulated circuit printed by flexible printed circuit (FPC) technique and output pulse voltage stimulus by inductively coupling an external circuit. The wireless implantable board was implanted in cats' unilateral epidural space for electrical stimulation of the primary visual cortex (V1) while the evoked responses were recorded on the contralateral V1 using a needle electrode...
February 5, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28163071/gaba-and-gaba-receptors-alterations-in-the-primary-visual-cortex-of-concave-lens-induced-myopic-model
#16
Wen Zhao, Ai-Ling Bi, Chao-Li Xu, Xiang Ye, Mei-Qing Chen, Xin-Ting Wang, Xiao-Yan Zhang, Jun-Guo Guo, Wen-Jun Jiang, Jin Zhang, Hong-Sheng Bi
Until recently most researches on myopia mechanisms have mainly been focused on the eye ball and few investigations were explored on the upper visual pathway, such as the visual cortex. The roles of gamma-aminobutyric acid (GABA) in the retinal and in the upper visual pathway are inter-correlated. As the retinal glutamate decarboxylase (GAD), GABA, and the mRNA levels of GABA receptors increased during the concave lens induced myopia formation, however, whether GABA alterations also occurred in the visual cortex during the concave lens induction is still unknown...
February 2, 2017: Brain Research Bulletin
https://www.readbyqxmd.com/read/28162806/a-neural-circuit-for-auditory-dominance-over-visual-perception
#17
You-Hyang Song, Jae-Hyun Kim, Hye-Won Jeong, Ilsong Choi, Daun Jeong, Kwansoo Kim, Seung-Hee Lee
When conflicts occur during integration of visual and auditory information, one modality often dominates the other, but the underlying neural circuit mechanism remains unclear. Using auditory-visual discrimination tasks for head-fixed mice, we found that audition dominates vision in a process mediated by interaction between inputs from the primary visual (VC) and auditory (AC) cortices in the posterior parietal cortex (PTLp). Co-activation of the VC and AC suppresses VC-induced PTLp responses, leaving AC-induced responses...
January 27, 2017: Neuron
https://www.readbyqxmd.com/read/28160739/effects-of-motion-speed-in-action-representations
#18
Wessel O van Dam, Laura J Speed, Vicky T Lai, Gabriella Vigliocco, Rutvik H Desai
Grounded cognition accounts of semantic representation posit that brain regions traditionally linked to perception and action play a role in grounding the semantic content of words and sentences. Sensory-motor systems are thought to support partially abstract simulations through which conceptual content is grounded. However, which details of sensory-motor experience are included in, or excluded from these simulations, is not well understood. We investigated whether sensory-motor brain regions are differentially involved depending on the speed of actions described in a sentence...
February 1, 2017: Brain and Language
https://www.readbyqxmd.com/read/28156250/efficacy-of-deep-rtms-for-neuropathic-pain-in-the-lower-limb-a-randomized-double-blind-crossover-trial-of-an-h-coil-and-figure-8-coil
#19
Takeshi Shimizu, Koichi Hosomi, Tomoyuki Maruo, Yuko Goto, Masaru Yokoe, Yu Kageyama, Toshio Shimokawa, Toshiki Yoshimine, Youichi Saitoh
OBJECTIVE Electrical motor cortex stimulation can relieve neuropathic pain (NP), but its use requires patients to undergo an invasive procedure. Repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex (M1) using a figure-8 coil can relieve NP noninvasively, but its ability to relieve lower limb pain is still limited. Deep rTMS using an H-coil can effectively stimulate deep brain regions and has been widely used for the treatment of various neurological diseases; however, there have been no clinical studies comparing the effectiveness of figure-8 coils and H-coils...
February 3, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/28154971/the-sensorimotor-network-dysfunction-in-migraineurs-without-aura-a-resting-state-fmri-study
#20
Jilei Zhang, Jingjing Su, Mengxing Wang, Ying Zhao, Qi-Ting Zhang, Qian Yao, Haifeng Lu, Hui Zhang, Ge-Fei Li, Yi-Lan Wu, Yi-Sheng Liu, Feng-Di Liu, Mei-Ting Zhuang, Yan-Hui Shi, Tian-Yu Hou, Rong Zhao, Yuan Qiao, Jianqi Li, Jian-Ren Liu, Xiaoxia Du
Migraine is a common recurrent neurological disorder combining nausea, vomiting, and hypersensitivities to visual, auditory, olfactory and somatosensory stimuli. However, the dysfunction of the sensorimotor network in migraineurs has not been well clarified. In the present study, we evaluated the dysfunction of the sensorimotor network in 30 migraineurs without aura and in 31 controls by combining regional homogeneity (ReHo), amplitudes of low-frequency fluctuation (ALFF) and degree centrality (DC) analysis methods based on resting-state fMRI...
February 2, 2017: Journal of Neurology
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