Journal articles on the topic 'Visual cortex (V1)'
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Beltramo, Riccardo, and Massimo Scanziani. "A collicular visual cortex: Neocortical space for an ancient midbrain visual structure." Science 363, no. 6422 (January 3, 2019): 64–69. http://dx.doi.org/10.1126/science.aau7052.
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Visual responses in the cerebral cortex are believed to rely on the geniculate input to the primary visual cortex (V1). Indeed, V1 lesions substantially reduce visual responses throughout the cortex. Visual information enters the cortex also through the superior colliculus (SC), but the function of this input on visual responses in the cortex is less clear. SC lesions affect cortical visual responses less than V1 lesions, and no visual cortical area appears to entirely rely on SC inputs. We show that visual responses in a mouse lateral visual cortical area called the postrhinal cortex are independent of V1 and are abolished upon silencing of the SC. This area outperforms V1 in discriminating moving objects. We thus identify a collicular primary visual cortex that is independent of the geniculo-cortical pathway and is capable of motion discrimination.
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Froudarakis, Emmanouil, Paul G. Fahey, Jacob Reimer, Stelios M. Smirnakis, Edward J. Tehovnik, and Andreas S. Tolias. "The Visual Cortex in Context." Annual Review of Vision Science 5, no. 1 (September 15, 2019): 317–39. http://dx.doi.org/10.1146/annurev-vision-091517-034407.
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In this article, we review the anatomical inputs and outputs to the mouse primary visual cortex, area V1. Our survey of data from the Allen Institute Mouse Connectivity project indicates that mouse V1 is highly interconnected with both cortical and subcortical brain areas. This pattern of innervation allows for computations that depend on the state of the animal and on behavioral goals, which contrasts with simple feedforward, hierarchical models of visual processing. Thus, to have an accurate description of the function of V1 during mouse behavior, its involvement with the rest of the brain circuitry has to be considered. Finally, it remains an open question whether the primary visual cortex of higher mammals displays the same degree of sensorimotor integration in the early visual system.
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White, Brian J., Janis Y. Kan, Ron Levy, Laurent Itti, and Douglas P. Munoz. "Superior colliculus encodes visual saliency before the primary visual cortex." Proceedings of the National Academy of Sciences 114, no. 35 (August 14, 2017): 9451–56. http://dx.doi.org/10.1073/pnas.1701003114.
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Models of visual attention postulate the existence of a bottom-up saliency map that is formed early in the visual processing stream. Although studies have reported evidence of a saliency map in various cortical brain areas, determining the contribution of phylogenetically older pathways is crucial to understanding its origin. Here, we compared saliency coding from neurons in two early gateways into the visual system: the primary visual cortex (V1) and the evolutionarily older superior colliculus (SC). We found that, while the response latency to visual stimulus onset was earlier for V1 neurons than superior colliculus superficial visual-layer neurons (SCs), the saliency representation emerged earlier in SCs than in V1. Because the dominant input to the SCs arises from V1, these relative timings are consistent with the hypothesis that SCs neurons pool the inputs from multiple V1 neurons to form a feature-agnostic saliency map, which may then be relayed to other brain areas.
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Hawken, M. J., R. M. Shapley, and D. H. Grosof. "Temporal-frequency selectivity in monkey visual cortex." Visual Neuroscience 13, no. 3 (May 1996): 477–92. http://dx.doi.org/10.1017/s0952523800008154.
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AbstractWe investigated the dynamics of neurons in the striate cortex (V1) and the lateral geniculate nucleus (LGN) to study the transformation in temporal-frequency tuning between the LGN and V1. Furthermore, we compared the temporal-frequency tuning of simple with that of complex cells and direction-selective cells with nondirection-selective cells, in order to determine whether there are significant differences in temporal-frequency tuning among distinct functional classes of cells within V1. In addition, we compared the cells in the primary input layers of V1 (4a, 4cα, and 4cβ) with cells in the layers that are predominantly second and higher order (2, 3, 4b, 5, and 6). We measured temporal-frequency responses to drifting sinusoidal gratings. For LGN neurons and simple cells, we used the amplitude and phase of the fundamental response. For complex cells, the elevation of impulse rate (F0) to a drifting grating was the response measure. There is significant low-pass filtering between the LGN and the input layers of V1 accompanied by a small, 3-ms increase in visual delay. There is further low-pass filtering between V1 input layers and the second- and higher-order neurons in V1. This results in an average decrease in high cutoff temporal-frequency between the LGN and V1 output layers of about 20 Hz and an increase in average visual latency of about 12–14 ms. One of the most salient results is the increased diversity of the dynamic properties seen in V1 when compared to the cells of the lateral geniculate, possibly reflecting specialization of function among cells in V1. Simple and complex cells had distributions of temporal-frequency tuning properties that were similar to each other. Direction-selective and nondirection-selective cells had similar preferred and high cutoff temporal frequencies, but direction-selective cells were almost exclusively band-pass while nondirection-selective cells distributed equally between band-pass and low-pass categories. Integration time, a measure of visual delay, was about 10 ms longer for V1 than LGN. In V1 there was a relatively broad distribution of integration times from 40–80 ms for simple cells and 60–100 ms for complex cells while in the LGN the distribution was narrower.
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Tehovnik, Edward J., and Warren M. Slocum. "What Delay Fields Tell Us About Striate Cortex." Journal of Neurophysiology 98, no. 2 (August 2007): 559–76. http://dx.doi.org/10.1152/jn.00285.2007.
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It is well known that electrical activation of striate cortex (area V1) can disrupt visual behavior. Based on this knowledge, we discovered that electrical microstimulation of V1 in macaque monkeys delays saccadic eye movements when made to visual targets located in the receptive field of the stimulated neurons. This review discusses the following issues. First, the parameters that affect the delay of saccades by microstimulation of V1 are reviewed. Second, the excitability properties of the V1 elements mediating the delay are discussed. Third, the properties that determine the size and shape of the region of visual space affected by stimulation of V1 are described. This region is called a delay field. Fourth, whether the delay effect is mainly due to a disruption of the visual signal transmitted through V1 or whether it is a disturbance of the motor signal transmitted between V1 and the brain stem saccade generator is investigated. Fifth, the properties of delay fields are used to estimate the number of elements activated directly by electrical microstimulation of macaque V1. Sixth, these properties are used to make inferences about the characteristics of visual percepts induced by such stimulation. Seventh, the disruptive effects of V1 stimulation in monkeys and humans are compared. Eighth, a cortical mechanism to account for the disruptive effects of V1 stimulation is proposed. Finally, these effects are related to normal vision.
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Schira, Mark M., Alex R. Wade, and Christopher W. Tyler. "Two-Dimensional Mapping of the Central and Parafoveal Visual Field to Human Visual Cortex." Journal of Neurophysiology 97, no. 6 (June 2007): 4284–95. http://dx.doi.org/10.1152/jn.00972.2006.
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Primate visual cortex contains a set of maps of visual space. These maps are fundamental to early visual processing, yet their form is not fully understood in humans. This is especially true for the central and most important part of the visual field—the fovea. We used functional magnetic resonance imaging (fMRI) to measure the mapping geometry of human V1 and V2 down to 0.5° of eccentricity. By applying automated atlas fitting procedures to parametrize and average retinotopic measurements of eight brains, we provide a reference standard for the two-dimensional geometry of human early visual cortex of unprecedented precision and analyze this high-quality mean dataset with respect to the 2-dimensional cortical magnification morphometry. The analysis indicates that 1) area V1 has meridional isotropy in areal projection: equal areas of visual space are mapped to equal areas of cortex at any given eccentricity. 2) V1 has a systematic pattern of local anisotropies: cortical magnification varies between isopolar and isoeccentricity lines, and 3) the shape of V1 deviates systematically from the complex-log model, the fit of which is particularly poor close to the fovea. We therefore propose that human V1 be fitted by models based on an equal-area principle of its two-dimensional magnification. 4) V2 is elongated by a factor of 2 in eccentricity direction relative to V1 and has significantly more local anisotropy. We propose that V2 has systematic intrinsic curvature, but V1 is intrinsically flat.
