Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “THALAMUS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 1,009 records · Page 56Linked to original sources
PubMed1991

Calcitonin gene-related peptide (CGRP) immunoreactive projections from the thalamus to the striatum and amygdala in the rat.

The organization of calcitonin gene-related peptide-like immunoreactive (CGRPir) innervation of the amygdala and caudate-putamen in the rat was examined by using immunohistochemistry for CGRP combined with retrograde transport of the fluorescent dye fluoro-gold, as well as anterograde transport of Phaseoleus vulgaris leucoagglutinin (PHA-L). The lateral part of the central nucleus of the amygdala and the amygdalostriatal transition zone was densely innervated by CGRPir terminals at all anterior-posterior levels. More caudally, the lateral part of the caudate-putamen also had large numbers of CGRPir terminals. Injections of fluoro-gold into the amygdala and amygdalostriatal transition area followed by immunohistochemistry for CGRP revealed double-labeled neurons in the subparafascicular, lateral subparafascicular, and posterior intralaminar nuclei of the thalamus and peripeduncular nucleus. Injections into the caudate-putamen demonstrated double-labeled neurons in the more lateral parts of this same nuclear complex. PHA-L injections into the posterior thalamic nuclei from which the CGRPir projections arise confirmed the medial-to-lateral organization of the projections to the amygdala and striatum. The subparafascicular nucleus and the rostral portion of the lateral subparafascicular nucleus primarily projected to the medial amygdala and the amygdalostriatal transition area, while the more lateral cell groups, including the caudal part of the lateral parafascicular, posterior intralaminar, and peripeduncular nuclei projected to the lateral amygdala and the caudate-putamen. These CGRPir projections may be involved in mediating conditioned autonomic and behavioral responses to acoustic stimuli or somatosensory stimuli.

Amygdala↗
PubMed1991

Localization and characterization of angiotensin II receptor binding sites in the human basal ganglia, thalamus, midbrain pons, and cerebellum.

Angiotensin II (Ang II) binding sites were localized in the thalamus, basal ganglia, midbrain, and pons of the human central nervous system by in vitro autoradiography, employing 125I-[Sar1, Ile8]angiotensin II as the radioligand. High-density binding occurs in the substantia nigra pars compacta, the interpeduncular nucleus and two of the raphe nuclei, the raphe magnus, and median raphe nucleus. Moderate densities occur in the caudate nucleus, putamen, bed nucleus of the stria terminalis, rostral linear nucleus, caudal linear nucleus, dorsal and paramedian raphe nuclei, locus coeruleus, and region of the subcoeruleus, oral dorsal paramedian nucleus, and A5/periolivary region. Low levels occur in the region between the subthalamic nucleus and the zona incerta, the mediodorsal thalamic nucleus, the central gray, the lateral and medial parabrachial nuclei, and the molecular layer of the cerebellum. The high density of Ang II receptor binding in the substantia nigra occurs over pigmented, presumably dopaminergic, neurons. The binding in this site, and in the striatum, is not observed in any of the other species we have studied. It displays similar pharmacological characteristics to the Ang II receptor binding site in other regions of the human brain. Overall we demonstrate a discrete pattern of Ang II receptor binding sites in the human brain, which shows a high correlation with the distribution observed in other mammalian species.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1991

Fine structure of the ventral lateral nucleus (VL) of the Macaca mulatta thalamus: cell types and synaptology.

Ultrastructure of the major cerebellar territory of the monkey thalamus, or VL as delineated in sagittal maps by Ilinsky and Kultas-Ilinsky (J. Comp. Neurol. 262:331-364, '87), was analyzed by using neuroanatomical tracing, immunocytochemical, and quantitative morphometric techniques. The VL nucleus contains nerve cells of two types. Multipolar neurons (PN) retrogradely labeled with wheat germ agglutinin-horseradish peroxidase (WGA-HRP) from the precentral gyrus display a tufted branching pattern of the proximal dendrites and have a range of soma areas from 200 to 1,000 microns2 (mean 535.2 microns2, SD = 159.5). Small glutamic acid decarboxylase (GAD) immunoreactive cells (LCN) exhibit sizes from 65 to 210 microns2 (mean 122.5 microns2, SD = 32.8) and remain unlabeled after cortical injections. The two cell types can be further distinguished by ultrastructural features. Unlike PN, LCN display little perikaryal cytoplasm, a small irregularly shaped nucleolus, and synaptic vesicles in proximal dendrites. The ratio of PN to LCN is 3:1. The LCN dendrites establish synaptic contacts on PN somata and all levels of dendritic arbor either singly or as a part of complex synaptic arrangements. They are also presynaptic to other LCN dendrites. Terminals known as LR type, i.e., large boutons containing round vesicles, are the most conspicuous in the neuropil. They form asymmetric contacts on somata and proximal dendrites of PN as well as on distal dendrites of LCN. The areas of these boutons range from 0.7 to 12 microns2 and the appositional length on PN dendrites ranges from 1.1 to 14 microns. All LR boutons except the largest ones become anterogradely labeled from large WGA-HRP injections in the deep cerebellar nuclei. These boutons are also encountered as part of triads and glomeruli, but very infrequently since the latter complex synaptic arrangements are rare. The most numerous axon terminals in the neuropil are the SR type, i.e., small terminals (mean area 0.42 micron2) containing round vesicles. The SR boutons become anterogradely labeled after WGA-HRP injections in the precentral gyrus. They form distinct asymmetric contacts predominantly on distal PN and LCN dendrites; however, their domain partially overlaps that of LR boutons at intermediate levels of PN dendrites. The SR boutons are components of serial synapses with LCN dendrites which, in turn, contact somata and all levels of dendritic arbors of PN. They also participate in complex arrangements that consist of sequences of LCN dendrites, serial synapses, and occasional boutons with symmetric contacts.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Substance P innervation of the rat and cat thalamus. I. Distribution and relation to ascending spinal pathways.

An antiserum for substance P (SP) with minimal cross-reactivity for other tachykinins was employed to map the distribution of SP-positive nerve fibers and terminals in the thalamus of cats and rats with special emphasis on the innervation by these fibers of nuclei related to the somatosensory system. In both species SP innervation is predominantly along the midline, in medial and posterior thalamic regions, and sparser in sensory relays for specific modalities. Among the most densely innervated nuclei are the parafascicular, paraventricular, rhomboid, central medial and parts of mediodorsal, lateral posterior, and ventral lateral geniculate. SP innervation of somatosensory-related nuclei is also evident in central lateral nucleus, posterior complex (PO), and in ventroposterolateral (VPL) nucleus of both cats and rats. In VPL of cats SP fibers and terminals are present along its ventral and lateral border, a paralaminar area in which spinothalamic fibers have been shown to terminate and where neurons responsive to noxious stimuli have been reported. Also in rats the SP innervation of VPL is similar to that of spinothalamic tract fibers. The SP innervation of somatosensory thalamic nuclei may be supplied, at least in part, by spinothalamic afferent as suggested by the depletion of SP after anterolateral chordotomy but not after ablation of the dorsal column nuclei. The presence of SP-positive spinothalamic neurons in the spinal cord is reported in the following paper.

Amino Acid Sequence↗
PubMed1992

Substance P innervation of the rat and cat thalamus. II. Cells of origin in the spinal cord.

Evidence in the preceding paper suggests that fibers and terminals immunopositive for substance P (SP) in somatosensory thalamic nuclei are part of the spinothalamic tract (STT). In this paper, more direct evidence on this point is provided by immunocytochemistry for SP on the cervical spinal cord, alone or combined with the retrograde transport of colloidal gold-labeled wheat germ agglutinin conjugated to enzymatically inactive horseradish peroxidase (WGAapoHRP-Au). In cats and rats pretreated with colchicine and/or anterolateral chordotomy (to increase SP content in cell bodies), many small to large cell bodies are SP-immunopositive especially in laminae I and V, but also in more ventral laminae of the upper cervical cord. SP neurons are also present in the dorsolateral funiculus (in the lateral spinal nucleus, LSN, in rats) but not in the lateral cervical nucleus or in the internal basilar nucleus. In both species there is a considerable degree of overlap in the distribution of SP-positive neurons and that of STT neurons. SP immunocytochemistry in rats after WGAapoHRP-Au injection in the somatosensory thalamus reveals SP-positive STT neurons in LSN, in lamina I and in lamina V, and, to a lesser extent, in more ventral laminae. These results demonstrate that SP is a marker and/or neuromediator for some STT neurons. Together with the evidence discussed in the preceding paper, the results also suggest that SP-positive neurons may be involved in the transmission of nociceptive input.

Animals↗
PubMed1992

The somatosensory thalamus of monkeys: cortical connections and a redefinition of nuclei in marmosets.

Thalamic connections of three subdivisions of somatosensory cortex in marmosets were determined by placing wheatgerm agglutinin conjugated with horseradish peroxidase and fluorescent dyes as tracers into electrophysiologically identified sites in S-I (area 3b), S-II, and the parietal ventral area, PV. The relation of the resulting patterns of transported label to the cytoarchitecture and cytochrome oxidase architecture of the thalamus lead to three major conclusions. 1) The region traditionally described as the ventroposterior nucleus (VP) is a composite of VP proper and parts of the ventroposterior inferior nucleus (VPi). Much of the VP region consists of groups of densely stained, closely packed neurons that project to S-I. VPi includes a ventral oval of pale, less densely packed neurons and finger-like protrusions that extend into VP proper and separate clusters of VP neurons related to different body parts. Neurons in both parts of VPi project to S-II rather than S-I. Connection patterns indicate that the proper and the embedded parts of VPi combine to form a body representation paralleling that in VP. 2) VPi also provides the major thalamic input into PV. 3) In architecture, location, and cortical connections, the region traditionally described as the anterior pulvinar (AP) of monkeys resembles the medial posterior nucleus, Pom, of other mammals and we propose that all or most of AP is homologous to Pom. AP caps VP dorsomedially, has neurons that are moderately dense in Nissl staining, and reacts moderately in CO preparations. AP neurons project to S-I, S-II, and PV in somatotopic patterns.

Animals↗
PubMed1994

Architectonic subdivisions of the motor thalamus of owl monkeys: Nissl, acetylcholinesterase, and cytochrome oxidase patterns.

As the first part of an investigation of the motor thalamus and its cortical connections in the owl monkey, a New World anthropoid primate, we studied thalamic architecture by using stains for Nissl, acetylcholinesterase (AChE), and cytochrome oxidase (CO), in order to identify subdivisions of the ventrolateral thalamic region as well as other nuclei with motor connections. Material was obtained from brains cut in the frontal, horizontal, and parasagittal planes. Our results indicate that the ventrolateral thalamic region (VL) of owl monkeys is a heterogeneous structure composed of several architectonic subdivisions that resemble divisions that have been described in macaques and other Old World anthropoids. All of these subdivisions are more readily distinguished in AChE than in Nissl or CO preparations. The anterior part of VL, VLa (VLo of Olszewski), is characterized by clusters of medium-sized, darkly stained neurons. VLa is also distinguished by AChE-positive cells embedded in a matrix of neurites as well as by a characteristic dark, irregular net of blood vessels. The posterior part of VL is rather uniform cytoarchitectonically and contains large, darkly stained, and sparsely distributed neurons. However, we were able to distinguish three subdivisions of posterior VL that closely correspond to structures described by Olszewski in macaques: a principal segment, VLp (VPLo of Olszewski), a medial segment, VLx ("area X" of Olszewski), and a dorsal segment, VLd (VLc and VLps of Olszewski). In AChE, VLd is much darker than the other divisions. The distinction between VLp and VLx, which together make up the largest part of VL, is less marked, although VLp is somewhat darker and more irregular in appearance in AChE than is VLx.

