Faculty Opinions recommendation of Neuronal responses during and after the presentation of static visual stimuli in macaque primary visual cortex.

2010 ◽  
Author(s):  
Marcello Rosa
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Stimuli ◽  
Neuronal Responses

scholarly journals Bottom-up saliency and top-down learning in the primary visual cortex of monkeys

2018 ◽  
Vol 115 (41) ◽  
pp. 10499-10504 ◽  
Author(s):  
Yin Yan ◽  
Li Zhaoping ◽  
Wu Li
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Detection Task ◽  
Late Response ◽  
Late Component ◽  
Neuronal Responses ◽  
Top Down ◽  
Bottom Up ◽  
Response Component ◽  
Orientation Contrast

Early sensory cortex is better known for representing sensory inputs but less for the effect of its responses on behavior. Here we explore the behavioral correlates of neuronal responses in primary visual cortex (V1) in a task to detect a uniquely oriented bar—the orientation singleton—in a background of uniformly oriented bars. This singleton is salient or inconspicuous when the orientation contrast between the singleton and background bars is sufficiently large or small, respectively. Using implanted microelectrodes, we measured V1 activities while monkeys were trained to quickly saccade to the singleton. A neuron’s responses to the singleton within its receptive field had an early and a late component, both increased with the orientation contrast. The early component started from the outset of neuronal responses; it remained unchanged before and after training on the singleton detection. The late component started ∼40 ms after the early one; it emerged and evolved with practicing the detection task. Training increased the behavioral accuracy and speed of singleton detection and increased the amount of information in the late response component about a singleton’s presence or absence. Furthermore, for a given singleton, faster detection performance was associated with higher V1 responses; training increased this behavioral–neural correlate in the early V1 responses but decreased it in the late V1 responses. Therefore, V1’s early responses are directly linked with behavior and represent the bottom-up saliency signals. Learning strengthens this link, likely serving as the basis for making the detection task more reflexive and less top-down driven.

scholarly journals Traumatic brain injury to primary visual cortex produces long-lasting circuit dysfunction

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jan C. Frankowski ◽  
Andrzej T. Foik ◽  
Alexa Tierno ◽  
Jiana R. Machhor ◽  
David C. Lyon ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Visual Cortex ◽  
Brain Injury ◽  
Primary Visual Cortex ◽  
Visual Stimuli ◽  
Orientation Tuning ◽  
V1 Neurons ◽  
Adult Mice ◽  
Electrophysiological Recordings

AbstractPrimary sensory areas of the mammalian neocortex have a remarkable degree of plasticity, allowing neural circuits to adapt to dynamic environments. However, little is known about the effects of traumatic brain injury on visual circuit function. Here we used anatomy and in vivo electrophysiological recordings in adult mice to quantify neuron responses to visual stimuli two weeks and three months after mild controlled cortical impact injury to primary visual cortex (V1). We found that, although V1 remained largely intact in brain-injured mice, there was ~35% reduction in the number of neurons that affected inhibitory cells more broadly than excitatory neurons. V1 neurons showed dramatically reduced activity, impaired responses to visual stimuli and weaker size selectivity and orientation tuning in vivo. Our results show a single, mild contusion injury produces profound and long-lasting impairments in the way V1 neurons encode visual input. These findings provide initial insight into cortical circuit dysfunction following central visual system neurotrauma.

scholarly journals Cortical reorganization of the visual system in post-stroke hemianopia studied with fMRI

Stroke ◽  
2001 ◽  
Vol 32 (suppl_1) ◽  
pp. 334-334
Author(s):  
Gereon Nelles ◽  
Guido Widmann ◽  
Joachim Esser ◽  
Anette Meistrowitz ◽  
Johannes Weber ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Visual System ◽  
Primary Visual Cortex ◽  
Visual Stimuli ◽  
Checkerboard Pattern ◽  
Partial Recovery ◽  
Area 18 ◽  
Area 19 ◽  
Stimulation Of

102 Introduction: Restitution of unilateral visual field defects following occipital cortex lesions occurs rarely. Partial recovery, however, can be observed in patients with incomplete lesion of the visual cortex. Our objective was to study the neuroplastic changes in the visual system that underlie such recovery. Methods and Results: Six patients with a left PCA-territory cortical stroke and 6 healthy control subjects were studied during rest and during visual stimulation using a 1.5 T fMRI with a 40 mT gradient. Visual stimuli were projected with a laptop computer onto a 154 x 115 cm screen, placed 90 cm in front of the gantry. Subjects were asked to fixate a red point in the center of the screen during both conditions. During stimulation, a black-and-white checkerboard pattern reversal was presented in each hemifield. For each side, 120 volumes of 48 contiguous axial fMRI images were obtained during rest and during hemifield stimulation in alternating order (60 volumes for each condition). Significant differences of rCBF between stimulation and rest were assessed as group analyses using statistical parametric mapping (SPM 99; p<0.01, corrected for multiple comparison). In controls, strong increases of rCBF (Z=7.6) occurred in the contralateral primary visual cortex V1 (area 17) and in V3a (area 18) and V5 (area 19). No differences were found between the right and left side in controls. During stimulation of the unaffected (left) visual field in hemianopic patients, activation occurred in contralateral V1, but the strongest increases of rCBF (Z>10) were seen in contralateral V3a (area 18) and V5 (area 19). During stimulation of the hemianopic (right) visual field, no activation was found in the primary visual cortex of either hemisphere. The most significant activation (Z=9.2) was seen in the ipsilateral V3a and V5 areas, and contralateral (left) V3a. Conclusions: Partial recovery from hemianopia is associated with strong ipsilateral activation of the visual system. Processing of visual stimuli in the hemianopic side spares the primary visual cortex and may involve recruitment of neurons in ipsilateral (contralesional) areas V3a and V5.

scholarly journals Pure tones modulate the representation of orientation and direction in the primary visual cortex

2019 ◽  
Vol 121 (6) ◽  
pp. 2202-2214 ◽  
Author(s):  
John P. McClure ◽  
Pierre-Olivier Polack
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Stimulus ◽  
Visual Stimuli ◽  
Direction Selectivity ◽  
Multimodal Integration ◽  
Visual Responses ◽  
V1 Neurons ◽  
Pure Tones ◽  
The Impact

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.

Effects of ketamine on orientation selectivity and variability of neuronal responses in primary visual cortex

2019 ◽  
Vol 1725 ◽  
pp. 146462
Author(s):  
A. Ouelhazi ◽  
V. Bharmauria ◽  
N. Chanauria ◽  
L. Bachatene ◽  
R. Lussiez ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Orientation Selectivity ◽  
Neuronal Responses

scholarly journals Modulation of Neuronal Responses by Exogenous Attention in Macaque Primary Visual Cortex

2015 ◽  
Vol 35 (39) ◽  
pp. 13419-13429 ◽  
Author(s):  
F. Wang ◽  
M. Chen ◽  
Y. Yan ◽  
L. Zhaoping ◽  
W. Li
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Exogenous Attention ◽  
Neuronal Responses

scholarly journals Locomotion enhances neural encoding of visual stimuli in mouse V1

2017 ◽  
Author(s):  
Maria C. Dadarlat ◽  
Michael P. Stryker
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Stimuli ◽  
Major Effect ◽  
Neural Population ◽  
Neural Encoding ◽  
Firing Rates ◽  
Fold Reduction ◽  
Layer V ◽  
The Relationship

AbstractNeurons in mouse primary visual cortex (V1) are selective for particular properties of visual stimuli. Locomotion causes a change in cortical state that leaves their selectivity unchanged but strengthens their responses. Both locomotion and the change in cortical state are initiated by projections from the mesencephalic locomotor region (MLR), the latter through a disinhibitory circuit in V1. The function served by this change in cortical state is unknown. By recording simultaneously from a large number of single neurons in alert mice viewing moving gratings, we investigated the relationship between locomotion and the information contained within the neural population. We found that locomotion improved encoding of visual stimuli in V1 by two mechanisms. First, locomotion-induced increases in firing rates enhanced the mutual information between visual stimuli and single neuron responses over a fixed window of time. Second, stimulus discriminability was improved, even for fixed population firing rates, because of a decrease in noise correlations across the population during locomotion. These two mechanisms contributed differently to improvements in discriminability across cortical layers, with changes in firing rates most important in the upper layers and changes in noise correlations most important in layer V. Together, these changes resulted in a three- to five-fold reduction in the time needed to precisely encode grating direction and orientation. These results support the hypothesis that cortical state shifts during locomotion to accommodate an increased load on the visual system when mice are moving.Significance StatementThis paper contains three novel findings about the representation of information in neurons within the primary visual cortex of the mouse. First, we show that locomotion reduces by at least a factor of three the time needed for information to accumulate in the visual cortex that allows the distinction of different visual stimuli. Second, we show that the effect of locomotion is to increase information in cells of all layers of the visual cortex. Third we show that the means by which information is enhanced by locomotion differs between the upper layers, where the major effect is the increasing of firing rates, and in layer V, where the major effect is the reduction in noise correlations.

scholarly journals Microstimulation in the primary visual cortex: activity patterns and their relation to visual responses and evoked saccades

2020 ◽  
Author(s):  
R. Oz ◽  
H. Edelman-Klapper ◽  
S. Nivinsky-Margalit ◽  
H. Slovin
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Neural Activity ◽  
Visual Processing ◽  
Visual Stimuli ◽  
Temporal Patterns ◽  
Visual Responses ◽  
Population Activity ◽  
Spatio Temporal ◽  
Saccade Generation

AbstractIntra cortical microstimulation (ICMS) in the primary visual cortex (V1) can generate the visual perception of phosphenes and evoke saccades directed to the stimulated location in the retinotopic map. Although ICMS is widely used, little is known about the evoked spatio-temporal patterns of neural activity and their relation to neural responses evoked by visual stimuli or saccade generation. To investigate this, we combined ICMS with Voltage Sensitive Dye Imaging in V1 of behaving monkeys and measured neural activity at high spatial (meso-scale) and temporal resolution. Small visual stimuli and ICMS evoked population activity spreading over few mm that propagated to extrastriate areas. The population responses evoked by ICMS showed faster dynamics and different spatial propagation patterns. Neural activity was higher in trials w/saccades compared with trials w/o saccades. In conclusion, our results uncover the spatio-temporal patterns evoked by ICMS and their relation to visual processing and saccade generation.

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