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At least 19 recordsLinked to original sources
PubMed1978

[Neuronal activity of the midbrain central grey upon stimulation of the amygdaloid complex and the subthalamus].

The influence of stimulation of the amygdaloid complex and the subthalamus on neuronal activity of the central grey substance were studied in acute experiments on rats. The amygdaloid stimulation produced inhibition in 72% of the central grey substance neurons; stimulation of subthalamus--activation in 59%. Repetitive stimulation of the amygdaloid complex evoked prolonged changes in the neuronal activity. The convergence of impulses from the amygdaloid complex and subthalamus was observed in 31 of 114 reactive neurons. 71% of cells showed inhibition.

Amygdala↗
PubMedDate not supplied

Effect and time course of deep brain stimulation of the globus pallidus and subthalamus on motor features of Parkinson's disease.

We studied the effect and temporal profile of deep brain stimulation (DBS) of the globus pallidus and subthalamic nucleus on the motor signs of Parkinson's disease (PD). Four patients with bilateral deep brain stimulators of the globus pallidus and four patients with bilateral deep brain stimulators of the subthalamus were studied while taking no medication and at 15 and 30 minutes and 1, 2, 4, and 6 hours after turning stimulation on. An immediate (15 minutes) and sustained (6 hours) benefit was observed for all the motor manifestations of PD for both stimulation sites. Deep brain stimulation of the globus pallidus and subthalamus is highly effective in reducing all the cardinal motor features of PD.

Electric Stimulation Therapy↗
PubMed1980

The morphology of the diencephalon in the Prosimii. II. The Lemuroidea and Lorisoidea. Part II. Epithalamus, subthalamus and hypothalamus.

This study (Part II) deals with the comparative structure of the epithalamus, subthalamus and hypothalamus. The same prosimian species used in the study of the thalamus and metathalamus (Part I) are used here. The epithalamus does not show any remarkable change in the phylogeny of the prosimian diencephalon. In the subthalamus, the nucleus subthalamicus enlarges progressively in size, and shows a very close relationship to the zona incerta, the fields of Forel and the pregeniculate body. The zona incerta is observed to consist of two parts the ventral part relating to the nucleus subthalamicus and the dorsal part ot the nucleus reticularis. The fields of Forel is well differentiated into fields H1 and H2. The hypothalamus is described here having four regions--preoptic, suraoptic, infundibular and mamillary. The preoptic and supraoptic regions appear to be indivisible in all prosimian species, for the constituent nuclei of both regions extend rostrally and caudally in the anterior part of the hypothalamus. The nucleus supraopticus is evidently complicated in structure, as it appears not only to have two separate parts, but also an isthmus that connects these parts. This interlinking strand of cells is termed not the nucleus supraopticus diffuses but the nucleus/area commissuralis postopticus. The nucleus paraventricularis is a massive nucleus, and appears to have a non-neurosecretory part and a neurosecretory part. An interesting feature has been observed in certain prisimian species such as Galago demidovii, Lepilemur and Loris gracilis, the nucleus paraventricularis accessorius which may be regarded as an erratic derivative of either nucleus paraventricularis or nucleus supraopticus. The nucleus tuberalis lateralis makes its first definitive appearance in the Prosimii. The nucleus ventromedialis hypothalami appears to be larger and more clearly defined than the nucleus dorsomedialis hypothalami. From the latter nucleus, a cellular condensation has been observed to stretch lateralwards--nucleus dorsolateralis hypothalami. The hypothalamic areas--anterior, dorsal, lateral and posterior--are not very much different among the prosimian species, although the anterior and posterior hypothalamic areas appear to have more attributes of a nucleus than an area. The mamillary region is very well developed in all prosimian species. The medial mamillary nucleus is clearly divided into several parts. The nucleus mamillaris lateralis is poorly developed, but can be identified lying between the lateral part of the medial mamillary nucleus and the nucleus intercalatus. In regard to the latter nucleus, there is some topographical confusion, but the nucleus intercalatus is easily identified as the bed nucleus of the supramamillary commissure.

Animals↗
PubMed1976

The diencephalon of the vervet monkey (Cercopithecus aethiops). Part II: epithalamus, subthalamus and hypothalamus.