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Watanabe, Takeo, Yuka Sasaki, Satoru Miyauchi, Benno Putz, Norio Fujimaki, Matthew Nielsen, Ryosuke Takino, and Satoshi Miyakawa. "Attention-Regulated Activity in Human Primary Visual Cortex." Journal of Neurophysiology 79, no. 4 (April 1, 1998): 2218–21. http://dx.doi.org/10.1152/jn.1998.79.4.2218.
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Watanabe, Takeo, Yuka Sasaki, Satoru Miyauchi, Benno Putz, Norio Fujimaki, Matthew Nielsen, Ryosuke Takino, and Satoshi Miyakawa. Attention-regulated activity in human primary visual cortex. J. Neurophysiol. 79: 2218–2221, 1998. Effects of attention to a local contour of a moving object on the activation of human primary visual cortex (area V1) were examined. Local cerebral oxygenation changes (an index of neuronal activity) in human area V1 were measured with functional magnetic resonance imaging (fMRI) in conditions including the following two: 1) when attention was selectively directed toward one side of a moving wedge (the attention condition) and 2) when the wedges were viewed passively (the passive condition). Activation in area V1 was found to be higher in the attention condition than in the passive condition. To our knowledge, this is the first finding that attention to motion activates as early as area V1. We suggest that attentional activation of area V1 is task dependent.
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Pereira, Catia M., Marco Aurelio M. Freire, José R. Santos, Joanilson S. Guimarães, Gabriella Dias-Florencio, Sharlene Santos, Antonio Pereira, and Sidarta Ribeiro. "Non-visual exploration of novel objects increases the levels of plasticity factors in the rat primary visual cortex." PeerJ 6 (October 23, 2018): e5678. http://dx.doi.org/10.7717/peerj.5678.
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Background Historically, the primary sensory areas of the cerebral cortex have been exclusively associated with the processing of a single sensory modality. Yet the presence of tactile responses in the primary visual (V1) cortex has challenged this view, leading to the notion that primary sensory areas engage in cross-modal processing, and that the associated circuitry is modifiable by such activity. To explore this notion, here we assessed whether the exploration of novel objects in the dark induces the activation of plasticity markers in the V1 cortex of rats. Methods Adult rats were allowed to freely explore for 20 min a completely dark box with four novel objects of different shapes and textures. Animals were euthanized either 1 (n = 5) or 3 h (n = 5) after exploration. A control group (n = 5) was placed for 20 min in the same environment, but without the objects. Frontal sections of the brains were submitted to immunohistochemistry to measure protein levels of egr-1 and c-fos, and phosphorylated calcium-dependent kinase (pCaKMII) in V1 cortex. Results The amount of neurons labeled with monoclonal antibodies against c-fos, egr-1 or pCaKMII increased significantly in V1 cortex after one hour of exploration in the dark. Three hours after exploration, the number of labeled neurons decreased to basal levels. Conclusions Our results suggest that non-visual exploration induces the activation of immediate-early genes in V1 cortex, which is suggestive of cross-modal processing in this area. Besides, the increase in the number of neurons labeled with pCaKMII may signal a condition promoting synaptic plasticity.
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DUFFY, KEVIN R., KATHRYN M. MURPHY, and DAVID G. JONES. "Analysis of the postnatal growth of visual cortex." Visual Neuroscience 15, no. 5 (May 1998): 831–39. http://dx.doi.org/10.1017/s0952523898155049.
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Development and growth of V1 begins during embryogenesis and continues postnatally. The growth of V1 has direct implications on the organization of features such as the retinotopic map and the pattern of visual cortical columns. We have examined the postnatal growth and two-dimensional shape of V1 in macaque monkeys, cats, and rats. The perimeter, area, and anterior–posterior length of V1 were measured from unfolded and flattened sections from neonatal and adult animals from each of these species. Although there were substantial differences in the overall amount of postnatal growth, from 18% in macaque monkeys to more than 100% in cats, in all three species the shape of V1 did not change during development. Thus, growth of the mammalian visual cortex is well described as an isotropic expansion, so the layout of the global features, such as the arrangement of ocular dominance columns and the retinotopic map, does not need to change during development. Furthermore, quantification of the shape confirms the observations that there is a similar, egg-like oval shape to the visual cortex of these mammalian species.
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Bressloff, Paul C., Jack D. Cowan, Martin Golubitsky, Peter J. Thomas, and Matthew C. Wiener. "What Geometric Visual Hallucinations Tell Us about the Visual Cortex." Neural Computation 14, no. 3 (March 1, 2002): 473–91. http://dx.doi.org/10.1162/089976602317250861.
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Many observers see geometric visual hallucinations after taking hallucinogens such as LSD, cannabis, mescaline or psilocybin; on viewing bright flickering lights; on waking up or falling asleep; in “near-death” experiences; and in many other syndromes. Klüver organized the images into four groups called form constants: (I) tunnels and funnels, (II) spirals, (III) lattices, including honeycombs and triangles, and (IV) cobwebs. In most cases, the images are seen in both eyes and move with them. We interpret this to mean that they are generated in the brain. Here, we summarize a theory of their origin in visual cortex (area V1), based on the assumption that the form of the retino–cortical map and the architecture of V1 determine their geometry. (A much longer and more detailed mathematical version has been published in Philosophical Transactions of the Royal Society B, 356 [2001].) We model V1 as the continuum limit of a lattice of interconnected hypercolumns, each comprising a number of interconnected iso-orientation columns. Based on anatomical evidence, we assume that the lateral connectivity between hypercolumns exhibits symmetries, rendering it invariant under the action of the Euclidean group E(2), composed of reflections and translations in the plane, and a (novel) shift-twist action. Using this symmetry, we show that the various patterns of activity that spontaneously emerge when V1's spatially uniform resting state becomes unstable correspond to the form constants when transformed to the visual field using the retino-cortical map. The results are sensitive to the detailed specification of the lateral connectivity and suggest that the cortical mechanisms that generate geometric visual hallucinations are closely related to those used to process edges, contours, surfaces, and textures.
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Johnson, Elizabeth N., Michael J. Hawken, and Robert Shapley. "Cone Inputs in Macaque Primary Visual Cortex." Journal of Neurophysiology 91, no. 6 (June 2004): 2501–14. http://dx.doi.org/10.1152/jn.01043.2003.
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To understand the role of primary visual cortex (V1) in color vision, we measured directly the input from the 3 cone types in macaque V1 neurons. Cells were classified as luminance-preferring, color-luminance, or color-preferring from the ratio of the peak amplitudes of spatial frequency responses to red/green equiluminant and to black/white (luminance) grating patterns, respectively. In this study we used L-, M-, and S-cone–isolating gratings to measure spatial frequency response functions for each cone type separately. From peak responses to cone-isolating stimuli we estimated relative cone weights and whether cone inputs were the same or opposite sign. For most V1 cells the relative S-cone weight was <0.1. All color-preferring cells were cone opponent and their L/M cone weight ratio was clustered around a value of –1, which is roughly equal and opposite L and M cone signals. Almost all cells (88%) classified as luminance cells were cone nonopponent, with a broad distribution of cone weights. Most cells (73%) classified as color-luminance cells were cone opponent. This result supports our conclusion that V1 color-luminance cells are double-opponent. Such neurons are more sensitive to color boundaries than to areas of color and thereby could play an important role in color perception. The color-luminance population had a broad distribution of L/M cone weight ratios, implying a broad distribution of preferred colors for the double-opponent cells.
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Lamme, Victor A. F., Hans Supèr, Rogier Landman, Pieter R. Roelfsema, and Henk Spekreijse. "The role of primary visual cortex (V1) in visual awareness." Vision Research 40, no. 10-12 (June 2000): 1507–21. http://dx.doi.org/10.1016/s0042-6989(99)00243-6.
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Seidemann, Eyal, and Wilson S. Geisler. "Linking V1 Activity to Behavior." Annual Review of Vision Science 4, no. 1 (September 15, 2018): 287–310. http://dx.doi.org/10.1146/annurev-vision-102016-061324.
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A long-term goal of visual neuroscience is to develop and test quantitative models that account for the moment-by-moment relationship between neural responses in early visual cortex and human performance in natural visual tasks. This review focuses on efforts to address this goal by measuring and perturbing the activity of primary visual cortex (V1) neurons while nonhuman primates perform demanding, well-controlled visual tasks. We start by describing a conceptual approach—the decoder linking model (DLM) framework—in which candidate decoding models take neural responses as input and generate predicted behavior as output. The ultimate goal in this framework is to find the actual decoder—the model that best predicts behavior from neural responses. We discuss key relevant properties of primate V1 and review current literature from the DLM perspective. We conclude by discussing major technological and theoretical advances that are likely to accelerate our understanding of the link between V1 activity and behavior.
