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At least 19 recordsLinked to original sources
PubMed1997

Motivation-related neuronal activity in the object discrimination task in monkey septal nuclei.

Septal nuclei are suggested to work as an interface between the hippocampal formation, involved in higher cognitive functions, and the hypothalamus, involved in motivational behaviors such as feeding, drinking, and intracranial self-stimulation. In the present study, to elucidate a role of the septal nuclei in motivational behaviors, single neuron activity was recorded from water- and food-deprived monkeys during discrimination of objects associated with juice, and during ingestion of juice. Of 349 neurons recorded from two monkeys, 67 responded in the ingestion phase of the object discrimination task. Of these 67 neurons, 31 were further tested with the noncontingent liquid (juice or water) test in which liquid was provided until the animals became satiated. These 31 septal neurons were classified into two groups: type I neurons (n = 10) responded to juice ingestion with inhibition, and type II neurons (n = 21) responded with excitation. The spontaneous firing rates of the type I neurons were higher in the deprived condition and decreased as the animal became satiated by intake of liquid. Nine type II neurons responded to the sight of a white object associated with juice as well as ingestion of juice. The response magnitudes of the type II neurons to both the sight of the white object and ingestion of juice also decreased by satiation. However, spontaneous firing rates of the type II neurons did not change. These activity changes of both type I and II neurons were well correlated with changes in motivational state of the monkey estimated by the behavioral test. The results suggest that the activity of type I neurons reflects thirst or hunger drive levels, and that responses of type II neurons are related to reward perception. These type I and II neurons were located mainly in the anterior part of the septal nuclei. Results of the present study suggest, along with previous lesion and anatomical studies, that the septal nuclei exert a powerful influence on the motivational/drive systems through the projection to the hypothalamus.

Animals↗
PubMed1989

[The afferent pathway of the septal nuclei on participation in acupuncture analgesia].

The afferent connections of septal nuclei from the brain areas relating to pain in the rat were studied with HRP, WGA-HRP and CB-HRP methods. Some brain areas relating to pain, for instance, locus coeruleus, raphe nuclei, periaqueductal gray, hypothalamus, lateral habenular nucleus, amygdaloid complex, hippocampus and cingulate cortex, project to medial septal nucleus, lateral nucleus and diagonal band nucleus. The many areas relating to acupuncture analgesia project to septal nuclei, it is possible that the septal nuclei participate in regulating pain in the central nervous system.

Acupuncture Analgesia↗
PubMed1987

Differential plasma corticosterone responses to electrical stimulation of the medial and lateral septal nuclei.

To pursue the possibility that subdivisions within the medial and lateral septal nuclei are differentially involved in adrenocortical function, plasma samples obtained prior to and following electrical stimulation of the septal nuclei of urethane (1.30 g/kg)-anesthetized female rats were assessed for corticosterone concentration. Hippocampal EEG, ECG, heart rate (HR), mean arterial pressure (MAP) and respiration were routinely monitored, and timed blood samples (0.15 ml) were obtained from a catheterized tail artery. Blood samples were taken 0.5 min prior to and at 5, 10, 15 and 30 min after initiation of stimulation. Whereas no change in Cpd B levels were observed following sham stimulation or stimulation of the corpus callosum, fornix or anterior commissure, stimulation of the medial septal nuclei produced differential responses. Decreased plasma Cpd B responses followed stimulation of the medial septal nucleus (MS); increases in plasma Cpd B followed stimulation of the dorsal (LSD) and ventral (LSV) division of the lateral septal nucleus. The overall increase in plasma Cpd B levels following LSD and LSV stimulation was 16 and 32%, respectively. The overall decrease in corticosterone concentration subsequent to MS stimulation was 18%. The largest increases in Cpd B levels occurred at 5 min (36%) and 10 min (24%) for LSV and LSD groups, respectively; the largest decrease was noted at 15 min (25%). Plasma Cpd B responses to stimulation of the intermediate area of the lateral septal nucleus produced varying and inconsistent responses. Collectively, these data support the hypothesis that subdivisions within the septal nuclei are differentially involved in adrenocortical function.

Animals↗
PubMed2003

Distribution of polysialylated neural cell adhesion molecule in rat septal nuclei and septohippocampal pathway: transient increase of polysialylated interneurons in the subtriangular septal zone during memory consolidation.

