Stria Medullaris

From the perspective of comparative morphology, the distribution of non-monoaminergic neurons in the common marmoset (Callithrix jacchus) was investigated using an immunohistochemical method with specific antibodies to tyrosine hydroxylase (TH) and aromatic-L-amino acid decarboxylase (AADC).TH-immunoreactive (IR) neurons (but not AADC-IR) neurons were observed in the olfactory tubercle, preoptic suprachiasmatic nucleus, periventricular hypothalamic nucleus, arcuate nucleus, paraventricular nucleus, periaqueductal gray matter, medial longitudinal fasciculus, substantia nigra, and nucleus solitaris.In contrast, AADC-IR (but not TH-IR), small, oval and spindle-shaped neurons were sparsely distributed in the following areas: the hypothalamus from the anterior nucleus to the lateral nucleus, the dorsomedial nucleus, the dorsomedial area of the medial mammillary nucleus and the arcuate nucleus; the midbrain, including the stria medullaris and substantia nigra; and the medulla oblongata, including the dorsal area of the nucleus solitaris and the medullary reticular nucleus.  

The CD138+ plasma cells were restricted to the choroid plexus and stria medullaris of diseased MRL-lpr mice.  

Pronounced and persistent signal increases (40-100% at 24 hr after injection) were observed in the corpus callosum, anterior commissure, fornix, and stria medullaris, as well as in the mammillothalamic tract and fasciculus retroflexus.  

(2002), we find that the following structures/tracts are absent or greatly reduced in the Fz3(-/-) brain: the anterior commissure, cerebral peduncle (corticospinal tract), corpus callosum, fornix, internal capsule (thalamocortical and corticothalamic tracts), stria medullaris, stria terminalis, and hippocampal commissure.  

In the diencephalon, c-fos immunoreactive cells were detected in the subcallosa, the lateral septal area, the bed nucleus of stria terminalis (BNST), the preoptic hypothalamic area (POA), the suprachiasmatic nucleus (SCN), the supraoptic nucleus, the paraventricular hypothalamic nucleus parvocellular (PVNp), the paraventricular hypothalamic nucleus magnocellular (PVNm), the arcuate nucleus (ARC), the paraventricular thalamic nucleus, and the stria medullaris in both control and transported goats.  

The posterior limbic midbrain complex comprising the stria medullaris, central gray and dorsal and ventral nuclei of Gudden are also key elements in the limbic midbrain.  

However, each axon population soon merged with other axons to form one of only two shared longitudinal tracts, both descending: the tract of the postoptic commissure (TPOC), and, in parallel, the stria medullaris.  

Our results confirmed that the levels of L1 transcripts were significantly increased after prenatal delta9-THC exposure in several regions such as the fimbria, stria terminalis, stria medullaris and corpus callosum, which share the properties of being white matter regions and containing, exclusively during development, an abundant population of cannabinoid CB1 receptors, the major targets for the action of plant-derived cannabinoids.  

The less numerous and peripherally located type II neurons had an axon that climbed the rostral thalamic pole, coursed along the stria medullaris, and arborized profusely within the lateral habenular nucleus, which stood out as the most densely innervated pallidal target.  

Strong p38 immunoreactivity was apparent in fiber bundles including the olfactory tract, anterior commissure, corpus callosum, cingulum, internal capsule, stria terminalis, fimbria and alveus hippocampi, fornix, stria medullaris, optic chiasm and optic tract.  

In this context, our results describe for the first time in the mammals central nervous system fibres containing LH-RH located in the stria medullaris of the thalamus, the supramammillary decussation, the laterodorsal and lateroposterior thalamic nuclei, the nucleus reuniens, the supraoptic nucleus, and the optic chiasm.  

Later, M2 expression is found in association with the corpus callosum, hippocampal commissure, fimbria, optic nerve, stria medullaris, mamillothalamic tract and habenulopeduncular tract.  

Additional neurons within the murine diencephalon also expressed calretinin positive cell bodies and, or neuronal processes, including the stria medullaris, the habenular commissure and the paraventricular thalamic nucleus.  

Occasionally, NPY- or CPON-immunoreactive fibers were found adjacent to the stria medullaris and in the posterior commissure, which could be followed to the adjacent deep pineal gland.  

As previously reported, specific binding for CB(1) receptors was also detected at GD21 in white matter areas, such as the corpus callosum, anterior commissure, fornix, fimbria, stria medullaris, stria terminalis, and fasciculus retroflexum.  

A medial and lateral stria medullaris were described.  

There were circadian rhythms of MUA outside of the SCN in the ventrolateral thalamic nucleus, the caudate putamen, the accumbens nucleus, the medial septum, the lateral septum, the ventromedial hypothalamic nucleus, the medial preoptic region, and the stria medullaris.  

Cx43 immunoreactivity was further localized in the stria medullaris of rabbit retina, in the nerve fiber layer of rat retina, most likely in astrocytes, and in the area of the outer limiting membrane of the fish retina, most likely representing Cx43 in Müller glia cells.  

During later stages, M2 expression was found in association with the corpus callosum, hippocampal commissure, fimbria, optic nerve, stria medullaris, tract of the zona limitans, and habenulopeduncular tract.  

CNPase is expressed early in oligodendroglia somata and fibre sheaths (myelin) in the forebrain and its persistence in the cell bodies is regionally heterogeneous, being ephemeral in cells within the optic pathway, supraoptic decussation, and posterior commissure, of intermediate duration in the mamillo-thalamic fascicle, and stria medullaris, and long-lasting in other diencephalic and in telencephalic tracts.  

The olfactory projection consists of three tracts: the lateral olfactory tract, which projects bilaterally to the lateral cortex and the rostral amygdala, crossing the midline through the stria medullaris-habenular commissure system; the intermediate olfactory tract, which projects ipsilaterally to the olfactory tubercle and contributes to the contralateral projection; and the medial olfactory tract, which projects ipsilaterally to the dorsomedial retrobulbar formation.  

A small number of projections, which join the stria medullaris, protrude into the diencephalon, decussate in the habenular commissure, and turn rostrally back into the telencephalon to synapse in the caudal part of the contralateral terminal field.  

At the time of birth (P0), the cerebral cortex is unformed, but two prominent fibre bundles are apparent in the forebrain: the medial forebrain bundle and the stria medullaris thalami.  

While analyzing the distribution of enkephalinergic neurons by in situ hybridization and immunohistochemistry in the septal region of untreated or colchicine-injected rats, a densely packed enkephalinergic group of neurons was identified that corresponds to a small nucleus first described by Cajal as the nucleus of the stria medullaris. The connections of this nucleus (which is called here the bed nucleus of the stria medullaris, BSM) are unclear, but evidence in the literature suggests that it may receive inputs from the fornix and project through the stria medullaris to the medial habenula..  

Lower densities of binding were found over the medial preoptic area (MPA), the septohypothalamic nuclei (SHy), the anterior hypothalamic area (AHA), the nuclei of the lateral olfactory tract (LOT), the paraventricular (PV), anteroventral (AV) and intermediodorsal (IMD) nuclei of the thalamus, the medial region of the lateral habenular (Lhb), the nuclei of the stria medullaris (SM), the basolateral (BL) and medial (ME) amygdaloid nuclei, the ventromedial nuclei (VMH), the arcuate nuclei (Arc), the subiculum of the hippocampus (S) and the lateral mammillary nuclei (LM).  

Fibers were observed in the medial diagonal band of Broca, the stria medullaris, the tuber cinerum, the area postrema, the medial vestibular nucleus, and the dorsal motor nucleus of the vagus.  

Some fibers and boutons were also observed in the rhomboid, interanterodorsal, and mediodorsal nuclei, and others course through the stria medullaris to the lateral habenula.  

The CCK-ir neurons projecting to the neurohypophysis were localized mainly in the magnocellular paraventricular nuclei (mPVN), periventricular PVN, medial parvocelullar PVN, medial preoptic area and dorsal accessory nuclei in region between the stria medullaris and fornix.  

The habenula, as the chief relay nucleus of the descending dorsal diencephalic system (consisting of stria medullaris, habenula and fasciculus retroflexus), is an important link between limbic and striatal forebrain and lower diencephalic and mesencephalic centers.  

Some substance P-immunoreactive nerve fibers were located in the stria medullaris and in the posterior commissure.  

MHN neurons fired spontaneously as well as in response to stimulation of the stria medullaris. The above observations suggest high efficacy of synaptic transmission from the stria medullaris to MHN neurons and variable areas of the soma-dentritic region invaded by action potentials generated in the initial segment..  

Medial dorsal thalamic lesions did not damage the stria medullaris or medial habenula.  

In contrast to the large numbers of axon varicosities observed through the entire length of lateral hypothalamus following shell injections, dense accumulations of axon collaterals and varicosities in hypothalamus were limited to the levels of origin of the stria medullaris bundle and entopeduncular nucleus and to the posterlateral region following medial injections.  

