title: Increased responses in the somatosensory thalamus immediately after spinal cord injury.
abstract: Spinal cord injury (SCI) involves large-scale deafferentation of supraspinal structures in the somatosensory system, producing well-known long-term effects at the thalamo-cortical level. We recently showed that SCI provokes immediate changes in cortical spontaneous and evoked responses and here, we have performed a similar study to define the immediate changes produced in the thalamic ventro-postero-lateral nucleus (VPL) that are associated with the forepaw and hindpaw circuits. Extracellular electrophysiological recordings from the VPL reflected the spontaneous activity and the responses to peripheral electrical stimulation applied to the paws. Accordingly, the activity of the neuronal populations recorded at specific thalamic locations that correspond to the forepaw and hindpaw circuits was recorded under control conditions and immediately after thoracic SCI. The results demonstrate that peripheral inputs from both extremities overlap on neuronal populations in the somatosensory thalamus. In addition, they show that the responses of thalamic neurons to forepaw and hindpaw stimuli are increased immediately after SCI, in association with a specific decrease in spontaneous activity in the hindpaw locations. Finally, the increased thalamic responses after SCI have a state-dependent component in relation with cortical activity. Together, our results indicate that the thalamic changes occurring immediately after SCI could contribute to the cortical changes also detected immediately after such spinal lesions.
authors.affiliation: Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, 45071 Toledo, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Alonso-Calviño
authors.affiliation: Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, 45071 Toledo, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Martínez-Camero
authors.affiliation: Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, 45071 Toledo, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Fernández-López
authors.affiliation: Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, 45071 Toledo, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Humanes-Valera
authors.affiliation: Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, 45071 Toledo, Spain; CINAC, HM Puerta del Sur, Hospitales de Madrid, Madrid, Spain; CEU-San Pablo University, Madrid, Spain.
authors.forename: G
authors.initials: G
authors.lastname: Foffani
authors.affiliation: Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, 45071 Toledo, Spain. Electronic address: jdaguilar@sescam.jccm.es.
authors.forename: J
authors.initials: J
authors.lastname: Aguilar
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005552:Forelimb / Q000503:physiopathology; D006614:Hindlimb / Q000503:physiopathology; D008297:Male; D009474:Neurons / Q000502:physiology; D010812:Physical Stimulation; D017208:Rats, Wistar; D013003:Somatosensory Cortex / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D020651:Ventral Thalamic Nuclei / Q000503:physiopathology*
keywords: Electrophysiology; Evoked responses; Nucleus ventralis posterior lateralis of the thalamus; Somatosensory system; Spinal cord injury; Spontaneous activity; Thalamocortical plasticity