During memory consolidation neuroplastic events in the mediotemporal corticohippocampal pathway are accompanied by transient increases in the frequency of neurons expressing polysialylated neural cell adhesion molecule (NCAM PSA), a posttranslational modification associated with morphofunctional change. As a bidirectional pathway between the hippocampus and the septal nuclei also influences memory processing, we have determined the distribution of NCAM PSA within this system before and after learning in the adult Wistar rat. The most intense NCAM PSA immunoreactivity was observed in the medial and triangular septal nuclei, regions that regulate hippocampal theta rhythm during memory consolidation. Within the fimbria, NCAM PSA was expressed only in a subpopulation of fibres, most likely cholinergic projections from the medial septum to the hippocampus. Grey level analysis or direct cell counting revealed no learning-specific change in NCAM PSA expression in these septal subregions after avoidance conditioning or spatial training. A population of discrete polysialylated neurons in the subtriangular septal zone, however, exhibited a transient twofold frequency increase at 12 hr after training in either task. Immunohistochemical analysis revealed these cells to be gamma-aminobutyric acid (GABAergic) interneurons co-expressing vasoactive intestinal peptide. The unique location of these interneurons is proposed to provide a natural plexus by which bidirectional communication between the septum and hippocampus may be modified during memory consolidation.

Animals↗
PubMedDate not supplied

Amygdalar catecholaminergic input to septal nuclei, relation to clomipramine actions on lateral septal neurons in the rat.

Antidepressants exert mixed actions on serotonergic and catecholaminergic systems. However, it is unknown whether a catecholaminergic blockade impinge on the actions of a tricyclic with serotonergic agonist properties (clomipramine) in limbic structures. The aim of the present study is to explore the effects of a catecholaminergic lesion in the basolateral amygdala on the firing rate of lateral septal, and hippocampal neurons in rats treated with clomipramine. An amygdaline lesion with 6-OHDA resembled the actions of clomipramine on the firing rate in lateral septal neurons, i.e. an increased rate of firing. However, the lesion blocked further effects of clomipramine on septal firing. Clomipramine decreased the firing rate in hippocampal neurons; however, neither the 6-OHDA lesion nor the added treatment with clomipramine modified the firing rate. It is concluded that an intact catecholaminergic amygdaloid input to lateral septal nuclei is necessary for clomipramine actions; however, the initial action of the tricyclic may involve a catecholaminergic blockade.

Action Potentials↗
PubMed2006

Estrus variation in anticonflict-like effects of the mGlu5 receptor antagonist MTEP, microinjected into lateral septal nuclei of female Wistar rats.

Anticonflict-like effects of the mGlu5 receptor antagonist MTEP (systemic administrations: 1.50, 3.0 or 6.0 mg/kg; i.p.; intra-lateral septal nuclei or intra-medial septal region infusions: 2.5 microg/microl, 5.0 microg/microl or 10.0 microg/microl) were assessed in Wistar rats during late proestrus or metestrus-diestrus. Results showed that control rats displayed an increased number of immediately punished reinforcers during late proestrus (P < 0.05), when compared to metestrus-diestrus. During late proestrus, systemic administrations (3.0 mg/kg, P < 0.05; 6.0 mg/kg P < 0.05) or intra-lateral septal nuclei infusions (5.0 microg/microl, P < 0.05; 10.0 microg/microl, P < 0.05) of MTEP increased the number of immediately punished reinforcers received. During metestrus-diestrus only the highest doses of MTEP (systemic administration: 6.0 mg/kg P < 0.05; intra-lateral septal nuclei infusions: 10.0 microg/microl, P < 0.05) increased the number of immediately punished reinforcers obtained. MTEP infusions into the medial septum produced neither of these anticonflict effects. In conclusion, data showed an estrus variation in those anticonflict-like effects of the mGlu5 receptor antagonist MTEP, systemically administered or microinjected into lateral septal nuclei of female Wistar rats.

Animals↗
PubMed1988

Ontogenetic development of septal nuclei in the rat.

Prenatal development of septal cell groups was studied in the rat on samples taken daily from the 14th day of gestation until birth. Coronal serial sections of brains were prepared in which the topography coordinates of septal nuclei were determined, their section profiles measured and their volumes calculated. The rat septum begins to develop on embryonic days 14-15. First the individual neurons start to differentiate, then cell groups characteristic for the adult are formed between days 14 and 17, which is followed by the delineation of nuclei. The only exception is the anterior subdivision of the lateral septal nucleus where the formation of the nucleus precedes the differentiation of its constituent cells. The individual nuclei start to develop at different times defined by a medio-lateral gradient of cell migration. By embryonic day 20 the formation of the nuclei can be considered as complete: all septal nuclei and their subdivisions are to be recognized and distinguished from each other.

