Electrophysiological analysis of the hippocampal-septal projections: II. Functional characteristics

DeFrance, Jon F.; Kitai, S.T.; Shimono, T.

doi:10.1007/bf00234862

Cited by 27 publications

(9 citation statements)

References 19 publications

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“…1 C) in all spontaneously firing lateral septal neurones was followed by a period of inhibition, the duration H. McLENNAN AND J. J. MILLER of which ranged from 50 to 700 msec ( Fig. 1 A and H Shimono, 1973;McLennan & Miller, 1974a).…”

Section: Resultsmentioning

confidence: 99%

Frequency‐related inhibitory mechanisms controlling rhythmical activity in the septal area.

McLennan¹,

Miller²

1976

The Journal of Physiology

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Section: Resultsmentioning

confidence: 99%

Frequency‐related inhibitory mechanisms controlling rhythmical activity in the septal area.

McLennan¹,

Miller²

1976

The Journal of Physiology

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“…Data on the influence of the ventral hippocampus on spontaneous and evoked electrical activity in various brain structures are less abundant. Siegel and Flynn [26] found that the ventral hippocampus has a tonic, facilRatory influence on hypothalamic neurons and that the dorsal hippocampus has an inhibitory influence on excitability of hypothalamic neurons, There is evidence to show that the dorsal hippocampus is easily activated by the ventral, whereas the converse is not observed [17].…”

Section: And Dtscussionmentioning

confidence: 97%

“…The experiments to study hippocampal-septal projections showed that stimulation of the hippocampus evokes prolonged inhibition of septal responses to stimulation of the ipsUateral fornix and fimbria [17]. Zolotukhina [5] observed that p r e l i m i n a r y stimulation of the hippocampus reduced s e n s o r y r e s p o n s e s of neurons of the septofimbrial nucleus to s e n s o r y stimulation; extinction of the r e s p o n s e s was accelerated.…”

Section: And Dtscussionmentioning

confidence: 99%

Effect of hippocampal stimulation on evoked electrical activity of various brain structures

Ungiadze

Davituliani

1976

Neurosci Behav Physiol

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Functional relations between the entorhinal cortex and hippocampus were stud~ ~d in acute and chronic experiments on cats. The dorsal hippocampus depresses electrical activity and responses of the ventral hippocampus evoked by stimulation of the entorhinal cortex and responses of the entorhinal cortex and ventral hippocampus to cutaneous electrical stimulation. The ventral hippocampus, on the other hand, facilitates evoked electrical activity of the dorsal hippocampus in response to stimulation of the entorhinal cortex. and also responses of the entorhinal cortex and dorsal hippocampus evoked by cutaneous electrical stimulation. The results suggest regional differences in nervous connections of the different parts of the hippocampus with the entorhinal cortex.According to the theory of Papez [23] emotion has its structural basis, and the "limbic brain," with extensive afferent and efferent connections, plays a major role in its organization. It has been postulated that emotions arise as a result of activation of interacting structures: the hippocampus, entorhinal cortex, gyrus cinguli, hypothalamus, and anterior thalamic nuclei. The whole of this system is known in the literature as the "circle of Papez."Many investigations ([3, 18, 22] etc.) have pointed to the participation of the hippocampus in the manifestation of autonomic and somatic elements of emotional responses. Morphological and electrophysiological data indicate its extensive afferent and efferent connections both with the neocortex and with many subcortical brain formations. It has been found that however different the formations of the forebrain are in their structural organization, they share one common morphological feature: They all project on the hippocampus and the hippocampal pyramids are as it were the "final common path for the varied afferentation converging on them from these formations." It is at the hippocampal level that the functional relations which lie at the basis of emotional experience and which determine its character are formed [7].One of the principal afferent inputs into the hippocampus has been described, namely, the powerful temporo-ammonic tract {perforating tract) running from the temporal region through the lateral regions of the entorhinal cortex to Ammon's horn. On reaching the latter, it penetrates into it and terminates in the layer of the alveus [14].Tracts from the temporal region to the hippocampus have been shown to contain a nonperforating alvear bundle as well as the perforating bundle. The number of axons of temporal neurons which penetrate into the hippocampus in the composition of the perforating and alvear tracts and the number of contacts which they form with neurons in each part of the hippocampus differ [2]. There is also evidence of the presence of axon collaterals of hippocampal pyramidal cells forming contacts with collaterals of neurons of the entorhinal cortex [14,20].In experiments on marsupials (Trichosurus vulpecula), to study relations of the hippocampus with the entorhinal cortex, it was assume...

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“…investigations have revealed that much of the innervation which the lateral septal complex (LX) receives from the hippocampal formation by way of the fimbria-fomix (fi-fx) fibers, is excitatory (9,10,20,23). Data indicating that the innervation is mediated by an excitatory amino acid were obtained from biochemical studies.…”

Section: Electrophysiologicalmentioning

confidence: 99%

Amino acid neurotransmission between fimbria-fornix fibers and neurons in the lateral septum of the rat: A microiontophoretic study

Joëls¹,

Urban²

1984

Experimental Neurology

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We investigated the nature of the excitatory amino acid and the type of amino acid receptor involved in the projection of fimbria-fomix (fi-fx) fibers on neurons in the lateral septal complex (LSC) of the rat. It appeared that neurons which were strongly orthodromically activated (SOA) by stimulation of fi-fx fibers were excited by glutamate (GLU) and aspartate (ASP) at much lower ejecting currents than neurons which were only weakly orthodromically excited. In addition, GLU was a stronger agent than ASP, particularly in SOA septal cells. Two amino acid antagonists tested, glutamic acid diethylester (GDEE) and 2-amino-S-phosphonovaleric acid (2-APV), selectively antagonized responses to the amino acid agonists quisqualate (QUIS) and N-methyl-D-aspartate (NMDA), respectively. They also depressed GLU-and ASP-induced responses, although in that case the antagonists frequently had to be expelled with currents higher than those needed to block QUIS-and NMDA-evoked excitations. Furthermore, GDEE frequently antagonized GLU-induced responses better than ASPevoked excitations, whereas 2-APV often blocked responses to ASP more effectively than those to GLU. It was observed that GDEE, ejected with currents that blocked responses to QUIS reversibly, decreased the number of synaptic responses induced in SOA cells by fi-fx stimuli. Synaptically induced excitation in these neurons was consistently una&cted by 2-APV, even when the antagonist was expelled with high currents. According to these results, LSC neurons, in particular the SOA neurons, are more Abbreviations: li-fx-fimbria-fomix; LSC-lateral septal complex; SOA, WOA-strongly, weakly orthodromically activated; GLU-glutamate; ASP-aspartate; GDEE-glutamic acid diethylester, 2-APV-2-amino%phosphonovaleric acid; QUIS-quisqualate; NMDA-N-methylDaspartate; KA-kainic acid.

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Electrophysiological analysis of the hippocampal-septal projections: II. Functional characteristics

Cited by 27 publications

References 19 publications

Frequency‐related inhibitory mechanisms controlling rhythmical activity in the septal area.

Frequency‐related inhibitory mechanisms controlling rhythmical activity in the septal area.

Effect of hippocampal stimulation on evoked electrical activity of various brain structures

Amino acid neurotransmission between fimbria-fornix fibers and neurons in the lateral septum of the rat: A microiontophoretic study

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