Changes in the organization of the ventroposterior lateral thalamic nucleus after digit removal in adult raccoon

Rasmusson, Douglas D.

doi:10.1002/(sici)1096-9861(19960101)364:1<92::aid-cne8>3.3.co;2-v

Cited by 17 publications

(23 citation statements)

References 32 publications

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“…2 B Left and C Left. The results from the deafferented, D4 representation studied before cortical lesion confirmed previous results indicating that peripherally denervated thalamus does undergo reorganization (14). The neurons in this area (n ϭ 135) had RFs that were located on the adjacent D3, D5, and͞or the underlying palm area.…”

Section: Resultsmentioning

confidence: 82%

“…The denervated D4 region of VPL was identified on the basis of the normal D3 and D5 RFs in surrounding penetrations and on the abnormal RFs within a penetration thought to be in the D4 region, as described (14). Examples are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Two raccoons were intact controls. The other 10 raccoons underwent amputation of the fourth digit (D4) in right hand at the metacarpo-phalangeal joint, as described (14). In five animals (short-term group), the interval between amputation and recording was between 2 and 6 weeks.…”

Section: Methodsmentioning

confidence: 99%

“…Similar to the case in somatosensory cortex, VPL thalamus also shows massive reorganizational plasticity (13)(14)(15)(16). Rapid (minutes to hours) reorganization in VPL thalamus can be blocked if somatosensory cortex is inactivated in the rat (6).…”

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confidence: 99%

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Changes in corticothalamic modulation of receptive fields during peripheral injury-induced reorganization

Chowdhury

Greek

Rasmusson

2004

Proc. Natl. Acad. Sci. U.S.A.

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The influence of corticothalamic projections on the thalamus during different stages of reorganization was determined in anesthetized raccoons that had undergone previous removal of a single forepaw digit. Single-unit recordings were made from 522 sites in the somatosensory nucleus of the thalamus (ventroposterior lateral nucleus) before and after lesioning parts of primary somatosensory cortex. In those parts of ventroposterior lateral nucleus that had intact input from the periphery, the cortical lesion resulted in an immediate 85% increase in receptive field (RF) size. In animals studied 2-6 weeks after digit amputation, peripherally denervated thalamic neurons had unique RFs that were larger than normal, and these were not further enlarged by cortical lesion. However, at longer periods of reorganization (>4 mo), when the new RFs of denervated neurons had decreased in size, cortical lesion again produced expansion of RF size. These data demonstrate that corticothalamic fibers modulate the spatial extent of thalamic RFs in intact animals, probably by controlling intrathalamic inhibition. This corticothalamic modulation is ineffective during the early stages of injury-induced reorganization when new RFs are being formed, but is reinstated after the new RFs have become stabilized. The fact that neurons in the denervated thalamic region retained their unique RFs after cortical lesion indicates that their new inputs are not being relayed from a reorganized cortex and support the view that some plasticity occurs in or below the thalamus. The processing of sensory information by the CNS is complicated by the complex interconnections between subcortical and cortical areas. Connections between the thalamus and cortex are largely reciprocal (1) with information being processed in both feed-forward (periphery to thalamus to cortex) and feedback (corticothalamic) directions. Although the majority of studies have concentrated on the ascending or feed-forward system, the feedback connections are actually much more numerous than the thalamocortical axons (1) and may contribute to focusing of information processing in the visual (2), auditory (3, 4), and somatosensory thalamus (5). Recently it has been proposed that this feedback from the cortex may contribute to plasticity in the ventroposterior lateral (VPL) nucleus, the main thalamic relay in the somatosensory system (6-8).The corticothalamic axons are excitatory, glutamatergic, and reciprocally focused on the thalamic neurons that project to the same cortical region (1). In addition to exciting thalamocortical relay neurons directly, they also produce inhibition by means of local ␥-aminobutyric acid (GABA)ergic interneurons, which are present in most species but not rats (9), and GABAergic neurons of the reticular thalamic nucleus, which project back into VPL (10). Electrophysiological studies have confirmed the monosynaptic excitatory and disynaptic inhibitory responses in VPL relay cells when cortical output cells are stimulated (11). Studies on the function of this fe...

