scholarly journals Serotonergic Modulation of Orientation Tuning of Neurons in Primary Visual Cortex of Anesthetized Mice

2021 ◽  
Author(s):  
Sareh Rostami ◽  
◽  
Amin Asgharzadeh Alvar ◽  
Parviz Ghaderi ◽  
Leila Dargahi ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Visual Cortex ◽  
Firing Rate ◽  
Primary Visual Cortex ◽  
Serotonergic System ◽  
Orientation Tuning ◽  
Visual Response ◽  
Visual Responses ◽  
Patch Clamp Recording ◽  
Serotonergic Modulation

Introduction: Sensory processing is profoundly regulated by brain neuromodulatory systems. One of the main neuromodulators is serotonin which influences higher cognitive functions such as different aspects of perceptual processing. So, malfunction in the serotonergic system may lead to visual illusion in psychiatric disorders such as autism and schizophrenia. In this work, we examined the serotonergic modulation of visual responses of neurons to stimulus orientation in the primary visual cortex. Methods: Eight-weeks old naive mice were anesthetized and craniotomy was done on the region of interest in primary visual cortex. Spontaneous and visual-evoked activities of neurons were recorded before and during the electrical stimulation of dorsal raphe nucleus using in vivo whole-cell patch-clamp recording. Square-wave grating of 12 orientations was presented. Data was analyzed and Wilcoxon signed-rank test, used in order to compare the data of two conditions that belong to the same neurons, with or without electrical stimulation. Results: The serotonergic system changed orientation tuning of about 60 % recorded neurons by decreasing the mean firing rate in two independent visual response components: gain and baseline response. It also increased mean firing rate in a small number of neurons (about 20%). Beyond that, it left the preferred orientation and sensitivity of neurons unchanged. Conclusion: However, serotonergic modulation showed a bi-directional effect; it seems to cause predominately divisive and subtractive decreases in the visual responses of the neurons in the primary visual cortex that can modify the balance between internal and external sensory signals and result in disorders.

Effect of longer periods of dark rearing on NMDA receptors in cat visual cortex

1994 ◽  
Vol 72 (3) ◽  
pp. 1220-1226 ◽  
Author(s):  
D. Czepita ◽  
S. N. Reid ◽  
N. W. Daw
Keyword(s):  
Visual Cortex ◽  
Nmda Receptor ◽  
Firing Rate ◽  
Spontaneous Activity ◽  
Visual Response ◽  
Visual Responses ◽  
Level Of Activity ◽  
Direction Of Movement ◽  
Excitatory Drive ◽  
Dark Rearing

1. Cats were reared in the dark to 3, 5, and 11 mo. We studied the N-methyl-D-aspartate (NMDA) receptor contribution to the visual response in the cortex, defined as the percentage reduction in visual response after application of 2-amino-5-phosphonovaleric acid (APV). We also studied the firing rate in response to the optimal visual stimulus and the spontaneous activity. We made comparisons of all these properties between light-reared and dark-reared animals. 2. The NMDA receptor contribution to the visual response in layers IV, V, and VI of dark-reared animals was substantially above that in light-reared animals at all ages tested. 3. The specificity of receptive field properties in dark-reared animals showed some degeneration between 6 wk and 3 mo of age. At > or = 3 mo, almost no cells were specific for orientation and direction of movement. 4. Firing rate was lower in dark-reared animals at all ages, suggesting a decrease in excitatory drive to the visual cortex. 5. Spontaneous activity was equal in dark- and light-reared animals, suggesting that the overall level of activity (including visual responses as well as spontaneous activity) in light-reared animals is higher than in dark-reared animals. This should tend to upregulate glutamate receptors in general in dark-reared animals.

scholarly journals Orientation Tuning of Input Conductance, Excitation, and Inhibition in Cat Primary Visual Cortex

2000 ◽  
Vol 84 (2) ◽  
pp. 909-926 ◽  
Author(s):  
Jeffrey S. Anderson ◽  
Matteo Carandini ◽  
David Ferster
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Stimulation ◽  
Gain Control ◽  
Orientation Tuning ◽  
Visual Responses ◽  
Stimulus Contrast ◽  
Simple Cells ◽  
Conductance Changes ◽  
Input Conductance

The input conductance of cells in the cat primary visual cortex (V1) has been shown recently to grow substantially during visual stimulation. Because increasing conductance can have a divisive effect on the synaptic input, theoretical proposals have ascribed to it specific functions. According to the veto model, conductance increases would serve to sharpen orientation tuning by increasing most at off-optimal orientations. According to the normalization model, conductance increases would control the cell's gain, by being independent of stimulus orientation and by growing with stimulus contrast. We set out to test these proposals and to determine the visual properties and possible synaptic origin of the conductance increases. We recorded the membrane potential of cat V1 cells while injecting steady currents and presenting drifting grating patterns of varying contrast and orientation. Input conductance grew with stimulus contrast by 20–300%, generally more in simple cells (40–300%) than in complex cells (20–120%), and in simple cells was strongly modulated in time. Conductance was invariably maximal for stimuli of the preferred orientation. Thus conductance changes contribute to a gain control mechanism, but the strength of this gain control does not depend uniquely on contrast. By assuming that the conductance changes are entirely synaptic, we further derived the excitatory and inhibitory synaptic conductances underlying the visual responses. In simple cells, these conductances were often arranged in push-pull: excitation increased when inhibition decreased and vice versa. Excitation and inhibition had similar preferred orientations and did not appear to differ in tuning width, suggesting that the intracortical synaptic inputs to simple cells of cat V1 originate from cells with similar orientation tuning. This finding is at odds with models where orientation tuning in simple cells is achieved by inhibition at off-optimal orientations or sharpened by inhibition that is more broadly tuned than excitation.

scholarly journals Influence of Contrast on Orientation and Temporal Frequency Tuning in Ferret Primary Visual Cortex

2004 ◽  
Vol 91 (6) ◽  
pp. 2797-2808 ◽  
Author(s):  
Henry J. Alitto ◽  
W. Martin Usrey
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Cortical Neurons ◽  
Frequency Tuning ◽  
Temporal Frequency ◽  
Orientation Tuning ◽  
Visual Response ◽  
Stimulus Contrast ◽  
Tuning Curves ◽  
Simple And Complex Cells

Neurons in primary visual cortex are highly sensitive to the contrast, orientation, and temporal frequency of a visual stimulus. These three stimulus properties can be varied independently of one another, raising the question of how they interact to influence neuronal responses. We recorded from individual neurons in ferret primary visual cortex to determine the influence of stimulus contrast on orientation tuning, temporal-frequency tuning, and latency to visual response. Results show that orientation-tuning bandwidth is not affected by contrast level. Thus neurons in ferret visual cortex display contrast-invariant orientation tuning. Stimulus contrast does, however, influence the structure of orientation-tuning curves as measures of circular variance vary inversely with contrast for both simple and complex cells. This change in circular variance depends, in part, on a contrast-dependent change in the ratio of null to preferred orientation responses. Stimulus contrast also has an influence on the temporal-frequency tuning of cortical neurons. Both simple and complex cells display a contrast-dependent rightward shift in their temporal frequency-tuning curves that results in an increase in the highest temporal frequency needed to produce a half-maximum response (TF50). Results show that the degree of the contrast-dependent increase in TF50 is similar for cortical neurons and neurons in the lateral geniculate nucleus (LGN) and indicate that subcortical mechanisms likely play a major role in establishing the degree of effect displayed by downstream neurons. Finally, results show that LGN and cortical neurons experience a contrast-dependent phase advance in their visual response. This phase advance is most pronounced for cortical neurons indicating a role for both subcortical and cortical mechanisms.

scholarly journals The Role of Spared Calcarine Cortex and Lateral Occipital Cortex in the Responses of Human Hemianopes to Visual Motion

2004 ◽  
Vol 16 (2) ◽  
pp. 204-218 ◽  
Author(s):  
Antony B. Morland ◽  
Sandra Lê ◽  
Erin Carroll ◽  
Michael B. Hoffmann ◽  
Alidz Pambakian
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Motion ◽  
Neural Mechanism ◽  
Visual Pathways ◽  
The Other ◽  
Visual Response ◽  
Visual Responses ◽  
Behavioral Experiments ◽  
Residual Vision

Some patients, who are rendered perimetrically blind in one hemifield by cortical lesions, nevertheless exhibit residual visual capacities within their field defects. The neural mechanism that mediates the residual visual responses has remained the topic of considerable debate. One explanation posits the subcortical visual pathways that bypass the primary visual cortex and innervate the extrastriate visual areas as the substrate that underlies the residual vision. The other explanation is that small islands of the primary visual cortex remain intact and provide the signals for residual vision. We have performed behavioral and functional magnetic resonance imaging experiments to investigate the validity of the two explanations of residual vision. Our behavioral experiments indicated that of the seven hemianopes tested, two had the ability to discriminate the direction of a drifting grating. This residual visual response was shown with fMRI to be the result of spared islands of calcarine cortical activity in one of the hemianopes, whereas only lateral occipital activity was documented in the other patient. These results indicate that the underlying neural correlates of residual vision can vary between patients. Moreover, our study emphasizes the necessity of ruling out the presence of islands of preserved function and primary visual cortex before assigning residual visual capacities to the properties of visual pathways that bypass the primary visual cortex.