The nuclear configuration and topography of the epithalamus, subthalamus and hypothalamus of the vervet monkey (Cercopithecus aethiops) are described and compared with those of other primates, particularly the macaque monkey. The epithalamus does not show any striking structural differences, except some architectonic differentiation in the lateral habenular nucleus. The subthalamus is a phylogenetically stable structure throughout the primate scale; it does not show any significant changes, except that it extends less rostrally and that the nuclei entopeduncularis and peripeduncularis are much smaller and less well defined in the vervet monkey than those in the diencephalon of lower primates. The nucleus subthalamicus and the fields of Forel, though small in size, are comparatively well developed; the zona incerta appears to be differentiated cytoarchitectonically into two parts. The hypothalamus is divided morphologically into four regions--the preoptic, supraoptic, infundibular and mamillary regions. Although the hypothalamus of the vervet monkey is topographically identifiable with those of other primates, there are cyto- and myeloarchitectonic differences to be found in certain hypothalamic nuclei and areas. The preoptic region is small and poorly delimited from the parolfactory region antierorly and the supraoptic region posteriorly. The nucleus paraventricularis is large and well differentiated into secretory and non-secretory portions; the nucleus supraopticus does not show cellular separation into dorsolateral and ventromedial parts as clearly as they are in other primates. The nucleus dorsomedialis is not as well defined as the nucleus ventromedialis like it is in other primates. The nucleus tuberalis lateralis is comparably small, and is not split into several cellular groups as it is in higher primates. The posterior hypothalamic area is morphologically the best definable of the hypothalamic areas. The mamillary region is developmentally advanced, and very well differentiated into medial, lateral and intercalated nuclei.

Animals↗
PubMed1979

Somatic and endocrine consequences of electrolytic lesions in the epi and subthalamus of weanling and mature rats.

Weanling rats received lesions in the zona incerta (ZIN). Sham-operated rats served as controls. Two experiments were performed several months apart. The animals were maintained on lab chow and tap water for 30 days and then sacrificed. Ponderal and linear growth, food and water intake, water/food-intake ratio, and pituitary weights were significantly reduced in rats with ZIN lesions. Plasma, growth hormone, insulin, glucose, and body composition were normal, however. Weanling and mature rats received lesions in the medial habenula (HAB). Sham-operated rats served as controls. The experiment lasted 44 days postoperatively. In the weanling Hab-lesioned rats, body weight changes, body composition pituitary, weight, food and water intake, water/food-intake ratio, and plasma insulin were normal. Linear growth was slightly (p < 0.05) reduced. In the mature HAB-lesioned rats, all the above parameters were normal except for water intake, which was slightly (p < 0.05) reduced. The pathways by which the epi- and subthalamus may influence the observed changes--or the lack thereof--are discussed.

Animals↗
PubMed2002

Subdyskinetic apomorphine responses in globus pallidus and subthalamus of parkinsonian patients: lack of clear evidence for the 'indirect pathway'.

OBJECTIVES: Previous studies suggested that the hypo-activity of the external pallidus (GPe) might drive the hyper-activity of subthalamic neurons, which underlies the cardinal symptoms of Parkinson's disease. We have challenged this view, based on the so-called 'indirect pathway', by recording apomorphine effects from both structures of parkinsonian patients, at rest and during passive movements. METHODS: We performed single-unit recordings from external pallidus (GPe), internal pallidus (GPi) and subthalamic nucleus (STN) during the stereotactic neurosurgery aimed to implant deep brain stimulating electrodes in GPi or STN. First, we verified the firing frequency of each structure in off-state conditions. Then, therapeutic, subdyskinetic concentrations of the dopaminergic agonist apomorphine was delivered to assess each nucleus response. RESULTS: The firing rate of STN averaged about 40 Hz; a large proportion (75%) of STN units exhibited marked responsiveness to passive movements. Apomorphine reduced the firing discharge of parkinsonian STN in all cells, although electrophysiological recovery was usually incomplete. Movement-related activity was also dramatically reduced. In contrast, apomorphine failed to modify the firing frequency of GPe, despite the amelioration of hypo-kinetic symptoms and the simultaneous inhibition of GPi firing discharge. CONCLUSIONS: We demonstrate that part of the models on basal ganglia circuitry needs to be revised. The re-balancing of STN hyper-activity, when patients benefit from dopaminergic therapy, is not due to an increased input from GPe, but, instead, due to changes in STN intrinsic firing properties and/or modulation of glutamatergic inputs.