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Vaiceliunaite, Agne, Sinem Erisken, Florian Franzen, Steffen Katzner, and Laura Busse. "Spatial integration in mouse primary visual cortex." Journal of Neurophysiology 110, no. 4 (August 15, 2013): 964–72. http://dx.doi.org/10.1152/jn.00138.2013.
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Responses of many neurons in primary visual cortex (V1) are suppressed by stimuli exceeding the classical receptive field (RF), an important property that might underlie the computation of visual saliency. Traditionally, it has proven difficult to disentangle the underlying neural circuits, including feedforward, horizontal intracortical, and feedback connectivity. Since circuit-level analysis is particularly feasible in the mouse, we asked whether neural signatures of spatial integration in mouse V1 are similar to those of higher-order mammals and investigated the role of parvalbumin-expressing (PV+) inhibitory interneurons. Analogous to what is known from primates and carnivores, we demonstrate that, in awake mice, surround suppression is present in the majority of V1 neurons and is strongest in superficial cortical layers. Anesthesia with isoflurane-urethane, however, profoundly affects spatial integration: it reduces the laminar dependency, decreases overall suppression strength, and alters the temporal dynamics of responses. We show that these effects of brain state can be parsimoniously explained by assuming that anesthesia affects contrast normalization. Hence, the full impact of suppressive influences in mouse V1 cannot be studied under anesthesia with isoflurane-urethane. To assess the neural circuits of spatial integration, we targeted PV+ interneurons using optogenetics. Optogenetic depolarization of PV+ interneurons was associated with increased RF size and decreased suppression in the recorded population, similar to effects of lowering stimulus contrast, suggesting that PV+ interneurons contribute to spatial integration by affecting overall stimulus drive. We conclude that the mouse is a promising model for circuit-level mechanisms of spatial integration, which relies on the combined activity of different types of inhibitory interneurons.
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Liang, Hualou, Xiajing Gong, Minggui Chen, Yin Yan, Wu Li, and Charles D. Gilbert. "Interactions between feedback and lateral connections in the primary visual cortex." Proceedings of the National Academy of Sciences 114, no. 32 (July 24, 2017): 8637–42. http://dx.doi.org/10.1073/pnas.1706183114.
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Perceptual grouping of line segments into object contours has been thought to be mediated, in part, by long-range horizontal connectivity intrinsic to the primary visual cortex (V1), with a contribution by top-down feedback projections. To dissect the contributions of intraareal and interareal connections during contour integration, we applied conditional Granger causality analysis to assess directional influences among neural signals simultaneously recorded from visual cortical areas V1 and V4 of monkeys performing a contour detection task. Our results showed that discounting the influences from V4 markedly reduced V1 lateral interactions, indicating dependence on feedback signals of the effective connectivity within V1. On the other hand, the feedback influences were reciprocally dependent on V1 lateral interactions because the modulation strengths from V4 to V1 were greatly reduced after discounting the influences from other V1 neurons. Our findings suggest that feedback and lateral connections closely interact to mediate image grouping and segmentation.
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Vermaercke, Ben, Florian J. Gerich, Ellen Ytebrouck, Lutgarde Arckens, Hans P. Op de Beeck, and Gert Van den Bergh. "Functional specialization in rat occipital and temporal visual cortex." Journal of Neurophysiology 112, no. 8 (October 15, 2014): 1963–83. http://dx.doi.org/10.1152/jn.00737.2013.
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Recent studies have revealed a surprising degree of functional specialization in rodent visual cortex. Anatomically, suggestions have been made about the existence of hierarchical pathways with similarities to the ventral and dorsal pathways in primates. Here we aimed to characterize some important functional properties in part of the supposed “ventral” pathway in rats. We investigated the functional properties along a progression of five visual areas in awake rats, from primary visual cortex (V1) over lateromedial (LM), latero-intermediate (LI), and laterolateral (LL) areas up to the newly found lateral occipito-temporal cortex (TO). Response latency increased >20 ms from areas V1/LM/LI to areas LL and TO. Orientation and direction selectivity for the used grating patterns increased gradually from V1 to TO. Overall responsiveness and selectivity to shape stimuli decreased from V1 to TO and was increasingly dependent upon shape motion. Neural similarity for shapes could be accounted for by a simple computational model in V1, but not in the other areas. Across areas, we find a gradual change in which stimulus pairs are most discriminable. Finally, tolerance to position changes increased toward TO. These findings provide unique information about possible commonalities and differences between rodents and primates in hierarchical cortical processing.
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Yeh, C. I., D. Xing, and R. M. Shapley. ""Black" Responses Dominate Macaque Primary Visual Cortex V1." Journal of Neuroscience 29, no. 38 (September 23, 2009): 11753–60. http://dx.doi.org/10.1523/jneurosci.1991-09.2009.
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Zhong, Haixin, and Rubin Wang. "A new discovery on visual information dynamic changes from V1 to V2: corner encoding." Nonlinear Dynamics 105, no. 4 (August 5, 2021): 3551–70. http://dx.doi.org/10.1007/s11071-021-06648-0.
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AbstractThe information processing mechanisms of the visual nervous system remain to be unsolved scientific issues in neuroscience field, owing to a lack of unified and widely accepted theory for explanation. It has been well documented that approximately 80% of the rich and complicated perceptual information from the real world is transmitted to the visual cortex, and only a small fraction of visual information reaches the primary visual cortex (V1). This, nevertheless, does not affect our visual perception. Furthermore, how neurons in the secondary visual cortex (V2) encode such a small amount of visual information has yet to be addressed. To this end, the current paper established a visual network model for retina-lateral geniculate nucleus (LGN)-V1–V2 and quantitatively accounted for that response to the scarcity of visual information and encoding rules, based on the principle of neural mapping from V1 to V2. The results demonstrated that the visual information has a small degree of dynamic degradation when it is mapped from V1 to V2, during which there is a convolution calculation occurring. Therefore, visual information dynamic degradation mainly manifests itself along the pathway of the retina to V1, rather than V1 to V2. The slight changes in the visual information are attributable to the fact that the receptive fields (RFs) of V2 cannot further extract the image features. Meanwhile, despite the scarcity of visual information mapped from the retina, the RFs of V2 can still accurately respond to and encode “corner” information, due to the effects of synaptic plasticity, but the similar function does not exist in V1. This is a new discovery that has never been noticed before. To sum up, the coding of the “contour” feature (edge and corner) is achieved in the pathway of retina-LGN-V1–V2.
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Scholl, Benjamin, Johnathan Rylee, Jeffrey J. Luci, Nicholas J. Priebe, and Jeffrey Padberg. "Orientation selectivity in the visual cortex of the nine-banded armadillo." Journal of Neurophysiology 117, no. 3 (March 1, 2017): 1395–406. http://dx.doi.org/10.1152/jn.00851.2016.
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Orientation selectivity in primary visual cortex (V1) has been proposed to reflect a canonical computation performed by the neocortical circuitry. Although orientation selectivity has been reported in all mammals examined to date, the degree of selectivity and the functional organization of selectivity vary across mammalian 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. Furthermore, the functional organization in cortex varies in that the primate and carnivore V1 is characterized by an organization in which nearby neurons share orientation preference while other mammals such as rodents and lagomorphs either lack or have only extremely weak clustering. To gain insight into the evolutionary emergence of orientation selectivity, we examined the nine-banded armadillo, a species within the early placental clade Xenarthra. Here we use a combination of neuroimaging, histological, and electrophysiological methods to identify the retinofugal pathways, locate V1, and for the first time examine the functional properties of V1 neurons in the armadillo ( Dasypus novemcinctus) V1. Individual neurons were strongly sensitive to the orientation and often the direction of drifting gratings. We uncovered a wide range of orientation preferences but found a bias for horizontal gratings. The presence of strong orientation selectivity in armadillos suggests that the circuitry responsible for this computation is common to all placental mammals.NEW & NOTEWORTHY 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 degree of selectivity for stimulus orientation and motion direction similar to that found in primate V1. Our findings in armadillo visual cortex suggest that the functional properties of V1 neurons emerged early in the mammalian lineage, near the time of the divergence of marsupials.
