Abstract
It is widely believed that the theta rhythm in the hippocampus is caused by the rhythmic input from the medial septum-diagonal band of Broca (MSDB). The main MSDB output is formed by GABAergic projection neurons which are divided into two subpopulations and fire at different phases of the hippocampal theta rhythm. The MSDB also contains projection cholinergic, glutamatergic, and non-projection GABAergic neurons. These cell populations innervate each other and also GABAergic projection neurons and participate in the formation of the synchronous rhythmic output to the hippocampus. The purpose of this study is to work out a model of interactions between all neural populations of the MSDB that underlie the formation of the synchronous septal theta signal. The model is built from biologically plausible neurons of the Hodgkin-Huxley type and its architecture reflects modern data on the morphology of neural connections in the MSDB. The model satisfies the following requirements: (1) a large portion of neurons is fast-spiking; (2) the subpopulations of GABAergic projection neurons contain endogenous pacemaker neurons; (3) the phase shift of activity between subpopulations of GABAergic projection neurons is equal to about 150°; and (4) the strengths of bidirectional connections between the subpopulations of GABAergic projection cells are different. It is shown that the theta rhythm generation can be performed by a system of glutamatergic and GABAergic non-projection neurons. We also show that bursting pacemaker neurons in the subpopulation of projection GABAergic neurons play a significant role in the formation of stable antiphase outputs from the MSDB to the hippocampus.
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References
Alreja, M., Wu, M., Liu, W., Atkins, J. B., Leranth, C., & Shanabrough, M. (2000). Muscarinic tone sustains impulse flow in the septohippocampal GABA but not cholinergic pathway: implications for learning and memory. Journal of Neuroscience, 20, 8103–8110.
Armstrong, J. N., & MacVicar, B. A. (2001). Theta-frequency facilitation of AMPA receptor-mediated synaptic currents in the principal cells of the medial septum. Journal of Neurophysiology, 85, 1709–1718.
Astasheva, E., Astashev, M., & Kitchigina, V. (2015). Changes in the behavior and oscillatory activity in cortical and subcortical brain structures induced by repeated l-glutamate injections to the medial septal area in guinea pigs. Epilepsy Research, 109, 134–145.
Bassant, M.-H., Simon, A., Poindessous-Jazat, F., Csaba, Z., Epelbaum, J., & Dournaud, P. (2005). Medial septal GABAergic neurons express the somatostatin sst2A receptor: functional consequences on unit firing and hippocampal theta. Journal of Neuroscience, 25, 2032–2041.
Belousov, A. B., & Vinogradova, O. S. (1990). Modelling the regulation of theta-rhythm by increasing afferent inflow in septal slices. Neuroscience and Behavioral Physiology, 20, 437–445.
Belousov, A. B., Vinogradova, O. S., & Pakhotin, P. I. (1990). Paradoxical state-dependent excitability of the medial septal neurons in brain slices of ground squirrel, Citellus Undulatus. Neuroscience, 38, 599–608.
Bland, B. H., Colom, L. V., Konopacki, J., & Roth, S. H. (1988). Intracellular records of carbachol-induced theta rhythm in hippocampal slices. Brain Research, 447(2), 364–368.
Borhegyi, Z., Varga, V., Szilágyi, N., Fabo, D., & Freund, T. F. (2004). Phase segregation of medial septal GABAergic neurons during hippocampal theta activity. Journal of Neuroscience, 24, 8470–8479.
Borisyuk, R. (2002). Oscillatory activity in the neural networks of spiking elements. BioSystems, 67, 3–16.
Borisyuk, R., & Hoppensteadt, F. (1999). Oscillatory models of the hippocampus: a study of spatio-temporal patterns of neural activity. Biological Cybernetics, 81, 359–371.
Brazhnik, E. S. (2004). Theta rhythmicity in the medial septum: entraining by the GABA-ergic neurons. Zhurnal Vysshei Nervnoi Deiatelnosti Imeni IP Pavlova, 54, 192–201 (in Russian).
Brazhnik, E. S., & Fox, S. E. (1999). Action potentials and relations to the theta rhythm of medial septal neurons in vivo. Experimental Brain Research, 127, 244–258.
Brown, D. (2010). Muscarinic acetylcholine receptors (mAChRs) in the nervous system: some functions and mechanisms. Journal of Molecular Neuroscience, 41, 340–346.
Buzsáki, G. (2002). Theta oscillations in the hippocampus. Neuron, 33, 325–340.
Carre, G. P., & Harley, C. W. (2000). Glutamatergic activation of the medial septum complex: an enhancement of the dentate gyrus population spike and accompanying EEG and unit changes. Brain Research, 861, 16–25.
Cissé, R. S., Krebs-Kraft, D. L., & Parent, M. B. (2008). Septal infusions of the hyperpolarization-activated cyclic nucleotide-gated channel (HCN-channel) blocker ZD7288 impair spontaneous alternation but not inhibitory avoidance. Behavioral Neuroscience, 122, 549–556.
Colgin, L. L. (2013). Mechanisms and functions of theta rhythms. Annual Review of Neuroscience, 36, 295–312.
Colom, L. V., & Garrido-Sanabria, E. (2007). Modulation of normal and altered hippocampal excitability states by septal networks. Journal of Neuroscience Research, 85, 2839–2843.
Colom, L. V., Castaneda, M. T., Reyna, T., Hernandez, S., & Garrido-Sanabria, E. (2005). Characterization of medial septal glutamatergic neurons and their projection to the hippocampus. Synapse, 58, 151–164.
Denham, M. J., & Borisyuk, R. M. (2000). A model of theta rhythm production in the septal-hippocampal system and its modulation by ascending brain stem pathways. Hippocampus, 10, 698–716.
Freund, T. F. (1989). GABAergic septohippocampal neurons contain parvalbumin. Brain Research, 478, 375–381.
Freund, T. F., & Antal, M. (1988). GABA-containing neurons in the septum control inhibitory interneurons in the hippocampus. Nature, 336, 170–173.
Garner, H. L., Whittington, M. A., & Henderson, Z. (2005). Induction by kainate of theta frequency rhythmic activity in the rat medial septum–diagonal band complex in vitro. Journal of Physiology, 564, 83–102.
Gogolák, G., Stumpf, C., Petsche, H., & Sterc, J. (1968). The firing pattern of septal neurons and the form of the hippocampal theta wave. Brain Research, 7, 201–207.
Goutagny, R., Jackson, J., & Williams, S. (2009). Self-generated theta oscillations in the hippocampus. Nature Neuroscience, 12, 614–626.
Griffith, W. H. (1988). Membrane properties of cell types within guinea pig basal forebrain nuclei in vitro. Journal of Neurophysiology, 59, 1590–1612.
Griffith, W. H., Sim, J. A., & Matthews, R. T. (1991). Electrophysiologic characteristics of basal forebrain neurons in vitro. In T. C. Napier, P. W. Kalivas, & I. Hanin (Eds.), The basal forebrain: anatomy to function: Advances in experimental medicine and biology (pp. 143–155). New York: Plenum Press.
Gulyás, A. I., Hájos, N., Katona, I., & Freund, T. F. (2003). Interneurons are the local targets of hippocampal inhibitory cells which project to the medial septum. European Journal of Neuroscience, 17, 1861–1872.
Hajszan, T., Alreja, M., & Leranth, C. (2004). Intrinsic vesicular glutamate transporter 2-immunoreactive input to septohippocampal parvalbumin-containing neurons: novel glutamatergic local circuit cells. Hippocampus, 14, 499–509.
Hangya, B., Borhegyi, Z., Szilágyi, N., Freund, T. F., & Varga, V. (2009). GABAergic neurons of the medial septum lead the hippocampal network during theta activity. Journal of Neuroscience, 29, 8094–8102.
Henderson, Z., Morris, N. P., Grimwood, P., Fiddler, G., Yang, H. W., & Appenteng, K. (2001). Morphology of local axon collaterals of electrophysiologically characterised neurons in the rat medial septal/diagonal band complex. Journal of Comparative Neurology, 430, 410–432.
Henderson, Z., Fiddler, G., Saha, S., Boros, A., & Halasy, K. (2004). A parvalbumin-containing, axosomatic synaptic network in the rat medial septum: relevance to rhythmogenesis. European Journal of Neuroscience, 19, 2753–2768.
Henderson, Z., Lu, C. B., Janzsó, G., Matto, N., McKinley, C. E., Yanagawa, Y., & Halasy, K. (2010). Distribution and role of Kv3.1b in neurons in the medial septum diagonal band complex. Neuroscience, 166, 952–969.
Hodgkin, A. L., & Huxley, A. F. (1952). A quantitative description of membrane current and its application to conduction and excitation in nerve. Journal of Physiology, 117, 500–544.
Hopfield, J. J., & Herz, A. V. (1995). Rapid local synchronization of action potentials: toward computation with coupled integrate-and-fire neurons. Proceedings of the National Academy of Sciences of the United States of America, 92, 6655–6662.
Huh, C. Y. L., Goutagny, R., & Williams, S. (2010). Glutamatergic neurons of the mouse medial septum and diagonal band of Broca synaptically drive hippocampal pyramidal cells: relevance for hippocampal theta rhythm. Journal of Neuroscience, 30, 15951–15961.
Kiss, J., Patel, A. J., Baimbridge, K. G., & Freund, T. F. (1990). Topographical localization of neurons containing parvalbumin and choline acetyltransferase in the medial septum-diagonal band region of the rat. Neuroscience, 36, 61–72.
Kiss, J., Maglóczky, Z., Somogyi, J., & Freund, T. F. (1997). Distribution of calretinin-containing neurons relative to other neurochemically identified cell types in the medial septum of the rat. Neuroscience, 78, 399–410.
Kocsis, B. (2006). The effect of descending theta rhythmic input from the septohippocampal system on firing in the supramammillary nucleus. Brain Research, 1086, 92–97.
Kocsis, B., & Kaminski, M. (2006). Dynamic changes in the direction of the theta rhythmic drive between supramammillary nucleus and the septohippocampal system. Hippocampus, 16, 531–540.
Konopacki, J., Eckersdorf, B., Kowalczyk, T., & Gołębiewski, H. (2006). Firing cell repertoire during carbachol-induced theta rhythm in rat hippocampal formation slices. European Journal of Neuroscience, 23, 1811–1818.
Kudela, P., Franaszczuk, P. J., & Bergey, G. K. (2003). Changing excitation and inhibition in simulated neural networks: effects on induced bursting behavior. Biological Cybernetics, 88, 276–285.
Leão, R. N., Targino, Z. H., Colom, L. V., & Fisahn, A. (2014). Interconnection and synchronization of neuronal populations in the mouse medial septum/diagonal band of Brocca. Journal of Neurophysiology, 113, 971–980.
Lu, C., Li, C., Li, D., & Henderson, Z. (2013). Nicotine induction of theta frequency oscillations in rodent medial septal diagonal band in vitro. Acta Pharmacologica Sinica, 34, 819–829.
Malkov, A. E., & Popova, I. Y. (2011). Functional changes in the septal GABAergic system of animals with a model of temporal lobe epilepsy. General Physiology and Biophysics, 30, 310–320.
Manseau, F., Danik, M., & Williams, S. (2005). A functional glutamatergic neurone network in the medial septum and diagonal band area. Journal of Physiology, 566, 865–884.
Mitchell, D. J., McNaughton, N., Flanagan, D., & Kirk, I. J. (2008). Frontal-midline theta from the perspective of hippocampal “theta.”. Progress in Neurobiology, 86, 156–185.
Moor, E., Schirm, E., Jacsó, J., & Westerink, B. H. (1998). Involvement of medial septal glutamate and GABAA receptors in behaviour-induced acetylcholine release in the hippocampus: a dual probe microdialysis study. Brain Research, 789, 1–8.
Morris, N. P., & Henderson, Z. (2000). Perineuronal nets ensheath fast spiking, parvalbumin-immunoreactive neurons in the medial septum/diagonal band complex. European Journal of Neuroscience, 12, 828–838.
Petsche, H., & Stumpf, C. (1960). Topographic and toposcopic study of origin and spread of the regular synchronized arousal pattern in the rabbit. Electroencephalography and Clinical Neurophysiology, 12, 589–600.
Puma, C., & Bizot, J.-C. (1999). Hippocampal theta rhythm in anesthetized rats: role of AMPA glutamate receptors. Neuroreport, 10, 2297–2300.
Segal, M. (1986). Properties of rat medial septal neurones recorded in vitro. Journal of Physiology, 379, 309–330.
Sotty, F., Danik, M., Manseau, F., Laplante, F., Quirion, R., & Williams, S. (2003). Distinct electrophysiological properties of glutamatergic, cholinergic and GABAergic rat septohippocampal neurons: novel implications for hippocampal rhythmicity. Journal of Physiology, 551, 927–943.
Stewart, M., & Fox, S. E. (1990). Do septal neurons pace the hippocampal theta rhythm? Trends in Neurosciences, 13, 163–169.
Suzuki, T., Matsugi, T., Takagi, R., & Kawashima, K. (2003). Endogenous glutamatergic synaptic activity elicits acetylcholine release from rat cultured septal cells. Neuroscience Research, 47, 341–347.
Tesche, C. D., & Karhu, J. (2000). Theta oscillations index human hippocampal activation during a working memory task. Proceedings of the National Academy of Sciences of the United States of America, 97, 919–924.
Thinschmidt, J. S., Frazier, C. J., King, M. A., Meyer, E. M., & Papke, R. L. (2005). Medial septal/diagonal band cells express multiple functional nicotinic receptor subtypes that are correlated with firing frequency. Neuroscience Letters, 389, 163–168.
Ujfalussy, B., & Kiss, T. (2006). How do glutamatergic and GABAergic cells contribute to synchronization in the medial septum? Journal of Computational Neuroscience, 21, 343–357.
Varga, V., Hangya, B., Kránitz, K., Ludányi, A., Zemankovics, R., Katona, I., Shigemoto, R., Freund, T. F., & Borhegyi, Z. (2008). The presence of pacemaker HCN channels identifies theta rhythmic GABAergic neurons in the medial septum. Journal of Physiology, 586, 3893–3915.
Vinogradova, O. S. (1995). Expression, control, and probable functional significance of the neuronal theta-rhythm. Progress in Neurobiology, 45, 523–583.
Wang, X.-J. (2002). Pacemaker neurons for the theta rhythm and their synchronization in the septohippocampal reciprocal loop. Journal of Neurophysiology, 87, 889–900.
Wang, J., Wang, Y., Wang, Y., Wang, R., Zhang, Y., Zhang, Q., & Lu, C. (2014). Contribution of α4β2 nAChR in nicotine-induced intracellular calcium response and excitability of MSDB neurons. Brain Research, 1592, 1–10.
Wen, D., Peng, C., Ou-yang, G., Henderson, Z., Li, X., & Lu, C. (2013). Effects of nicotine stimulation on spikes, theta frequency oscillations, and spike-theta oscillation relationship in rat medial septum diagonal band Broca slices. Acta Pharmacologica Sinica, 34, 464–472.
Wu, M., Shanabrough, M., Leranth, C., & Alreja, M. (2000). Cholinergic excitation of septohippocampal GABA but not cholinergic neurons: implications for learning and memory. Journal of Neuroscience, 20, 3900–3908.
Wu, M., Hajszan, T., Leranth, C., & Alreja, M. (2003). Nicotine recruits a local glutamatergic circuit to excite septohippocampal GABAergic neurons. European Journal of Neuroscience, 18, 1155–1168.
Wu, M., Hajszan, T., Xu, C., Leranth, C., & Alreja, M. (2004). Group I metabotropic glutamate receptor activation produces a direct excitation of identified septohippocampal cholinergic neurons. Journal of Neurophysiology, 92, 1216–1225.
Xu, C., Wu, M., Morozova, E., & Alreja, M. (2006). Muscarine activates the sodium-calcium exchanger via M receptors in basal forebrain neurons. European Journal of Neuroscience, 24, 2309–2313.
Yoder, R. M., & Pang, K. C. H. (2005). Involvement of GABAergic and cholinergic medial septal neurons in hippocampal theta rhythm. Hippocampus, 15, 381–392.
Acknowledgments
This work was supported by a grant from the Russian Foundation for Basic Research № 12-04-00776 and a regional grant from the Russian Foundation for Basic Research № 14-44-03607.
Conflict of interest
This study was supported by the grants of the Russian Foundation for Basic Research (№№12-04-00776-a, 14-44-03607-a, 15-04-05463-a), and grant of President of RF “Scientific schools”, НШ-850.2012.4).
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Appendix
Appendix
1.1 A1. Description of currents
The dynamics of the gate variables of the channels are described by the equations (Wang 2002)
where α and β are the functions of the potential:
For the computation of other gate variables we use the expressions
Initial values of all gate variables are x ∞ computed at the initial moment of time. The parameters of the equations are given in Table 1.
The value of I ext is chosen randomly from the Gaussian distribution at each moment of time with the variance equal to 0.1. In the basic model, the mean of the value I ext for Glu, GABA(PV1), GABA(PV1 burst), GABA(PV2 burst) is 0.3 nA, for GABA(CR) it is 0 nA, and for GABA(PV2) it is 0.7 nA.
1.2 A2. Parameters of synaptic currents
The gate variable s is described by the equation (Ujfalussy and Kiss, 2006)
where
V pre is the potential of the presynaptic neuron. The initial value of s is 0. The parameters for the equations of synaptic currents are given in Table 2.
In the basic model the weights of connections from the GABA(PV1) population to the GABA(PV2) population and from the glutamatergic population to GABA(CR) population are set to 0.2, the weights of connections from GABA(PV2) to GABA(PV1) are set to 0.1. Other weights are equal to 1.
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Mysin, I.E., Kitchigina, V.F. & Kazanovich, Y. Modeling synchronous theta activity in the medial septum: key role of local communications between different cell populations. J Comput Neurosci 39, 1–16 (2015). https://doi.org/10.1007/s10827-015-0564-6
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DOI: https://doi.org/10.1007/s10827-015-0564-6