scholarly journals An image-computable model for the stimulus selectivity of gamma oscillations

2019 ◽  
Author(s):  
Dora Hermes ◽  
Natalia Petridou ◽  
Kendrick Kay ◽  
Jonathan Winawer
Keyword(s):  
Visual Cortex ◽  
Visual Information ◽  
Information Transfer ◽  
Gain Control ◽  
Gamma Oscillations ◽  
Small Subset ◽  
Computable Model ◽  
Human Visual Cortex ◽  
Fundamental Mechanism

AbstractGamma oscillations in visual cortex have been hypothesized to be critical for perception, cognition, and information transfer. However, observations of these oscillations in visual cortex vary widely; some studies report little to no stimulus-induced narrowband gamma oscillations, others report oscillations for only some stimuli, and yet others report large oscillations for most stimuli. To reconcile these findings and better understand this signal, we developed a model that predicts gamma responses for arbitrary images and validated this model on electrocorticography (ECoG) data from human visual cortex. The model computes variance across the outputs of spatially pooled orientation channels, and accurately predicts gamma amplitude across 86 images. Gamma responses were large for a small subset of stimuli, differing dramatically from fMRI and ECoG broadband (non-oscillatory) responses. We suggest that gamma oscillations in visual cortex serve as a biomarker of gain control rather than being a fundamental mechanism for communicating visual information.

scholarly journals An image-computable model for the stimulus selectivity of gamma oscillations

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Dora Hermes ◽  
Natalia Petridou ◽  
Kendrick N Kay ◽  
Jonathan Winawer
Keyword(s):  
Visual Cortex ◽  
Visual Information ◽  
Information Transfer ◽  
Gain Control ◽  
Gamma Oscillations ◽  
Small Subset ◽  
Computable Model ◽  
Human Visual Cortex ◽  
Fundamental Mechanism

Gamma oscillations in visual cortex have been hypothesized to be critical for perception, cognition, and information transfer. However, observations of these oscillations in visual cortex vary widely; some studies report little to no stimulus-induced narrowband gamma oscillations, others report oscillations for only some stimuli, and yet others report large oscillations for most stimuli. To better understand this signal, we developed a model that predicts gamma responses for arbitrary images and validated this model on electrocorticography (ECoG) data from human visual cortex. The model computes variance across the outputs of spatially pooled orientation channels, and accurately predicts gamma amplitude across 86 images. Gamma responses were large for a small subset of stimuli, differing dramatically from fMRI and ECoG broadband (non-oscillatory) responses. We propose that gamma oscillations in visual cortex serve as a biomarker of gain control rather than being a fundamental mechanism for communicating visual information.

scholarly journals Orientation and color tuning of the human visual gamma rhythm

2021 ◽  
Author(s):  
Ye Li ◽  
William Bosking ◽  
Michael S Beauchamp ◽  
Sameer A Sheth ◽  
Daniel Yoshor ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Large Scale ◽  
Brain Activity ◽  
Population Level ◽  
Gamma Oscillations ◽  
Cell Orientation ◽  
Population Activity ◽  
Color Tuning ◽  
Human Visual Cortex ◽  
Gamma Rhythm

Narrowband gamma oscillations (NBG: ~20-60Hz) in visual cortex reflect rhythmic fluctuations in population activity generated by underlying circuits tuned for stimulus location, orientation, and color. Consequently, the amplitude and frequency of induced NBG activity is highly sensitive to these stimulus features. For example, in the non-human primate, NBG displays biases in orientation and color tuning at the population level. Such biases may relate to recent reports describing the large-scale organization of single-cell orientation and color tuning in visual cortex, thus providing a potential bridge between measurements made at different scales. Similar biases in NBG population tuning have been predicted to exist in the human visual cortex, but this has yet to be fully examined. Using intracranial recordings from human visual cortex, we investigated the tuning of NBG to orientation and color, both independently and in conjunction. NBG was shown to display a cardinal orientation bias (horizontal) and also an end- and mid-spectral color bias (red/blue and green). When jointly probed, the cardinal bias for orientation was attenuated and an end-spectral preference for red and blue predominated. These data both elaborate on the close, yet complex, link between the population dynamics driving NBG oscillations and known feature selectivity biases in visual cortex, adding to a growing set of stimulus dependencies associated with the genesis of NBG. Together, these two factors may provide a fruitful testing ground for examining multi-scale models of brain activity, and impose new constraints on the functional significance of the visual gamma rhythm.

scholarly journals Input-dependent modulation of MEG gamma oscillations reflects gain control in the visual cortex

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Elena V. Orekhova ◽  
Olga V. Sysoeva ◽  
Justin F. Schneiderman ◽  
Sebastian Lundström ◽  
Ilia A. Galuta ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Gain Control ◽  
Gamma Oscillations

Research on Visual Cortex Prosthesis System and Visual Information Coding Strategy Based on Sustainable Materials

2013 ◽  
Vol 340 ◽  
pp. 339-343
Author(s):  
Heng Zhang ◽  
Jie Wang
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Visual Information ◽  
Information Transfer ◽  
Sensory System ◽  
Information Coding ◽  
Response Characteristics ◽  
Coding Strategy ◽  
Sustainable Materials ◽  
Representation Method

The visual system is human know the important sensory system of the external world, due to a variety of diseases or other injury, leading to the increasing number of blind visual loss, the visual cortex prosthesis research is expected to provide a way of blind sight. Based on unique information transfer mechanism of the biological visual system, the visual cortex prosthesis framework is designed, and for the core module of the prosthesis, it is proposed based on the simple cell selective characteristics of visual system, sparse response characteristics, synchronous oscillations and other image information coding strategy of the mechanism. The algorithm is used for the actual image analysis, to compared with conventional sparse representation method, under the prerequisite of assuring image quality, the strategy can be used as little as possible neuronal to characterize the important information of natural images, thus effectively reducing the prosthesis embedded cortex stimulation electrode quantity, to achieve better information transfer effect.

