Increased excitability and reduced GABAergic levels in somatosensory cortex under chronic spinal cord injury

The complete or partial damage of ascending somatosensory pathways produced by a spinal cord injury triggers changes in the somatosensory cortex consisting in a functional expansion of activity from intact cortical regions towards deafferented ones, a process known as cortical reorganization. Howeve...

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Detalles Bibliográficos
Autor: Aguilar Lepe, Juan de los Reyes
Tipo de recurso: artículo
Fecha de publicación:2023
País:España
Institución:Universidad de Castilla-La Mancha
Repositorio:RUIdeRA. Repositorio Institucional de la UCLM
OAI Identifier:oai:ruidera.uclm.es:10578/41313
Acceso en línea:http://10.1016/j.expneurol.2023.114504
https://hdl.handle.net/10578/41313
Access Level:acceso abierto
Palabra clave:Cortical hyperexcitability
Cortical reorganization
GABA
Sensory-evoked responses
Slow-wave activity
Somatosensory cortex
Spinal cord injury
Triggered up-states
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spelling Increased excitability and reduced GABAergic levels in somatosensory cortex under chronic spinal cord injuryAguilar Lepe, Juan de los ReyesCortical hyperexcitabilityCortical reorganizationGABASensory-evoked responsesSlow-wave activitySomatosensory cortexSpinal cord injuryTriggered up-statesThe complete or partial damage of ascending somatosensory pathways produced by a spinal cord injury triggers changes in the somatosensory cortex consisting in a functional expansion of activity from intact cortical regions towards deafferented ones, a process known as cortical reorganization. However, it is still unclear whether cortical reorganization depends on the severity of the spinal cord damage or if a spinal cord injury always leads to a similar cortical reorganization process in the somatosensory cortex. To answer these open questions in the field, we obtained longitudinal somatosensory evoked responses from bilateral hindlimb and forelimb cortex from animals with chronic full-transection or contusive spinal cord injury at thoracic level (T9-T10) to induce sensory deprivation of hindlimb cortex while preserving intact the forelimb cortex. Electrophysiological recordings from the four locations were obtained before lesion and weekly for up to 4 weeks. Our results show that cortical reorganization depends on the type of spinal cord injury, which tends to be more bilateral in full transection while is more unilateral in the model of contusive spinal cord injury. Moreover, in full transection of spinal cord, the deafferented and intact cortex exhibited similar increments of somatosensory evoked responses in both models of spinal cord injury - a feature observed in about 80% of subjects. The other 20% were unaffected by the injury indicating that cortical reorganization does not undergo in all subjects. In addition, we demonstrated an increased probability of triggered up-states in animals with spinal cord injury. This data indicates increased cortical excitability that could be proposed as a new feature of cortical reorganization. Finally, decreased levels of GABA marker GAD67 across cortical layers were only found in those animals with increased somatosensory evoked responses, but not in the unaffected population. In conclusion, cortical reorganization depends on the types of spinal cord injuries, and suggest that the phenomenon is strongly determined by cortical circuits. Moreover, changes in GABAergic transmission at the deprived cortex may be considered one of the mechanisms underlying the process of cortical reorganization and increased excitability.Academic Press Inc202520252023info:eu-repo/semantics/articleapplication/pdfapplication/pdfhttp://10.1016/j.expneurol.2023.114504https://hdl.handle.net/10578/41313reponame:RUIdeRA. Repositorio Institucional de la UCLMinstname:Universidad de Castilla-La ManchaInglésinfo:eu-repo/semantics/openAccessoai:ruidera.uclm.es:10578/413132026-05-27T07:36:41Z
dc.title.none.fl_str_mv Increased excitability and reduced GABAergic levels in somatosensory cortex under chronic spinal cord injury
title Increased excitability and reduced GABAergic levels in somatosensory cortex under chronic spinal cord injury
spellingShingle Increased excitability and reduced GABAergic levels in somatosensory cortex under chronic spinal cord injury
