title: Neuronal responses to tactile stimuli and tactile sensations evoked by microstimulation in the human thalamic principal somatic sensory nucleus (ventral caudal).
abstract: 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.
authors: Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland; Department of Neural and Pain Sciences, Center to Advance Chronic Pain Research, University of Maryland, Baltimore, Maryland; and Brain Imaging and NeuroStimulation (BINS) Laboratory, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors: Anne-Christine
authors: AC
authors: Schmid
authors: Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland;
authors: Jui-Hong
authors: JH
authors: Chien
authors: Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland; Department of Neural and Pain Sciences, Center to Advance Chronic Pain Research, University of Maryland, Baltimore, Maryland; and.
authors: Joel D
authors: 0000-0003-4062-9797
authors: JD
authors: Greenspan
authors: Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland;
authors: Ira
authors: I
authors: Garonzik
authors: Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland;
authors: Nirit
authors: N
authors: Weiss
authors: Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland;
authors: Shinji
authors: S
authors: Ohara
authors: Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland; flenz1@jhmi.edu.
authors: Frederick Arthur
authors: FA
authors: Lenz
mesh_terms: D000818:Animals; D005073:Evoked Potentials, Somatosensory; D006801:Humans; D009069:Movement Disorders / Q000503:physiopathology; D009474:Neurons / Q000502:physiology*; D013787:Thalamic Nuclei / Q000166:cytology / Q000502:physiology* / Q000503:physiopathology; D014110:Touch; D055698:Touch Perception
keywords: amputation; dystonia; neurophysiology; single neuron recordings; spinal transection; ventral posterior thalamus