Synchronization dynamics in response to plaid stimuli in monkey V1.
Gamma synchronization has generally been associated with grouping processes in the visual system. Here, we examine in monkey V1 whether gamma oscillations play a functional role in segmenting surfaces of plaid stimuli. Local field potentials (LFPs) and spiking activity were recorded simultaneously from multiple sites in the opercular and calcarine regions while the monkeys were presented with sequences of single and superimposed components of plaid stimuli. In accord with the previous studies, responses to the single components (gratings) exhibited strong and sustained gamma-band oscillations (30-65 Hz). The superposition of the second component, however, led to profound changes in the temporal structure of the responses, characterized by a drastic reduction of gamma oscillations in the spiking activity and systematic shifts to higher frequencies in the LFP ( approximately 10% increase). Comparisons between cerebral hemispheres and across monkeys revealed robust subject-specific spectral signatures. A possible interpretation of our results may be that single gratings induce strong cooperative interactions among populations of cells that share similar response properties, whereas plaids lead to competition. Overall, our results suggest that the functional architecture of the cortex is a major determinant of the neuronal synchronization dynamics in V1.
Lima
Bruss
B
Max-Planck Institute for Brain Research, 60528 Frankfurt am Main, Germany.
Singer
Wolf
W
Chen
Nan-Hui
NH
Neuenschwander
Sergio
S
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001288:Attention / Q000502:physiology; D003344:Cortical Synchronization; D005074:Evoked Potentials, Visual / Q000502:physiology*; D007839:Functional Laterality; D008253:Macaca mulatta; D009474:Neurons / Q000502:physiology; D017711:Nonlinear Dynamics; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D013057:Spectrum Analysis; D013997:Time Factors; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology