scholarly journals Superior colliculus encodes visual saliency before the primary visual cortex

2017 ◽  
Vol 114 (35) ◽  
pp. 9451-9456 ◽  
Author(s):  
Brian J. White ◽  
Janis Y. Kan ◽  
Ron Levy ◽  
Laurent Itti ◽  
Douglas P. Munoz
Keyword(s):  
Visual Cortex ◽  
Superior Colliculus ◽  
Primary Visual Cortex ◽  
Visual Processing ◽  
Visual Saliency ◽  
Saliency Map ◽  
Stimulus Onset ◽  
Brain Areas ◽  
V1 Neurons ◽  
Processing Stream

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.

scholarly journals Spatial integration in mouse primary visual cortex

2013 ◽  
Vol 110 (4) ◽  
pp. 964-972 ◽  
Author(s):  
Agne Vaiceliunaite ◽  
Sinem Erisken ◽  
Florian Franzen ◽  
Steffen Katzner ◽  
Laura Busse
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Neural Circuits ◽  
Temporal Dynamics ◽  
Visual Saliency ◽  
Brain State ◽  
Inhibitory Interneurons ◽  
Spatial Integration ◽  
V1 Neurons ◽  
Contrast Normalization

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.

scholarly journals Continuous multiplexed population representations of task context in the mouse primary visual cortex

2021 ◽  
Author(s):  
Marton Albert Hajnal ◽  
Duy Tran ◽  
Michael Einstein ◽  
Mauricio Vallejo Martelo ◽  
Karen Safaryan ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Activity Patterns ◽  
Visual Stimuli ◽  
Stimulus Onset ◽  
Decision Task ◽  
Cognitive Variables ◽  
Task Context ◽  
Population Activity ◽  
V1 Neurons

Primary visual cortex (V1) neurons integrate motor and multisensory information with visual inputs during sensory processing. However, whether V1 neurons also integrate and encode higher-order cognitive variables is less understood. We trained mice to perform a context-dependent cross-modal decision task where the interpretation of identical audio-visual stimuli depends on task context. We performed silicon probe population recordings of neuronal activity in V1 during task performance and showed that task context (whether the animal should base its decision on visual or auditory stimuli) can be decoded during both intertrial intervals and stimulus presentations. Context and visual stimuli were represented in overlapping populations but were orthogonal in the population activity space. Context representation was not static but displayed distinctive dynamics upon stimulus onset and offset. Thus, activity patterns in V1 independently represent visual stimuli and cognitive variables relevant to task execution.

scholarly journals Perceptual Expertise and Top–Down Expectation of Musical Notation Engages the Primary Visual Cortex

2014 ◽  
Vol 26 (8) ◽  
pp. 1629-1643 ◽  
Author(s):  
Yetta Kwailing Wong ◽  
Cynthia Peng ◽  
Kristyn N. Fratus ◽  
Geoffrey F. Woodman ◽  
Isabel Gauthier
Keyword(s):  
Visual Cortex ◽  
Object Recognition ◽  
Primary Visual Cortex ◽  
Visual Processing ◽  
Reading Ability ◽  
Stimulus Onset ◽  
Perceptual Expertise ◽  
Stimulus Category ◽  
Music Reading ◽  
Musical Notation

Most theories of visual processing propose that object recognition is achieved in higher visual cortex. However, we show that category selectivity for musical notation can be observed in the first ERP component called the C1 (measured 40–60 msec after stimulus onset) with music-reading expertise. Moreover, the C1 note selectivity was observed only when the stimulus category was blocked but not when the stimulus category was randomized. Under blocking, the C1 activity for notes predicted individual music-reading ability, and behavioral judgments of musical stimuli reflected music-reading skill. Our results challenge current theories of object recognition, indicating that the primary visual cortex can be selective for musical notation within the initial feedforward sweep of activity with perceptual expertise and with a testing context that is consistent with the expertise training, such as blocking the stimulus category for music reading.

scholarly journals Comparison of superior colliculus and primary visual cortex in the coding of visual saliency

2014 ◽  
Vol 14 (10) ◽  
pp. 517-517 ◽  
Author(s):  
B. White ◽  
D. Berg ◽  
T. Ikeda ◽  
R. Levy ◽  
L. Itti ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Superior Colliculus ◽  
Primary Visual Cortex ◽  
Visual Saliency

scholarly journals Dynamic distortion of the orientation representational space after learning in the mouse primary visual cortex

