Long-wavelength (reddish) hues induce unusually large gamma oscillations in the primate primary visual cortex

Gamma oscillations (∼30–80 Hz) are a prominent signature of electrophysiological signals, with a purported role in natural vision. Previous studies in the primary visual cortex (area V1) have shown that achromatic gratings or gabor stimuli generate salient gamma oscillations, whose strength and frequency depend on stimulus properties such as their size, contrast, and orientation. Surprisingly, although natural images are rarely achromatic, the effect of chromatic input on gamma has not been thoroughly investigated. Recording from primate V1, we show that gamma oscillations of extremely high magnitude (peak increase of ∼300-fold in some cases), far exceeding the gamma generated by optimally tuned achromatic gratings, are induced in the local field potentials by full-field color stimuli of different hues. Furthermore, gamma oscillations are sensitive to the hue of the chromatic input, with the strongest oscillations for long-wavelength (reddish) hues and another, smaller gamma response peak for hues in the short-wavelength (bluish) range, which lie approximately on the two cardinal chromatic response axes of the upstream lateral geniculate nucleus neurons. These oscillations depended critically on the purity of the hue, decreasing with hue desaturation, but remained robust for pure hue stimuli even at reduced luminance. Importantly, the magnitude of gamma oscillations was highly correlated with positive L−M cone contrast produced by the stimuli, suggesting that gamma could be a marker of the specific mechanisms underlying this computation. These findings provide insights into the generation of gamma oscillations, as well as the processing of color along the visual pathway.

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Superimposed gratings induce diverse response patterns of gamma oscillations in primary visual cortex

Scientific Reports ◽

10.1038/s41598-021-83923-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Bin Wang ◽

Chuanliang Han ◽

Tian Wang ◽

Weifeng Dai ◽

Yang Li ◽

...

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Field Potential ◽

Gamma Oscillations ◽

Neural Mechanisms ◽

Model Parameters ◽

Response Patterns ◽

Region Difference ◽

High Gamma ◽

Spiking Activity

AbstractStimulus-dependence of gamma oscillations (GAMMA, 30–90 Hz) has not been fully understood, but it is important for revealing neural mechanisms and functions of GAMMA. Here, we recorded spiking activity (MUA) and the local field potential (LFP), driven by a variety of plaids (generated by two superimposed gratings orthogonal to each other and with different contrast combinations), in the primary visual cortex of anesthetized cats. We found two distinct narrow-band GAMMAs in the LFPs and a variety of response patterns to plaids. Similar to MUA, most response patterns showed that the second grating suppressed GAMMAs driven by the first one. However, there is only a weak site-by-site correlation between cross-orientation interactions in GAMMAs and those in MUAs. We developed a normalization model that could unify the response patterns of both GAMMAs and MUAs. Interestingly, compared with MUAs, the GAMMAs demonstrated a wider range of model parameters and more diverse response patterns to plaids. Further analysis revealed that normalization parameters for high GAMMA, but not those for low GAMMA, were significantly correlated with the discrepancy of spatial frequency between stimulus and sites’ preferences. Consistent with these findings, normalization parameters and diversity of high GAMMA exhibited a clear transition trend and region difference between area 17 to 18. Our results show that GAMMAs are also regulated in the form of normalization, but that the neural mechanisms for these normalizations might differ from those of spiking activity. Normalizations in different brain signals could be due to interactions of excitation and inhibitions at multiple stages in the visual system.

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Anatomical organization of the primary visual cortex (area 17) of the cat. A comparison with area 17 of the macaque monkey

The Journal of Comparative Neurology ◽

10.1002/cne.901840402 ◽

1979 ◽

Vol 184 (4) ◽

pp. 599-618 ◽

Cited By ~ 245

Author(s):

J. S. Lund ◽

G. H. Henry ◽

C. L. Macqueen ◽

A. R. Harvey

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Macaque Monkey ◽

Area 17 ◽

Cortex Area

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Man's Triune Conscious Mind: Part III

Perceptual and Motor Skills ◽

10.1177/003151259508100220 ◽

1995 ◽

Vol 81 (2) ◽

pp. 463-466

Author(s):

Carl G. Aurell

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Conscious Mind ◽

Perceptual Model ◽

Cortex Area ◽

Layer 4

The perceptual model, discussed previously in Part II, is applied to the organization of the visual cortex in a search for “consciousness neurons,” i.e., sources of sensations, images, and percepts. It is hypothesized that these three conscious phenomena emerge in the primary visual cortex, Area VI, possibly from neurons in its Layer 4.

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Neural responses to relative speed in the primary visual cortex of rhesus monkey

Visual Neuroscience ◽

10.1017/s0952523803201085 ◽

2003 ◽

Vol 20 (1) ◽

pp. 77-84 ◽

Cited By ~ 24

Author(s):

AN CAO ◽

PETER H. SCHILLER

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Relative Motion ◽

Motion Parallax ◽

Relative Speed ◽

Neural Responses ◽

Tuning Curves ◽

V1 Neurons ◽

Cortex Area ◽

Ground Segmentation

Relative motion information, especially relative speed between different input patterns, is required for solving many complex tasks of the visual system, such as depth perception by motion parallax and motion-induced figure/ground segmentation. However, little is known about the neural substrate for processing relative speed information. To explore the neural mechanisms for relative speed, we recorded single-unit responses to relative motion in the primary visual cortex (area V1) of rhesus monkeys while presenting sets of random-dot arrays moving at different speeds. We found that most V1 neurons were sensitive to the existence of a discontinuity in speed, that is, they showed higher responses when relative motion was presented compared to homogenous field motion. Seventy percent of the neurons in our sample responded predominantly to relative rather than to absolute speed. Relative speed tuning curves were similar at different center–surround velocity combinations. These relative motion-sensitive neurons in macaque area V1 probably contribute to figure/ground segmentation and motion discontinuity detection.