ESS was found along the epithalamic route (stria medullaris, habenula, and fasciculus retroflexus) and in the following thalamic nuclei: mediodorsal, paratenial, interanteromedial, centromedial, reuniens, and rhomboid. The lowest threshold (approximately 5 pulses/train), which was found in the stria medullaris and the junction of the paratenial and centromedial nuclei, was comparable to that usually obtained for the brain areas where the ESS is most effectively rewarding (medial forebrain bundle, dorsal raphe, and amygdala).  

A number of immunoreactive nerve fibers were also found in the habenular area and stria medullaris projections. Some of the fibers in the stria medullaris projections could be followed into the pineal gland via the rostral part of the pineal stalk.  

These areas were the lateral habenula, medial part; the sphenoid nucleus; and the stria medullaris.  

Immunoreactivity was present in a number of pathways which project to or originate from diencephalic nuclei; these include the ansa peduncularis, medial forebrain bundle, inferior thalamic peduncle, stria terminalis, stria medullaris, mammillary peduncle, and dorsal longitudinal fasiculus.  

Nerve fibers immunoreactive for all the peptides were also observed in the posterior commissure and in the stria medullaris thalami.  

Within the central nervous system (CNS), LHRH-ir perikarya and fibers were distributed throughout the olfactory tubercle, diagonal band, preoptic area, suprachiasmatic and supraoptic nuclei, the bed nuclei of stria terminalis and stria medullaris, the anterior lateral and posterior hypothalamus, and the tuber cinereum.  

Both OXT and VP fibers were distributed in the lateral habenular nucleus, stria medullaris thalami, lateral preoptic area, stria terminalis, and medial and supracapsular part of the bed nucleus of the stria terminalis.  

More restricted input comes from the nucleus eminentiae thalami and the nucleus of the stria medullaris. The lateral habenular nucleus is innervated by various fiber groups originating from the bed nucleus of the anterior commissure, the diagonal band nucleus, the lateral preoptic area, the anterior entopeduncular nucleus, the lateral hypothalamic and mammillary areas, the nucleus of the stria medullaris, the area tegmentalis ventralis and a scattered neuronal subpopulation in the large-celled dorsolateral nucleus of the dorsal thalamus. Habenulopetal fibers generally follow the stria medullaris, but hypothalamic, entopeduncular and dorsal thalamic afferents course through the dorsal peduncle of the lateral forebrain bundle in a transthalamic route.  

Some fibers course rostrally from the nucleus habenularis lateralis in the stria medullaris and could be followed to the dorsal septum..  

Deposits involving the anterior intralaminar nuclei and the striatally projecting cells located lateral to the stria medullaris (anterior intralaminar complex) produced an even, diffuse labelling of the matrix tissue and weak labelling of the striosomes.  

Afferent fibers to the habenular ganglion (HG) were derived mainly from the stria medullaris thalami (SM), which was roughly divided into a dorsal and ventral bundle.  

In addition, a large number of immunoreactive fibers was found in the lemniscus medialis and a scarce number in the stria medullaris.  

In addition, a light projection arrived at several thalamic nuclei by returning toward the thalamus from the tectal or pretectal areas via stria medullaris, and thus was not a part of the RHT.  

The medial and lateral olfactory tracts combine in the region of the amygdala to form a part of the stria medullaris thalami.  

Several fiber tracts were also revealed, i.e., the lateral olfactory tract, mamillothalamic tract, fasciculus retroflexus, optic tract, and stria medullaris.  

In each animal, high-affinity (dissociation constant approximately 40 pM) 2-iodomelatonin binding sites were observed in the hypophysial pars tuberalis, in the suprachiasmatic nucleus of the hypothalamus, and in the thalamus (paraventricular nucleus, reuniens nucleus, and nucleus of the stria medullaris).  

Reactive fibers were present in the supraoptic decussation, medial forebrain bundle, and stria medullaris thalami.  

Another group of labelled fibers extends, throughout the lateral and ventral walls, to the most caudal part of the telencephalon, and, through the stria medullaris and the habenular commissure, crosses over to the controlateral hemisphere.  

However, varying degrees of immunostaining were detectable in perivascular glia, stria medullaris thalamus, the basal cerebral peduncle and the dentate molecular layer of the hippocampus.  

The lateral habenula receives massive afferents from dopamine-rich forebrain areas through the stria medullaris and sends efferents to mesencephalic dopaminergic systems through the fasciculus retroflexus. In the present study, effects of electrolytic lesions of the habenula, transections of the stria medullaris, and kainic acid-induced lesions of the entopeduncular nucleus on methamphetamine-induced inhibition of substantia nigra dopamine neurons were investigated in rats. There was no significant difference in cumulative dose-response curves between habenular-lesioned, stria medullaris-transected and entopeduncular-lesioned animals. These results, along with other findings, indicate possibly that the pathways running through the entopeduncular nucleus, the stria medullaris, the habenula, probably the lateral habenula, and the fasciculus retroflexus are involved in a feedback loop from the striatum to the substantia nigra and regulate the activity of dopamine neurons..  

