We analyzed the electrophysiological patterns of synchronization of cortical EEG (areas 4, 5, 7, 21, 17, 18, 22) and thalamic field (EThG) (ventral posterior lateral nucleus-VPL), and the influence of modulatory systems originating in the pedunculo-pontine tegmentum (PPT) and locus coeruleus (LC) on the discharge pattern of thalamic neurons during OA. 
Here we used laser scanning photostimulation to compare in young mice (9-12 days old) the organization of the reticular inputs to first- and higher-order somatosensory relays, namely, the ventral posterior lateral nucleus and posterior nucleus, respectively. The reticulothalamic input footprints to the ventral posterior lateral nucleus neurons consisted of small, single, topographically organized elliptical regions in a tier away from the reticulothalamic border.
Area PE sends a major projection terminating with small endings to the thalamic lateral posterior nucleus (LP), ventral posterior lateral nucleus (VPL), medial pulvinar (PuM) and, but fewer, to ventral lateral posterior nucleus, dorsal division (VLpd), central lateral nucleus (CL) and center median nucleus (CM), whereas giant endings formed restricted terminal fields in LP, VPL and PuM.
This report focuses on STT input to the ventral posterior lateral nucleus (VPL) and the subjacent ventral posterior inferior nucleus (VPI), where prior anterograde tracing studies identified scattered STT terminal bursts and a dense terminal field, respectively.
During our pathoanatomical study we disclosed (i) a consistent degeneration of the ventral anterior, ventral lateral and reticular thalamic nuclei; (ii) a degeneration of the ventral posterior lateral nucleus and inferior and lateral subnuclei of the pulvinar in the majority of these SCA3 patients; and (iii) a degeneration of the ventral posterior medial and lateral posterior thalamic nuclei, the lateral geniculate body and some of the limbic thalamic nuclei in some of them.
Magnetic resonance imaging showed low intensity areas (left posterior limb of internal capsule, left cerebral peduncle of middle brain, a part of left substantia nigra, left amygdala, ventral posterior lateral nucleus and ventral anterior nucleus of left thalamus, left lateral geniculate body, and left occipital lobe) in T1 weighted image, due to the infarct in the left anterior choroidal artery territory.
For WDR neurons, the latency to antidromic activation of the ventral posterior lateral nucleus of the thalamus showed no difference between the aged and adult rats.
We used laser scanning photostimulation through a focused UV laser of caged glutamate in an in vitro slice preparation through the rat's somatosensory thalamus to study topography and connectivity between the thalamic reticular nucleus and ventral posterior lateral nucleus. We were thus able to confirm and extend previous observations based mainly on neuroanatomical pathway tracing techniques: the projections from the thalamic reticular nucleus to the ventral posterior lateral nucleus have precise topography. The reticular zone, which we refer to as a "footprint," within which photostimulation evoked inhibitory postsynaptic currents (IPSCs) in relay cells, was relatively small and oval, with the long axis being parallel to the border between the thalamic reticular nucleus and ventral posterior lateral nucleus.
Projection of 3D magnetic resonance images onto a human thalamic atlas revealed a lesion involving the anterior two thirds of the ventral posterior lateral nucleus (VPL) and, to a lesser extent, the ventral posterior medial (VPM) and inferior (VPI) nuclei.
In the course of mapping the dorsal thalamus, we also studied neurons in a subset of thalamic nuclei (the caudal part of the ventral lateral nucleus (VLc), the oral part of the ventral posterior lateral nucleus (VPLo), the parvocellular part of the ventral anterior nucleus (VApc)) lateral to the MD and just across the internal medullary lamina.
By defining the boundaries of the thalamic nuclei, they were able to relate effective DBS to electrode location within the anterior region of the ventral posterior lateral nucleus--the proprioceptive shell of the sensory nucleus--and the posteroventral region of the ventral lateral nucleus, which are equivalent to the Vim defined by Hassler, et al..
The model consists of three regions integrated into a single structure: tactile receptors representing the glabrous surface of the hand, ventral posterior lateral nucleus of the thalamus and area 3b of the primary somatosensory cortex, reproducing the main aspects of the connectivity of these regions.
Each neuron was identified by antidromic activation from the ventral posterior lateral nucleus of thalamus and classified by its initial responses to mechanical stimuli as wide dynamic range (WDR) or high-threshold (HT).
Magnetic resonance image examination was performed, and it showed acute cerebral infarction at right posterior cerebral artery territory including right thalamus (ventral posterior lateral nucleus).
The ventral anterior nucleus (VA) and the ventral lateral nucleus pars oralis (VLo) contained a greater density of pallidal labeling while a greater density of cerebellar label was observed more caudally in the ventral posterior lateral nucleus pars oralis (VPLo) as well as in nucleus X (X).