Effects of Feedback Projections From Area 18 Layers 2/3 to Area 17 Layers 2/3 in the Cat Visual Cortex

1999 ◽  
Vol 82 (5) ◽  
pp. 2667-2675 ◽  
Author(s):  
Susana Martinez-Conde ◽  
Javier Cudeiro ◽  
Kenneth L. Grieve ◽  
Rosa Rodriguez ◽  
Casto Rivadulla ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Small Region ◽  
Orientation Tuning ◽  
Area 17 ◽  
Visual Responses ◽  
Area 18 ◽  
Cat Visual Cortex ◽  
Effects Of Feedback ◽  
Feedback Connections

In the absence of a direct geniculate input, area 17 cells in the cat are nevertheless able to respond to visual stimuli because of feedback connections from area 18. Anatomic studies have shown that, in the cat visual cortex, layer 5 of area 18 projects to layer 5 of area 17, and layers 2/3 of area 18 project to layers 2/3 of area 17. What is the specific role of these connections? Previous studies have examined the effect of area 18 layer 5 blockade on cells in area 17 layer 5. Here we examine whether the feedback connections from layers 2/3 of area 18 influence the orientation tuning and velocity tuning of cells in layers 2/3 of area 17. Experiments were carried out in anesthetized and paralyzed cats. We blocked reversibly a small region (300 μm radius) in layers 2/3 of area 18 by iontophoretic application of GABA and recorded simultaneously from cells in layers 2/3 of area 17 while stimulating with oriented sweeping bars. Area 17 cells showed either enhanced or suppressed visual responses to sweeping bars of various orientations and velocities during area 18 blockade. For most area 17 cells, orientation bandwidths remained unaltered, and we never observed visual responses during blockade that were absent completely in the preblockade condition. This suggests that area 18 layers 2/3 modulate visual responses in area 17 layers 2/3 without fundamentally altering their specificity.

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 Temporo-nasally biased moving grating selectivity in mouse primary visual cortex

2019 ◽  
Author(s):  
Marie Tolkiehn ◽  
Simon R. Schultz
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Primary Visual Cortex ◽  
Moving Objects ◽  
Direction Selectivity ◽  
Orientation Tuning ◽  
High Signal ◽  
Forward Movement ◽  
Upward Moving

AbstractOrientation tuning in mouse primary visual cortex (V1) has long been reported to have a random or “salt-and-pepper” organisation, lacking the structure found in cats and primates. Laminar in-vivo multi-electrode array recordings here reveal previously elusive structure in the representation of visual patterns in the mouse visual cortex, with temporo-nasally drifting gratings eliciting consistently highest neuronal responses across cortical layers and columns, whilst upward moving gratings reliably evoked the lowest activities. We suggest this bias in direction selectivity to be behaviourally relevant as objects moving into the visual field from the side or behind may pose a predatory threat to the mouse whereas upward moving objects do not. We found furthermore that direction preference and selectivity was affected by stimulus spatial frequency, and that spatial and directional tuning curves showed high signal correlations decreasing with distance between recording sites. In addition, we show that despite this bias in direction selectivity, it is possible to decode stimulus identity and that spatiotemporal features achieve higher accuracy in the decoding task whereas spike count or population counts are sufficient to decode spatial frequencies implying different encoding strategies.Significance statementWe show that temporo-nasally drifting gratings (i.e. opposite the normal visual flow during forward movement) reliably elicit the highest neural activity in mouse primary visual cortex, whereas upward moving gratings reliably evoke the lowest responses. This encoding may be highly behaviourally relevant, as objects approaching from the periphery may pose a threat (e.g. predators), whereas upward moving objects do not. This is a result at odds with the belief that mouse primary visual cortex is randomly organised. Further to this biased representation, we show that direction tuning depends on the underlying spatial frequency and that tuning preference is spatially correlated both across layers and columns and decreases with cortical distance, providing evidence for structural organisation in mouse primary visual cortex.

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