Electrical stimulation of prelymbic with different currents intensities on morphine induced spatial memory deficit in rats

Document Type : Original Article


Department of Physiology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran


Background: The medial prefrontal cortex (mPFC) is a part of brain reward system involved in cognitive functions such as learning and memory. Previous studies showed that electrical stimulation of prelymbic produced different effects on morphine-induced condition place preference. In this study, we investigated the electrical stimulation with different current intensities on spatial memory in rats.
Materials and Methods: In this study, male Wister rats weighing approximately 200–300 g were used. The effect of prelymbic electrical stimulation with 25 and 150 μA currents intensities in healthy and addicted rats on spatial memory was studied. Spatial memory was investigated using the Morris water maze test in addicted rats after 9 days of electrical stimulation.
Results: Our findings have shown that morphine reduces the memory and learning, whereas the present results indicated that electrical stimulation of prelymbic area with current intensity of the 25 μA shortened the time and distance to reach to platform that indicated improvement in spatial memory on addicted rats. Whereas the electrical stimulation of prelymbic area with the current intensity of 150 μA has special weakening effects on spatial memory and prolongs the time and distance to reach the platform.
Conclusions: The electrical stimulations of prelymbic with 25 μA current intensity improved the spatial memory in addicted rats while with 150 μA current intensity weakened spatial memory in rats. It is possible that increase in the release of some neurotransmitters reverses the effect of morphine on spatial memory.