However, these changes in representational maps were in most cases unaccompanied by significant alterations in gene expression for calcium calmodulin-dependent protein kinase isoforms, for glutamic acid decarboxylase, GABA(A) receptor subunits, GABA(B) receptors, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) or N-methyl-D-aspartate (NMDA) receptor subunits.Mapping studies after lesions in the ventral posterior lateral nucleus (VPL) of the thalamus revealed no changes in cortical representations of the hand or fingers until >15% of the thalamic representation was destroyed, and only slight changes until approximately 45% of the representation was destroyed, at which point the cortical representation of the finger at the center of a lesion began to shrink.
Intracellular potentials were recorded from nociceptive neurons(NCNs) in primary somatosensory cortex area (SI) of cats in response to stimulation of ventral posterior lateral nucleus (VPL).
Anterograde transport of wheat germ agglutinin-horseradish peroxidase conjugate and biotinylated dextran amine demonstrated that the ferret CTT terminates extensively in the peripheral parts of the ventral posterior lateral nucleus.
Imagery of pain uniquely activated the somatosensory area, and areas in the left insula and bilaterally in the ventral posterior lateral nucleus of the thalamus.
The ventral posterior lateral nucleus contains the largest proportion of the cervicothalamic tract terminals (79%) and most (72%) of these are type I terminals (form compact clusters of 5-30 boutons). These findings indicate a high degree of synaptic security in the transmission between cervicothalamic tract fibers and neurons in the ventral posterior lateral nucleus and highlight the role of this nucleus in faithful transmission of cervicothalamic tract input to the cerebral cortex.
The long-term consequences of thoracic spinothalamic tract lesion on the physiological properties of neurons in the ventral posterior lateral nucleus of the thalamus in monkeys were assessed.
The somatosensory thalamus (here we examine neurons in the caudal cutaneous portion of ventral posterior lateral nucleus, VPL) is composed of a somatotopic arrangement of anteroposteriorly oriented rods.
We found that the SMA thalamocortical neurons occupied a wide band extending from the ventral anterior nucleus pars principalis (VApc) through the ventral lateral nucleus pars oralis (VLo) and the ventral lateral nucleus pars medialis (VLm) and into to the ventral lateral nucleus pars caudalis (VLc) including a portion of ventral posterior lateral nucleus pars oralis (VPLo) and nucleus X.
The authors used electron microscopic immunocytochemistry to localize AMPA selective GluR 2/3 subunits (GluR2/3) and NMDA receptor subunit 1 (NMDAR1) in rat and cat ventral posterior lateral nucleus (VPL) and in the associated sector of the reticular nucleus (RTN).
We found dense single label in the central portion of the ventral anterior nucleus pars principalis (VApc) and the ventral lateral nucleus pars oralis (VLo) following the GPi injections or in the central portion of the ventral posterior lateral nucleus pars oralis (VPLo) and nucleus X (X) following the cerebellar nuclei injections.
The axons of labeled RTN cells gave rise to collaterals within the RTN and continued into the dorsal thalamus where they terminated predominately in the ventral posterior lateral nucleus (VPL).
Four physiologically identified thalamocortical relay neurons in the ventral posterior lateral nucleus (VPL) of the cat thalamus were injected with horseradish peroxidase and subjected to quantitative electron microscopy after pre- or postembedding immunostaining for gamma-aminobutyric acid to reveal synaptic terminals of thalamic inhibitory neurons.
Terminals from the anterior interposed nucleus were located slightly rostral and lateral to those from the posterior interposed nucleus, predominantly in the rostral pole of the ventral posterior lateral nucleus.
Most neurons were located in the ventral posterior lateral nucleus (VPL), and a smaller number of cells was also found in a variety of thalamic nuclei around VPL.
Dorsoventral penetrations were made through the ventral posterior lateral nucleus (VPL) using high intensity electrical stimulation of the medial articular nerve (MAN), which contains a high proportion (80%) of A delta and C afferent fibres.
Pre-embedding immunoperoxidase (for serotonin) and postembedding immunogold (for gamma-aminobutyric acid; GABA) labelling were combined at light and electron microscopic levels to demonstrate the neuronal targets of serotonin (5-HT) afferents in the ventral posterior lateral nucleus (VPL) of the cat thalamus.
The ventral posterior lateral nucleus (VPL) of the monkey thalamus was investigated by histochemical staining for cytochrome oxidase (CO) activity and by immunocytochemical staining for the calcium-binding proteins parvalbumin and 28 kDa calbindin.
Cells antidromically activated from the thalamus projected to the rostral part of the ventral posterior lateral nucleus, regardless of their physiological category, and included many with nociceptive input.
Single- and multi-unit recordings were made with tungsten electrodes in dorsoventral penetrations through the ventral posterior lateral nucleus (VPL) during electrical stimulation of the medial articular nerve (MAN) of the cat's knee joint at an intensity sufficient to excite slowly conducting unmyelinated fibers.
