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08:02
Generation of Local CA1 γ Oscillations by Tetanic Stimulation
Published on: August 14, 2015
Hemodynamic signals correlate tightly with synchronized gamma oscillations
Jörn Niessing1, Boris Ebisch, Kerstin E Schmidt
1Max Planck Institute for Brain Research, 60528 Frankfurt/M., Germany.
Science (New York, N.Y.)
|August 6, 2005
Summary
Functional imaging measures hemodynamic signals related to neural activity. Hemodynamic responses correlate with local field potential (LFP) oscillations, not just action potentials, suggesting a link to neuronal synchronization.
Area of Science:
- Neuroscience
- Neuroimaging
- Electrophysiology
Background:
- Functional imaging techniques like fMRI measure hemodynamic signals to infer neural activity.
- Hemodynamic responses are generally considered to reflect local field potentials (LFPs) more than action potentials.
Purpose of the Study:
- To investigate the relationship between electrical neural activity and hemodynamic responses.
- To determine whether hemodynamic signals correlate more closely with spiking activity or LFP oscillations.
Main Methods:
- Simultaneous recording of electrical and hemodynamic responses in the cat visual cortex.
- Modulation of stimulus strength and intensity to observe changes in neural and hemodynamic signals.
Main Results:
- Increasing stimulus strength enhanced spiking activity, gamma-band LFP power, and hemodynamic responses.
- Hemodynamic response fluctuations at constant stimulus intensity correlated strongly with gamma-band LFP power, but weakly with spiking activity.
- Neuronal synchronization, indicated by LFP oscillations, is closely linked to hemodynamic responses.
Conclusions:
- Hemodynamic responses are tightly coupled to the synchronization of neuronal activity, particularly LFP oscillations in the gamma range.
- This finding refines our understanding of what functional imaging signals represent.
- Neuronal synchronization is a key factor driving the hemodynamic response.
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