Acetylcholinesterase↗
PubMed1995

Barreloids in adult rat thalamus: three-dimensional architecture and relationship to somatosensory cortical barrels.

Histochemical staining for cytochrome oxidase (CO) and axonal transport of horseradish peroxidase (HRP) were used to investigate thalamocortical connections in the vibrissa-barrel system of adult rats. CO staining revealed that the medial division of the ventrobasal thalamic nucleus (VBm) consists of intensely stained rod-like configurations, containing thalamocortical projection neurons and intervening neuropil, separated by lighter-stained septa. CO-dark rods span the thickness of VBm, are arranged in a pattern of rows and arcs that resembles the distribution of vibrissae on the mystacial pad, and are similar to the cytoarchitectonic structures termed "barreloids" in the mouse thalamus. Based upon the dimensions of CO-dark structures and the numerical density of neurons in VBm we estimated that a barreloid in the rat may contain 250-300 neurons. HRP injections into lamina IV of the somatosensory cortex led to retrograde labeling of neurons within one or more barreloids. When injections were centered within the CO-dark hollows of cortical barrels about 95% of retrogradely labeled neurons were located in the barreloid that is isomorphic to the injected barrel; up to 5% of labeled neurons were located within a single adjacent barreloid. Barrel hollow injections that also included a barrel side yielded a larger proportion of labeled neurons in non-isomorphic barreloids. Interestingly, such extra-barreloid labeling was topologically consistent in that HRP-labeled neurons were distributed among barreloids that corresponded to cortical barrels nearest the injected barrel side. Injections into the septa between barrels similarly resulted in labeling within barreloids that corresponded to cortical barrels flanking the septal injection site. Following lamina IV injections the density of labeled neurons tended to be highest in the ventrolateral one-half to two-thirds of VBm. Retrograde labeling of neurons in the dorsomedial one-third to one-half of VBm was more often observed after HRP injections at the lamina V/VI border. Thus, barreloid neurons may be heterogeneous with respect to their laminar pattern of terminations within the somatosensory cortex. Some HRP injections in the cortex resulted in orthograde labeling of corticothalamic axons in the barreloids. When observed, labeled corticothalamic axons arborized principally within the barreloid isomorphic to the injected barrel column. Indeed, terminal labeling was densest in the vicinity of neurons retrogradely labeled by the same injection.

Animals↗
PubMed1980

Neurophysiological evidence for tolerance and dependence on opiates: simultaneous multiunit recordings from septum, thalamus, and caudate nucleus.

Multiunit activity was recorded simultaneously from the septum (Spt), medial thalamus (PF-CM complex), and caudate nucleus (CN) in freely behaving rats previously implanted with permanent nichrone semimicroelectrodes (62 mu in diameter). A challenge dose of morphine (10 mg/kg) and its antagonist (naloxone 1.0 mg/kg) was examined in the same animals while they were morphine naive and after they had become morphine physically dependent. Electrophysiological observations indicated that it would be possible to identify three physiological phenomena: 1) activity related to morphine dependency; 2) activity related to tolerance; and 3) activity related to withdrawal. Experimental observations yielded three different electrophysiological patterns of activity related to tolerance. Each of the three central sites (Spt, PF-CM, and CN) exhibited a different response pattern to morphine in morphine physically dependent animals.

Animals↗
PubMed1980

Effects of morphine on sensory-evoked responses recorded from central gray, reticular formation, thalamus, hypothalamus, limbic system, basal ganglia, dorsal raphe, locus ceruleus, and pineal body.

