Early and moderate sensory stimulation exerts a protective effect on perilesion representations of somatosensory cortex after focal ischemic damage

PLoS One. 2014 Jun 10;9(6):e99767. doi: 10.1371/journal.pone.0099767. eCollection 2014.

Abstract

Previous studies have shown that intensive training within an early critical time window after focal cortical ischemia increases the area of damaged tissue and is detrimental to behavioral recovery. We postulated that moderate stimulation initiated soon after the lesion could have protective effects on peri-infarct cortical somatotopic representations. Therefore, we have assessed the effects of mild cutaneous stimulation delivered in an attention-demanding behavioral context on the functional organization of the perilesion somatosensory cortex using high-density electrophysiological mapping. We compared the effects of 6-day training initiated on the 3rd day postlesion (early training; ET) to those of same-duration training started on the 8th day (delayed training; DT). Our findings confirm previous work showing that the absence of training aggravates representational loss in the perilesion zone. In addition, ET was found to be sufficient to limit expansion of the ischemic lesion and reduce tissue loss, and substantially maintain the neuronal responsiveness to tactile stimulation, thereby preserving somatotopic map arrangement in the peri-infarct cortical territories. By contrast, DT did not prevent tissue loss and only partially reinstated lost representations in a use-dependent manner within the spared peri-infarct cortical area. This study differentiates the effects of early versus delayed training on perilesion tissue and cortical map reorganization, and underscores the neuroprotective influence of mild rehabilitative stimulation on neuronal response properties in the peri-infarct cortex during an early critical period.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain Ischemia / drug therapy*
  • Brain Ischemia / pathology*
  • Brain Ischemia / physiopathology
  • Male
  • Neurons / drug effects
  • Neurons / pathology
  • Neuroprotective Agents / pharmacology*
  • Neuroprotective Agents / therapeutic use
  • Physical Stimulation
  • Rats, Long-Evans
  • Somatosensory Cortex / drug effects
  • Somatosensory Cortex / pathology*
  • Somatosensory Cortex / physiopathology
  • Touch / drug effects

Substances

  • Neuroprotective Agents

Grant support

This work was supported by grants from Ministère de l'Enseignement Supérieur et de la Recherche and CNRS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript