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Primary visual cortex

Jo-Fu Lotus Lin, Juan Silva-Pereyra, Chih-Che Chou, Fa-Hsuan Lin
Variability in neuronal response latency has been typically considered caused by random noise. Previous studies of single cells and large neuronal populations have shown that the temporal variability tends to increase along the visual pathway. Inspired by these previous studies, we hypothesized that functional areas at later stages in the visual pathway of face processing would have larger variability in the response latency. To test this hypothesis, we used magnetoencephalographic data collected when subjects were presented with images of human faces...
April 11, 2018: Scientific Reports
Jiajia Zhu, Yajun Wang, Haibao Wang, Wenwen Cheng, Zipeng Li, Yinfeng Qian, Xiaohu Li, Xiaoshu Li, Yongqiang Yu
Previous voxel-based morphometry studies have provided evidence that patients with alcohol dependence (AD) have widespread gray matter morphological abnormalities. However, brain structural asymmetry in AD has not been assessed to date. Here, we aimed to use a recently developed voxel-based morphometry-based approach to investigate global and regional gray matter asymmetry alterations in AD. A total of 39 male individuals, including 19 AD patients and 20 age-matched healthy controls, underwent high-resolution structural MRI...
April 6, 2018: Neuroreport
Amalia Papanikolaou, Georgios A Keliris, T Dorina Papageorgiou, Ulrich Schiefer, Nikos K Logothetis, Stelios M Smirnakis
Damage to the primary visual cortex (V1) leads to a visual field loss (scotoma) in the retinotopically corresponding part of the visual field. Nonetheless, a small amount of residual visual sensitivity persists within the blind field. This residual capacity has been linked to activity observed in the middle temporal area complex (V5/MT+). However, it remains unknown whether the organization of hV5/MT + changes following early visual cortical lesions. We studied the organization of area hV5/MT+ of five patients with dense homonymous defects in a quadrant of the visual field as a result of partial V1+ or optic radiation lesions...
April 5, 2018: NeuroImage
Satoru Ikemoto, Shin-Ichiro Hamano, Yuko Hirata, Ryuki Matsuura, Kenjiro Kikuchi
BACKGROUND: Iodine 123 (I-123) iomazenil is a specific ligand of the central benzodiazepine receptor, which is a part of the postsynaptic gamma-aminobutyric acid A receptor complex. We performed statistical image processing of I-123 iomazenil single-photon emission computed tomography to elucidate maturational changes in the GABAergic system. METHODS: Thirty patients (18 boys and 12 girls, aged 17 days to 14 years) with cryptogenic focal epilepsy were enrolled and underwent I-123 iomazenil single-photon emission computed tomography...
April 3, 2018: Pediatric Neurology
Paolo Melillo, Anna Prinster, Valentina Di Iorio, Gaia Olivo, Francesco Maria D'Alterio, Sirio Cocozza, Ada Orrico, Mario Quarantelli, Francesco Testa, Arturo Brunetti, Francesca Simonelli
Purpose: Primary visual cortex (PVC) contains a retinotopic map in which the central visual field (CVF) is highly magnified compared to the peripheral field. Several studies have used functional magnetic resonance imaging (fMRI) in patients with macular degeneration to assess the reorganization of visual processing in relationship with the development of extrafoveal preferred retinal locus (PRL). We evaluated the functional response in PVC and its correlation with retinal parameters in patients with Stargardt disease due to ABCA4 mutations (STGD1)...
March 1, 2018: Investigative Ophthalmology & Visual Science
Antonio García-Tabernero, Angel Peña-Melián, Antonio Rosas
The comparative analysis of the endocranial surface of the El Sidrón new occipital fragment SD-2300 shows meaningful differences in the configuration of the occipital pole region between neandertals and anatomically modern humans (AMH). The particular asymmetries found in neandertals in the venous sinus drainage and the petalial patterns are recognizable in this new specimen as well. In addition, the supra- and infracalcarine fossae of the occipital pole region appear to deviate obliquely from the mid-line when compared with sapiens...
April 6, 2018: Journal of Anatomy
Michael G White, Brian N Mathur
The claustrum is a telencephalic gray matter nucleus that is richly interconnected with the neocortex. This structure subserves top-down executive functions that require frontal cortical control of posterior cortical regions. However, functional anatomical support for the claustrum allowing for long-range intercortical communication is lacking. To test this, we performed a channelrhodopsin-assisted long-circuit mapping strategy in mouse brain slices. We find that anterior cingulate cortex input to the claustrum is transiently amplified by claustrum neurons that, in turn, project to parietal association cortex or to primary and secondary visual cortices...