Field potential recordings of acoustic and photic-evoked responses were obtained from 15 brain sites of freely behaving unanesthetized rats previously implanted stereotaxically with permanent electrodes. Several dosages of morphine (1, 5, 10, 30, and 50 mg/kg) were examined. The activities recorded from all the structures in this study, except the cochlear nucleus (CoN), were affected by morphine. Different sensitivities to morphine threshold were observed between structures, and several structures exhibited dose-related patterns (ventromedial hypothalamus (VMH), caudate nuucleus (CN), central gray (CG), hippocampus (Hipp), and lateral septum (Spt)). Several brain sites, after the initial dose of morphine, did not recruit more responses to subsequent doses of the drug, ie, exhibited all-or-none responses (pineal body (PB), medial thalamus (MTh), anterior hypothalamus (AH), mesencephalic reticular formation (MRF), and the dorsal raphe (DR)). In some structures, morphine induced increases in the response amplitudes, while in other sites decreases in response amplitudes were elicited. Biphasic responses, ie, increases in response amplitude after low doses of the drug and decreases in response amplitude after higher dosages, were also observed (VMH, CN, DR, CG, and MRF). The acoustic-evoked responses were affected by morphine more than the photic responses. The present observations indicated that 1) morphine exerts effects in many parts of the central nervous system (CNS); 2) some structures are more sensitive to morphine than others; 3) only a few structures exhibit dose-related patterns and, thus, may represent sites of direct morphine action; 4) some structures exhibit all-or-none responses; and 5) morphine depressed activity in some structures and increased activity in others, ie, morphine elicited different effects in different structures.

Acoustic Stimulation↗
PubMed1998

Improvements in daily functioning after deep brain stimulation of the thalamus for intractable tremor.

Deep brain stimulation (DBS) of the thalamus reduces tremor in patients with essential tremor (ET). However, few studies have determined the degree of improvement in daily functioning associated with DBS. We developed a self-report Tremor Activities of Daily Living Scale (TADLS) to compare daily functioning with the stimulator turned on and off. Patients rated their performance on the 30 items of the TADLS with the stimulator turned off and then on. They also performed 10 activities under the supervision of a clinician who rated their functional ability with stimulation off and then on. There was a 58% improvement in self-rated TADLS scores in patients with DBS with the stimulator on compared with stimulation off. When activities were rated by the clinician, the average improvement in functioning with the stimulator on was 54%. There were reasonably high correlations between patient and clinician ratings of functioning. ET patients have a marked improvement in daily functioning with thalamic DBS.

Activities of Daily Living↗
PubMed2004

BOLD response to direct thalamic stimulation reveals a functional connection between the medial thalamus and the anterior cingulate cortex in the rat.

Recent functional neuroimaging studies in humans and rodents have shown that the anterior cingulate cortex (ACC) is activated by painful stimuli, and plays an important role in the affective aspect of pain sensation. The aim of the present study was to develop a suitable stimulation method for direct activation of the brain in fMRI studies and to investigate the functional connectivity in the thalamo-cingulate pathway. In the first part of the study, tungsten, stainless steel, or glass-coated carbon fiber microelectrodes were implanted in the left medial thalamus (MT) of anesthetized rats, and T2*-weighted gradient-echo (GE) images were obtained in the sagittal plane on a 4.7 T system (Biospec BMT 47/40). Only the images obtained with the carbon fiber electrode were acceptable without a reduction of the signal-to-noise ratio (SNR) and image distortion. In the second part of the study, a series of two-slice GE images were acquired during electrical stimulation of the MT with the use of a carbon fiber electrode. A cross-correlation analysis showed that the signal intensities of activated areas in the ipsilateral ACC were significantly increased by about 4.5% during MT stimulation. Functional activation, as assessed by the distribution of c-Fos immunoreactivity, showed strong c-Fos expression in neurons in the ipsilateral ACC. The present study shows that glass-coated carbon fiber electrodes are suitable for fMRI studies and can be used to investigate functional thalamocortical activation.

Animals↗
PubMed2004

Comparative proteome analysis of thalamus in MK-801-treated rats.

Two-dimensional gel-electrophoresis in combination with mass spectrometry is a powerful approach to compare protein expression in brain tissues. Using this proteomic approach, and based on the hypothesis that schizophrenia involves hypoglutamergic brain function, alterations in protein levels in the thalamus of rats treated with the N-methyl-D-aspartate (NMDA) receptor antagonist [+]-5-methyl-10,11-dihydro-5H-dibenzo-[a,d]-cycloheptene-5,10-iminehydrogenmaleate (MK-801), as compared to saline-treated animals, were assessed in an unbiased fashion. The rats were divided into two groups; group 1 (short-term treated) and group 2 (long-term treated). In group 1, the levels of seven proteins were increased and four proteins reduced. In group 2, the levels of six proteins were reduced. Several of the altered proteins (heat shock proteins 60 and 72, albumin, dihydropyrimidinase related protein-2, aldolase c, and malate dehydrogenase) have previously been connected to schizophrenia. Alterations of other proteins (dihydrolipoamide acetyltransferase component of pyruvate dehydrogenase complex E2, guanine deaminase, alpha-enolase, aconitase, ATP-synthase and alpha-internexin), have not, to the best of our knowledge, earlier been implicated in schizophrenia pathology. Our results show the high potential of using proteomic methods for the validation of animal models of schizophrenia and to identify new proteins involved in the pathophysiological mechanisms of schizophrenia.

Animals↗
PubMed1999

Subcortical mechanisms in language: lexical-semantic mechanisms and the thalamus.

Four previously published cases of dominant thalamic lesion in which the author has participated are reviewed to gain a better understanding of thalamic participation in lexical-semantic functions. Naming deficits in two cases support Nadeau and Crosson's (1997) hypothesis of a selective engagement mechanism involving the frontal lobes, inferior thalamic peduncle, nucleus reticularis, and other thalamic nuclei, possibly the centromedian nucleus. This mechanism selectively engages those cortical areas required to perform a cognitive task, while maintaining other areas in a state of relative disengagement. Deficits in selective engagement disproportionately affect lexical retrieval based on semantic input, as opposed to lexical and sublexical processes, because the former is more dependent upon this attentional system. The concept of selective engagement is also useful in understanding thalamic participation in working memory, as supported by data from one recent functional neuroimaging study. Other processes also may be compromised in more posterior thalamic lesions which damage the pulvinar but not other components of this selective engagement system. A third case with aphasia after a more superior and posterior thalamic lesion also had oral reading errors similar to those in neglect dyslexia. The pattern of deficits suggested a visual processing problem in the early stages of reading. The fourth case had a category-specific naming deficit after posterior thalamic lesion. Taken together, the latter two cases indicate that the nature of language functions in more posterior regions of the dominant thalamus depends upon the cortical connectivity of the thalamic region. Together, findings from the four cases suggest that thalamic nuclei and systems are involved in multiple processes which directly or indirectly support cortical language functions.

Aphasia↗
PubMed2002

Disruption of the blood-brain barrier and neuronal cell death in cingulate cortex, dentate gyrus, thalamus, and hypothalamus in a rat model of Gulf-War syndrome.

We investigated the effects of a combined exposure to restraint stress and low doses of chemicals pyridostigmine bromide (PB), N, N-diethyl-m-toluamide (DEET), and permethrin in adult male rats, a model of Gulf-War syndrome. Animals were exposed daily to one of the following for 28 days: (i) a combination of stress and chemicals (PB, 1.3 mg/kg/day; DEET, 40 mg/kg/day; and permethrin, 0.13 mg/kg/day); (ii) stress and vehicle; (iii) chemicals alone; and (iv) vehicle alone. All animals were evaluated for: (i) the disruption of the blood-brain barrier (BBB) using intravenous horseradish peroxidase (HRP) injections and endothelial barrier antigen (EBA) immunostaining; (ii) neuronal cell death using H&E staining, silver staining, and glial fibrillary acidic protein (GFAP) immunostaining; and (iii) acetylcholinesterase (AChE) activity and m2-muscarinic acetylcholine receptors (m2-AChR). Animals subjected to stress and chemicals exhibited both disruption of the BBB and neuronal cell death in the cingulate cortex, the dentate gyrus, the thalamus, and the hypothalamus. Other regions of the brain, although they demonstrated some neuronal cell death, did not exhibit disruption of the BBB. The neuropathological changes in the above four brain regions were highly conspicuous and revealed by a large number of HRP-positive neurons (21-40% of total neurons), a decreased EBA immunostaining (42-51% reduction), a decreased number of surviving neurons (27-40% reduction), the presence of dying neurons (4-10% of total neurons), and an increased GFAP immunostaining (45-51% increase). These changes were also associated with decreased forebrain AChE activity and m2-AchR (19-25% reduction). In contrast, in animals exposed to stress and vehicle or chemicals alone, the above indices were mostly comparable to that of animals exposed to vehicle alone. Thus, a combined exposure to stress and low doses of PB, DEET, and permethrin leads to significant brain injury. The various neurological symptoms reported by Gulf-War veterans could be linked to this kind of brain injury incurred during the war.

Animals↗
PubMed1996

The role of the thalamus in "top down" modulation of attention to sound.

By correlating rCBF with rate of presentation of tones we used PET to identify brain regions where auditory signals elicited a transient neural response. In one condition volunteers were asked to attend to the tones and ignore visual signals, while in the second condition they were asked to attend to the visual signals and ignore the tones. Activity in primary auditory cortex and adjacent areas was strongly correlated with rate of tone presentation, but this relationship was not affected by the direction of attention. In only one area, the right midthalamus, was the response to tones modulated by attention. In this area responses to tones occurred when attention was directed to sound, but not when attention was directed to visual stimuli. There is considerable evidence that the EEG evoked response to tones (N100/Nd response) is strongly modulated by attention and arises in auditory cortex. The ERP is the sum of activity from many sources. The amplitude of this response reflects not only the amount of activity in these sources, but also the degree of synchrony between them. The difference between these typical ERP results and our result from PET could be resolved if we assume that, in our paradigm, attention did not increase the amount of neural activity in auditory cortex, but rather the degree of synchrony between many sources. The signal in the thalamus, which we observed only when volunteers were attending to the tones, might provide the basis for this synchrony.

Adult↗
PubMed1980

Chronic self-stimulation of the medial posterior inferior thalamus for the alleviation of deafferentation pain.

Since current techniques yield uncertain results on deafferentation pain, chronic brain stimulation may presumably be a valuable alternative method, without deterrent side-effects. Disappointing results with stimulation of the somato-sensory structures prompted the selection of the medial posterior inferior thalamus and adjacent brain stem for chronic stimulation in pain states of central origin. Six such cases are reported. Abolition of the hyperpathia and marked reduction in the deep background pain was achieved in 2 cases, and disappearance of the hyperpathia and moderate reduction in the deep pain was obtained in another 2, but none had complete alleviation of pain. The follow-up time ranged between 6 and 42 months. Reversal of analgesia by naloxone was not observed. Acute experimentally-induced pain was not modified by stimulation.

Analgesia↗
PubMed1987

Computer-assisted analysis of functional anatomy of human ventrolateral thalamus.

A three-dimensional map was created by a computer-assisted analysis of functional and somatotopic organization of the target area in the human ventrolateral thalamus. Stimulation in the target area mostly elicited increased tone in skeletal muscles, with a concomitant decrease or stop of tremor. Despite averaging of all responses, no clear somatotopic organization could be demonstrated for the tonifying stimulation effects. In addition, somatosensory-evoked potentials were recorded, indicating an afferent projection to the target area.

Brain Mapping↗