(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. 
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.
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.
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.
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.
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).
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.
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.
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).
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.
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.
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).
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..
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.
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.
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 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.
By contrast, hypothyroidism did not reduce mabN210-immunoreactivity in the lateral olfactory tract or the stria medullaris.
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.
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.
Stained axons were particularly concentrated in the ventrobasal complex, and in the stria medullaris, stria terminalis and inferior thalamic peduncle.
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 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.
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.
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.
No LHb projections follow the stria medullaris.
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..
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).
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.
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 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..
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