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Examining Local Network Processing using Multi-contact Laminar Electrode Recording
Published on: September 8, 2011
Direct evidence for local oscillatory current sources and intracortical phase gradients in turtle visual cortex
J C Prechtl1, T H Bullock, D Kleinfeld
1Department of Physics, University of California at San Diego, La Jolla, CA 92093, USA.
Summary
Visual stimuli create traveling waves in turtle brains. These brain waves result from phase shifts in networks of coupled neuronal oscillators, not a single pacemaker.
Area of Science:
- Neuroscience
- Computational Neuroscience
- Visual Cortex Research
Background:
- Visual stimuli trigger neuronal membrane potential oscillations in various species' cortices.
- In turtles, these oscillations manifest as linear and circular traveling waves.
Purpose of the Study:
- To investigate the origin of wave propagation in the turtle visual cortex.
- To differentiate between pacemaker-driven waves and coupled oscillator networks.
Main Methods:
- Simultaneous local field potential measurements at multiple depths within the turtle visual cortex.
- Analysis of spectral coherence between spatially separated cortical oscillators.
Main Results:
- Broadband current sources (gamma band, ~20 Hz) activated by visual stimulation were identified.
- Systematic timing differences between localized cortical oscillators were detected along the rostral-caudal axis.
Conclusions:
- The findings support the model of traveling waves arising from phase shifts in a network of coupled neuronal oscillators.
- This provides direct evidence for stimulus-induced electrical waves in the turtle visual cortex being a network phenomenon.