2021 ◽  
Author(s):  
Julien Corbo ◽  
John P McClure ◽  
Orhan Batuhan Erkat ◽  
Pierre-Olivier Polack
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Processing ◽  
Sensory Integration ◽  
Orientation Discrimination ◽  
Stimulus Generalization ◽  
Behavioral Adaptation ◽  
V1 Neurons ◽  
Orientation Space ◽  
Representational Space

Learning is an essential cognitive mechanism that supports behavioral adaptation through neural processing adjustments. Learning was shown to modify sensory integration, yet the nature of those modifications and the computational advantages they confer remain unclear. By comparing the responses of primary visual cortex (V1) neurons evoked by oriented stimuli in naive mice and mice performing an orientation discrimination task, we found that the representations of rewarded and non-rewarded cues were sparser, more accurate and more stable in trained mice. This improved representation was associated with a distortion of the V1 orientation space such that stimuli close to the task cues were represented as the task stimuli themselves. This distortion was context-dependent, as it was absent in trained mice passively viewing the cues. Hence, visual processing in V1 was dynamically adapted to enhance the reliability of the representation of the learned cues and favor stimulus generalization in the task-relevant computational space.

scholarly journals Model-based characterization of the selectivity of neurons in primary visual cortex

2021 ◽  
Author(s):  
Felix Bartsch ◽  
Bruce G Cumming ◽  
Daniel A Butts
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Primary Visual Cortex ◽  
Visual Processing ◽  
Frequency Tuning ◽  
Nonlinear Models ◽  
Field Size ◽  
V1 Neurons ◽  
Model Based ◽  
Spatial Frequencies

To understand the complexity of stimulus selectivity in primary visual cortex (V1), models constructed to match observed responses to complex time-varying stimuli, instead of to explain responses to simple parametric stimuli, are increasingly used. While such models often can more accurately reflect the computations performed by V1 neurons in more natural visual environments, they do not by themselves provide insight into established measures of V1 neural selectivity such as receptive field size, spatial frequency tuning and phase invariance. Here, we suggest a series of analyses that can be directly applied to encoding models to link complex encoding models to more interpretable aspects of stimulus selectivity, applied to nonlinear models of V1 neurons recorded in awake macaque in response to random bar stimuli. In linking model properties to more classical measurements, we demonstrate several novel aspects of V1 selectivity not available to simpler experimental measurements. For example, we find that individual spatiotemporal elements of the V1 models often have a smaller spatial scale than the overall neuron sensitivity, and that this results in non-trivial tuning to spatial frequencies. Additionally, our proposed measures of nonlinear integration suggest that more classical classifications of V1 neurons into simple versus complex cells are spatial-frequency dependent. In total, rather than obfuscate classical characterizations of V1 neurons, model-based characterizations offer a means to more fully understand their selectivity, and provide a means to link their classical tuning properties to their roles in more complex, natural, visual processing.

scholarly journals A Bioinspired Visual Saliency Model

2019 ◽  
Vol 37 (3) ◽  
pp. 503-508
Author(s):  
Ke Zhang ◽  
Xinbo Zhao ◽  
Rong Mo
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Saliency ◽  
Saliency Map ◽  
Input Image ◽  
Visual Signals ◽  
Bottom Up ◽  
Saliency Model ◽  
Visual Saliency Model ◽  
Public Datasets

This paper presents a bioinspired visual saliency model. The end-stopping mechanism in the primary visual cortex is introduced in to extract features that represent contour information of latent salient objects such as corners, line intersections and line endpoints, which are combined together with brightness, color and orientation features to form the final saliency map. This model is an analog for the processing mechanism of visual signals along from retina, lateral geniculate nucleus(LGN)to primary visual cortex V1:Firstly, according to the characteristics of the retina and LGN, an input image is decomposed into brightness and opposite color channels; Then, the simple cell is simulated with 2D Gabor filters, and the amplitude of Gabor response is utilized to represent the response of complex cell; Finally, the response of an end-stopped cell is obtained by multiplying the response of two complex cells with different orientation, and outputs of V1 and LGN constitute a bottom-up saliency map. Experimental results on public datasets show that our model can accurately predict human fixations, and the performance achieves the state of the art of bottom-up saliency model.

scholarly journals The Visual Cortex in Context

2019 ◽  
Vol 5 (1) ◽  
pp. 317-339 ◽  
Author(s):  
Emmanouil Froudarakis ◽  
Paul G. Fahey ◽  
Jacob Reimer ◽  
Stelios M. Smirnakis ◽  
Edward J. Tehovnik ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Processing ◽  
Hierarchical Models ◽  
Sensorimotor Integration ◽  
Brain Areas ◽  
Cortex Area ◽  
Brain Circuitry ◽  
Open Question ◽  
The Brain