April 6, 2018: Brain Structure & Function
Anastasia Shuster, Dino J Levy
Although it is well established that the ventromedial prefrontal cortex (vmPFC) represents value using a common currency across categories of rewards, it is unknown whether the vmPFC represents value irrespective of the sensory modality in which alternatives are presented. In the current study, male and female human subjects completed a decision-making task while their neural activity was recorded using functional magnetic resonance imaging. On each trial, subjects chose between a safe alternative and a lottery, which was presented visually or aurally...
March 2018: ENeuro
Meng Hu, Wu Li, Hualou Liang
In systems neuroscience, it is becoming increasingly common to record the activity of hundreds of neurons simultaneously via electrode arrays. The ability to accurately measure the causal interactions among multiple neurons in the brain is crucial to understanding how neurons work in concert to generate specific brain functions. The development of new statistical methods for assessing causal influence between spike trains is still an active field of neuroscience research. Here, we suggest a copula-based Granger causality measure for the analysis of neural spike train data...
March 2018: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Fengling Li, Weiqian Jiang, Tian-Yi Wang, Taorong Xie, Haishan Yao
In the primary visual cortex (V1), neuronal responses to stimuli within the receptive field (RF) are modulated by stimuli in the RF surround. A common effect of surround modulation is surround suppression, which is dependent on the feature difference between stimuli within and surround the RF and is suggested to be involved in the perceptual phenomenon of figure-ground segregation. In this study, we examined the relationship between feature-specific surround suppression of V1 neurons and figure detection behavior based on figure-ground feature difference...
March 30, 2018: Neuroscience
Steffen R Hage
Monkey vocalization is a complex behavioral pattern, which is flexibly used in audio-vocal communication. A recently proposed dual neural network model suggests that cognitive control might be involved in this behavior, originating from a frontal cortical network in the prefrontal cortex and mediated via projections from the rostral portion of the ventral premotor cortex (PMvr) and motor cortex to the primary vocal motor network in the brainstem. For the rapid adjustment of vocal output to external acoustic events, strong interconnections between vocal motor and auditory sites are needed, which are present at cortical and subcortical levels...
March 20, 2018: Hearing Research
Yunyun Han, Justus M Kebschull, Robert A A Campbell, Devon Cowan, Fabia Imhof, Anthony M Zador, Thomas D Mrsic-Flogel
Neocortical areas communicate through extensive axonal projections, but the logic of information transfer remains poorly understood, because the projections of individual neurons have not been systematically characterized. It is not known whether individual neurons send projections only to single cortical areas or distribute signals across multiple targets. Here we determine the projection patterns of 591 individual neurons in the mouse primary visual cortex using whole-brain fluorescence-based axonal tracing and high-throughput DNA sequencing of genetically barcoded neurons (MAPseq)...
March 28, 2018: Nature
Lua Koenig, Tony Ro
As with some patients with primary visual cortex (V1) damage, transcranial magnetic stimulation (TMS) over V1 reliably induces blindsight, whereby observers can correctly discriminate the attributes of visual stimuli despite being unable to detect them. This TMS-induced blindsight has been demonstrated to reflect a form of unconscious vision that relies upon different neural pathways than with conscious vision. However, the timing of the neural processes in mediating TMS-induced blindsight has been unclear, especially when considering suggestions that TMS interferes with feedback processes to V1 that mediate conscious visual perception...
March 24, 2018: Neuropsychologia
Yi Shao, Jing Bao, Xin Huang, Fu-Qing Zhou, Lei Ye, You-Lan Min, Lin Yang, Zubin Sethi, Qing Yuan, Qiong Zhou
Objective: In the present study, we investigated the brain interhemispheric functional connectivity changes in left eye MB versus right eye MB patients by voxel-mirrored homotopic connectivity (VMHC) methods. Methods: A total of 31 patients with MB (15 with left eye MB and 16 with right eye MB), and 31 healthy controls (HCs) closely matched for age were recruited. All subjects underwent functional magnetic resonance imaging (fMRI) examinations. The VMHC method was used to evaluate directly functional interactions between the hemispheres...