Animals↗
PubMed1989

[Septal nuclei in the mechanisms of lateral hypothalamic self stimulation in rabbits].

Unilateral lesions of medial septal nucleus and lateral septal nuclei (dorsalis, intermedius, ventralis) decreased ipsilateral hypothalamic self-stimulation; the lesions of n. dorsalis, n. medialis and lateral septal nuclei (intermedius and ventralis) has the opposite effect on contralateral self-stimulation. The inhibition of ipsilateral self-stimulation was neither total nor permanent; 25-32% decrease in stimulation rate was seen, but behaviour returned to near-normal levels over a period of few days. In contrast, the augmentation of contralateral self-stimulation showed no significant change over the same period; in this case the 35-40% shift in stimulation rate was immediate and permanent. Bilateral lesions of septal nuclei had no effect if the initial level of self-stimulation rate was high and significantly increased self-stimulation.

Animals↗
PubMed1994

Two different molecules, NGF and free-HCNP, stimulate cholinergic activity in septal nuclei in vitro in a different manner.

Hippocampal cholinergic neurostimulating peptide (HCNP), a novel peptide purified from 10- to 12-day-old rat hippocampus, specifically enhances acetylcholine (AcCho) synthesis in medial septal nuclei in vitro, synthetic de-acetylated HCNP (free-HCNP) elicits more potent enhancement than HCNP. Nerve growth factor (NGF), a neurotrophic substance found in the hippocampus, enhances the cholinergic activity of medial septal nuclei both in vivo and in vitro. The effects of free-HCNP on the development of various cholinergic phenotypes and the interaction of NGF and free-HCNP on cholinergic neurons in vitro were studied. In medial septal nuclei, free-HCNP enhanced AcCho synthesis and choline acetyltransferase (ChoATase) activity and increased Vmax. It did not modulate culture morphology, choline (Cho) uptake, or acetylcholinesterase (AcChoEase) activity. NGF stimulated AcCho synthesis and both ChoATase and AcChoEase activity in the medial septal nuclei and also enhanced AcCho synthesis in a corpus striatum culture. Compared with the effect of either agent alone, the simultaneous application of 3.8 x 10(-11) M NGF and 3 x 10(-11) M free-HCNP (maximal stimulation) to medial septal nucleus culture resulted in a more than additive enhancement of AcCho synthesis, an additive increase in ChoATase activity, and a significant increase in Cho uptake. In corpus striatum and spinal cord cultures, there was no cooperative increase in AcCho synthesis with NGF and free-HCNP nor any enhancement of AcCho synthesis by free-HCNP. These findings suggest that NGF and free-HCNP play a cooperative role during the biochemical differentiation of cholinergic neurons in medial septal nuclei.

Acetylcholine↗
PubMed1990

Chronic clomipramine increases firing rate in lateral septal nuclei of the rat.

A single dosage of several antidepressants produces an increased rate of firing in lateral septal nuclei of the rat. The objective of the present study was to clarify the long-term treatment action of clomipramine on the septal nuclei of the rat. A progressive increase of firing rate appeared after long-term treatment with clomipramine (1.25 mg/kg, IP; twice a day, for 25 days). The most noticeable firing increase occurred in the lateral septal nuclei, which primarily receive serotonergic innervation. Irregular changes occurred in the corpus callosum and cingulum. Finally, in other poorly innervated serotonergic septal regions, the treatment lacked effects. This suggested that the action of clomipramine was primarily due to interaction with the serotonergic system.

Animals↗
PubMed2001

Estrus variation in anticonflict effects of midazolam microinjected into septal nuclei in female Wistar rats.

Effects of midazolam intraperitoneally (3.0 mg/kg) administered, or locally applied into lateral septal nuclei (10 microg/microl), or into the medial septum (10 microg/microl) were assessed in Wistar rats during late proestrus or metestrus-diestrus in a conflict-operant task. A reduction in conflict behavior was found in control rats during late proestrus (P<.05), when compared to metestrus-diestrus. Systemic injections of midazolam (P<.05) or midazolam infusions into lateral septal nuclei (P<.05) also reduced conflict behavior only during late proestrus, whereas midazolam infusions into the medial septum produced neither of these anticonflict effects in any estrous phase. In conclusion, an endocrine-related variation in anticonflict effects of midazolam microinjected into lateral septal nuclei was displayed by female rats.

Animals↗
PubMed1986

Extent of survival and vascularization of adult superior cervical sympathetic or nodose ganglia transplanted into the septal nuclei or choroid fissure of adult rats.