Cortical EPs were produced by test stimuli delivered to a hindpaw or the thalamic ventral posterior lateral nucleus (VPL; electrical stimulation), or by photic stimulation of the eyes or electrical stimulation of contralateral homotopical cortex (transcallosal EPs).
Recording sites were located throughout VL, including the "border region" with the ventral posterior lateral nucleus (VPL).
The other two STT fibers were smaller, with diameters of 2.5 and 2.3 microns, conduction velocities of 15 and 19 m/s, and terminal fields made up of a few small boutons at the borders of the ventral posterior lateral nucleus (VPL).
Area 6DC also exhibited reciprocal connections with the ventral lateral (VL) complex and the ventral posterior lateral nucleus, pars oralis (VPLo).
A recording electrode was placed stereotactically in the ventral posterior lateral nucleus of thalamus (VPL), and a ball electrode was placed over the surface of the hind limb region of primary sensory cortex.
Stimulation to the limbs produced crescent-shaped clusters of metabolic label arranged in a somatotopically organized fashion in the ventral posterior lateral nucleus (VPL).
The nociceptive units were located in the periphery of the ventral posterior lateral nucleus (VPL) of the thalamus.
We recorded regional cerebral blood flow, somatosensory evoked potentials, and auditory evoked potentials in the thalamic relay nuclei (ventral posterior lateral nucleus and medial geniculate body) and in the somatosensory and auditory cortices during and after 1 hour of transient left middle cerebral artery occlusion in nine cats.
In these animals, label was located mainly in suprageniculate and pulvinar oralis, caudal and oral divisions of ventral posterior lateral nucleus, the lateral half of ventral posterior inferior nucleus, and zona incerta, while in the medial thalamus label was primarily in two distinct bands in medial dorsal nucleus and in the posterior dorsal portion of central lateral nucleus.
All neurons were antidromically activated from the ventral posterior lateral nucleus of the thalamus.
The responses to lateralized flank stimulation included reliable contralateral elevations in 2DG uptake in the ventral posterior lateral nucleus of the thalamus (VPL), the dorsal mesencephalic central gray (dCG), and the tectum.
Medial lemniscal axons were identified by extra- and intracellular recording in the thalamic ventral posterior lateral nucleus (VPL) of cats and injected intracellularly with horseradish peroxidase (HRP).
Evoked responses to peripheral stimulation were recorded in the medial lemniscus, sensory thalamus (ventral posterior lateral nucleus, caudal division, VPLc) and somatosensory cortex.
cells were in or around the ventral posterior lateral nucleus.
STT cells were antidromically activated from the medial thalamus (MT) and the ventral posterior lateral nucleus (VPL) and received viscerosomatic convergent input from the cardiopulmonary sympathetic afferents and the left chest-forearm region.
The activity of 132 neurons in the caudal part of the ventral posterior lateral nucleus (VPLc) of the thalamus was recorded from 23 anesthetized monkeys.
Twenty-two STT cells projected to the ventral posterior lateral nucleus (L-STT cells), 11 to the medial thalamus (M-STT cells), and 9 to both thalamic regions (LM-STT cells).
Effects of injecting bradykinin (2 micrograms/kg) into the left atrium on spinothalamic tract neurons projecting to medial thalamus (M-STT cells), to the ventral posterior lateral nucleus of the thalamus (L-STT cells), or to both (LM-STT cells) were examined in 18 monkeys (Macaca fascicularis) anesthetized with alpha-chloralose.
In the diencephalon, gracile fibers leave the MLLC and form a crescentlike terminal field along the extreme lateral border of the ventral posterior lateral nucleus (VPL) of the thalamus.
Spinothalamic tract neurons projecting to medial thalamus (M-STT cells), ventral posterior lateral nucleus (VPL) of the thalamus (L-STT cells), or both thalamic regions (LM-STT cells) were studied in 19 monkeys anesthetized with alpha-chloralose.
Neurons of T2 to T4 spinal segments were antidromically activated from the medullary reticular formation and the contralateral region in or near the ventral posterior lateral nucleus of the thalamus.
The cells were identified by antidromic activation from the contralateral ventral posterior lateral nucleus of the thalamus.
Raphe- and reticulospinal tract cells could often (31/46 cells tested) be excited following stimulation in the ventral posterior lateral nucleus of the thalamus.
A survey was made of neurons located in the ventral posterior lateral nucleus of the cat thalamus and its immediate vicinity for elements with specifically nociceptive properties. The nociceptive neurons appear to be located in a shell that surrounds the main tactile projection to the ventral posterior lateral nucleus and that retains at least part of the topographic arrangement characteristic of the tactile core.
The cells were generally activated antidromically from the caudal part of the ventral posterior lateral nucleus of the thalamus..
The spread of cooling from the tip of a cryoprobe placed in the ventral posterior lateral nucleus of the thalamus in 10 cats was determined.
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