Adult↗
PubMed1981

Slow potentials in the human subthalamus associated with rapid arm movements.

During stereotactic operations brain potentials were recorded from the zona incerta of Parkinsonian patients. When the patient performed a rapid contralateral elbow flexion in response to a light signal, a slow positive or positive-negative EEG potential preceded the EMG activation by 30-130 ms (average 60 ms) and extended into the biceps activation phase. It was not evoked by the light flash alone or by rapid passive flexion. The potential may be interpreted as a correlate of movement-related activity of cerebellothalamic pathways mediating command signals for rapid arm movements. In support of this assumption, a marked delay of contralateral biceps activation followed coagulation of the recording site.

Arm↗
PubMed1983

Pallidal inputs to subthalamus: intracellular analysis.

Neuronal responses of the subthalamic nucleus (STH) to stimulation of the globus pallidus (GP) and the substantia nigra (SN) were studied by intracellular recording in the decorticated rat. (1) GP and SN stimulation evoked antidromic spikes in STH neurons with a mean latency of 1.2 ms and 1.1 ms, respectively. Based on the above latencies, the mean conduction velocity of the STH neurons projecting toward GP was estimated to be 2.5 m/s, and that toward SN was 1.4 m/s. Many STH neurons could be activated following stimulation of both GP and SN, indicating that single STH neurons project to two diversely distant areas. In spite of differences in conduction distance of GP and SN from STH, differences in the conduction velocities of bifurcating axons make it possible for a simultaneous arrival of impulses in the target areas to which these STH neurons project. (2) GP stimulation evoked short duration (5-24 ms) hyperpolarizing potentials which were usually followed by depolarizing potentials with durations of 10-20 ms. These potentials were tested by intracellular current applications and intracellular injections of chloride ions. The results indicated that the hyper- and depolarizing potentials were IPSPs and EPSPs respectively. These IPSPs were considered to be monosynaptic in nature since changes in the stimulus intensities of GP did not alter the latency of IPSPs. The mean latency of the IPSPs was 1.3 ms. Based on the above mean latency the mean conduction velocity of GP axons projecting to STH was estimated to be 3.8 m/s. (3) Analysis of electrical properties of STH neurons indicated that: (i) input resistance estimated by a current-voltage relationship ranged from 9 to 28 M omega; (ii) the membrane showed rectification in the hyperpolarizing direction; (iii) direct stimulation of neurons by depolarizing current pulses produced repetitive firings with frequencies up to 500 Hz. (4) Morphology of the recorded STH neurons was identified by intracellular labeling of neurons with horseradish peroxidase. Light microscopic analysis indicated that the recorded neurons were Golgi type I neurons with bifurcating axons projecting toward GP and SN.

Animals↗
PubMed1998

Trigeminal projections to thalamus and subthalamus in the hedgehog tenrec.

The objective of the present study was the identification and characterization of the trigemino-diencephalic target areas in the Madagascan lesser hedgehog tenrec in order to get a more comprehensive view on the mammalian somatosensory thalamus, its evolution and representation in different species. Such an analysis has been considered important because in lower mammals the head and face are relatively well represented, but their ascending trigeminal projections have scarcely been analysed. Following injections of different tracer substances into the rostral and caudal portions of the trigeminal nuclear complex the most prominent area of termination was found in the medial ventroposterior nucleus. These projections were patchy and scarcely overlapped the region previously shown to receive spinal and dorsal column nuclear afferents. On the basis of the laterality and the intensity of the projections, two subdivisions were distinguished, the principal portion and the accessory portion receiving a dense contralateral and a weak bilateral input, respectively. They were considered equivalents to the magnocellular and parvocellular subdivisions of the medial ventroposterior nucleus in more differentiated mammals. In the latter species, however, the overlap between trigeminal and parabrachial fibres appears less extensive than in the tenrec. In addition, a weak bilateral projection was shown from the caudal trigeminal nucleus to the caudal and dorsal subdivision of the nucleus submedius. There was little, if any evidence for a trigeminal projection to the intralaminar nuclei and we failed to identify a correlate to the posterior nuclear complex of higher mammals. On the other hand, there was a distinct contralateral projection to the ventral portion of the zona incerta. This projection was of similar strength as the projection to the medial ventroposterior nucleus; it supports the notion that the zona incerta may play a crucial role in relaying trigeminal information.

Animals↗