Induced visual illusions and gamma oscillations in human primary visual cortex

  title={Induced visual illusions and gamma oscillations in human primary visual cortex},
  author={Peyman Adjamian and Ian E. Holliday and Gareth R. Barnes and Arjan Hillebrand and Avgis Hadjipapas and Krish D. Singh},
  journal={European Journal of Neuroscience},
Using magnetoencephalography, we studied the spatiotemporal properties of cortical responses in terms of event‐related synchronization and event‐related desynchronization to a range of stripe patterns in subjects with no neurological disorders. These stripes are known for their tendency to induce a range of abnormal sensations, such as illusions, nausea, dizziness, headache and attacks of pattern‐sensitive epilepsy. The optimal stimulus must have specific physical properties, and maximum… 
SHORT COMMUNICATION Induced visual illusions and gamma oscillations in human primary visual cortex
Using magnetoencephalography, we studied the spatiotemporal properties of cortical responses in terms of event-related synchronization and event-related desynchronization to a range of stripe
Abnormal waveform of the human pattern VEP: contribution from gamma oscillatory components.
The human gamma oscillatory response mediating in cortical visual information processing further proved independent of the VEPs.
Spontaneous local alpha oscillations predict motion‐induced blindness
It is demonstrated that the spontaneous changes in visual alpha activity have perceptual consequences, and early alpha activity was predictive of onset and length of the illusory percept, and gamma activity showed no modulation in relation to the illusion.
Cortical oscillatory activity associated with the perception of illusory and real visual contours.
Evidence for increased visual gamma responses in photosensitive epilepsy
Induced Gamma activity in primary visual cortex is related to luminance and not color contrast: An MEG study.
This work showed that induced gamma activity is maximal in response to gratings of 3 cycles per degree (3 cpd) of high luminance contrast, and examined stimulus contrast further by using isoluminant red/green gratings that possess color but not Luminance contrast using the same cohort of subjects.
Differential impact of movement on the alpha and gamma dynamics serving visual processing.
The results suggest that even basic motor responses alter occipital visual oscillations in healthy adults, and provide valuable evidence of visuomotor integration and underscore the importance of careful task design and interpretation, especially in the context of complex visual processing.
Spectral properties of induced and evoked gamma oscillations in human early visual cortex to moving and stationary stimuli.
It is suggested that early visual areas encode moving and stationary percepts via activity at higher and lower gamma frequencies, respectively.


Interhemispheric differences in photosensitive epilepsy. I. Pattern sensitivity thresholds.
Dynamics of striate cortical activity in the alert macaque: I. Incidence and stimulus-dependence of gamma-band neuronal oscillations.
The overall similarity of rhythmic neuronal activity in the primary visual cortex of cats and monkeys suggests that the phenomenon is not species-specific, and the stimulus-dependence of the rhythmic activity is consistent with a functional role in visual perception.
Neurophysiological aspects of pattern-sensitive epilepsy.
The capacity of striped patterns (square-wave gratings) to induce paroxysmal EEG activity in a group of pattern-sensitive epileptic patients is shown to depend on the spatial frequency and orientation, which are compatible with the hypothesis of a seizure trigger in the striate cortex and incompatible with a trigger confined to the lateral geniculate nucleus of the thalamus.
Stimulus-specific neuronal oscillations in orientation columns of cat visual cortex.
  • C. Gray, W. Singer
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1989
The results demonstrate that local neuronal populations in the visual cortex engage in stimulus-specific synchronous oscillations resulting from an intracortical mechanism, and may provide a general mechanism by which activity patterns in spatially separate regions of the cortex are temporally coordinated.
Dynamics of striate cortical activity in the alert macaque: II. Fast time scale synchronization.
It is found that neuronal synchronization with millisecond precision is a prevalent and robust feature of stimulus-evoked activity in striate cortex and suggests that neuronal rhythmicity is an important mechanism contributing to synchronization.
Oscillatory γ-Band (30–70 Hz) Activity Induced by a Visual Search Task in Humans
It is suggested that this γ-band energy increase reflects both bottom-up (binding of elementary features) and top-down (search for the hidden dog) activation of the same neural assembly coding for the Dalmatian.
Gamma-band phase clustering and photosensitivity: is there an underlying mechanism common to photosensitive epilepsy and visual perception?
An enhancement of phase synchrony in the gamma-band, harmonically related to the frequency of stimulation, preceded the stimulation trials that evolved into PPRs, and differed significantly from that encountered in trials not followed by PPR or in control subjects, leading to postulate that a pathological deviation of normally occurring synchronization of gamma oscillations, underlying perceptional processes, mediates the epileptic transition in PSE.
Stimulus-specific fast oscillations at zero phase between visual areas V1 and V2 of awake monkey.
The presence of, and phase-locking between, high amplitude stimulus specific oscillations in striate and extra striate visual cortex of an awake monkey demonstrates the presence of near zero-phase synchronization among cortical areas that might enable fast and effective communication via the many reciprocal cortico-cortical connections.
A neurological basis for visual discomfort.
The parameters of the patterns that induce illusions closely resemble those that elicit epileptiform electroencephalographic abnormalities in patients with photosensitive epilepsy and those under which more illusions are seen.
Task-Related Changes in Cortical Synchronization Are Spatially Coincident with the Hemodynamic Response
This study demonstrates how SAM, spatial normalization, and intersubject averaging enable group MEG studies to be performed and represents an important advance in the use of MEG as a cognitive neuroimaging technique and also allows mutual cross-validation with fMRI.