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McClure, John P., and Pierre-Olivier Polack. "Pure tones modulate the representation of orientation and direction in the primary visual cortex." Journal of Neurophysiology 121, no. 6 (June 1, 2019): 2202–14. http://dx.doi.org/10.1152/jn.00069.2019.
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Multimodal sensory integration facilitates the generation of a unified and coherent perception of the environment. It is now well established that unimodal sensory perceptions, such as vision, are improved in multisensory contexts. Whereas multimodal integration is primarily performed by dedicated multisensory brain regions such as the association cortices or the superior colliculus, recent studies have shown that multisensory interactions also occur in primary sensory cortices. In particular, sounds were shown to modulate the responses of neurons located in layers 2/3 (L2/3) of the mouse primary visual cortex (V1). Yet, the net effect of sound modulation at the V1 population level remained unclear. In the present study, we performed two-photon calcium imaging in awake mice to compare the representation of the orientation and the direction of drifting gratings by V1 L2/3 neurons in unimodal (visual only) or multimodal (audiovisual) conditions. We found that sound modulation depended on the tuning properties (orientation and direction selectivity) and response amplitudes of V1 L2/3 neurons. Sounds potentiated the responses of neurons that were highly tuned to the cue’s orientation and direction but weakly active in the unimodal context, following the principle of inverse effectiveness of multimodal integration. Moreover, sound suppressed the responses of neurons untuned for the orientation and/or the direction of the visual cue. Altogether, sound modulation improved the representation of the orientation and direction of the visual stimulus in V1 L2/3. Namely, visual stimuli presented with auditory stimuli recruited a neuronal population better tuned to the visual stimulus orientation and direction than when presented alone. NEW & NOTEWORTHY The primary visual cortex (V1) receives direct inputs from the primary auditory cortex. Yet, the impact of sounds on visual processing in V1 remains controverted. We show that the modulation by pure tones of V1 visual responses depends on the orientation selectivity, direction selectivity, and response amplitudes of V1 neurons. Hence, audiovisual stimuli recruit a population of V1 neurons better tuned to the orientation and direction of the visual stimulus than unimodal visual stimuli.
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Larsson, Jonas, and Sarah J. Harrison. "Spatial specificity and inheritance of adaptation in human visual cortex." Journal of Neurophysiology 114, no. 2 (August 2015): 1211–26. http://dx.doi.org/10.1152/jn.00167.2015.
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Adaptation at early stages of sensory processing can be propagated to downstream areas. Such inherited adaptation is a potential confound for functional magnetic resonance imaging (fMRI) techniques that use selectivity of adaptation to infer neuronal selectivity. However, the relative contributions of inherited and intrinsic adaptation at higher cortical stages, and the impact of inherited adaptation on downstream processing, remain unclear. Using fMRI, we investigated how adaptation to visual motion direction and orientation influences visually evoked responses in human V1 and extrastriate visual areas. To dissociate inherited from intrinsic adaptation, we quantified the spatial specificity of adaptation for each visual area as a measure of the receptive field sizes of the area where adaptation originated, predicting that adaptation originating in V1 should be more spatially specific than adaptation intrinsic to extrastriate visual cortex. In most extrastriate visual areas, the spatial specificity of adaptation did not differ from that in V1, suggesting that adaptation originated in V1. Only in one extrastriate area—MT—was the spatial specificity of direction-selective adaptation significantly broader than in V1, consistent with a combination of inherited V1 adaptation and intrinsic MT adaptation. Moreover, inherited adaptation effects could be both facilitatory and suppressive. These results suggest that adaptation at early visual processing stages can have widespread and profound effects on responses in extrastriate visual areas, placing important constraints on the use of fMRI adaptation techniques, while also demonstrating a general experimental strategy for systematically dissociating inherited from intrinsic adaptation by fMRI.
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Strother, Lars, Cheryl Lavell, and Tutis Vilis. "Figure–Ground Representation and Its Decay in Primary Visual Cortex." Journal of Cognitive Neuroscience 24, no. 4 (April 2012): 905–14. http://dx.doi.org/10.1162/jocn_a_00190.
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We used fMRI to study figure–ground representation and its decay in primary visual cortex (V1). Human observers viewed a motion-defined figure that gradually became camouflaged by a cluttered background after it stopped moving. V1 showed positive fMRI responses corresponding to the moving figure and negative fMRI responses corresponding to the static background. This positive–negative delineation of V1 “figure” and “background” fMRI responses defined a retinotopically organized figure–ground representation that persisted after the figure stopped moving but eventually decayed. The temporal dynamics of V1 “figure” and “background” fMRI responses differed substantially. Positive “figure” responses continued to increase for several seconds after the figure stopped moving and remained elevated after the figure had disappeared. We propose that the sustained positive V1 “figure” fMRI responses reflected both persistent figure–ground representation and sustained attention to the location of the figure after its disappearance, as did subjects' reports of persistence. The decreasing “background” fMRI responses were relatively shorter-lived and less biased by spatial attention. Our results show that the transition from a vivid figure–ground percept to its disappearance corresponds to the concurrent decay of figure enhancement and background suppression in V1, both of which play a role in form-based perceptual memory.
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Petro, L. S., A. T. Paton, and L. Muckli. "Contextual modulation of primary visual cortex by auditory signals." Philosophical Transactions of the Royal Society B: Biological Sciences 372, no. 1714 (February 19, 2017): 20160104. http://dx.doi.org/10.1098/rstb.2016.0104.
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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. We speculate which cellular mechanisms allow V1 to be contextually modulated by auditory input to facilitate perception, cognition and behaviour. Beyond cortical feedback that facilitates perception, we argue that there is also feedback serving counterfactual processing during imagery, dreaming and mind wandering, which is not relevant for immediate perception but for behaviour and cognition over a longer time frame. This article is part of the themed issue ‘Auditory and visual scene analysis’.
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Chong, Edmund, Ariana M. Familiar, and Won Mok Shim. "Reconstructing representations of dynamic visual objects in early visual cortex." Proceedings of the National Academy of Sciences 113, no. 5 (December 28, 2015): 1453–58. http://dx.doi.org/10.1073/pnas.1512144113.
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As raw sensory data are partial, our visual system extensively fills in missing details, creating enriched percepts based on incomplete bottom-up information. Despite evidence for internally generated representations at early stages of cortical processing, it is not known whether these representations include missing information of dynamically transforming objects. Long-range apparent motion (AM) provides a unique test case because objects in AM can undergo changes both in position and in features. Using fMRI and encoding methods, we found that the “intermediate” orientation of an apparently rotating grating, never presented in the retinal input but interpolated during AM, is reconstructed in population-level, feature-selective tuning responses in the region of early visual cortex (V1) that corresponds to the retinotopic location of the AM path. This neural representation is absent when AM inducers are presented simultaneously and when AM is visually imagined. Our results demonstrate dynamic filling-in in V1 for object features that are interpolated during kinetic transformations.
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Abolpour, Nahid, Reza Boostani, Mohammad-Ali Masnadi-Shirazi, Bahman Tahayori, and Ali Almasi. "A CHAOTIC MULTILAYER LIF SCHEME TO MODEL THE PRIMARY VISUAL CORTEX." Biomedical Engineering: Applications, Basis and Communications 33, no. 04 (May 4, 2021): 2150030. http://dx.doi.org/10.4015/s1016237221500307.
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Precise mathematical modeling of the primary visual cortex (V1) is still a challenging problem. Due to the high similarity of visual system of cat and human, in this paper, we present a hybrid model to track the electrical responses of neurons that are measured by a multi-electrode array implanted in cat V1. The proposed model combines a stochastic phenomenological model with a multilayer leaky integrate-and-fire (LIF) model to predict V1 responses. Since all the existing visual cortex models do not capture the stochastic properties of synaptic changes, the proposed phenomenological model provides input currents for V1 by utilizing continuous chaotic neural equations with a quantization rule. Then a multilayer LIF model is presented to mimic the functions of lateral geniculate nucleus (LGN) and V1 neurons by their corresponding differential equations. The input current in these models is from the presynaptic neurons, which are computed using the LIF model. The LGN-V1 neuronal connections are adopted from previous studies, where the receptive fields (RFs) of LGN neurons converge onto elongated spatial structures that denote RFs of V1 neurons. The main purpose of this paper is to develop a short-term plasticity model that is more consistent with the nature of the LGN and V1 responses compared to state-of-the-art models. Previous studies have not incorporated the stochastic and quantized behaviors of neurons that in the recorded data of implemented electrodes. The experimental results show the ability of the proposed model to accurately predict spikes recorded experimentally, indicating the model outperforms the state-of-the-art method.