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An intrinsic neural eye tracker in primary visual cortex

10.1101/443507 ◽

2018 ◽

Author(s):

Adam P. Morris ◽

Bart Krekelberg

Keyword(s):

Visual Cortex ◽

Eye Movements ◽

Primary Visual Cortex ◽

Visual Information ◽

Moving Objects ◽

Receptive Fields ◽

Gaze Direction ◽

Eye Tracker ◽

Electrode Arrays ◽

Full Field

SummaryHumans and other primates rely on eye movements to explore visual scenes and to track moving objects. As a result, the image that is projected onto the retina – and propagated throughout the visual cortical hierarchy – is almost constantly changing and makes little sense without taking into account the momentary direction of gaze. How is this achieved in the visual system? Here we show that in primary visual cortex (V1), the earliest stage of cortical vision, neural representations carry an embedded “eye tracker” that signals the direction of gaze associated with each image. Using chronically implanted multi-electrode arrays, we recorded the activity of neurons in V1 during tasks requiring fast (exploratory) and slow (pursuit) eye movements. Neurons were stimulated with flickering, full-field luminance noise at all times. As in previous studies 1-4, we observed neurons that were sensitive to gaze direction during fixation, despite comparable stimulation of their receptive fields. We trained a decoder to translate neural activity into metric estimates of (stationary) gaze direction. This decoded signal not only tracked the eye accurately during fixation, but also during fast and slow eye movements, even though the decoder had not been exposed to data from these behavioural states. Moreover, this signal lagged the real eye by approximately the time it took for new visual information to travel from the retina to cortex. Using simulations, we show that this V1 eye position signal could be used to take into account the sensory consequences of eye movements and map the fleeting positions of objects on the retina onto their stable position in the world.

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VIP interneurons in mouse primary visual cortex selectively enhance responses to weak but specific stimuli

eLife ◽

10.7554/elife.55130 ◽

2020 ◽

Vol 9 ◽

Author(s):

Daniel J Millman ◽

Gabriel Koch Ocker ◽

Shiella Caldejon ◽

India Kato ◽

Josh D Larkin ◽

...

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Pyramidal Neurons ◽

Feedback Inhibition ◽

Neuron Activity ◽

Low Contrast ◽

Visual Coding ◽

Mutual Antagonism ◽

Layer 2 ◽

Highly Correlated

Vasoactive intestinal peptide-expressing (VIP) interneurons in the cortex regulate feedback inhibition of pyramidal neurons through suppression of somatostatin-expressing (SST) interneurons and, reciprocally, SST neurons inhibit VIP neurons. Although VIP neuron activity in the primary visual cortex (V1) of mouse is highly correlated with locomotion, the relevance of locomotion-related VIP neuron activity to visual coding is not known. Here we show that VIP neurons in mouse V1 respond strongly to low contrast front-to-back motion that is congruent with self-motion during locomotion but are suppressed by other directions and contrasts. VIP and SST neurons have complementary contrast tuning. Layer 2/3 contains a substantially larger population of low contrast preferring pyramidal neurons than deeper layers, and layer 2/3 (but not deeper layer) pyramidal neurons show bias for front-to-back motion specifically at low contrast. Network modeling indicates that VIP-SST mutual antagonism regulates the gain of the cortex to achieve sensitivity to specific weak stimuli without compromising network stability.

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Numerical relationship between neurons in the lateral geniculate nucleus and primary visual cortex in macaque monkeys

Visual Neuroscience ◽

10.1017/s0952523800008269 ◽

1996 ◽

Vol 13 (3) ◽

pp. 585-590 ◽

Cited By ~ 15

Author(s):

Ivan Suner ◽

Pasko Rakic

Keyword(s):

Visual Cortex ◽

Lateral Geniculate Nucleus ◽

Primary Visual Cortex ◽

Rhesus Monkeys ◽

Three Dimensional ◽

Area 17 ◽

Counting Method ◽

Lateral Geniculate ◽

Cortex Area ◽

The Right

AbstractWe examined the numerical correlation between total populations of neurons in the lateral geniculate nucleus (LGN) and the primary visual cortex (area 17 of Brodmann) in ten cerebral hemispheres of five normal rhesus monkeys using an unbiased three-dimensional counting method. There were 1.4 ± 0.2 million and 341 ±54 million neurons in the LGN and area 17, respectively. In each animal, a larger LGN on one side was in register with a larger area 17 of the cortex on the same side. Furthermore, asymmetry in the number of neurons in both the LGN and area 17 favored the right side. However, because of small variations across subjects, correlation between the total neuron number in LGN and area 17 was weak (r = 0.29). These results suggest that the final numbers of neurons in these visual centers may be established independently or by multiple factors controlling elimination of initially overproduced neurons.

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