Motor improvements after focal cortical ischemia in adult rats are mediated by compensatory mechanisms

Behav Brain Res. 2005 Jul 1;162(1):71-82. doi: 10.1016/j.bbr.2005.03.002. Epub 2005 Mar 28.

Abstract

Initial functional impairments after cerebral ischemia often improve considerably during the early period after the insult. Although pathological changes associated with post-lesion improvements have been widely investigated, it has not been resolved whether behavioral improvement represents true restoration of function (recovery) or development of new strategies (compensation). This study investigated whether early motor improvements after focal cerebral ischemia reflect recovery or compensation. Adult female Wistar rats were trained to retrieve food pellets in a skilled reaching task prior to receiving a unilateral cortical infarction induced by photothrombosis in forelimb motor cortex. Animals were continuously tested in the reaching task up to 3 weeks after lesion. The end point measures revealed that reaching success rates remained at pre-lesion levels, however, qualitative analysis of reaching movements indicated permanent changes in forelimb movement patterns. Similar observations were made in a skilled walking task and a test for forelimb asymmetry. These data indicate that lesion animals adopted alternative movement strategies in order to successfully perform the tasks. The changes in postoperative performance were compared to anatomical data in individual animals. The finding that reaching success was not related to lesion size supports the idea that the degree of adaptive behavior after cortical ischemia depends on plastic properties of the remaining intact tissue.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Behavior, Animal
  • Brain Ischemia / etiology
  • Brain Ischemia / physiopathology*
  • Female
  • Functional Laterality / physiology
  • Intracranial Thrombosis / complications
  • Intracranial Thrombosis / physiopathology
  • Motor Activity / physiology
  • Motor Skills / physiology*
  • Motor Skills Disorders / etiology
  • Rats
  • Rats, Wistar
  • Recovery of Function / physiology*
  • Somatosensory Cortex / pathology
  • Somatosensory Cortex / physiopathology*
  • Statistics as Topic
  • Supination / physiology
  • Time Factors