Adult superior cervical sympathetic ganglia were auto-transplanted, and adult nodose ganglia were homografted into the septal nuclei or the choroid fissure of adult Wistar rats. At times from 4 h to 9 weeks after operation, the distribution of surviving transplanted neurons was compared with the development of the transplant vascularization, as visualized by transcardial Indian ink filling of the host vascular system. Within 24 h, the ganglionic neurons and Schwann cells of the interior of the transplants in both sites were necrotic. The surviving neurons and Schwann cells formed a shell, occupying those areas of the transplant periphery which were in direct contact with the host circulation. Occasional ink-filled vessels were evident at this time in transplants in the choroid fissure, but there were none in the septal nuclei, where vessels did not appear until the next day. Blood vessels reached the centre of the ganglia by 3-4 days in the choroid fissure and one week in the septal nuclei, the finest diameter capillaries forming last. At longer survivals there was a slow loss of neurons, notable between 1 and 2 months, and leading progressively (especially in the septal transplantation site) to the disappearance of all but a very small number of ganglionic neurons. The general findings were similar for both types of ganglion, and in both sites, but the initial cell loss was much greater for both types of ganglia in the septum (over 90%) as compared with about a 50% loss in the choroid fissure. The initial rapid cell loss was probably a result of ischaemia. The subsequent, slow progressive loss may be associated with failure to make or receive neuronal connections, or the absence of appropriate growth factors.

Animals↗
PubMed1993

The neurons of the human magnocellular septal nuclei: a Golgi study.

The morphology of neurons in the magnocellular septal nuclei (medial septal and diagonal band nucleus) were studied in frontal sections of 15 human brains by means of the Golgi method. We classified neurons in the diagonal band nucleus according to their size and morphology into four types: type I--multipolar neurons, type II--fusiform neurons, type III--triangular neurons and type IV--fusiform multipolar neurons. The neurons of the medial septal nucleus we classified into two types: type I--multipolar neurons and type II--fusiform neurons. Our results indicated greater morphological variability of neurons in the human diagonal band nucleus than in the medial septal nucleus.

Adult↗
PubMed1990

[The efferent pathway of the septal nuclei on participation in acupuncture analgesia].

The efferent projections of septal nuclei from the brain areas relating to pain in the rat were studied with WGA-HRP and HRP methods. The results are obtained as follows: The septal areas project widely to some brain areas relating to pain, for instance, locus coeruleus, raphe nuclei, periaqueductal gray, thalamus, hypothalamus, habenular, amygdaloid complex, cingulate cortex and hippocampus ets, but the projections of medial septal nucleus, lateral septal nucleus and diagonal band nucleus are different. It is possible that these fiber projections are one of the morphological basis of septal nuclei for regulating pain.

Acupuncture Analgesia↗
PubMed2004

Responses of respiratory neurons in the medulla oblongata to stimulation of the septal nuclei during hypoxia.

Dynamic studies were performed in conditions of hypoxia on the effects of stimulation of the ventral, lateral, and medial nuclei of the septum on the spike activity of bulbar respiratory neurons and respiration. The various phases of hypoxia provided a model experiment over which the overall effects of the septal neurons were summed. Electrical stimulation of these septal nuclei in conditions of normal atmospheric pressure had both facilitatory and inhibitory effects on the spike activity of respiratory neurons in the respiratory center of the medulla oblongata, inhibitory effects being predominant. The ventral nucleus had the most effective inhibitory effect on the activity of respiratory neurons. Electrical stimulation of the septal nuclei in the initial phase (4000-5000 m) of hypoxia, on the background of activation, had a predominantly inhibitory influence on the activity of respiratory neurons. During the phase of severe hypoxia (7500-8000 m), on the background of marked hypoxic suppression of respiratory neuron activity, stimulation of the septal nuclei produced no characteristic changes in the activity of these neurons.

Action Potentials↗
PubMed1993

Zinc-containing neuronal innervation of the septal nuclei.

A zinc-specific retrograde transport method has been employed to map the zinc-containing neuronal projections to the septal nuclei. Sodium selenite was infused iontophoretically into the lateral or medial septal nuclei to precipitate vesicular zinc as ZnSe in situ, and the neurons that were subsequently labeled by the retrograde transport of ZnSe to their perikarya were mapped. Zinc-containing cells of origin were found only in the hippocampal formation and predominantly in two regions thereof: (i) in s. oriens and deep s. pyramidale of fields CA3a and CA2 and (ii) in s. pyramidale of distal CA1 and adjacent prosubiculum.

Animals↗