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Zhang, Qing-fang, Hao Li, Ming Chen, Aike Guo, Yunqing Wen, and Mu-ming Poo. "Functional organization of intrinsic and feedback presynaptic inputs in the primary visual cortex." Proceedings of the National Academy of Sciences 115, no. 22 (May 14, 2018): E5174—E5182. http://dx.doi.org/10.1073/pnas.1719711115.
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In the primary visual cortex (V1) of many mammalian species, neurons are spatially organized according to their preferred orientation into a highly ordered map. However, whether and how the various presynaptic inputs to V1 neurons are organized relative to the neuronal orientation map remain unclear. To address this issue, we constructed genetically encoded calcium indicators targeting axon boutons in two colors and used them to map the organization of axon boutons of V1 intrinsic and V2–V1 feedback projections in tree shrews. Both connections are spatially organized into maps according to the preferred orientations of axon boutons. Dual-color calcium imaging showed that V1 intrinsic inputs are precisely aligned to the orientation map of V1 cell bodies, while the V2–V1 feedback projections are aligned to the V1 map with less accuracy. Nonselective integration of intrinsic presynaptic inputs around the dendritic tree is sufficient to reproduce cell body orientation preference. These results indicate that a precisely aligned map of intrinsic inputs could reinforce the neuronal map in V1, a principle that may be prevalent for brain areas with function maps.
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Weil, R. S., N. Furl, C. C. Ruff, M. Symmonds, G. Flandin, R. J. Dolan, J. Driver, and G. Rees. "Rewarding Feedback After Correct Visual Discriminations Has Both General and Specific Influences on Visual Cortex." Journal of Neurophysiology 104, no. 3 (September 2010): 1746–57. http://dx.doi.org/10.1152/jn.00870.2009.
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Reward can influence visual performance, but the neural basis of this effect remains poorly understood. Here we used functional magnetic resonance imaging to investigate how rewarding feedback affected activity in distinct areas of human visual cortex, separating rewarding feedback events after correct performance from preceding visual events. Participants discriminated oriented gratings in either hemifield, receiving auditory feedback at trial end that signaled financial reward after correct performance. Greater rewards improved performance for all but the most difficult trials. Rewarding feedback increased blood-oxygen-level-dependent (BOLD) signals in striatum and orbitofrontal cortex. It also increased BOLD signals in visual areas beyond retinotopic cortex, but not in primary visual cortex representing the judged stimuli. These modulations were seen at a time point in which no visual stimuli were presented or expected, demonstrating a novel type of activity change in visual cortex that cannot reflect modulation of response to incoming or anticipated visual stimuli. Rewarded trials led on the next trial to improved performance and enhanced visual activity contralateral to the judged stimulus, for retinotopic representations of the judged visual stimuli in V1. Our findings distinguish general effects in nonretinotopic visual cortex when receiving rewarding feedback after correct performance from consequences of reward for spatially specific responses in V1.
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Andelin, Adrian K., Jaime F. Olavarria, Ione Fine, Erin N. Taber, Daniel Schwartz, Christopher D. Kroenke, and Alexander A. Stevens. "The Effect of Onset Age of Visual Deprivation on Visual Cortex Surface Area Across-Species." Cerebral Cortex 29, no. 10 (December 18, 2018): 4321–33. http://dx.doi.org/10.1093/cercor/bhy315.
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Abstract Blindness early in life induces permanent alterations in brain anatomy, including reduced surface area of primary visual cortex (V1). Bilateral enucleation early in development causes greater reductions in primary visual cortex surface area than at later times. However, the time at which cortical surface area expansion is no longer sensitive to enucleation is not clearly established, despite being an important milestone for cortical development. Using histological and MRI techniques, we investigated how reductions in the surface area of V1 depends on the timing of blindness onset in rats, ferrets and humans. To compare data across species, we translated ages of all species to a common neuro-developmental event-time (ET) scale. Consistently, blindness during early cortical expansion induced large (~40%) reductions in V1 surface area, in rats and ferrets, while blindness occurring later had diminishing effects. Longitudinal measurements on ferrets confirmed that early enucleation disrupted cortical expansion, rather than inducing enhanced pruning. We modeled the ET associated with the conclusion of the effect of blindness on surface area at maturity (ETc), relative to the normal conclusion of visual cortex surface area expansion, (ETdev). A final analysis combining our data with extant published data confirmed that ETc occurred well before ETdev.
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Celeghin, Alessia, Matteo Diano, Beatrice de Gelder, Lawrence Weiskrantz, Carlo A. Marzi, and Marco Tamietto. "Intact hemisphere and corpus callosum compensate for visuomotor functions after early visual cortex damage." Proceedings of the National Academy of Sciences 114, no. 48 (November 13, 2017): E10475—E10483. http://dx.doi.org/10.1073/pnas.1714801114.
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Unilateral damage to the primary visual cortex (V1) leads to clinical blindness in the opposite visual hemifield, yet nonconscious ability to transform unseen visual input into motor output can be retained, a condition known as “blindsight.” Here we combined psychophysics, functional magnetic resonance imaging, and tractography to investigate the functional and structural properties that enable the developing brain to partly overcome the effects of early V1 lesion in one blindsight patient. Visual stimuli appeared in either the intact or blind hemifield and simple responses were given with either the left or right hand, thereby creating conditions where visual input and motor output involve the same or opposite hemisphere. When the V1-damaged hemisphere was challenged by incoming visual stimuli, or controlled manual responses to these unseen stimuli, the corpus callosum (CC) dynamically recruited areas in the visual dorsal stream and premotor cortex of the intact hemisphere to compensate for altered visuomotor functions. These compensatory changes in functional brain activity were paralleled by increased connections in posterior regions of the CC, where fibers connecting homologous areas of the parietal cortex course.
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Mock, Vanessa L., Kimberly L. Luke, Jacqueline R. Hembrook-Short, and Farran Briggs. "Dynamic communication of attention signals between the LGN and V1." Journal of Neurophysiology 120, no. 4 (October 1, 2018): 1625–39. http://dx.doi.org/10.1152/jn.00224.2018.
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Correlations and inferred causal interactions among local field potentials (LFPs) simultaneously recorded in distinct visual brain areas can provide insight into how visual and cognitive signals are communicated between neuronal populations. Based on the known anatomical connectivity of hierarchically organized visual cortical areas and electrophysiological measurements of LFP interactions, a framework for interareal frequency-specific communication has emerged. Our goals were to test the predictions of this framework in the context of the early visual pathways and to understand how attention modulates communication between the visual thalamus and primary visual cortex. We recorded LFPs simultaneously in retinotopically aligned regions of the visual thalamus and primary visual cortex in alert and behaving macaque monkeys trained on a contrast-change detection task requiring covert shifts in visual spatial attention. Coherence and Granger-causal interactions among early visual circuits varied dynamically over different trial periods. Attention significantly enhanced alpha-, beta-, and gamma-frequency interactions, often in a manner consistent with the known anatomy of early visual circuits. However, attentional modulation of communication among early visual circuits was not consistent with a simple static framework in which distinct frequency bands convey directed inputs. Instead, neuronal network interactions in early visual circuits were flexible and dynamic, perhaps reflecting task-related shifts in attention. NEW & NOTEWORTHY Attention alters the way we perceive the visual world. For example, attention can modulate how visual information is communicated between the thalamus and cortex. We recorded local field potentials simultaneously in the visual thalamus and cortex to quantify the impact of attention on visual information communication. We found that attentional modulation of visual information communication was not static, but dynamic over the time course of trials.
