The Experts below are selected from a list of 10491 Experts worldwide ranked by ideXlab platform
Nicholas J Priebe - One of the best experts on this subject based on the ideXlab platform.
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emergent Orientation Selectivity from random networks in mouse visual cortex
Cell Reports, 2018Co-Authors: Jagruti J Pattadkal, Nicholas J Priebe, Carl Van Vreeswijk, German Mato, David HanselAbstract:The connectivity principles underlying the emergence of Orientation Selectivity in primary visual cortex (V1) of mammals lacking an Orientation map (such as rodents and lagomorphs) are poorly understood. We present a computational model in which random connectivity gives rise to Orientation Selectivity that matches experimental observations. The model predicts that mouse V1 neurons should exhibit intricate receptive fields in the two-dimensional frequency domain, causing a shift in Orientation preferences with spatial frequency. We find evidence for these features in mouse V1 using calcium imaging and intracellular whole-cell recordings.
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emergent Orientation Selectivity from random networks in mouse visual cortex
bioRxiv, 2018Co-Authors: Jagruti J Pattadkal, Nicholas J Priebe, Carl Van Vreeswijk, German Mato, David HanselAbstract:We study the connectivity principles underlying the emergence of Orientation Selectivity in primary visual cortex (V1) of mammals lacking an Orientation map. We present a computational model in which random connectivity gives rise to Orientation Selectivity that matches experimental observations. It predicts that mouse V1 neurons should exhibit intricate receptive fields in the two-dimensional frequency domain, causing shift in Orientation preferences with spatial frequency. We find evidence for these features in mouse V1 using calcium imaging and intracellular whole cell recordings.
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functional characterization and spatial clustering of visual cortical neurons in the predatory grasshopper mouse onychomys arenicola
Journal of Neurophysiology, 2017Co-Authors: Benjamin Scholl, Jagruti J Pattadkal, Ashlee H Rowe, Nicholas J PriebeAbstract:Carnivores and primates possess a map for Orientation Selectivity in primary visual cortex (V1), whereas rodents and lagomorphs lack this organization. We examine, for the first time, V1 of a wild ...
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Orientation Selectivity in the visual cortex of the nine banded armadillo
Journal of Neurophysiology, 2017Co-Authors: Benjamin Scholl, Nicholas J Priebe, Johnathan Rylee, Jeffrey J Luci, Jeffrey PadbergAbstract:The current study shows that armadillo primary visual cortex (V1) neurons share the signature properties of V1 neurons of primates, carnivorans, and rodents. Furthermore, these neurons exhibit a de...
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mechanisms of Orientation Selectivity in the primary visual cortex
Annual Review of Vision Science, 2016Co-Authors: Nicholas J PriebeAbstract:The mechanisms underlying the emergence of Orientation Selectivity in the visual cortex have been, and continue to be, the subjects of intense scrutiny. Orientation Selectivity reflects a dramatic change in the representation of the visual world: Whereas afferent thalamic neurons are generally Orientation insensitive, neurons in the primary visual cortex (V1) are extremely sensitive to stimulus Orientation. This profound change in the receptive field structure along the visual pathway has positioned V1 as a model system for studying the circuitry that underlies neural computations across the neocortex. The neocortex is characterized anatomically by the relative uniformity of its circuitry despite its role in processing distinct signals from region to region. A combination of physiological, anatomical, and theoretical studies has shed some light on the circuitry components necessary for generating Orientation Selectivity in V1. This targeted effort has led to critical insights, as well as controversies, concerning how neural circuits in the neocortex perform computations.
Kenichi Ohki - One of the best experts on this subject based on the ideXlab platform.
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mixed functional microarchitectures for Orientation Selectivity in the mouse primary visual cortex
Nature Communications, 2016Co-Authors: Satoru Kondo, Kenichi Ohki, Takashi YoshidaAbstract:A minicolumn is the smallest anatomical module in the cortical architecture, but it is still in debate whether it serves as functional units for cortical processing. In the rodent primary visual cortex (V1), neurons with different preferred Orientations are mixed horizontally in a salt and pepper manner, but vertical functional organization was not examined. In this study, we found that neurons with similar Orientation preference are weakly but significantly clustered vertically in a short length and horizontally in the scale of a minicolumn. Interestingly, the vertical clustering is found only in a part of minicolumns, and others are composed of neurons with a variety of Orientation preferences. Thus, the mouse V1 is a mixture of vertical clusters of neurons with various degrees of Orientation similarity, which may be the compromise between the brain size and keeping the vertical clusters of similarly tuned neurons at least in a subset of clusters.
