Alpha band amplification during illusory jitter perception.
Synchronization is thought to have a role in linking disparate components into neural assemblies. However, the particular frequency of the synchronization is generally considered to be incidental to its functional role. Here we report a link between enhanced alpha activations and an illusory jitter of the same frequency. We measured perceived jitter rates and the magnetoencephalography during presentations of a stimulus wherein red squares and superimposed vertical green bars moved together across a black background. The green bars were either darker, equiluminant with, or brighter than the red squares. We established that the illusory jitter rate, robustly seen only in the equiluminant condition, was approximately 10 Hz. Crucially, neural oscillations around 10 Hz were enhanced in this condition. Surprisingly, approximately 10 Hz oscillations were also enhanced during illusory jitter perception relative to a moving stimulus that contained physical 10 Hz jitter. This suggests that the enhanced synchronization is associated with illusory jitter generation rather than with jitter perception. Since the stimulus eliciting illusory jitter moves smoothly and rigidly, both the percept and enhanced neural synchrony must be generated within the visual system. Our data therefore indicate a match between the dynamics of synchronous neural activity and the dynamics of a sensory experience offering the intriguing possibility of a common cause.
Amano
Kaoru
K
NTT Communication Science Laboratories, Nippon Telegraph and Telephone Corporation, Japan. amano@brain.k.u-tokyo.ac.jp
Arnold
Derek H
DH
Takeda
Tsunehiro
T
Johnston
Alan
A
D000328:Adult; D000513:Alpha Rhythm / Q000523:psychology*; D003116:Color; D015350:Contrast Sensitivity; D003344:Cortical Synchronization / Q000523:psychology*; D005133:Eye Movements; D006801:Humans; D007088:Illusions / Q000523:psychology*; D015225:Magnetoencephalography; D008297:Male; D009039:Motion Perception / Q000502:physiology; D010775:Photic Stimulation; D013028:Space Perception / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology