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Changes in posterior hypothalamic self-stimulation following experimental cerebral infarction in the rat
Journal of Comparative and Physiological Psychology
|October 1, 1978
Summary
Rats undergoing experimental stroke showed biphasic changes in brain reward function, measured by intracranial self-stimulation (ICSS). Reward function initially decreased then increased, returning to normal within 20 days post-stroke.
Area of Science:
- Neuroscience
- Neurobiology
- Stroke Research
Background:
- Intracranial self-stimulation (ICSS) is a model for studying brain reward pathways.
- Experimental stroke models are crucial for understanding post-stroke neurological deficits.
- The posterior hypothalamus plays a role in reward and motivation.
Purpose of the Study:
- To investigate the biphasic changes in brain reward function following an experimental stroke.
- To assess the impact of middle cerebral artery ligation on intracranial self-stimulation (ICSS) rates and thresholds.
- To explore the neurophysiological underpinnings of altered reward sensitivity after stroke.
Main Methods:
- Bilateral electrodes were implanted in the posterior hypothalamus of rats for ICSS.
- Rats were trained for stable ICSS rates before middle cerebral artery ligation.
- ICSS rates and minimum current thresholds were measured for 25 days post-stroke.
Main Results:
- A 33% decrease in ipsilateral ICSS frequency was observed 2 days post-stroke.
- Maximal ICSS rate increased by 16% above baseline by day 8, returning to control levels by day 20.
- Minimum current thresholds showed a biphasic change, initially increasing then decreasing below preoperative levels.
Conclusions:
- Experimental stroke induces biphasic alterations in the brain's reward circuitry.
- These changes in ICSS reflect dynamic neurophysiological shifts in response to ischemic injury.
- Understanding these biphasic responses is key to developing targeted stroke therapies.