Evaluation of neurobehavioral deficits following different severities of cerebral ischemia in rats: A comparison between the modified hole board test and the Morris water maze test

Abstract

ObjectiveWhile histological injury following cerebral ischemia has been extensively characterized in rodents, evidence on the effects on executive functioning is still missing. This study was designed to evaluate neuropsychological outcome following different severities of cerebral ischemia in rats with the modified hole board test or the Morris water maze. SettingWith institutional review board approval, anesthetized rats were exposed to bilateral carotid artery occlusion (BCAO) for escalating time intervals (0–12.5min). Postoperatively cognitive performance was assessed using either the modified hole board test (mHB) or the Morris water maze (MWM). On postoperative day 14 rats were euthanized and intact neurons in five cerebral regions were counted. ResultsRats of the 0 and 5min groups showed normal functional outcome with mild histological damage after 5min of BCAO. Following 7.5min of BCAO the mHB test showed cognitive deficits reflecting histological damage of the hippocampus while the MWM revealed normal functional outcome. Rats of the 10 and 12.5min groups showed cognitive deficits in both tests, motor dysfunction and behavioral alterations in the mHB test and profound histological damage. ConclusionsThe results indicate that the mHB is not inferior to the MWM for the evaluation of cognitive impairment following incomplete forebrain ischemia in rats. As the mHB additionally investigates a variety of behavioral dimensions and motor parameters in the same test environment, it is advantageous for the evaluation of interacting and potentially confounding behavioral changes following cerebral ischemia in rats.