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Section: Resultsmentioning

confidence: 82%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Changes in corticothalamic modulation of receptive fields during peripheral injury-induced reorganization

Chowdhury

Greek

Rasmusson

2004

Proc. Natl. Acad. Sci. U.S.A.

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“…However, plasticity of VP in response to nervous system injury is less well studied Pollin and Albe-Fessard 1979;Rasmusson 1996aRasmusson , 1996b. Even less well studied are the normal organization and plasticity of the human thalamic somatic sensory nucleus (ventral caudal, Vc) (Hassler 1959;Hirai and Jones 1989).…”

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confidence: 99%

Neuronal responses to tactile stimuli and tactile sensations evoked by microstimulation in the human thalamic principal somatic sensory nucleus (ventral caudal)

Schmid

Chien

Greenspan

et al. 2016

Journal of Neurophysiology

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. Neuronal responses to tactile stimuli and tactile sensations evoked by microstimulation in the human thalamic principal somatic sensory nucleus (ventral caudal). J Neurophysiol 115: 2421-2433, 2016. First published February 10, 2016 doi:10.1152/jn.00611.2015.-The normal organization and plasticity of the cutaneous core of the thalamic principal somatosensory nucleus (ventral caudal, Vc) have been studied by single-neuron recordings and microstimulation in patients undergoing awake stereotactic operations for essential tremor (ET) without apparent somatic sensory abnormality and in patients with dystonia or chronic pain secondary to major nervous system injury. In patients with ET, most Vc neurons responded to one of the four stimuli, each of which optimally activates one mechanoreceptor type. Sensations evoked by microstimulation were similar to those evoked by the optimal stimulus only among rapidly adapting neurons. In patients with ET, Vc was highly segmented somatotopically, and vibration, movement, pressure, and sharp sensations were usually evoked by microstimulation at separate sites in Vc. In patients with conditions including spinal cord transection, amputation, or dystonia, RFs were mismatched with projected fields more commonly than in patients with ET. The representation of the border of the anesthetic area (e.g., stump) or of the dystonic limb was much larger than that of the same part of the body in patients with ET. This review describes the organization and reorganization of human Vc neuronal activity in nervous system injury and dystonia and then proposes basic mechanisms. amputation; dystonia; neurophysiology; spinal transection; single neuron recordings; ventral posterior thalamus

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Shifting brain circuits in pain chronicity

Youssef

Azqueta‐Gavaldon²,

Silva

et al. 2019

Human Brain Mapping

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The evaluation of brain changes to a specific pain condition in pediatric and adult patients allows for insights into potential mechanisms of pain chronicity and possibly long‐term brain changes. Here we focused on the primary somatosensory system (SS) involved in pain processing, namely the ventroposterolateral thalamus (VPL) and the primary somatosensory cortex (SI). We evaluated, using MRI, three specific processes: (a) somatotopy of changes in the SS for different pain origins (viz., foot vs. arm); (b) differences in acute (ankle sprain versus complex regional pain syndrome‐CRPS); and (c) differences of the effects of CRPS on SS in pediatric versus adult patients. In all cases, age‐ and sex‐matched individuals were used as controls. Our results suggest a shift in concurrent gray matter density (GMD) and resting functional connectivity strengths (rFC) across pediatric and adult CRPS with (a) differential patterns of GMD (VPL) and rFC (SI) on SS in pediatric vs. adult patterns that are consistent with upper and lower limb somatotopical organization; and (b) widespread GMD alterations in pediatric CRPS from sensory, emotional and descending modulatory processes to more confined sensory‐emotional changes in adult CRPS and rFC patterns from sensory‐sensory alterations in pediatric populations to a sensory‐emotional change in adult populations. These results support the idea that pediatric and adult CRPS are differentially represented and may reflect underlying differences in pain chronification across age groups that may contribute to the well‐known differences between child and adult pain vulnerability and resilience.

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Changes in the organization of the ventroposterior lateral thalamic nucleus after digit removal in adult raccoon

Cited by 17 publications

References 32 publications

Changes in corticothalamic modulation of receptive fields during peripheral injury-induced reorganization

Changes in corticothalamic modulation of receptive fields during peripheral injury-induced reorganization

Neuronal responses to tactile stimuli and tactile sensations evoked by microstimulation in the human thalamic principal somatic sensory nucleus (ventral caudal)

Shifting brain circuits in pain chronicity

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