They correspond largely to the subcommissural substantia innominata (SIC), the sublenticular substantia innominata (SIL), the nucleus of the diagonal band of Broca, the olfactory tubercle, the magnocellular preoptic nucleus (POMA), the lateral preoptic area (LPOA), and the interstitial nucleus of the stria medullaris (ISM).  

Fibre tracts associated with some of these neuronal groups, such as the fasciculus retroflexus, the stria medullaris and the commissura habenulae, also contained immunopositive fibres.  

The olfactory areas are connected with the habenular nuclei by a well developed stria medullaris thalami.  

In other thalamic nuclei such as habenularis medialis, paraventricularis anterior, centralis medialis, medialis dorsalis and in the stria medullaris no alteration on the distribution of immunoreactive fibres was observed in the animals treated with electroacupuncture in comparison with the distribution of such fibres found in the control animals.  

Following placements of tracer within the entire septum, labeled axons were observed in the stria medullaris and in the medial and lateral subnuclei of the habenula.  

Injections of tritiated proline and leucine were placed into the central lateral, paracentral, central medial, and para-stria medullaris nuclei. The para-stria medullaris nucleus projects only to the presylvian sulcus and orbitofrontal cortex laterally, but, medially, has an extensive input similar to the central lateral and paracentral projections in that label is present in the Of, Prag, La, Cg, Rs, and Ps areas, in the cruciate and splenial sulci, and in the posterior lateral gyrus. The laminar distribution of label is as follows: the central lateral, paracentral and para-stria medullaris nuclei project primarily to layers I and III, whereas the central medial nucleus projects to layers I and VI.  

Studies of the distribution of I-MEL binding in rat, Syrian hamster, and Djungarian hamster brain confirm that the median eminence and suprachiasmatic nucleus are major sites of I-MEL binding in rodent brain; other brain areas labeled in one or more of these species were the thalamus (paraventricular, anteroventral, and reuniens nuclei, nucleus of the stria medullaris, and medial part of the lateral habenular nucleus), hypothalamus (dorsomedial nucleus), subiculum, and area postrema.  

The boundaries and relative fiber density of the brain stimulation reward systems of the anterior hypothalamic area were mapped at the level of the stria medullaris using a dorsal-ventral moveable electrode. One cluster was just medial to the stria medullaris, a second larger cluster was within the boundaries of the myelinated fibers of the stria, and a third cluster was observed just lateral to the stria in the medial forebrain bundle.  

In the diencephalon, cholinergic fibers were found in the stria medullaris, the fasciculus retroflexus, and the ventral portion of the supraoptic decussation.  

In addition to the preoptico-terminal and the septo-preoptico-infundibular pathways, we also observed GAP-immunopositive processes in several major tracts and areas of the brain, including the amygdala, stria terminals, stria medullaris thalami, fasciculus retroflexus, stria longitudinalis medialis, periventricular plexus, periaqueductal gray of the mesencephalon and extra-cerebral regions, such as the nervus terminalis and its associated ganglion.  

The globus pallidus, thalamic areas, inferior olive, and pontine nuclei showed low density, while no binding sites were observed in the white matter tract regions such as the internal and external capsule, corpus callosum, fimbria of the hippocampus, fornix, stria medullaris of the thalamus, and fasciculus retroflexus.  

Labeled fibers traveled caudally from the injection site and entered the stria medullaris.  

The area lateral to the stria medullaris and the fornix at the level of the interventricular foramen, an area known to be occupied by the medial dorsal accessory group and the anterior fornical nucleus of the magnocellular neurosecretory system, was found to be studded with serotonin (5-HT)-like immunoreactive (LI) varicosities.  

Only a very small number of fibers reaches the ventral mesencephalon, and possibly the IP, via the stria medullaris and the fasciculus retroflexus.  

In the present experiments, this enzymatic activity was studied in the following white matter structures, which were microdissected using the punch technique of Palkovits: anterior commissure (CA), fornix (FX), habenulo-interpeduncular tract (HP), corpus callosum (CC), stria medullaris (SM), optic chiasm (CO), fimbria of the hippocampus (FI), cerebral peduncle (PC), pontine fibers (FP), cerebellar medulla (CMD) and corticospinal tract (TCS).  

