Date of Completion

5-7-2011

Embargo Period

11-2-2011

Advisors

Etan J. Markus, Louise D. McCullough

Field of Study

Psychology

Degree

Master of Arts

Open Access

Open Access

Abstract

Stoke is characterized by a loss or alteration in neurological and/or bodily function resulting from a cerebral vascular accident (interruption of blood flow to the brain). Acute ischemic stroke is the third leading cause of death in the United States, and the leading cause of long-term functional disability in adults. Stroke-induced deficits may include various forms of aphasia (language loss), cognitive deficits (including attentional and memory impairments), and motor impairments. Through the use of animal models, researchers can experimentally induce “stroke-like” injuries comparable to those seen in clinical populations. Such models allow us to study and understand the neurophysiological, anatomical, and neurobehavioral consequences associated with ischemic insults to the brain. Middle cerebral artery occlusion (MCAO) can be induced in rodents, and is a widely used experimental technique to model focal ischemia in rodents. Various neurobehavioral tasks have been developed to assess the motor and cognitive dysfunctions associated with MCAO in rodents, and these studies have shown deficits related to impaired long-term sensorimotor function, as well as retention of spatial memory.

The current study was designed to develop a more comprehensive neurobehavioral profile associated with experimental focal cerebral ischemia induced by transient MCAO in adult C57Bl/6 mice. Using a modified pre-pulse inhibition auditory discrimination paradigm, and other tasks thought to tap language-related processing, mice subjected to 60 minute MCAO or Sham injury were assessed. These tasks were selected based on evidence that rapid auditory processing (RAP) skills are associated with language processing indices in clinical populations, as well as infant research showing that early RAP scores are predictive of language development. Importantly, deficits in the encoding of temporal sound features have also been associated with deficits in speech perception in elderly listeners and aphasics. In addition, cognitive and sensorimotor ability was also evaluated using the Morris water maze, non-spatial water maze, and rotarod task. Combined behavioral results from post-MCAO mice provide evidence of a RAP deficit (suggesting “aphasia-like” deficits), and deficits in learning and memory, as well as sensorimotor function. Overall results support the ongoing use of MCAO mice as a valid model to study ischemic stroke in humans, and further suggest that language-related tasks can be used to model “aphasia-like” deficits in rodents.

Major Advisor

Roslyn H. Fitch

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