Slow Gamma Activity of Local Field Potentials (LFP) in the Freely Moving Rat Relates to Movement

Wilfried Dimpfel¹, Leonie Schombert²

¹Justus-Liebig-Unversitat-Giessen, Giessen, Germany.
²NeuroCode AG, Wetzlar, Germany.

DOI: 10.4236/jbbs.2015.510040                

Abstract

Quantitative assessment of local field potentials by means of Fast Fourier Transformation (FFT) results in the so-called power density spectrum. Within this spectrum particular frequency ranges are defined in order to relate these to behavior. Frequencies above 35 Hz are generally labeled as gamma oscillations, especially as low gamma (40 - 55 Hz) or high gamma (70 - 100 Hz). In order to learn more about this feature, we implanted a set of 4 bipolar concentric steel electrodes in frontal cortex, hippocampus, striatum and midbrain reticular formation of 10 rats. After recovery, field potentials were recorded and wirelessly transmitted to our computer for frequency analysis. At the same time, motion was registered during the whole experimental period of 5.75 hours. Results revealed that low gamma activity only emerged when the animal moved—at least his head. FFT of the data showed—besides other frequencies—a slow gamma activity peaking around 47 Hz pre-dominantly within the striatum, less in frontal cortex and reticular formation and nearly none in the hippocampus. Spectral analysis was performed for single epochs of 4 seconds and all 15 minutes intervals. Correlation analysis of these intervals was done to motion data. All rats showed a highly significant correlation between gamma activity and movement. We therefore conclude from these experiments that this slow gamma activity of the field potentials is not only related to movement, but possibly part of the general neuronal coding of movement.

Keywords

Local Field Potential (LFP), Gamma Activity, Rat, Movement

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Igarashi, J., Isomura, Y., Arai K., Harukuni, R. and Fukai T. (2013) A θ-γOscillation Code for Neuronal Coordination during Motor Behavior. The Journal of Neuroscience, 33, 18515-18530. http://dx.doi.org/10.1523/JNEUROSCI.2126-13.2013
[2]	Masimore, B., Kakalios, J. and Redish, A.D. (2004) Measuring Fundamental Frequencies in Local Field Potentials. Journal of Neuroscience Methods, 138, 97-105. http://dx.doi.org/10.1016/j.jneumeth.2004.03.014
[3]	Masimore, B., Schmitzer-Torbert, N.C., Kakalios, J. and Redish, A.D. (2005) Transient Striatal Gamma Local Field Potentials Signal Movement Initiation in Rats. Neuroreport, 16, 2021-2024. http://dx.doi.org/10.1097/00001756-200512190-00010
[4]	Van der Meer, M.A. and Redish, A.D. (2009) Low and High Gamma Oscillations in Rat Ventral Striatum Have Distinct Relationships to Behavior, Reward, and Spiking Activity on a Learned Spatial Decision Task. Frontiers in Integrative Neuroscience, 3, 9.
[5]	Dimpfel, W. (2003) Preclinical Data Base of Pharmaco-Specific Rat EEG Fingerprints (Tele-Stereo-EEG). European Journal of Medical Research, 8, 199-207.
[6]	Paxinos, G. and Watson, C. (1982) The Rat Brain in Stereotactic Coordinates. Academic Press, New York.
[7]	Dimpfel, W., Spüler, M., Koch, R. and Schatton, W. (1987) Radio-electroencephalographic Comparison of Memantine with Receptor-Specific Drugs Acting on Dopaminergic Transmission in Freely Moving Rats. Neuropsychobiology, 18, 212-218. http://dx.doi.org/10.1159/000118420
[8]	Popescu, A.T., Popa, D. and Paré, D. (2009) Coherent Gamma Oscillations Couple the Amygdala and Striatum during Learning. Nature Neuroscience, 12, 801-807.
[9]	Darvas, F., Murias, M. and Rao, R.P.N. (2013) Localized High Gamma Motor Oscillations Respond to Perceived Biological Motion. Journal of Clinical Neurophysiology, 30, 299-307. http://dx.doi.org/10.1097/WNP.0b013e3182872f40
[10]	Morra, T., Glick, S.D. and Cheer, J.F. (2012) Canna-binoid Receptors Mediate Metamphetamine Induction of High Gamma Oscillations in the Nucleus Accumbens. Neuropharmacology, 63, 565-574. http://dx.doi.org/10.1016/j.neuropharm.2012.04.036
[11]	Chen, C-M.A., Stanford, A.D., Mao, X., Abi-Dargham, A., Shungu, D.C., Lisanby, S.H., Schroeder, C.E. and Kegeles, L.S. (2014) GABA Level, Gamma Oscillation, and Working Memory Performance in Schizophrenia. NeuroImage: Clinical, 4, 531-539. http://dx.doi.org/10.1016/j.nicl.2014.03.007
[12]	Gray, C.M. (1994) Synchronous Oscillations in Neuronal Systems: Mechanism and Functions. Journal of Computational Neuroscience, 1, 11-38. http://dx.doi.org/10.1007/BF00962716
[13]	Donoghue, J.P., Sanes, J.N., Hatsopoulos, N.G. and Gaál, G. (1998) Neural Discharge and Local Field Potemtial Oscillations in Primate Motor Cortex During Voluntary Movements. Journal of Neurophysiology, 79, 159-173.