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Kirchberger, Lisa, Sreedeep Mukherjee, Ulf H. Schnabel, Enny H. van Beest, Areg Barsegyan, Christiaan N. Levelt, J. Alexander Heimel, et al. "The essential role of recurrent processing for figure-ground perception in mice." Science Advances 7, no. 27 (June 2021): eabe1833. http://dx.doi.org/10.1126/sciadv.abe1833.
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The segregation of figures from the background is an important step in visual perception. In primary visual cortex, figures evoke stronger activity than backgrounds during a delayed phase of the neuronal responses, but it is unknown how this figure-ground modulation (FGM) arises and whether it is necessary for perception. Here, we show, using optogenetic silencing in mice, that the delayed V1 response phase is necessary for figure-ground segregation. Neurons in higher visual areas also exhibit FGM and optogenetic silencing of higher areas reduced FGM in V1. In V1, figures elicited higher activity of vasoactive intestinal peptide–expressing (VIP) interneurons than the background, whereas figures suppressed somatostatin-positive interneurons, resulting in an increased activation of pyramidal cells. Optogenetic silencing of VIP neurons reduced FGM in V1, indicating that disinhibitory circuits contribute to FGM. Our results provide insight into how lower and higher areas of the visual cortex interact to shape visual perception.
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Smith, Matthew A., Xiaoxuan Jia, Amin Zandvakili, and Adam Kohn. "Laminar dependence of neuronal correlations in visual cortex." Journal of Neurophysiology 109, no. 4 (February 15, 2013): 940–47. http://dx.doi.org/10.1152/jn.00846.2012.
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Neuronal responses are correlated on a range of timescales. Correlations can affect population coding and may play an important role in cortical function. Correlations are known to depend on stimulus drive, behavioral context, and experience, but the mechanisms that determine their properties are poorly understood. Here we make use of the laminar organization of cortex, with its variations in sources of input, local circuit architecture, and neuronal properties, to test whether networks engaged in similar functions but with distinct properties generate different patterns of correlation. We find that slow timescale correlations are prominent in the superficial and deep layers of primary visual cortex (V1) of macaque monkeys, but near zero in the middle layers. Brief timescale correlation (synchrony), on the other hand, was slightly stronger in the middle layers of V1, although evident at most cortical depths. Laminar variations were also apparent in the power of the local field potential, with a complementary pattern for low frequency (<10 Hz) and gamma (30–50 Hz) power. Recordings in area V2 revealed a laminar dependence similar to V1 for synchrony, but slow timescale correlations were not different between the input layers and nearby locations. Our results reveal that cortical circuits in different laminae can generate remarkably different patterns of correlations, despite being tightly interconnected.
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Song, You-Hyang, Yang-Sun Hwang, Kwansoo Kim, Hyoung-Ro Lee, Jae-Hyun Kim, Catherine Maclachlan, Anaelle Dubois, et al. "Somatostatin enhances visual processing and perception by suppressing excitatory inputs to parvalbumin-positive interneurons in V1." Science Advances 6, no. 17 (April 2020): eaaz0517. http://dx.doi.org/10.1126/sciadv.aaz0517.
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Somatostatin (SST) is a neuropeptide expressed in a major subtype of GABAergic interneurons in the cortex. Despite abundant expression of SST and its receptors, their modulatory function in cortical processing remains unclear. Here, we found that SST application in the primary visual cortex (V1) improves visual discrimination in freely moving mice and enhances orientation selectivity of V1 neurons. We also found that SST reduced excitatory synaptic transmission to parvalbumin-positive (PV+) fast-spiking interneurons but not to regular-spiking neurons. Last, using serial block-face scanning electron microscopy (SBEM), we found that axons of SST+ neurons in V1 often contact other axons that exhibit excitatory synapses onto the soma and proximal dendrites of the PV+ neuron. Collectively, our results demonstrate that the neuropeptide SST improves visual perception by enhancing visual gain of V1 neurons via a reduction in excitatory synaptic transmission to PV+ inhibitory neurons.
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Li, Ming, Xue Mei Song, Tao Xu, Dewen Hu, Anna Wang Roe, and Chao-Yi Li. "Subdomains within orientation columns of primary visual cortex." Science Advances 5, no. 6 (June 2019): eaaw0807. http://dx.doi.org/10.1126/sciadv.aaw0807.
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In the mammalian visual system, early stages of visual form processing begin with orientation-selective neurons in primary visual cortex (V1). In many species (including humans, monkeys, tree shrews, cats, and ferrets), these neurons are organized in a beautifully arrayed pinwheel-like orientation columns, which shift in orientation preference across V1. However, to date, the relationship of orientation architecture to the encoding of multiple elemental aspects of visual contours is still unknown. Here, using a novel, highly accurate method of targeting electrode position, we report for the first time the presence of three subdomains within single orientation domains. We suggest that these zones subserve computation of distinct aspects of visual contours and propose a novel tripartite pinwheel-centered view of an orientation hypercolumn.
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Scholte, H. Steven, Jacob Jolij, Johannes J. Fahrenfort, and Victor A. F. Lamme. "Feedforward and Recurrent Processing in Scene Segmentation: Electroencephalography and Functional Magnetic Resonance Imaging." Journal of Cognitive Neuroscience 20, no. 11 (November 2008): 2097–109. http://dx.doi.org/10.1162/jocn.2008.20142.
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In texture segregation, an example of scene segmentation, we can discern two different processes: texture boundary detection and subsequent surface segregation [Lamme, V. A. F., Rodriguez-Rodriguez, V., & Spekreijse, H. Separate processing dynamics for texture elements, boundaries and surfaces in primary visual cortex of the macaque monkey. Cerebral Cortex, 9, 406–413, 1999]. Neural correlates of texture boundary detection have been found in monkey V1 [Sillito, A. M., Grieve, K. L., Jones, H. E., Cudeiro, J., & Davis, J. Visual cortical mechanisms detecting focal orientation discontinuities. Nature, 378, 492–496, 1995; Grosof, D. H., Shapley, R. M., & Hawken, M. J. Macaque-V1 neurons can signal illusory contours. Nature, 365, 550–552, 1993], but whether surface segregation occurs in monkey V1 [Rossi, A. F., Desimone, R., & Ungerleider, L. G. Contextual modulation in primary visual cortex of macaques. Journal of Neuroscience, 21, 1698–1709, 2001; Lamme, V. A. F. The neurophysiology of figure ground segregation in primary visual-cortex. Journal of Neuroscience, 15, 1605–1615, 1995], and whether boundary detection or surface segregation signals can also be measured in human V1, is more controversial [Kastner, S., De Weerd, P., & Ungerleider, L. G. Texture segregation in the human visual cortex: A functional MRI study. Journal of Neurophysiology, 83, 2453–2457, 2000]. Here we present electroencephalography (EEG) and functional magnetic resonance imaging data that have been recorded with a paradigm that makes it possible to differentiate between boundary detection and scene segmentation in humans. In this way, we were able to show with EEG that neural correlates of texture boundary detection are first present in the early visual cortex around 92 msec and then spread toward the parietal and temporal lobes. Correlates of surface segregation first appear in temporal areas (around 112 msec) and from there appear to spread to parietal, and back to occipital areas. After 208 msec, correlates of surface segregation and boundary detection also appear in more frontal areas. Blood oxygenation level-dependent magnetic resonance imaging results show correlates of boundary detection and surface segregation in all early visual areas including V1. We conclude that texture boundaries are detected in a feedforward fashion and are represented at increasing latencies in higher visual areas. Surface segregation, on the other hand, is represented in “reverse hierarchical” fashion and seems to arise from feedback signals toward early visual areas such as V1.
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Scholl, Benjamin, Johannes Burge, and Nicholas J. Priebe. "Binocular integration and disparity selectivity in mouse primary visual cortex." Journal of Neurophysiology 109, no. 12 (June 15, 2013): 3013–24. http://dx.doi.org/10.1152/jn.01021.2012.
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Signals from the two eyes are first integrated in primary visual cortex (V1). In many mammals, this binocular integration is an important first step in the development of stereopsis, the perception of depth from disparity. Neurons in the binocular zone of mouse V1 receive inputs from both eyes, but it is unclear how that binocular information is integrated and whether this integration has a function similar to that found in other mammals. Using extracellular recordings, we demonstrate that mouse V1 neurons are tuned for binocular disparities, or spatial differences, between the inputs from each eye, thus extracting signals potentially useful for estimating depth. The disparities encoded by mouse V1 are significantly larger than those encoded by cat and primate. Interestingly, these larger disparities correspond to distances that are likely to be ecologically relevant in natural viewing, given the stereo-geometry of the mouse visual system. Across mammalian species, it appears that binocular integration is a common cortical computation used to extract information relevant for estimating depth. As such, it is a prime example of how the integration of multiple sensory signals is used to generate accurate estimates of properties in our environment.
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Reynaud, Alexandre, Sébastien Roux, Sandrine Chemla, Frédéric Chavane, and Robert F. Hess. "AB015. Interocular normalization in monkey primary visual cortex (V1)." Annals of Eye Science 4 (December 2019): AB015. http://dx.doi.org/10.21037/aes.2019.ab015.
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Muckli, L., P. Vetter, and F. Smith. "Predictive coding - contextual processing in primary visual cortex V1." Journal of Vision 11, no. 11 (September 23, 2011): 25. http://dx.doi.org/10.1167/11.11.25.
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Tootell, R. B. H., N. K. Hadjikhani, W. Vanduffel, A. K. Liu, J. D. Mendola, M. I. Sereno, and A. M. Dale. "Functional analysis of primary visual cortex (V1) in humans." Proceedings of the National Academy of Sciences 95, no. 3 (February 3, 1998): 811–17. http://dx.doi.org/10.1073/pnas.95.3.811.
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Komatsu, Hidehiko, and Masaharu Kinoshita. "Surface representation in the monkey primary visual cortex (V1)." International Congress Series 1250 (October 2003): 53–61. http://dx.doi.org/10.1016/s0531-5131(03)00972-5.
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Mante, Valerio, and Matteo Carandini. "Mapping of Stimulus Energy in Primary Visual Cortex." Journal of Neurophysiology 94, no. 1 (July 2005): 788–98. http://dx.doi.org/10.1152/jn.01094.2004.
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A recent optical imaging study of primary visual cortex (V1) by Basole, White, and Fitzpatrick demonstrated that maps of preferred orientation depend on the choice of stimuli used to measure them. These authors measured population responses expressed as a function of the optimal orientation of long drifting bars. They then varied bar length, direction, and speed and found that stimuli of a same orientation can elicit different population responses and stimuli with different orientation can elicit similar population responses. We asked whether these results can be explained from known properties of V1 receptive fields. We implemented an “energy model” where a receptive field integrates stimulus energy over a region of three-dimensional frequency space. The population of receptive fields defines a volume of visibility, which covers all orientations and a plausible range of spatial and temporal frequencies. This energy model correctly predicts the population response to bars of different length, direction, and speed and explains the observations made with optical imaging. The model also readily explains a related phenomenon, the appearance of motion streaks for fast-moving dots. We conclude that the energy model can be applied to activation maps of V1 and predicts phenomena that may otherwise appear to be surprising. These results indicate that maps obtained with optical imaging reflect the layout of neurons selective for stimulus energy, not for isolated stimulus features such as orientation, direction, and speed.
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Garner, Aleena R., and Georg B. Keller. "A cortical circuit for audio-visual predictions." Nature Neuroscience 25, no. 1 (December 2, 2021): 98–105. http://dx.doi.org/10.1038/s41593-021-00974-7.
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AbstractLearned associations between stimuli in different sensory modalities can shape the way we perceive these stimuli. However, it is not well understood how these interactions are mediated or at what level of the processing hierarchy they occur. Here we describe a neural mechanism by which an auditory input can shape visual representations of behaviorally relevant stimuli through direct interactions between auditory and visual cortices in mice. We show that the association of an auditory stimulus with a visual stimulus in a behaviorally relevant context leads to experience-dependent suppression of visual responses in primary visual cortex (V1). Auditory cortex axons carry a mixture of auditory and retinotopically matched visual input to V1, and optogenetic stimulation of these axons selectively suppresses V1 neurons that are responsive to the associated visual stimulus after, but not before, learning. Our results suggest that cross-modal associations can be communicated by long-range cortical connections and that, with learning, these cross-modal connections function to suppress responses to predictable input.
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Bányai, Mihály, Andreea Lazar, Liane Klein, Johanna Klon-Lipok, Marcell Stippinger, Wolf Singer, and Gergő Orbán. "Stimulus complexity shapes response correlations in primary visual cortex." Proceedings of the National Academy of Sciences 116, no. 7 (January 28, 2019): 2723–32. http://dx.doi.org/10.1073/pnas.1816766116.
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Spike count correlations (SCCs) are ubiquitous in sensory cortices, are characterized by rich structure, and arise from structured internal dynamics. However, most theories of visual perception treat contributions of neurons to the representation of stimuli independently and focus on mean responses. Here, we argue that, in a functional model of visual perception, featuring probabilistic inference over a hierarchy of features, inferences about high-level features modulate inferences about low-level features ultimately introducing structured internal dynamics and patterns in SCCs. Specifically, high-level inferences for complex stimuli establish the local context in which neurons in the primary visual cortex (V1) interpret stimuli. Since the local context differentially affects multiple neurons, this conjecture predicts specific modulations in the fine structure of SCCs as stimulus identity and, more importantly, stimulus complexity varies. We designed experiments with natural and synthetic stimuli to measure the fine structure of SCCs in V1 of awake behaving macaques and assessed their dependence on stimulus identity and stimulus statistics. We show that the fine structure of SCCs is specific to the identity of natural stimuli and changes in SCCs are independent of changes in response mean. Critically, we demonstrate that stimulus specificity of SCCs in V1 can be directly manipulated by altering the amount of high-order structure in synthetic stimuli. Finally, we show that simple phenomenological models of V1 activity cannot account for the observed SCC patterns and conclude that the stimulus dependence of SCCs is a natural consequence of structured internal dynamics in a hierarchical probabilistic model of natural images.
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Ahmad, Hena, R. Edward Roberts, Mitesh Patel, Rhannon Lobo, Barry Seemungal, Qadeer Arshad, and Adolfo Bronstein. "Downregulation of early visual cortex excitability mediates oscillopsia suppression." Neurology 89, no. 11 (August 16, 2017): 1179–85. http://dx.doi.org/10.1212/wnl.0000000000004360.
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Objective:To identify in an observational study the neurophysiologic mechanisms that mediate adaptation to oscillopsia in patients with bilateral vestibular failure (BVF).Methods:We directly probe the hypothesis that adaptive changes that mediate oscillopsia suppression implicate the early visual-cortex (V1/V2). Accordingly, we investigated V1/V2 excitability using transcranial magnetic stimulation (TMS) in 12 avestibular patients and 12 healthy controls. Specifically, we assessed TMS-induced phosphene thresholds at baseline and cortical excitability changes while performing a visual motion adaptation paradigm during the following conditions: baseline measures (i.e., static), during visual motion (i.e., motion before adaptation), and during visual motion after 5 minutes of unidirectional visual motion adaptation (i.e., motion adapted).Results:Patients had significantly higher baseline phosphene thresholds, reflecting an underlying adaptive mechanism. Individual thresholds were correlated with oscillopsia symptom load. During the visual motion adaptation condition, no differences in excitability at baseline were observed, but during both the motion before adaptation and motion adapted conditions, we observed significantly attenuated cortical excitability in patients. Again, this attenuation in excitability was stronger in less symptomatic patients.Conclusions:Our findings provide neurophysiologic evidence that cortically mediated adaptive mechanisms in V1/V2 play a critical role in suppressing oscillopsia in patients with BVF.
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Shushruth, S., Jennifer M. Ichida, Jonathan B. Levitt, and Alessandra Angelucci. "Comparison of Spatial Summation Properties of Neurons in Macaque V1 and V2." Journal of Neurophysiology 102, no. 4 (October 2009): 2069–83. http://dx.doi.org/10.1152/jn.00512.2009.