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laminar differences in the Orientation Selectivity of geniculate afferents in mouse primary visual cortex
Nature Neuroscience, 2016Co-Authors: Satoru Kondo, Kenichi OhkiAbstract:It has been debated whether Orientation Selectivity in mouse primary visual cortex (V1) is derived from tuned lateral geniculate nucleus (LGN) inputs or computed from untuned LGN inputs. However, few studies have measured Orientation tuning of LGN axons projecting to V1. We measured the response properties of mouse LGN axons terminating in V1 and found that LGN axons projecting to layer 4 were generally less tuned for Orientation than axons projecting to more superficial layers of V1. We also found several differences in response properties between LGN axons and V1 neurons in layer 4. These results suggest that Orientation Selectivity of mouse V1 may not simply be inherited from LGN inputs, but could also depend on thalamocortical or V1 circuits.
Benjamin Scholl - One of the best experts on this subject based on the ideXlab platform.
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functional characterization and spatial clustering of visual cortical neurons in the predatory grasshopper mouse onychomys arenicola
Journal of Neurophysiology, 2017Co-Authors: Benjamin Scholl, Jagruti J Pattadkal, Ashlee H Rowe, Nicholas J PriebeAbstract:Carnivores and primates possess a map for Orientation Selectivity in primary visual cortex (V1), whereas rodents and lagomorphs lack this organization. We examine, for the first time, V1 of a wild ...
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Orientation Selectivity in the visual cortex of the nine banded armadillo
Journal of Neurophysiology, 2017Co-Authors: Benjamin Scholl, Nicholas J Priebe, Johnathan Rylee, Jeffrey J Luci, Jeffrey PadbergAbstract:The current study shows that armadillo primary visual cortex (V1) neurons share the signature properties of V1 neurons of primates, carnivorans, and rodents. Furthermore, these neurons exhibit a de...
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Orientation Selectivity and the functional clustering of synaptic inputs in primary visual cortex
Nature Neuroscience, 2016Co-Authors: Benjamin Scholl, Daniel E Wilson, David E Whitney, David FitzpatrickAbstract:In this study, Wilson et al. find that dendritic spines on neurons in the visual cortex cluster according to Orientation preference. The degree of clustering on single neurons strongly predicts somatic Orientation Selectivity and the prevalence of local dendritic signals in the dendritic field, suggesting a role for dendritic computation in shaping Orientation Selectivity. The majority of neurons in primary visual cortex are tuned for stimulus Orientation, but the factors that account for the range of Orientation selectivities exhibited by cortical neurons remain unclear. To address this issue, we used in vivo two-photon calcium imaging to characterize the Orientation tuning and spatial arrangement of synaptic inputs to the dendritic spines of individual pyramidal neurons in layer 2/3 of ferret visual cortex. The summed synaptic input to individual neurons reliably predicted the neuron's Orientation preference, but did not account for differences in Orientation Selectivity among neurons. These differences reflected a robust input–output nonlinearity that could not be explained by spike threshold alone and was strongly correlated with the spatial clustering of co-tuned synaptic inputs within the dendritic field. Dendritic branches with more co-tuned synaptic clusters exhibited greater rates of local dendritic calcium events, supporting a prominent role for functional clustering of synaptic inputs in dendritic nonlinearities that shape Orientation Selectivity.
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Orientation Selectivity and the functional clustering of synaptic inputs in primary visual cortex
Nature Neuroscience, 2016Co-Authors: Benjamin Scholl, Daniel E Wilson, David E Whitney, David FitzpatrickAbstract:The majority of neurons in primary visual cortex are tuned for stimulus Orientation, but the factors that account for the range of Orientation selectivities exhibited by cortical neurons remain unclear. To address this issue, we used in vivo two-photon calcium imaging to characterize the Orientation tuning and spatial arrangement of synaptic inputs to the dendritic spines of individual pyramidal neurons in layer 2/3 of ferret visual cortex. The summed synaptic input to individual neurons reliably predicted the neuron's Orientation preference, but did not account for differences in Orientation Selectivity among neurons. These differences reflected a robust input-output nonlinearity that could not be explained by spike threshold alone and was strongly correlated with the spatial clustering of co-tuned synaptic inputs within the dendritic field. Dendritic branches with more co-tuned synaptic clusters exhibited greater rates of local dendritic calcium events, supporting a prominent role for functional clustering of synaptic inputs in dendritic nonlinearities that shape Orientation Selectivity.
