Do septal neurons pace the hippocampal theta rhythm?

@article{Stewart1990DoSN,
  title={Do septal neurons pace the hippocampal theta rhythm?},
  author={Mark Stewart and Steven E Fox},
  journal={Trends in Neurosciences},
  year={1990},
  volume={13},
  pages={163-169}
}
  • M. Stewart, S. Fox
  • Published 1 May 1990
  • Psychology, Medicine
  • Trends in Neurosciences
The hippocampal theta rhythm (rhythmical slow activity, RSA) is one of the most thoroughly studied EEG phenomena. Much of this experimental interest has been stimulated by suggestions that the mnemonic functions of the hippocampus may depend upon theta-related neuronal activity. Inputs from the medial septal nuclei to the hippocampus were shown to be essential for the theta rhythm in the 1950s, but the role of these basal forebrain projections has not been clearly defined. Four models of the… Expand
Pacemaker neurons for the theta rhythm and their synchronization in the septohippocampal reciprocal loop.
Hippocampal theta (4-10 Hz) oscillation represents a well-known brain rhythm implicated in spatial cognition and memory processes. Its cellular mechanisms remain a matter of debate, and previousExpand
The septal EEG suggests a distributed organization of the pacemaker of hippocampal theta in the rat
TLDR
The relationships of periodic EEG both among various parts of the septum and with dorsal hippocampal theta recorded concurrently in freely moving rats suggest that the pacemaker of hippocampal Theta may best be thought of as a set of functionally differentiated components rather than as a single homogenous unit. Expand
Inducing theta oscillations in the entorhinal hippocampal network in vitro
  • Z. Gu, J. Yakel
  • Psychology, Medicine
  • Brain Structure and Function
  • 2016
TLDR
This study established an in vitro theta model in a septo-entorhinal-hippocampal brain slice tri-culture system by pairing septal cholinergic inputs with hippocampal local activities and reveals a potential mechanism for theta rhythms to emerge as the functional results of dynamic interactions among the septum, hippocampus, and the entorHinal cortex, in the absence of clear pace makers. Expand
Membrane and circuit properties of lateral septum neurons: relationships with hippocampal rhythms
TLDR
The marked functional relationship between lateral sePTum neurons and hippocampal theta rhythm supports the proposal that lateral septum represents a feedback system for the improvement of medial septal networks to modulate the theta Rhythm. Expand
Action potentials and relations to the theta rhythm of medial septal neurons in vivo
TLDR
The results suggest that generation of theta rhythm requires a background of excitatory influences on the hippocampus in combination with the phasic disinhibitory action mediated by the GABAergic MS-DB projection. Expand
Theta Rhythm in Hippocampus and Cognition
Theta rhythm is a large 4–12 Hz oscillatory activity that is predominant during wake and REM (rapid eye movement) sleep in the hippocampus. Theta rhythm is generated by the interplay between neuronsExpand
Intracellular correlates of hippocampal theta rhythm in identified pyramidal cells, granule cells, and basket cells
TLDR
Observations suggest that dendritic currents underlying theta in the awake rat may not be revealed under urethane anesthesia, and cellular‐synaptic generation of rhythmic slow activity in the hippocampus is investigated by intracellular recording from principal cells and basket cells in anesthetized rats. Expand
Rhythmic firing of medial septum non-cholinergic neurons
TLDR
It is demonstrated here that medial septum non-cholinergic neurons, putatively GABAergic, have the ability to discharge in rhythmic clusters of action potentials occurring at frequencies ranging from 1 to 8 Hz. Expand
Hippocampal theta activity following selective lesion of the septal cholinergic systeM
TLDR
Findings indicate that the integrity of the septohippocampal GABAergic projection is sufficient to maintain some hippocampal theta activity, and hypothesize that cholinergic neurons serve to increase the population phase-locking of septal cells and thereby regulate the magnitude of hippocampalTheta. Expand
Effects of atropine on hippocampal theta cells and complex-spike cells
TLDR
In urethane anesthetized rats, iontophoretic application of atropine to 17 hippocampal theta cells (presumed interneurons) during the theta rhythm, reduced their firing rates to an average of 24% of control rates, and the data suggest thatInterneuronal firing, during the hippocampal Theta Rhythm, is dominated by an excited cholinergic input and not by excitatory collaterals of pyramidal cells. Expand
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References

SHOWING 1-10 OF 53 REFERENCES
Model of the origin of rhythmic population oscillations in the hippocampal slice.
TLDR
This issue has been pursued with a computer model of the CA3 region of the hippocampus that generates a rhythmic activity at a frequency faster than the firing of individual cells that resembles the hippocampal theta rhythm as well as synchronized synaptic events observed in vitro. Expand
Phase relations of hippocampal projection cells and interneurons to theta activity in the anesthetized rat
TLDR
It was suggested that septal theta "pacemaker' cells directly excite hippocampal interneurons which in turn rhythmically inhibit a large number of projection cells. Expand
Two populations of rhythmically bursting neurons in rat medial septum are revealed by atropine.
TLDR
Evaluating the mechanism(s) of action of systemic antimuscarinic drugs in eliminating the theta rhythm in rats suggests that the loss of rhythmic activity in the group of atropine-sensitive septal cells is sufficient for the elimination of the theTA rhythm. Expand
Lonf-term potentiation in the dentate gyrus is preferentially induced at theta rhythm periodicity
TLDR
In urethane-anesthetized rats, high frequency stimulation was applied to the medial perforant pathway at various time intervals following stimulation of the same pathway by a single pulse of equal intensity, suggesting the correlation between theta rhythm periodicity and LTP is a general phenomenon within the hippocampal formation. Expand
The firing pattern of septal neurons and the form of the hippocampal theta wave.
TLDR
Septum units in the rabbit discharge in regular bursts synchronous with the hippocampus theta rhythm but with different phase relationships, and superimposition of time histograms of these bursts results in a curve similar to the theta wave in shape. Expand
Phase shifting of CA1 and dentate EEG theta rhythms in hippocampal formation slices
TLDR
Carbachol-induced hippocampal EEG theta-rhythms were recorded simultaneously from the CA1 and dentate areas in rat hippocampal brain slices to study differences in slow wave theta phase relations between in vitro and in vivo preparations. Expand
Subthreshold Na+-dependent theta-like rhythmicity in stellate cells of entorhinal cortex layer II
TLDR
The finding of a subthreshold, voltage-gated, Na+-dependent rhythmic membrane oscillation in mammalian neurons indicates that rhythmicity in heterogeneous neuronal networks may be supported by different sets of intrinsic ionic mechanisms in each of the neuronal elements involved. Expand
Arousal-related sustained potentials in neocortex and hippocampus of rats.
TLDR
This chapter discusses arousal-related sustained potentials in neocortex and hippocampus of rats and reports that negative sustained potential shifts (SPs) develop over the neocortex or in the hypothalamus during arousal. Expand
Medial septal facilitation of hippocampal granule cell activity is mediated by inhibition of inhibitory interneurones
TLDR
It is suggested that effects of barbiturate anaesthesia are mediated through an inhibitory connection from the medial septum onto inhibitory interneurones in the dentate gyrus, and that this connection may utilize the neurotransmitter GABA. Expand
Detection of an atropine-resistant component of the hippocampal theta rhythm in urethane-anesthetized rats
TLDR
The coupling of the signal to the atropine-resistant septal cells strengthens the previous suggestion that these septo-hippocampal neurons are not cholinergic, and are therefore probably GABAergic. Expand
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