The main features of stage 19 (approximately 48 days) are the cochlear nuclei, the ganglion of the nervus terminalis, nuclei of the prosencephalic septum, the appearance of the subcommissural organ, the presence of villi in the choroid plexuses of the fourth and lateral ventricles, and the stria medullaris thalami..  

In addition, fine, non-varicose, ADA-IR fibers appeared to emanate from the postcommissural cell groups and these coalesced within the stria medullaris, continued caudally within this fiber bundle, and gave rise to a dense field of very fine immunoreactive elements within a restricted zone of the dorsal half of the medial habenula. Unilateral transections of the stria medullaris caused substantial depletions of ADA-immunoreactivity and reduced enzymatically determined ADA activity by up to 80% in the medial habenula on the lesioned compared with the contralateral control side.  

Labelled fibers apparently arising from these neurons travelled in the stria medullaris and the habenular commissure to terminate in the contralateral basal forebrain.  

Immunoreactive ESN fibers were observed in the stria medullaris, in the lateral habenula, in the pineal stalk, and in the pineal organ.  

From both areas, positive fibers which varied in density were observed in the mediodorsal and ventral parts of the ventroposterior and ventromedial thalamic nuclei, the lateral habenula, the stria medullaris, the lateral hypothalamus and the ventral tegmental area. A minor descending pathway through the stria medullaris was also noted which terminated in the lateral habenula and the mediodorsal thalamic nucleus.  

Regenerating retinal ganglion cell axons, observed by the autoradiographic tracing method and by horseradish peroxidase (HRP) fiber filling, grew anteriorly along the olfactory tracts and posteriorly along the ipsilateral lateral forebrain bundle and stria medullaris. The optic axons formed terminal plexuses in the olfactory cortex, lateral geniculate complex, pretectum, tectum, and basal optical nucleus but not in the amygdala or other cerebral territories not postsynaptic to the olfactory bulb, nor in the cell groups associated with the lateral forebrain bundle or stria medullaris.  

Pro-somatostatin-derived-peptide-positive fibre tracts include the bed nucleus of the stria terminalis, the diagonal band of Broca, the stria medullaris, the inter-thalamic adhesion, the posterior commissure and the spinothalamic tract.  

Lesions of the FR eliminated all ChAT from the IPN while lesions of the stria medullaris produced a modest decrease.  

To investigate a possible central neural influence on nocturnal pineal metabolic activity in rats, frontal transsections of the stria medullaris thalami were conducted.  

Knife-cut studies demonstrated that almost all the fibers were supplied via the stria medullaris. Our findings also suggested that the L-ENKI fibers in the BZHb are supplied via the stria medullaris with an ipsilateral predominance and that, at the most caudal level, they arise not only from the ipsilateral stria medullaris but also from the contralateral stria medullaris via the habenular commissure..  

In further studies, bilateral electrolytic lesions of the stria medullaris (which conveys the major afferents to the habenula) decreased glucose use in the interpeduncular nucleus less than that observed after bilateral electrolytic lesions of the habenular nuclei.  

The accessory cell groups or nuclei labelled included: the medial preoptic and anterior hypothalamic areas, the anterior and posterior fornical nuclei, the lateral hypothalamic area, the nucleus circularis and nucleus of the forebrain bundle and hitherto unknown or not fully appreciated retrochiasmatic area, the dorsal accessory groups in an area between the stria medullaris and fornix, on the one hand, and the stria terminalis and internal capsule, on the other, and a well developed subependymalperiventricular zone.  

By contrast, hypothyroidism did not reduce mabN210-immunoreactivity in the lateral olfactory tract or the stria medullaris.  

The potential role of the habenula in the transsynaptic regulation of the activity of ascending dopaminergic systems has been investigated in the rat by studying the effect of an acute interruption of impulse traffic in the diencephalic conduction system (stria medullaris-habenula-fasciculus retroflexus) and of pharmacological manipulation of various neurotransmitter systems in the interpeduncular nucleus on dopamine metabolism in several dopaminergic projection fields. Similar changes in dopamine metabolism were observed in these areas after bilateral infusion of tetrodotoxin into the stria medullaris (which conveys most of the afferents to the habenula).  

Destruction of the stria medullaris, which contains most habenular afferents, did not alter the inhibitory effect of habenular stimulation.  

With the Fink-Heimer method, habenular efferents have been traced to the basal telencephalon, the pallium, the stria medullaris, the dorsal and ventral thalamus, the preoptic and anterior hypothalamus, the fasciculus retroflexus, the tegmentum and the interpeduncular neuropil.  