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emergence of Orientation Selectivity in the mammalian visual pathway
The Journal of Neuroscience, 2013Co-Authors: Benjamin Scholl, Joseph Corey, Nicholas J PriebeAbstract:Orientation Selectivity is a property of mammalian primary visual cortex (V1) neurons, yet its emergence along the visual pathway varies across species. In carnivores and primates, elongated receptive fields first appear in V1, whereas in lagomorphs such receptive fields emerge earlier, in the retina. Here we examine the mouse visual pathway and reveal the existence of Orientation Selectivity in lateral geniculate nucleus (LGN) relay cells. Cortical inactivation does not reduce this Orientation Selectivity, indicating that cortical feedback is not its source. Orientation Selectivity is similar for LGN relay cells spiking and subthreshold input to V1 neurons, suggesting that cortical Orientation Selectivity is inherited from the LGN in mouse. In contrast, Orientation Selectivity of cat LGN relay cells is small relative to subthreshold inputs onto V1 simple cells. Together, these differences show that although Orientation Selectivity exists in visual neurons of both rodents and carnivores, its emergence along the visual pathway, and thus its underlying neuronal circuitry, is fundamentally different.
Robert Shapley - One of the best experts on this subject based on the ideXlab platform.
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Orientation Selectivity from very sparse lgn inputs in a comprehensive model of macaque v1 cortex
The Journal of Neuroscience, 2016Co-Authors: Logan Chariker, Robert Shapley, Lai Sang YoungAbstract:A new computational model of the primary visual cortex (V1) of the macaque monkey was constructed to reconcile the visual functions of V1 with anatomical data on its LGN input, the extreme sparseness of which presented serious challenges to theoretically sound explanations of cortical function. We demonstrate that, even with such sparse input, it is possible to produce robust Orientation Selectivity, as well as continuity in the Orientation map. We went beyond that to find plausible dynamic regimes of our new model that emulate simultaneously experimental data for a wide range of V1 phenomena, beginning with Orientation Selectivity but also including diversity in neuronal responses, bimodal distributions of the modulation ratio (the simple/complex classification), and dynamic signatures, such as gamma-band oscillations. Intracortical interactions play a major role in all aspects of the visual functions of the model. SIGNIFICANCE STATEMENT We present the first realistic model that has captured the sparseness of magnocellular LGN inputs to the macaque primary visual cortex and successfully derived Orientation Selectivity from them. Three implications are (1) even in input layers to the visual cortex, the system is less feedforward and more dominated by intracortical signals than previously thought, (2) interactions among cortical neurons in local populations produce dynamics not explained by single neurons, and (3) such dynamics are important for function. Our model also shows that a comprehensive picture is necessary to explain function, because different visual properties are related. This study points to the need for paradigm shifts in neuroscience modeling: greater emphasis on population dynamics and, where possible, a move toward data-driven, comprehensive models.
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integrate and fire vs poisson models of lgn input to v1 cortex noisier inputs reduce Orientation Selectivity
Journal of Computational Neuroscience, 2012Co-Authors: Ichun Lin, Dajun Xing, Robert ShapleyAbstract:One of the reasons the visual cortex has attracted the interest of computational neuroscience is that it has well-defined inputs. The lateral geniculate nucleus (LGN) of the thalamus is the source of visual signals to the primary visual cortex (V1). Most large-scale cortical network models approximate the spike trains of LGN neurons as simple Poisson point processes. However, many studies have shown that neurons in the early visual pathway are capable of spiking with high temporal precision and their discharges are not Poisson-like. To gain an understanding of how response variability in the LGN influences the behavior of V1, we study response properties of model V1 neurons that receive purely feedforward inputs from LGN cells modeled either as noisy leaky integrate-and-fire (NLIF) neurons or as inhomogeneous Poisson processes. We first demonstrate that the NLIF model is capable of reproducing many experimentally observed statistical properties of LGN neurons. Then we show that a V1 model in which the LGN input to a V1 neuron is modeled as a group of NLIF neurons produces higher Orientation Selectivity than the one with Poisson LGN input. The second result implies that statistical characteristics of LGN spike trains are important for V1’s function. We conclude that physiologically motivated models of V1 need to include more realistic LGN spike trains that are less noisy than inhomogeneous Poisson processes.