Aguilar Lepe, Juan de los Reyes
Cortical hyperexcitability
Cortical reorganization
GABA
Sensory-evoked responses
Slow-wave activity
Somatosensory cortex
Spinal cord injury
Triggered up-states
title_short Increased excitability and reduced GABAergic levels in somatosensory cortex under chronic spinal cord injury
title_full Increased excitability and reduced GABAergic levels in somatosensory cortex under chronic spinal cord injury
title_fullStr Increased excitability and reduced GABAergic levels in somatosensory cortex under chronic spinal cord injury
title_full_unstemmed Increased excitability and reduced GABAergic levels in somatosensory cortex under chronic spinal cord injury
title_sort Increased excitability and reduced GABAergic levels in somatosensory cortex under chronic spinal cord injury
dc.creator.none.fl_str_mv Aguilar Lepe, Juan de los Reyes
author Aguilar Lepe, Juan de los Reyes
author_facet Aguilar Lepe, Juan de los Reyes
author_role author
dc.subject.none.fl_str_mv Cortical hyperexcitability
Cortical reorganization
GABA
Sensory-evoked responses
Slow-wave activity
Somatosensory cortex
Spinal cord injury
Triggered up-states
topic Cortical hyperexcitability
Cortical reorganization
GABA
Sensory-evoked responses
Slow-wave activity
Somatosensory cortex
Spinal cord injury
Triggered up-states
description The complete or partial damage of ascending somatosensory pathways produced by a spinal cord injury triggers changes in the somatosensory cortex consisting in a functional expansion of activity from intact cortical regions towards deafferented ones, a process known as cortical reorganization. However, it is still unclear whether cortical reorganization depends on the severity of the spinal cord damage or if a spinal cord injury always leads to a similar cortical reorganization process in the somatosensory cortex. To answer these open questions in the field, we obtained longitudinal somatosensory evoked responses from bilateral hindlimb and forelimb cortex from animals with chronic full-transection or contusive spinal cord injury at thoracic level (T9-T10) to induce sensory deprivation of hindlimb cortex while preserving intact the forelimb cortex. Electrophysiological recordings from the four locations were obtained before lesion and weekly for up to 4 weeks. Our results show that cortical reorganization depends on the type of spinal cord injury, which tends to be more bilateral in full transection while is more unilateral in the model of contusive spinal cord injury. Moreover, in full transection of spinal cord, the deafferented and intact cortex exhibited similar increments of somatosensory evoked responses in both models of spinal cord injury - a feature observed in about 80% of subjects. The other 20% were unaffected by the injury indicating that cortical reorganization does not undergo in all subjects. In addition, we demonstrated an increased probability of triggered up-states in animals with spinal cord injury. This data indicates increased cortical excitability that could be proposed as a new feature of cortical reorganization. Finally, decreased levels of GABA marker GAD67 across cortical layers were only found in those animals with increased somatosensory evoked responses, but not in the unaffected population. In conclusion, cortical reorganization depends on the types of spinal cord injuries, and suggest that the phenomenon is strongly determined by cortical circuits. Moreover, changes in GABAergic transmission at the deprived cortex may be considered one of the mechanisms underlying the process of cortical reorganization and increased excitability.
publishDate 2023
dc.date.none.fl_str_mv 2023
2025
2025
dc.type.none.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv http://10.1016/j.expneurol.2023.114504
https://hdl.handle.net/10578/41313
url http://10.1016/j.expneurol.2023.114504
https://hdl.handle.net/10578/41313
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Academic Press Inc
publisher.none.fl_str_mv Academic Press Inc
dc.source.none.fl_str_mv reponame:RUIdeRA. Repositorio Institucional de la UCLM
instname:Universidad de Castilla-La Mancha
instname_str Universidad de Castilla-La Mancha
reponame_str RUIdeRA. Repositorio Institucional de la UCLM
collection RUIdeRA. Repositorio Institucional de la UCLM
repository.name.fl_str_mv
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