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.

scholarly journals The Timing and Neuroanatomy of Conscious Vision as Revealed by TMS-induced Blindsight

2014 ◽  
Vol 26 (7) ◽  
pp. 1507-1518 ◽  
Author(s):  
Christopher P. G. Allen ◽  
Petroc Sumner ◽  
Christopher D. Chambers
Keyword(s):  
Visual Cortex ◽  
Superior Colliculus ◽  
Primary Visual Cortex ◽  
Visual Stimuli ◽  
Stimulus Onset ◽  
Neural Basis ◽  
The Unconscious ◽  
Intermediate Period ◽  
Residual Capacity ◽  
Apparent Conflict

Following damage to the primary visual cortex, some patients exhibit “blindsight,” where they report a loss of awareness while retaining the ability to discriminate visual stimuli above chance. Transient disruption of occipital regions with TMS can produce a similar dissociation, known as TMS-induced blindsight. The neural basis of this residual vision is controversial, with some studies attributing it to the retinotectal pathway via the superior colliculus whereas others implicate spared projections that originate predominantly from the LGN. Here we contrasted these accounts by combining TMS with visual stimuli that either activate or bypass the retinotectal and magnocellular (R/M) pathways. We found that the residual capacity of TMS-induced blindsight occurs for stimuli that bypass the R/M pathways, indicating that such pathways, which include those to the superior colliculus, are not critical. We also found that the modulation of conscious vision was time and pathway dependent. TMS applied either early (0–40 msec) or late (280–320 msec) after stimulus onset modulated detection of stimuli that did not bypass R/M pathways, whereas during an intermediate period (90–130 msec) the effect was pathway independent. Our findings thus suggest a prominent role for the R/M pathways in supporting both the preparatory and later stages of conscious vision. This may help resolve apparent conflict in previous literature by demonstrating that the roles of the retinotectal and geniculate pathways are likely to be more nuanced than simply corresponding to the unconscious/conscious dichotomy.

scholarly journals Altered functional interactions between neurons in primary visual cortex of macaque monkeys with experimental amblyopia

2019 ◽  
Vol 122 (6) ◽  
pp. 2243-2258 ◽  
Author(s):  
Katerina Acar ◽  
Lynne Kiorpes ◽  
J. Anthony Movshon ◽  
Matthew A. Smith
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Control Animal ◽  
Visual Processing ◽  
Visual Representations ◽  
Macaca Nemestrina ◽  
Macaque Monkeys ◽  
Fellow Eye ◽  
V1 Neurons ◽  
Evoked Activity

Amblyopia, a disorder in which vision through one of the eyes is degraded, arises because of defective processing of information by the visual system. Amblyopia often develops in humans after early misalignment of the eyes (strabismus) and can be simulated in macaque monkeys by artificially inducing strabismus. In such amblyopic animals, single-unit responses in primary visual cortex (V1) are appreciably reduced when evoked by the amblyopic eye compared with the other (fellow) eye. However, this degradation in single V1 neuron responsivity is not commensurate with the marked losses in visual sensitivity and resolution measured behaviorally. Here we explored the idea that changes in patterns of coordinated activity across populations of V1 neurons may contribute to degraded visual representations in amblyopia, potentially making it more difficult to read out evoked activity to support perceptual decisions. We studied the visually evoked activity of V1 neuronal populations in three macaques ( Macaca nemestrina) with strabismic amblyopia and in one control animal. Activity driven through the amblyopic eye was diminished, and these responses also showed more interneuronal correlation at all stimulus contrasts than responses driven through the fellow eye or responses in the control animal. A decoding analysis showed that responses driven through the amblyopic eye carried less visual information than other responses. Our results suggest that part of the reduced visual capacity of amblyopes may be due to changes in the patterns of functional interaction among neurons in V1. NEW & NOTEWORTHY Previous work on the neurophysiological basis of amblyopia has largely focused on relating behavioral deficits to changes in visual processing by single neurons in visual cortex. In this study, we recorded simultaneously from populations of primary visual cortical (V1) neurons in macaques with amblyopia. We found changes in the strength and pattern of shared response variability between neurons. These changes in neuronal interactions could impair the visual representations of V1 populations driven by the amblyopic eye.

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