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In visual cortex, responses to stimulation of the receptive field (RF) are modulated by simultaneous stimulation of the RF surround. The mechanisms for surround modulation remain unidentified. We previously proposed that in the primary visual cortex (V1), near surround modulation is mediated by geniculocortical and horizontal connections and far surround modulation by interareal feedback connections. To understand spatial integration in the secondary visual cortex (V2) and its underlying circuitry, we have characterized spatial summation in different V2 layers and stripe compartments and compared it to that in V1. We used grating stimuli in circular and annular apertures of different sizes to estimate the extent and sensitivity of RF and surround components in V1 and V2. V2 RFs and surrounds were twice as large as those in V1. As in V1, V2 RFs doubled in size when measured at low contrast. In both V1 and V2, surrounds were about fivefold the size of the RF and the far surround could exceed 12.5° in radius, averaging 5.5° in V1 and 9.2° in V2. The strength of surround suppression was similar in both areas. Thus although differing in spatial scale, the interactions among RF components are similar in V1 and V2, suggesting similar underlying mechanisms. As in V1, the extent of V2 horizontal connections matches that of the RF center, but is much smaller than the largest far surrounds, which likely derive from interareal feedback. In V2, we found no laminar or stripe differences in size and magnitude of surround suppression, suggesting conservation across stripes of the basic circuit for surround modulation.
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Scholl, Benjamin, Jagruti J. Pattadkal, Ashlee Rowe, and Nicholas J. Priebe. "Functional characterization and spatial clustering of visual cortical neurons in the predatory grasshopper mouse Onychomys arenicola." Journal of Neurophysiology 117, no. 3 (March 1, 2017): 910–18. http://dx.doi.org/10.1152/jn.00779.2016.
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Mammalian neocortical circuits are functionally organized such that the selectivity of individual neurons systematically shifts across the cortical surface, forming a continuous map. Maps of the sensory space exist in cortex, such as retinotopic maps in the visual system or tonotopic maps in the auditory system, but other functional response properties also may be similarly organized. For example, many carnivores and primates possess a map for orientation selectivity in primary visual cortex (V1), whereas mice, rabbits, and the gray squirrel lack orientation maps. In this report we show that a carnivorous rodent with predatory behaviors, the grasshopper mouse ( Onychomys arenicola), lacks a canonical columnar organization of orientation preference in V1; however, neighboring neurons within 50 μm exhibit related tuning preference. Using a combination of two-photon microscopy and extracellular electrophysiology, we demonstrate that the functional organization of visual cortical neurons in the grasshopper mouse is largely the same as in the C57/BL6 laboratory mouse. We also find similarity in the selectivity for stimulus orientation, direction, and spatial frequency. Our results suggest that the properties of V1 neurons across rodent species are largely conserved. NEW & NOTEWORTHY 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 carnivorous rodent with predatory behaviors, the grasshopper mouse ( Onychomys arenicola). We demonstrate the cellular organization of V1 in the grasshopper mouse is largely the same as the C57/BL6 laboratory mouse, suggesting that V1 neuron properties across rodent species are largely conserved.
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Dagnino, Bruno, Marie-Alice Gariel-Mathis, and Pieter R. Roelfsema. "Microstimulation of area V4 has little effect on spatial attention and on perception of phosphenes evoked in area V1." Journal of Neurophysiology 113, no. 3 (February 1, 2015): 730–39. http://dx.doi.org/10.1152/jn.00645.2014.
Full textAbstract:
Previous transcranial magnetic stimulation (TMS) studies suggested that feedback from higher to lower areas of the visual cortex is important for the access of visual information to awareness. However, the influence of cortico-cortical feedback on awareness and the nature of the feedback effects are not yet completely understood. In the present study, we used electrical microstimulation in the visual cortex of monkeys to test the hypothesis that cortico-cortical feedback plays a role in visual awareness. We investigated the interactions between the primary visual cortex (V1) and area V4 by applying microstimulation in both cortical areas at various delays. We report that the monkeys detected the phosphenes produced by V1 microstimulation but subthreshold V4 microstimulation did not influence V1 phosphene detection thresholds. A second experiment examined the influence of V4 microstimulation on the monkeys' ability to detect the dimming of one of three peripheral visual stimuli. Again, microstimulation of a group of V4 neurons failed to modulate the monkeys' perception of a stimulus in their receptive field. We conclude that conditions exist where microstimulation of area V4 has only a limited influence on visual perception.
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Resca, Lorenzo G., and Nicholas A. Mecholsky. "Geometry and Geodesy on the Primary Visual Cortex as a Surface of Revolution." Mathematical and Computational Applications 25, no. 4 (September 29, 2020): 64. http://dx.doi.org/10.3390/mca25040064.
Full textAbstract:
Biological mapping of the visual field from the eye retina to the primary visual cortex, also known as occipital area V1, is central to vision and eye movement phenomena and research. That mapping is critically dependent on the existence of cortical magnification factors. Once unfolded, V1 has a convex three-dimensional shape, which can be mathematically modeled as a surface of revolution embedded in three-dimensional Euclidean space. Thus, we solve the problem of differential geometry and geodesy for the mapping of the visual field to V1, involving both isotropic and non-isotropic cortical magnification factors of a most general form. We provide illustrations of our technique and results that apply to V1 surfaces with curve profiles relevant to vision research in general and to visual phenomena such as ‘crowding’ effects and eye movement guidance in particular. From a mathematical perspective, we also find intriguing and unexpected differential geometry properties of V1 surfaces, discovering that geodesic orbits have alternative prograde and retrograde characteristics, depending on the interplay between local curvature and global topology.
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Yang, Chaojuan, Yonglu Tian, Feng Su, Yangzhen Wang, Mengna Liu, Hongyi Wang, Yaxuan Cui, et al. "Restoration of FMRP expression in adult V1 neurons rescues visual deficits in a mouse model of fragile X syndrome." Protein & Cell 13, no. 3 (October 29, 2021): 203–19. http://dx.doi.org/10.1007/s13238-021-00878-z.
Full textAbstract:
AbstractMany people affected by fragile X syndrome (FXS) and autism spectrum disorders have sensory processing deficits, such as hypersensitivity to auditory, tactile, and visual stimuli. Like FXS in humans, loss of Fmr1 in rodents also cause sensory, behavioral, and cognitive deficits. However, the neural mechanisms underlying sensory impairment, especially vision impairment, remain unclear. It remains elusive whether the visual processing deficits originate from corrupted inputs, impaired perception in the primary sensory cortex, or altered integration in the higher cortex, and there is no effective treatment. In this study, we used a genetic knockout mouse model (Fmr1KO), in vivo imaging, and behavioral measurements to show that the loss of Fmr1 impaired signal processing in the primary visual cortex (V1). Specifically, Fmr1KO mice showed enhanced responses to low-intensity stimuli but normal responses to high-intensity stimuli. This abnormality was accompanied by enhancements in local network connectivity in V1 microcircuits and increased dendritic complexity of V1 neurons. These effects were ameliorated by the acute application of GABAA receptor activators, which enhanced the activity of inhibitory neurons, or by reintroducing Fmr1 gene expression in knockout V1 neurons in both juvenile and young-adult mice. Overall, V1 plays an important role in the visual abnormalities of Fmr1KO mice and it could be possible to rescue the sensory disturbances in developed FXS and autism patients.
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Vreysen, Samme, Bin Zhang, Yuzo M. Chino, Lutgarde Arckens, and Gert Van den Bergh. "Dynamics of spatial frequency tuning in mouse visual cortex." Journal of Neurophysiology 107, no. 11 (June 1, 2012): 2937–49. http://dx.doi.org/10.1152/jn.00022.2012.
Full textAbstract:
Neuronal spatial frequency tuning in primary visual cortex (V1) substantially changes over time. In both primates and cats, a shift of the neuron's preferred spatial frequency has been observed from low frequencies early in the response to higher frequencies later in the response. In most cases, this shift is accompanied by a decreased tuning bandwidth. Recently, the mouse has gained attention as a suitable animal model to study the basic mechanisms of visual information processing, demonstrating similarities in basic neuronal response properties between rodents and highly visual mammals. Here we report the results of extracellular single-unit recordings in the anesthetized mouse where we analyzed the dynamics of spatial frequency tuning in V1 and the lateromedial area LM within the lateral extrastriate area V2L. We used a reverse-correlation technique to demonstrate that, as in monkeys and cats, the preferred spatial frequency of mouse V1 neurons shifted from low to higher frequencies later in the response. However, this was not correlated with a clear selectivity increase or enhanced suppression of responses to low spatial frequencies. These results suggest that the neuronal connections responsible for the temporal shift in spatial frequency tuning may considerably differ between mice and monkeys.