Induced Gamma activity in primary visual cortex is related to luminance and not color contrast: An MEG study.

@article{Adjamian2008InducedGA,
  title={Induced Gamma activity in primary visual cortex is related to luminance and not color contrast: An MEG study.},
  author={Peyman Adjamian and Avgis Hadjipapas and Gareth R. Barnes and Arjan Hillebrand and Ian E. Holliday},
  journal={Journal of vision},
  year={2008},
  volume={8 7},
  pages={
          4.1-7
        }
}
Gamma activity in the visual cortex has been reported in numerous EEG studies of coherent and illusory figures. A dominant theme of many such findings has been that temporal synchronization in the gamma band in response to these identifiable percepts is related to perceptual binding of the common features of the stimulus. In two recent studies using magnetoencephalography (MEG) and the beamformer analysis technique, we have shown that the magnitude of induced gamma activity in visual cortex is… 

Figures from this paper

BOLD Responses in Human Primary Visual Cortex are Insensitive to Substantial Changes in Neural Activity
TLDR
The relationship between blood oxygenation level dependent-functional magnetic resonance imaging (BOLD-fMRI) and magnetoencephalography (MEG) metrics were explored using low-level visual stimuli known to elicit a rich variety of neural responses, providing further evidence that the relationship between the fMRI-BOLD response and cortical neural activity is complex.
The gamma response to colour hue in humans: Evidence from MEG
TLDR
Increased gamma power in response to full-screen stimulation with four different colour hues is demonstrated and it is found that the gamma response is particularly strong for long wavelength (i.e. red) stimulation, as was found in previous studies.
Early gamma-band activity as a function of threat processing in the extrastriate visual cortex
Various neuroimaging investigations have revealed that perception of emotional pictures is associated with greater visual cortex activity than their neutral counterparts. It has further been proposed
Linear Tuning of Gamma Amplitude and Frequency to Luminance Contrast: Evidence from a Continuous Mapping Paradigm
TLDR
Both gamma amplitude and frequency were linearly modulated by stimulus contrast, but that the gain of this modulation varied across individuals, suggesting that these may be independent traits driven by distinct neurophysiological processes.
Cortical oscillatory activity associated with the perception of illusory and real visual contours.
Increased gamma band activity for lateral interactions in humans
TLDR
The findings suggest that gamma-band ERP spectrum analysis may serve as a useful and reliable tool for exploring basic perception, both in normal adults and in special populations.
Individual differences in excitation and inhibition in visual cortex
TLDR
There were no strong relationships between increased or decreased functional responses in visual cortex and measures of brain structure or of neurotransmitter concentration, and age was the major determinant of individual variability in the frequency of neuronal oscillations.
...
...

References

SHOWING 1-10 OF 29 REFERENCES
Cortical mapping of gamma oscillations in areas V1 and V4 of the macaque monkey
TLDR
The results show that gamma oscillations are dependent upon the same parameters as the VEPs (retinotopic position, luminance, and color), however, the differences in the time course of V EPs and gamma activity suggests that these two responses may reflect different cell populations, different networks, or different firing modes.
Induced visual illusions and gamma oscillations in human primary visual cortex
TLDR
It is hypothesize that the intrinsic properties of gamma oscillations may underlie visual discomfort and play a role in the onset of seizures.
Visually induced gamma-band responses in human electroencephalographic activity — a link to animal studies
TLDR
It is demonstrated that stimulus-induced gamma-band responses can be recorded non-invasively from human subjects attending to a single moving bar, indicating the synchronization of oscillatory activity in a large group of cortical neurons.
Coherent oscillations: A mechanism of feature linking in the visual cortex?
TLDR
This work assumes that the coherence of SE-resonances is mediated by recurrent excitatory intra- and inter-areal connections via phase locking between assemblies that represent the linking features of the actual visual scene.
Human Gamma Band Activity and Perception of a Gestalt
TLDR
The topography of gamma band spectral power and event-related potentials in human EEG associated with perceptual switching effected by rotating ambiguous (bistable) figures support the notion that formation of a visual percept may involve oscillations in a distributed neuronal assembly.
A direct demonstration of functional specialization in human visual cortex
TLDR
PET is used to demonstrate directly the specialization of function in the normal human visual cortex, and provides direct evidence to show that, just as in the macaque monkey, different areas of the human prestriate visual cortex are specialized for different attributes of vision.
Contour decouples gamma activity across texture representation in monkey striate cortex.
TLDR
The results of decoupling in late LFP gamma-components among figure and ground representations suggest that these signals may support figure-ground segregation.
Retinotopy and color sensitivity in human visual cortical area V8
TLDR
The location of the human color-selective region did not match the location of area V4 (neither its dorsal nor ventral subdivisions), as extrapolated from macaque maps, and instead this region coincides with a new retinotopic area that is called 'V8', which includes a distinct representation of the fovea and both upper and lower visual fields.
Gamma‐range Activity Evoked by Coherent Visual Stimuli in Humans
TLDR
A 30 Hz component whose power correlates with stimulus coherency supports the hypothesis of a functional role of high‐frequency synchronization in feature binding and seemed specific to the gamma‐frequency range.
...
...