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untuned suppression makes a major contribution to the enhancement of Orientation Selectivity in macaque v1
The Journal of Neuroscience, 2011Co-Authors: Dajun Xing, Michael J. Hawken, Dario L Ringach, Robert ShapleyAbstract:One of the functions of the cerebral cortex is to increase the Selectivity for stimulus features. Finding more about the mechanisms of increased cortical Selectivity is important for understanding how the cortex works. Up to now, studies in multiple cortical areas have reported that suppressive mechanisms are involved in feature Selectivity. However, the magnitude of the contribution of suppression to tuning Selectivity is not yet determined. We use Orientation Selectivity in macaque primary visual cortex, V1, as an archetypal example of cortical feature Selectivity and develop a method to estimate the magnitude of the contribution of suppression to Orientation Selectivity. The results show that untuned suppression, one form of cortical suppression, decreases the orthogonal-to-preferred response ratio ( O/P ratio) of V1 cells from an average of 0.38 to 0.26. Untuned suppression has an especially large effect on Orientation Selectivity for highly selective cells ( O/P < 0.2). Therefore, untuned suppression is crucial for the generation of highly Orientation-selective cells in V1 cortex.
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The Orientation Selectivity of color-responsive neurons in macaque V1
J Neurosci, 2008Co-Authors: E.n. Johnson, Michael J. Hawken, Robert ShapleyAbstract:Form has a strong influence on color perception. We investigated the neural basis of the form-color link in macaque primary visual cortex (V1) by studying Orientation Selectivity of single V1 cells for pure color patterns. Neurons that responded to color were classified, based on cone inputs and spatial Selectivity, into chromatically single-opponent and double-opponent groups. Single-opponent cells responded well to color but weakly to luminance contrast; they were not Orientation selective for color patterns. Most double-opponent cells were Orientation selective to pure color stimuli as well as to achromatic patterns. We also found non-opponent cells that responded weakly or not at all to pure color; most were Orientation selective for luminance patterns. Double-opponent and non-opponent cells' Orientation selectivities were not contrast invariant; Selectivity usually increased with contrast. Double-opponent cells were approximately equally Orientation selective for luminance and equiluminant color stimuli when stimuli were matched in average cone contrast. V1 double-opponent cells could be the neural basis of the influence of form on color perception. The combined activities of single- and double-opponent cells in V1 are needed for the full repertoire of color perception.
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effect of stimulus size on the dynamics of Orientation Selectivity in macaque v1
Journal of Neurophysiology, 2005Co-Authors: Dajun Xing, Michael J. Hawken, Robert Shapley, Dario L RingachAbstract:Previous research has established that Orientation Selectivity depends to a great extent on suppressive mechanisms in the visual cortex. In this study, we investigated the spatial organization and ...
David Fitzpatrick - One of the best experts on this subject based on the ideXlab platform.
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Orientation Selectivity and the functional clustering of synaptic inputs in primary visual cortex
Nature Neuroscience, 2016Co-Authors: Benjamin Scholl, Daniel E Wilson, David E Whitney, David FitzpatrickAbstract:In this study, Wilson et al. find that dendritic spines on neurons in the visual cortex cluster according to Orientation preference. The degree of clustering on single neurons strongly predicts somatic Orientation Selectivity and the prevalence of local dendritic signals in the dendritic field, suggesting a role for dendritic computation in shaping Orientation Selectivity. The majority of neurons in primary visual cortex are tuned for stimulus Orientation, but the factors that account for the range of Orientation selectivities exhibited by cortical neurons remain unclear. To address this issue, we used in vivo two-photon calcium imaging to characterize the Orientation tuning and spatial arrangement of synaptic inputs to the dendritic spines of individual pyramidal neurons in layer 2/3 of ferret visual cortex. The summed synaptic input to individual neurons reliably predicted the neuron's Orientation preference, but did not account for differences in Orientation Selectivity among neurons. These differences reflected a robust input–output nonlinearity that could not be explained by spike threshold alone and was strongly correlated with the spatial clustering of co-tuned synaptic inputs within the dendritic field. Dendritic branches with more co-tuned synaptic clusters exhibited greater rates of local dendritic calcium events, supporting a prominent role for functional clustering of synaptic inputs in dendritic nonlinearities that shape Orientation Selectivity.