The properties of induced gamma oscillations in human visual cortex show individual variability in their dependence on stimulus size

NeuroImage ◽  
2013 ◽  
Vol 68 ◽  
pp. 83-92 ◽  
Author(s):  
Gavin Perry ◽  
Khalid Hamandi ◽  
Lisa M. Brindley ◽  
Suresh D. Muthukumaraswamy ◽  
Krish D. Singh
Keyword(s):  
Visual Cortex ◽  
Gamma Oscillations ◽  
Individual Variability ◽  
Stimulus Size ◽  
Human Visual Cortex

scholarly journals Stimulus Dependence of Gamma Oscillations in Human Visual Cortex

2014 ◽  
Vol 25 (9) ◽  
pp. 2951-2959 ◽  
Author(s):  
D. Hermes ◽  
K.J. Miller ◽  
B.A. Wandell ◽  
J. Winawer
Keyword(s):  
Visual Cortex ◽  
Gamma Oscillations ◽  
Human Visual Cortex

scholarly journals Distinct Narrow and Broadband Gamma Responses in Human Visual Cortex

2019 ◽  
Author(s):  
Eleonora Bartoli ◽  
William Bosking ◽  
Ye Li ◽  
Michael S. Beauchamp ◽  
Daniel Yoshor ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Critical Role ◽  
Visual Stimuli ◽  
Field Potential ◽  
Gamma Oscillations ◽  
Systematic Change ◽  
Human Visual Cortex ◽  
Gamma Range ◽  
High Gamma ◽  
Differential Properties

AbstractHigh frequency activity (> 30 Hz) in the neocortical local field potential, typically referred to as the ‘gamma’ range, is thought to have a critical role in visual perception and cognition more broadly. Historically, animal studies recording from visual cortex documented clear narrowband gamma oscillations (NBG; ∼20-60 Hz) in response to visual stimuli. However, invasive measurements from human neocortex have highlighted a different broadband or ‘high’ gamma response (BBG; ∼70-150+ Hz). Growing evidence suggests these two forms of gamma response are distinct, but often conceptually or analytically conflated as the same ‘gamma’ response. Furthermore, recent debate has highlighted that both the occurrence and spectral properties of gamma band activity in visual cortex appears to be dependent on the attributes and class of presented visual stimuli. Using high-density intracranial recordings from human visual cortex, we integrate and extend these findings, dissociating the spectral, temporal and functional properties of NBG and BBG activity. We report results from two experiments, manipulating visual stimulus attributes (contrast-varying gratings) and class (object categories) dissecting the differential properties of NBG and BBG responses. NBG oscillations were only reliably recorded for grating stimuli, while their peak frequency varied with contrast level. Whereas BBG activity was observed in response to all stimulus classes tested, with no systematic change in its spectral features. Temporally, induced NBG was sustained throughout stimulus presentation, in opposition to a more transient response for the BBG. These findings challenge the ubiquity of ‘gamma’ activity in visual cortex, by clearly dissociating oscillatory and broadband effects.Significance StatementNeocortical narrowband gamma oscillations (∼20-60 Hz) have been implicated in vision and cognition as a mechanism for synchronizing brain regions. Efforts to study this phenomenon have revealed an additional ‘high-gamma’ range response (∼70-150+ Hz), which is broadband and non-oscillatory. These different gamma range activities are often conflated in support of the same functional role. Using invasive recordings from human visual cortex, we show that narrow and broadband gamma can be dissociated by spectral, temporal and functional response properties. While broadband gamma responses were more transient to the presentation of all stimuli, narrowband gamma responses were sustained and only occurred reliably to grating stimuli. These differences have important implications for the study, analysis and interpretation of neocortical gamma range activity.

Functional Organisation of Human Visual Cortex Revealed by fMRI

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 9-9 ◽  
Author(s):  
R B H Tootell ◽  
A M Dale ◽  
N Hadjikhani ◽  
A K Liu ◽  
S Marrett ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Information ◽  
Visual Stimulation ◽  
Frequency Tuning ◽  
Human Subjects ◽  
Planar Imaging ◽  
Posterior Cortex ◽  
Human Visual Cortex ◽  
Wide Range ◽  
Functional Organisation

Until recently, comparatively little was known about the functional organisation of human visual cortex. Functional magnetic resonance imaging (fMRI), in conjunction with cortical flattening techniques and psychophysically relevant visual stimulation, has greatly clarified human visual-information processing. To date, we have completed cortical surface reconstructions (flattening), coupled with a wide range of visual stimulus testing, on 28 normal human subjects. Visual activation was acquired on a 1.5 T GE MR scanner with ANMR echo-planar imaging, with the use of a custom, bilateral, quadrature surface coil covering posterior cortex. Approximately ten visual cortical areas can now be functionally localised each with unique functional and topographical properties. The most well-defined areas are: V1, V2, V3, VP, V3A, V4v, MT, SPO, and perhaps MSTd. Most of the properties in these human areas are similar to those reported in presumably homologous areas of macaque, but distinctive species differences also appear to exist, notably in V3/VP, V4v, and V3A. Human areas showing prominant motion-selectivity include V3A, MT/MSTd, SPO, and a small area near the superior sylvian fissure. Retinotopic areas include V1, V2, V3, VP, V4v, and V3A. The human cortical magnification factor appears higher towards the fovea than in macaque, but, like macaque, preferred spatial frequency tuning varies inversely with eccentricity in all retinotopic areas in which sinusoidal gratings are effective stimuli.

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