Numerous peroxidase-positive fibers were observed, ipsilateral to the injection site, in the stria medullaris thalami and could be followed into the medial habenular nucleus and the habenular commissure.  

A similar blockade of the effects of GABA mimetics was seen after ibotenate-induced lesion of the habenula but not after electrolytic lesion of the stria medullaris (which conveys most of the afferents to the habenula).  

This work was undertaken to examine the influence of propylthiouracil-induced (PTU-induced) pre- and postnatal hypothyroidism on collateral sprouting of noradrenergic (NA) axons in the habenula (Hb), following lesions in the stria medullaris (SM) of the adult rat.  

Knife cuts that separated the habenular nuclei from the stria medullaris and neural regions lateral and posterior to those nuclei while leaving the fasciculus retroflexus intact resulted in a reduction of ChAT-like immunoreactivity in the medial habenular nucleus, fasciculus retroflexus, and interpeduncular nucleus.  

Microknife lesions of the stria medullaris left this DA innervation unaffected while cuts through the fasciculus retroflexus resulted in the virtual disappearance of the DA innervation.  

Control injections in the stria medullaris, rostral to the habenular complex, caused only sparse degeneration in the interpeduncular nucleus and did not involve S and crest terminals.  

Destruction of the stria medullaris input to the habenulae prevented the Althesin-induced increase in 2-DG uptake by the MHb and LHb..  

In extrahypothalamic areas, these fibers were especially abundant in the stria medullaris/habenula and stria terminalis/amygdala, but also contributed to the diagonal band of Broca and the olfactory tracts.  

The third ventricle can be approached by performing a few surgical maneuvers: (a) dividing the ependyma on the inferolateral aspect of the choroid plexus of the lateral ventricle; (b) separating leptomeningeal bundles within the tela chorioidea, and (c) dividing the roof of the third ventricle along the stria medullaris.  

These include the fasciculus retroflexus, the fasciculus mamillothalamicus, the stria medullaris, and the stria terminalis.  

Projections closely associated with those of the rostral intralaminar group arise from cells of the paraventricular nucleus (PV) and a region lateral to the stria medullaris. The medially located cells in Rh, PV, and those alongside the stria medullaris project mainly to medial parts of Acc and CD; the dorsolaterally located cells of CL project mainly to the dorsolateral parts of CD and PU; cells in PC and CeM project to progressively more ventral and medial parts of CD and PU, and the lateral part of Acc.  

The majority of the small axons which are apparently devoid of granules and dense-cored vesicles may come from the habenular nuclei and the stria medullaris.  

Stained axons were particularly concentrated in the ventrobasal complex, and in the stria medullaris, stria terminalis and inferior thalamic peduncle.  

In addition to the known GnRH-pathways (preoptico-terminal, preoptico-infundibular, periventricular), we also observed GnRH-immunopositive processes in several major tracts and areas of the brain, including the medial and cortical amygdaloid complex, stria terminalis, stria medullaris thalami, fasciculus retroflexus, medial forebrain bundle, indusium griseum, stria longitudinalis medialis and lateralis, hippocampus, periaqueductal gray of the mesencephalon, and extracerebral regions, such as the lamina cribrosa, nervus terminalis and its associated ganglia.  

Lordotic behavior and LH release were measured in ovariectomized rats after radiofrequency lesions of the midbrain central gray (MCG), interpeduncular nucleus (IPN), mammillary bodies (MMM), stria medullaris (SM), or fasciculus retroflexus (FR), areas which are reported to contain immunoactive luteinizing hormone-releasing hormone (LHRH), a hypothalamic decapeptide which has been implicated in the neuroendocrine control of lordosis.  

Bilateral transection of the stria medullaris caused a 50% decrease of choline acetyltransferase in both the habenula and nucleus interpeduncularis, and a 65% decrease of glutamate decarboxylase in the habenula.  

In addition to the pattern of degeneration seen after olfactory peduncle lesions, degenerating fibers could be distinguished both in the stria medullaris and basal forebrain bundle.  

Adult rats received bilateral stria medullaris lesions and after 4 weeks a second lesion was produced which removed bilaterally the dorsal NA bundle or the superior cervical ganglia.  

In the centripetal direction these fibers were traced to the stria medullaris and to the habenular nuclei, where they turned laterad and then occupied a position immediately ventral to the optic tract. AChE-positive perikarya were located in the projections of the stria medullaris, the lateral portions of the deep pineal, the area of the posterior commissure, and the periventricular gray of the mesencephalon.  