March 6, 2018: Oncotarget
Dong-Wha Kang, Dongho Kim, Li-Hung Chang, Yong-Hwan Kim, Emi Takahashi, Matthew S Cain, Takeo Watanabe, Yuka Sasaki
The neural mechanisms of visual perceptual learning (VPL) remain unclear. Previously we found that activation in the primary visual cortex (V1) increased in the early encoding phase of training, but returned to baseline levels in the later retention phase. To examine neural changes during the retention phase, we measured structural and functional connectivity changes using MRI. After weeks of training on a texture discrimination task, the fractional anisotropy of the inferior longitudinal fasciculus, a major tract connecting visual and anterior areas, was increased, as well as the functional connectivity between V1 and anterior regions mediated by the ILF...
March 26, 2018: Scientific Reports
Sofie C Sundberg, Björn Granseth
Genetically modified mouse strains that express Cre-recombinase in specific neuronal sub-populations have become widely used tools for investigating neuronal function. The Ntsr1-Cre GN220 mouse expresses this enzyme in corticothalamic neurons in layer 6 of cerebral cortex. We observed that about 7% of Cre-expressing cells in the primary visual cortex are found within the white matter bordering layer 6. By using the immunohistochemical marker for layer 6 neurons, Forkhead box protein 2 (FoxP2), and fluorescently conjugated latex beads injected into the dorsal lateral geniculate nucleus, we show that about half of these cells are similar to and could belong to the layer 6 corticothalamic neuron population...
March 23, 2018: Neuroscience Letters
Mariana F Farias, Leslie G Ungerleider, Sandra S Pereira, Ana Karla J Amorim, Juliana G M Soares, Ricardo Gattass
We studied the time course of changes of cytochrome oxidase (CytOx) blob spatial density and blob cross-sectional area of deprived and non-deprived portions of V1 in four capuchin monkeys after massive and restricted retinal laser lesions. Laser shots at the border of the optic disc produced massive retinal lesions, while low power laser shots in the retina produced restricted retinal lesions. These massive and restricted retinal lesions were intended to stimulate glaucoma and diabetic retinopathy, respectively...
March 25, 2018: Journal of Comparative Neurology
Marco Marcondes, Marcello G P Rosa, Mario Fiorani, Bruss Lima, Ricardo Gattass
We studied the tangential distribution of cytochrome oxidase (CytOx)-rich patches (blobs) in the striate cortex (V1) of normally sighted Homo sapiens. We analyzed the spatial density and cross-sectional area of patches in CytOx-reacted tangential sections of flat-mounted preparations of V1 and surrounding areas. CytOx-rich patches were most clearly defined in the supragranular cortical layers of V1, particularly at middle levels of layer III. Variations in patch spatial density were subtle across different visual eccentricity representations...
March 25, 2018: Journal of Comparative Neurology
Stephanie M Hare, Alicia S Law, Judith M Ford, Daniel H Mathalon, Aral Ahmadi, Eswar Damaraju, Juan Bustillo, Aysenil Belger, Hyo Jong Lee, Bryon A Mueller, Kelvin O Lim, Gregory G Brown, Adrian Preda, Theo G M van Erp, Steven G Potkin, Vince D Calhoun, Jessica A Turner
Hallucinations characterize schizophrenia, with approximately 59% of patients reporting auditory hallucinations and 27% reporting visual hallucinations. Prior neuroimaging studies suggest that hallucinations are linked to disrupted communication across distributed (sensory, salience-monitoring and subcortical) networks. Yet, our understanding of the neurophysiological mechanisms that underlie auditory and visual hallucinations in schizophrenia remains limited. This study integrates two resting-state functional magnetic resonance imaging (fMRI) analysis methods - amplitudes of low-frequency fluctuations (ALFF) and functional network connectivity (FNC) - to explore the hypotheses that (1) abnormal FNC between salience and sensory (visual/auditory) networks underlies hallucinations in schizophrenia, and (2) disrupted hippocampal oscillations (as measured by hippocampal ALFF) beget changes in FNC linked to hallucinations...
March 20, 2018: Schizophrenia Research
Anna M Wirth, Sebastian M Frank, Mark W Greenlee, Anton L Beer
The parieto-insular vestibular cortex (PIVC) and the posterior insular cortex (PIC) are key regions of the cortical vestibular network, both located in the mid-posterior section of the lateral sulcus. Little is known about the structural connectivity pattern of these areas. We employed probabilistic fiber tracking based on diffusion-weighted magnetic resonance imaging (MRI) and compared the ipsilateral connectivity of PIVC and PIC. Seed areas for the tracking algorithm were identified in each brain by functional MRI activity during caloric and visual motion stimulation, respectively...
March 23, 2018: Brain Connectivity
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