Long-term ongoing reorganizations of the processes of analysis of kinesthetic afferentation at the level of cat motor cortex neurons after damage to the ventrolateral nucleus of the thalamus

Sidorov, B. M.

doi:10.1007/bf02359277

Cited by 2 publications

(3 citation statements)

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“…37 In non-human primate and cat experiments, there is strong evidence for the role of the cortex in recovery from thalamic lesions, specifically via changes to cortico-cortical connections. [38][39][40][41][42] In some studies, it is especially the changes in connections between the motor and sensory cortices that leads to recovery. 39,40 In humans, outside of a diseased population in which a lesion is therapeutic, it is currently impossible to study the effects of specific neuronal lesions.…”

Section: Discussionmentioning

confidence: 99%

“…In non‐human primate and cat experiments, there is strong evidence for the role of the cortex in recovery from thalamic lesions, specifically via changes to cortico‐cortical connections 38‐42 . In some studies, it is especially the changes in connections between the motor and sensory cortices that leads to recovery 39,40 …”

Section: Discussionmentioning

confidence: 99%

“…[38][39][40][41][42] In some studies, it is especially the changes in connections between the motor and sensory cortices that leads to recovery. 39,40 In humans, outside of a diseased population in which a lesion is therapeutic, it is currently impossible to study the effects of specific neuronal lesions. The stroke literature can be informative.…”

Section: Discussionmentioning

confidence: 99%

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Limb Preference Changes after Focused‐Ultrasound Thalamotomy for Tremor

et al. 2023

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Background Magnetic resonance‐guided focused‐ultrasound (MRgFUS) thalamotomy is an effective treatment for essential and other tremors. It targets the ventrointermedius (Vim) nucleus, which is the thalamic relay in a proprioceptive pathway, and contains kinesthetic cells. Although MRgFUS thalamotomy reduces some risks associated with more invasive surgeries, it still has side effects, such as balance and gait disturbances; these may be caused by the lesion impacting proprioception. Objectives Our aim was to quantitatively measure the effects of MRgFUS on proprioception and limb use in essential tremor patients. We hypothesized that this thalamotomy alters proprioception, because the sensorimotor Vim thalamus is lesioned. Methods Proprioception was measured using the Kinarm exoskeleton robot in 18 patients. Data were collected pre‐operatively, and then 1 day, 3 months, and 1 year after surgery. Patients completed four tasks, assessing motor coordination and postural control, goal‐directed movement and bimanual planning, position sense, and kinesthesia. Results Immediately after surgery there were changes in posture speed (indicating tremor improvement), and in bimanual hand use, with the untreated limb being preferred. However, these measures returned to pre‐operative baseline over time. There were no changes in parameters related to proprioception. None of these measures correlated with lesion size or lesion‐overlap with the dentato‐rubro‐thalamic tract. Conclusions This is the first quantitative assessment of proprioception and limb preference following MRgFUS thalamotomy. Our results suggest that focused‐ultrasound lesioning of the Vim thalamus does not degrade proprioception but alters limb preference. This change may indicate a required “relearning” in the treated limb, because the effect is transient. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Limb Preference Changes after Focused‐Ultrasound Thalamotomy for Tremor

et al. 2023

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Neuronal activity reorganization in motor cortex for successful locomotion after a lesion in the ventrolateral thalamus

Beloozerova

2022

Journal of Neurophysiology

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Thalamic stroke leads to ataxia if the cerebellum-receiving ventrolateral thalamus (VL) is affected. The compensation mechanisms for this deficit are not well understood, particularly the roles that single neurons and specific neuronal subpopulations outside the thalamus play in recovery. The goal of this study was to clarify neuronal mechanisms of the motor cortex involved in mitigation of ataxia during locomotion when part of the VL is inactivated or lesioned. In freely ambulating cats, we recorded the activity of neurons in layer V of the motor cortex as the cats walked on a flat surface and horizontally placed ladder. We first reversibly inactivated approximately 10% of the VL unilaterally using glutamatergic transmission antagonist CNQX and analyzed how the activity of motor cortex reorganized to support successful locomotion. We next lesioned 50-75% of the VL bilaterally using kainic acid and analyzed how the activity of motor cortex reorganized when locomotion recovered. When a small part of the VL was inactivated, the discharge rates of motor cortex neurons decreased, but otherwise the activity was near normal, and the cats walked fairly well. Individual neurons retained their ability to respond to the demand for accuracy during ladder locomotion; however, most changed their response. When the VL was lesioned, the cat walked normally on the flat surface but was ataxic on the ladder for several days post-lesion. When ladder locomotion normalized, neuronal discharge rates on the ladder were normal, and the shoulder-related group was preferentially active during the stride's swing phase.

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Long-term ongoing reorganizations of the processes of analysis of kinesthetic afferentation at the level of cat motor cortex neurons after damage to the ventrolateral nucleus of the thalamus

Cited by 2 publications

References 9 publications

Limb Preference Changes after Focused‐Ultrasound Thalamotomy for Tremor

Limb Preference Changes after Focused‐Ultrasound Thalamotomy for Tremor

Neuronal activity reorganization in motor cortex for successful locomotion after a lesion in the ventrolateral thalamus

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