In comparison with other mammalian brains the telencephalon and diencephalon of the bat demonstrate a high concentration of enzyme, especially in the nucleus caudatus and putamen, stria medullaris and the nuclei of the thalamus.  

Afferents to the LPA originate in the prefrontal corex, nucleus accumbens, diagonal band and olfactory structures, lateral and medial septum, stria hypothalamic tract and stria terminalis, the magnocellular and medial preoptic nuclei, along the extent of the medial forebrain bundle in the LPA and LH, anterior and basolateral amygdala, ventromedial caudate-putamen, stria medullaris and lateral habenula, the stellatocellular-periventricular, ventromedial, arcuate and anterior hypothalamic nuclei, the perifornical area, zona incerta, ventral medial thalamic area, ventral tegmental area of Tsai, interpeduncular nucleus, reticular zone of the substantia nigra, mesencephalic periaqueductal gray and reticular formation, all aspects of the raphe nuclei and the locus coeruleus.  

Somatostatin-immunoreactive fiber bundles project via the stria medullaris toward the habenular nucleus; they also course in the dorsomedial-ventrolateral direction at the level of the pretectal-tegmental area, and within the ventral and dorsal tegmentum.  

Labeled fibers in the stria medullaris project to the lateral habenular nucleus.  

All serotonergic axons that enter the prosencephalon ascend in the medial forebrain bundle From this bundle fascicles of immunoreactive axons enter several well-defined fiber tracts: specifically, the fasciculus retroflexus, stria medullaris, external capsule, fornix, and supracallosal stria.  

The lateral nucleus of the habenula is the main source of AChE-rich fibres in the fasciculus retroflexus, and a number of stained fibres also derive from the stria medullaris.  

Enkephalinergic fibers and terminals are found in the above-mentioned areas as well as in the pallium (medial and dorsal cortex, dorsal ventricular ridge), dorsomedial and anterior dorsolateral nucleus of the thalamus, habenula, nucleus of the stria medullaris, torus semicircularis, mesencephalic tegmental area, interpeduncular nucleus, mesencephalic trigeminal nucleus, central gray, reticular formation, raphe nucleus, substantia nigra, isthmus region, and nucleus of the trapezoid body.  

The lateral hypothalamus, preoptic region, and anterior portion of the entopeduncular nucleus projected primarily through the inferior thalamic peduncle and stria medullaris, while the posterior portion of the entopeduncular nucleus projected more diffusely through thalamus to enter LHB from its ventral aspect. Entopeduncular and lateral hypothalamic axons passed through the habenular commissure to the contralateral stria medullaris to reach the contralateral LHB.  

caudatus), foramen of Monro (stria medullaris), third ventricle (habenula) and floor of the fourth ventricle in brains of the five cases examined.  

These projections originate in the periventricular somatostatin-immunoreactive perikarya of the hypothalamus and form three main pathways: (1) along the stria medullaris thalami and the fasciculus retroflexus into the interpeduncular nucleus; (2) along the medial forebrain bundle into the mammillary body; and (3) via the periventricular gray and the bundle of Schütz into the midbrain tegmentum.  

Other labeled fibers could be followed dorsally from medial preoptic area injections adjacent to the stria medullaris, and in the periventricular fiber system and the stria terminalis and its bed nucleus.  

Caudal efferents reach the havenula, interpeduncular nucleus, midbrain raphe, and central gray of the rostral fourth ventricle via the stria medullaris and fasciculus retroflexus and by a ventral projection via the periventricular and subventricular hypothalamus.  

No LHb projections follow the stria medullaris.  

Along the course of this bundle numerous fibers branched successively into the mammillary peduncle, the fasciculus retroflexus, the stria medullaris, the fornix and the cingulum.  

Following HRP injections into stria medullaris, only cells in the rostral part of the EPN were labeled, providing evidence that rostrally and caudally located EPN neurons have different paths to LHB.  

LH-RH neurons in both the medial septal nucleus and medial preoptic area project via the stria medullaris to the medial habenular nucleus and from there via the fasciculus retroflexus to the interpeduncular nucleus of the midbrain.  

Rostrally the major group in the medial forebrain bundle divides into several components: fibers entering the stria medullaris to terminate in thalamus; fibers entering the stria terminalis to terminate in the amygdala; fibers traversing the fornix to the hippocampus; fibers running through septum to enter the cingulum and terminate in dorsal and medial cortex and in hippocampus; fibers entering the external capsule to innervate rostral and lateral cortex; and fibers continuing forward in the medial olfactory stria to terminate in the anterior olfactory nucleus and olfactory bulb..  