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Orientation Selectivity and the functional clustering of synaptic inputs in primary visual cortex
Nature Neuroscience, 2016Co-Authors: Benjamin Scholl, Daniel E Wilson, David E Whitney, David FitzpatrickAbstract:The majority of neurons in primary visual cortex are tuned for stimulus Orientation, but the factors that account for the range of Orientation selectivities exhibited by cortical neurons remain unclear. To address this issue, we used in vivo two-photon calcium imaging to characterize the Orientation tuning and spatial arrangement of synaptic inputs to the dendritic spines of individual pyramidal neurons in layer 2/3 of ferret visual cortex. The summed synaptic input to individual neurons reliably predicted the neuron's Orientation preference, but did not account for differences in Orientation Selectivity among neurons. These differences reflected a robust input-output nonlinearity that could not be explained by spike threshold alone and was strongly correlated with the spatial clustering of co-tuned synaptic inputs within the dendritic field. Dendritic branches with more co-tuned synaptic clusters exhibited greater rates of local dendritic calcium events, supporting a prominent role for functional clustering of synaptic inputs in dendritic nonlinearities that shape Orientation Selectivity.
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the contribution of sensory experience to the maturation of Orientation Selectivity in ferret visual cortex
Nature, 2001Co-Authors: Leonard E White, David M Coppola, David FitzpatrickAbstract:Sensory experience begins when neural circuits in the cerebral cortex are still immature; however, the contribution of experience to cortical maturation remains unclear. In the visual cortex, the Selectivity of neurons for oriented stimuli at the time of eye opening is poor1,2,3,4,5 and increases dramatically after the onset of visual experience3,4,5,6,7,8. Here we investigate whether visual experience has a significant role in the maturation of Orientation Selectivity and underlying cortical circuits9,10,11,12 using two forms of deprivation: dark rearing, which completely eliminates experience, and binocular lid suture, which alters the pattern of sensory driven activity13. Orientation maps were present in dark-reared ferrets, but fully mature levels of tuning were never attained. In contrast, only rudimentary levels of Orientation Selectivity were observed in lid-sutured ferrets. Despite these differences, horizontal connections in both groups were less extensive and less clustered than normal, suggesting that long-range cortical processing is not essential for the expression of Orientation Selectivity, but may be needed for the full maturation of tuning. Thus, experience is beneficial or highly detrimental to cortical maturation, depending on the pattern of sensory driven activity.
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Orientation Selectivity and the arrangement of horizontal connections in tree shrew striate cortex
The Journal of Neuroscience, 1997Co-Authors: William H Bosking, Ying Zhang, Brett R Schofield, David FitzpatrickAbstract:Horizontal connections, formed primarily by the axon collaterals of pyramidal neurons in layer 2/3 of visual cortex, extend for millimeters parallel to the cortical surface and form patchy terminations. Previous studies have provided evidence that the patches formed by horizontal connections exhibit modular specificity, preferentially linking columns of neurons with similar response characteristics, such as preferred Orientation. The issue of how these connections are distributed with respect to the topographic map of visual space, however, has not been resolved. Here we combine optical imaging of intrinsic signals with small extracellular injections of biocytin to assess quantitatively the specificity of horizontal connections with respect to both the map of Orientation preference and the map of visual space in tree shrew V1. Our results indicate that horizontal connections outside a radius of 500 μm from the injection site exhibit not only modular specificity, but also specificity for axis of projection. Labeled axons extend for longer distances, and give off more terminal boutons, along an axis in the map of visual space that corresponds to the preferred Orientation of the injection site. Inside of 500 μm, the pattern of connections is much less specific, with boutons found along every axis, contacting sites with a wide range of preferred Orientations. The system of long-range horizontal connections can be summarized as preferentially linking neurons with co-oriented, co-axially aligned receptive fields. These observations suggest specific ways that horizontal circuits contribute to the response properties of layer 2/3 neurons and to mechanisms of visual perception.
