PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Midline Thalamic Nuclei”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1998

Lesions of the midline thalamic nuclei impair classical conditioning under partial but not continuous reinforcement conditions.

Rabbits with lesions of the midline thalamic nuclei were compared to rabbits with sham lesions on classical eyeblink (EB) and heart rate (HR) conditioning. Separate groups of sham and lesioned animals received either 25, 50 or 100% reinforcement with a periorbital shock unconditioned stimulus. Animals with lesions showed slightly impaired EB conditioning, compared to sham animals, under the partial but not continuous reinforcement schedules. Midline lesions also reduced the magnitude of the decelerative HR conditioned response under partial but not continuous reinforcement conditions. These findings suggest that the midline thalamic nuclei, like the mediodorsal nucleus of the thalamus, process information required for response selection under non-optimal learning conditions.

Animals↗
PubMed1984

Effects of electrical stimulation of various midline thalamic nuclei on the bilateral release of dopamine from dendrites and nerve terminals of neurons in the nigro-striatal dopaminergic pathways.

The effects of electrical stimulation of midline thalamic nuclei on the release of [3H]dopamine ( [3H]DA) were determined in both substantiae nigrae (SN) and caudate nuclei of halothane-anesthetized cats using the push-pull cannula method. [3H]DA release was increased in the four structures following stimulation of the interanteromedialis nucleus (IAM) but only enhanced in both SN when nucleus reuniens (RE) was stimulated. In contrast, no effect was detected after delivery of the stimuli to nucleus centralis medialis. These results indicate that the anterior part of the thalamic massa intermedia (IAM and RE particularly) is involved in the bilateral regulation of DA release from nerve terminals and dendrites of the nigro-striatal dopaminergic neurons.

Afferent Pathways↗
PubMed1997

Avian homologues of mammalian intralaminar, mediodorsal and midline thalamic nuclei: immunohistochemical and hodological evidence.

This paper presents and reviews data suggesting that the dorsal thalamic zone (abbreviated DTZ) in birds is homologous to the intralaminar, midline, and mediodorsal thalamic nuclear complex (abbreviated IMMC) in mammals. The DTZ is located dorsomedially in the diencephalon of birds and consists of several subnuclei: nucleus dorsomedialis anterior thalami (DMA), nucleus dorsomedialis posterior thalami (DMP), nucleus dorsolateralis anterior thalami, pars medialis (DLM), nucleus dorsointermedius posterior thalami (DIP), nucleus dorsolateralis posterior thalami (DLP), and nucleus subhabenularis lateralis (SHL). Our immunohistochemical studies show that: (1) SHL and medial and dorsal parts of DMA and DMP are relatively rich in GABAergic, enkephalin-containing, substance P-containing, and cholinergic fibers; (2) lateral parts of DMA and DMP are relatively poor in these neurotransmitters; and (3) DIP, DLP, and DLM are moderately rich in cholinergic and substance P-containing fibers. Our retrograde pathway tracing studies indicate that the DIP and DLP in the more lateral parts of DTZ project to somatic striatum, while the DMA, DMP, and SHL located more medially in the DTZ project to visceral/limbic striatum. Our anterograde tracing studies indicate that DIP receives afferents from the dorsal pallidum, whereas DMA and DMP appear to receive afferents from both the ventral striatum and ventral pallidum. Diverse prior studies have shown that in general medial and lateral components of DTZ are connected with visceral/ limbic and somatic brain regions, respectively. These characteristics indicate that: (1) SHL and medial and dorsal parts of DMA and DMP are comparable to mammalian midline thalamic nuclei, including the medial components of the intralaminar nuclei; (2) lateral parts of DMA and DMP are comparable to the mediodorsal nucleus in mammals; (3) DIP is comparable to the parafascicular nucleus in mammals; and (4) DLM and DLP are comparable to the laterally located intralaminar nuclei in mammals. The comparability of avian DTZ and mammalian IMMC suggests that they evolved from thalamic precursor nuclei present in the common reptilian ancestors and that they may perform similar roles in the movement control function of the basal ganglia.

Animals↗
PubMed1998

Activation of midline thalamic nuclei by antipsychotic drugs.

The thalamus has been proposed as a site which may be involved in the production of the syndrome of schizophrenia and the response of schizophrenic symptoms to treatment. These studies test whether, consistent with this hypothesis, the activation of thalamic nuclei is a shared property of neuroleptic antipsychotic drugs. Rats were given single doses of the typical high and low potency neuroleptics haloperidol (1 mg/kg) and chlorpromazine (20 mg/kg), the atypical neuroleptics thiroridazine (20 mg/kg) and clozapine (20 mg/kg), the specific dopamine antagonist raclopride (3 mg/kg), the mixed dopamine/serotonin antagonist risperidone (3 mg/kg) or drug-free vehicle. Increased expression of Fos-like protein was utilized as a marker of cellular activation. All drugs tested, including typical and atypical antipsychotic agents, led to similar effects on the midline thalamic paraventricular, centromedian and rhomboid nuclei and the nucleus reuniens. These results suggest that midline thalamic nuclei may participate in neural circuits mediating some of the shared effects of antipsychotic drugs.

Animals↗
PubMed1994

Neuronal activity in the midline thalamic nuclei during Pavlovian heart rate conditioning.

Multiple unit activity (MUA) was recorded from chronically implanted electrodes in the midline nuclei of the thalamus in rabbits receiving either Pavlovian heart rate (HR) conditioning, or explicitly unpaired presentations of the conditioned stimulus (CS) and unconditioned stimulus. Animals receiving paired training demonstrated increases in CS-evoked MUA compared to animals receiving unpaired training; however, these increases were small and only weakly correlated with the HR conditioned response, suggesting that the midline nuclei are only minimally, if at all, involved in associative learning.

Animals↗
PubMed1998

Daily rhythms in Fos activity in the rat ventrolateral preoptic area and midline thalamic nuclei.

The present experiment investigated the expression of the nuclear phosphoprotein Fos over the 24-h light-dark cycle in regions of the rat brain related to sleep and vigilance, including the ventrolateral preoptic area (VLPO), the paraventricular thalamic nucleus (PVT), and the central medial thalamic nucleus (CMT). Immunocytochemistry for Fos, an immediate-early gene product used as an index of neuronal activity, was carried out on brain sections from rats perfused at zeitgeber time (ZT) 1, ZT 5, ZT 12.5, and ZT 17 (lights on ZT 0-ZT 12). The number of Fos-immunopositive (Fos+) cells in the VLPO was elevated at ZT 5 and 12.5 (i.e., during or just after the rest phase of the cycle). Fos+ cell number increased at ZT 17 and ZT 1 in the PVT and CMT, 180 degrees out of phase with the VLPO. A positive correlation was found between the numbers of Fos+ cells in the PVT and CMT, and Fos expression in each thalamic nucleus was negatively correlated with VLPO Fos+ cell number. The VLPO, PVT, and CMT may integrate circadian and homeostatic influences to regulate the sleep-wake cycle.

Animals↗
PubMed2005

Retinal projections to the midline and intralaminar thalamic nuclei in the common marmoset (Callithrix jacchus).

In this study, we report the identification of a hitherto not reported direct retinal projection to midline and intralaminar thalamic nuclei in the marmoset brain. After unilateral intravitreal injections of cholera toxin subunit B (CTb), anterogradely transported CTb-immunoreactive fibers and presumptive terminals were seen in the following thalamic midline nuclei: paraventricular, rhomboid, interanteromedial, and reuniens, and thalamic intralaminar nuclei: central medial, central lateral, central dorsal, and parafascicular. Studies employing sensitive tracers in other primate species are needed in order to verify the possible universality of these projections. Some of the possible functional correlates of the present data are briefly discussed. The present results may contribute to the elucidation of the anatomical substrate of the functionally demonstrated involvement of this midline/intralaminar thalamic nuclear complex in several domains that include arousal and awareness, besides specific cognitive, sensory, and motor functions.

Animals↗
PubMed1994

The specificity of the 'nonspecific' midline and intralaminar thalamic nuclei.

The midline and intralaminar thalamic nuclei have long been considered to be a 'nonspecific' nuclear complex that relays the activity of the brain-stem reticular formation to widespread cerebral-cortical areas. Over the past decade, it has become clear that individual midline and intralaminar nuclei each receive specific sets of afferents and project to specific parts of the cerebral cortex and striatum. Moreover, the targets of the thalamocortical and thalamostriatal projections of a given nucleus are interconnected through corticostriatal projections. Therefore, the midline and intralaminar nuclei might have a dual role in corticosubcortical interactions in the forebrain. Through distinct sets of inputs to individual midline or intralaminar thalamic nuclei, these nuclei are in a position to interact selectively with particular, functionally segregated basal-ganglia-thalamocortical circuits. By way of nonselective inputs, in particular from cholinergic brain-stem nuclei, the midline and intralaminar nuclei might act in concert to modify the level of activity of the entire basal-ganglia-thalamocortical system.

Animals↗
PubMed1998

Re-examination of topographic distribution of thalamic neurons projecting to the caudate nucleus. A retrograde labeling study in the cat.

The distribution of thalamic neurons projecting directly to the caudate nucleus (CN) was examined using the retrograde labeling method. Horseradish peroxidase conjugated with wheat germ agglutinin (HRP-WGA) or a fluorescent tracer (either Fast Blue (FB) or Diamidino Yellow (DY)) was injected into various parts of the CN. The main findings were as follows: (1) labeled neurons were distributed most densely in the intralaminar nuclei, midline thalamic nuclei and centre median-parafascicular complex, and less densely in the ventroanterior (VA), ventrolateral (VL) and ventromedial (VM) nuclei. (2) After injections into the rostral parts of the CN, a moderate number of retrogradely labeled neuronal cell bodies was observed in VA, VL and VM. However, only very few, if any, labeled neurons were found in these nuclei after injections into the caudal parts of the CN. (3) After injections into the most dorsolateral parts of the CN, labeled neurons were seen in the lateralmost part of the VA and VL. (4) Many retrogradely labeled neurons were consistently found in the lateral wing of the rhomboid nucleus after injections into the CN. (5) No clear topography was detected in the arrangement of labeled neurons in the rhomboid, dorsal mediodorsal, centrolateral or paracentral nuclei. (6) After injections into the rostral parts of the CN, the most prominent labeling was observed in the ventral part of the centre médian-parafascicular complex.

Amidines↗
PubMed1994

Kappa 1 receptor mRNA distribution in the rat CNS: comparison to kappa receptor binding and prodynorphin mRNA.

Three opioid receptor types have been identified in the CNS and periphery that are referred to as mu, delta, and kappa. The present study examines the mRNA distribution of the kappa 1 receptor in the rat brain and compares it to the distribution of kappa receptor-binding sites and prodynorphin mRNA using a combination of in situ hybridization and receptor autoradiographic techniques. kappa 1 receptor mRNA was localized with a cRNA probe generated with a BamHI-HindIII cDNA fragment of the rat kappa 1 receptor and corresponds to the last 45 bp of the protein coding region and 728 nucleotides of the 3' untranslated region. Prodynorphin mRNA was localized with a cRNA probe corresponding to a 733-bp BamHI-HincII fragment of prodynorphin. kappa receptor-binding sites were labeled in one of two ways: [3H]U69,593 or [3H]bremazocine in the presence of a 300-fold excess of DAMGO and DPDPE. A high degree of correspondence between the kappa 1 receptor mRNA and kappa receptor binding was observed in several brain regions, including the endopiriform nucleus, claustrum, nucleus accumbens, olfactory tubercle, bed nucleus of the stria terminalis, medial preoptic area, paraventricular, supraoptic, suprachiasmatic, dorsomedial and ventromedial hypothalamic nuclei, basolateral, medial and cortical amygdaloid nuclei, midline thalamic nuclei, periaqueductal grey, parabrachial nucleus, locus coeruleus, and the nucleus of the solitary tract. Differences in the localization of kappa 1 receptor mRNA and binding and the relationship between the distribution of kappa 1 receptor and prodynorphin mRNAs are discussed.

Animals↗
PubMed1998

Down-regulated NPY receptor subtype-5 mRNA expression in genetically obese mouse brain.

Brain neuropeptide Y (NPY) subtype-5 (Y5 receptor) mRNA expression in lean (+/+) and obese (ob/ob) C57Bl/6 mice was examined using a non-radioactive in situ hybridization detection method. Significant decreases in Y5 receptor mRNA expression were found in the ventromedial, dorsomedial and arcuate hypothalamic nuclei, midline thalamic nuclei, piriform, cingulate and retrosplenial granular cortices of the obese mouse brain. There were minor changes in the amount of Y5 receptor mRNA expression in the hippocampal formation and medial habenular nucleus. Results indicated that Y5 receptor mRNA expression is downregulated in hereditary obese (ob/ob) mice. This is possibly due to over-expression of hypothalamic NPY which occurs in this phenotype.

Animals↗
PubMed2002

The intralaminar and midline nuclei of the thalamus. Anatomical and functional evidence for participation in processes of arousal and awareness.

The thalamic midline and intralaminar nuclei, long thought to be a non-specific arousing system in the brain, have been shown to be involved in separate and specific brain functions, such as specific cognitive, sensory and motor functions. Fundamental to the participation of the midline and intralaminar nuclei in such diverse functions seems to be a role in awareness. It is unknown whether the midline and intralaminar nuclei, together often referred to as the 'non-specific' nuclei of the thalamus, act together or whether each nucleus is involved idiosyncratically in separate circuits underlying cortical processes. Detailed knowledge of the connectivity of each of these nuclei is needed to judge the nature of their contribution to cortical functioning. The present account provides an overview of the results of neuroanatomical tracing studies on the connections of the individual intralaminar and midline thalamic nuclei in the rat, that have been performed over the past decade in our laboratory. The results are discussed together with those reported by other laboratories, and with those obtained in other species. On the basis of the patterns of the afferent and efferent projections, we conclude that the midline and intralaminar thalamic nuclei can be clustered into four groups. Each of the groups can be shown to have its own set of target and input structures, both cortically and subcortically. These anatomical relationships, in combination with functional studies in animals and in humans, lead us to propose that the midline and intralaminar nuclei as a whole play a role in awareness, with each of the groups subserving a role in a different aspect of awareness. The following groups can be discerned: (1) a dorsal group, consisting of the paraventricular, parataenial and intermediodorsal nuclei, involved in viscero-limbic functions; (2) a lateral group, comprising the central lateral and paracentral nuclei and the anterior part of the central medial nucleus, involved in cognitive functions; (3) a ventral group, made up of the reuniens and rhomboid nucleus and the posterior part of the central medial nucleus, involved in multimodal sensory processing; (4) a posterior group, consisting of the centre médian and parafascicular nuclei, involved in limbic motor functions.

Animals↗
PubMed2006

Thalamo-striatal projections in the hedgehog tenrec.

Unlike the basal ganglia input from the midline and intralaminar nuclei, the origin and prominence of striatal projections arising in the lateral thalamus varies considerably among mammals being most restricted in the opossum and monkey, most extensive in the rat. To get further insight into the evolution of thalamo-striatal pathways the Madagascar lesser hedgehog tenrec (Afrotheria) was investigated using anterograde and retrograde flow techniques. An extensive medial thalamic region (including presumed equivalents to the paraventricular, parataenial and dorsomedial nuclei as well as the reuniens complex), the rostral (central) and caudal (parafascicular) intralaminar nuclei were shown to give rise to striatal projections. Additional projections originated in the ventral anterolateral nuclear group and regions within and around the medial geniculate complex. Similar to the rat there was also substantial projections from the lateral posterior-pulvinar complex and the ventral posterior nucleus. The fibers terminated extensively across the striatum in a mainly homogeneous fashion. Isolated patches of low-density terminations were found in the caudoputamen. This inhomogeneous labeling pattern appeared similar to one described in the cat with the unlabeled islands showing features of striosomes. The medial and intralaminar nuclei also projected heavily upon the olfactory tubercle. Differential innervation patterns were noted in the polymorphous layer, the deep and the superficial molecular layer.

Animals↗
PubMed2003

Distribution of trigeminothalamic and spinothalamic lamina I terminations in the cat.

The distribution in the thalamus of terminal projections from lamina I neurons of the trigeminal, cervical, and lumbosacral dorsal horn was investigated with the anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L) in the cat. Iontophoretic injections were guided by single- and multi-unit physiological recordings. The injections in particular cases were essentially restricted to lamina I, whereas in others they spread across laminae I-III or laminae I-V. The trigemino- and spinothalamic (TSTT) terminations were identified immunohistochemically. In all cases, regardless of the level of the injections, terminal fibers were consistently distributed in three main locations: the submedial nucleus; the ventral aspect of the basal ventral medial nucleus and ventral posterior nuclei; and, the dorsomedial aspect of the ventral posterior medial nucleus. The terminal fields in the submedial nucleus and the ventral aspect of the ventral posterior group were topographically organized. Terminations along the ventral aspect of the ventral posterior group extended posterolaterally into the caudal part of the posterior nucleus and anteromedially into the ventromedial part of the ventral lateral nucleus. In several cases with trigeminal lamina I injections, a terminal labeling patch was observed within the core of the ventral posterior medial nucleus. In cases with spinal lamina I injections, terminations were also consistently found in the lateral habenula, the parafascicular nucleus, and the nucleus reuniens. Isolated terminal fibers were occasionally seen in the zona incerta, the dorsomedial hypothalamus, and other locations. These anatomical observations extend prior studies of TSTT projections and identify lamina I projection targets that are important for nociceptive, thermoreceptive, and homeostatic processing in the cat. The findings are consistent with evidence from physiological (single-unit and antidromic mapping) and behavioral studies. The novel identification of spinal lamina I input to the lateral habenula could be significant for homeostatic behaviors.

Animals↗