Oxytocin and vasopressin containing pathways could be traced from the paraventricular nucleus to the lateral ventricle, the stria terminalis and the stria medullaris.  

Surgical transection of the stria medullaris (SM) reliably interfered with the acquisition of a one-way avoidance response but had no effect on two-way shuttle box avoidance, passive avoidance, intake of palatable fluids, or locomotor activity.  

The descending fibers travel in the medial and lateral forebrain bundles and in the tracts comprising the stria medullaris.  

One group of fibers enters the stria medullaris to terminate in the paraventricular nucleus and habenular nuclei.  

HRP injected into the stria medullaris labeled cells in all of the afore-mentioned areas and, in addition, cells in several olfactory structures, confirming that HRP may be taken up by fibers of passage and label their cells of origin, and suggesting that olfactory structures contribute fibers to the stria medullaris that do not terminate in the habenula..  

The vast majority of axons of these projection neurons passed ventrally or ventrocaudally to enter the FR; only a few axons of these neurons were traced into the stria medullaris thalami (SM).  

The impaired acquisition of most other avoidance problems seems to be due to an interruption of components of the stria medullaris.  

Other fibers from this region project through the stria medullaris to the medial habenular nucleus and anteromedial nuclhe pars posterior of the medial mammillary nucleus. Other fibers which originate from this region project through the stria medullaris to both the medial and lateral habenular nuclei and the paratenial nucleus of the thalamus, and through the medial forebrain bundle to the pars posterior of the medial mammillary nucleus. These cells also send fibers through the stria medullaris to the lateral habenular nucleus and mediodorsal thalamic nucleus.  

In addition, some axons enter the ipsilateral stria medullaris thalami, cross the midline in the habenular commissure, enter the contralateral stria medullaris thalami and terminate in the contralateral lateral pallium.  

Cells in sublenticular portions of SI, and those extending into the medullary laminae of the pallidum, appear to project to: (1) HB1 via the stria medullaris, (2) the pars compacta of SN, (3) lateral and posterior regions of the hypothalamus, and (4) the so-called nucleus of the ansa lenticularis.  

Other AHA efferents distributed to the periventricular thalamus, to the medial amygdala via the stria terminalis or supraoptic commissure, and to the lateral habenula through the stria medullaris.  

Projections from the mPOA were also observed to the amygdala through the stria terminalis, to the lateral habenula through the stria medullaris, and to the periventricular thalamus. The pvPOA did not send axons through the stria medullaris but did project more heavily than the more lateral mPOA to the arcuate nucleus and median eminence.  

the main efferent projections were localized to the fornix, stria medullaris and the medial forebrain bundle. Stimulation of the stria medullaris elicited hypotension and bradycardia whereas stimulation of the medial forebrain bundle elicited hypertension and bradycardia. Ipsilateral lesions of the stria medullaris, signicicantly attenuated the hypotension and bradycardia elicited by stimulation of the lateral septum but did not affect the responses to stimulation of the medial septum. It is suggested that the cardiovascular responses elicited by stimulation of the lateral septum are mediated via the stria medullaris and that the hypertension elicited by stimulation of the medial septum is mediated via the medial forebrain bundle.  

The posteromedial lateral preoptic area projects to the same regions, as well as to the medial septal-diagonal band complex, and to the lateral habenula through the stria medullaris. The transition region between the lateral preoptic and lateral hypothalamic areas at the level of the supraoptic nucleus has widespread connections as a whole (a) with the medial septal-diagonal band complex, lateral septum and bed nucleus of the stria terminalis, (b) through or to most of the hypothalamus, the substantia nigra, central tegmental field, central gray, superior central nucleus, and the locus coeruleus, (c) through the stria medullaris to the lateral habenula (bilaterally), parataenial, paraventricular, and mediodorsal nuclei of the thalamus, (d) through the stria terminalis and ansa peduncularis to the central, medial and cortical nuclei of the amygdala, and (e) to the main olfactory bulb, anterior olfactory nucleus, cingulate bundle, olfactory tubercle, medial septal-diagonal band complex and the lateral septum..  

Two crossed secondary olfactory pathways to the contralateral telencephalon decussate via the habenular commissure after entering the ipsilateral stria medullaris.  

Basic fiber systems in Galeichthys felis which are homologous to those of higher vertebrates include the medial and the lateral olfactory tracts, the fornix, the medial and the lateral forebrain bundles, the stria medullaris pathways and the stria terminalis.  

The lateral hypothalamic nucleus (LH) belongs to area parasympathica C of the SPH-System and its fibers to make up the medial forebrain bundle and stria medullaris.  

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