اثر متفاوت غيرفعال سازي موقتي دوطرفه و يك طرفه هسته اكومبنس بر حافظه در موش صحرايي

Differential Effects of The Right and Left Accumbens Nucleus InActivation on Retrieval of Memory in Rats

Background :Extensive evidences indicate that the two hemispheres of brain are differentially involved in emotional memory and Accumbens Nucleus (AN) is a key subcortical structure involved in emotional experiences. The present work investigated possible lateralization of AN involvement in passive avoidance learning (PAL). Materials and Methods:Male Wistar rats were surgically implanted bilaterally with cannulae aimed at the AN were trained to Place avoidance learning by mild footshock. They received one trial PAT (1 milliam pere 3s) foot shock. Retention was tested 2, 4 and 6 days after the training. One hour before retention test bilateral or unilateral injections of Tetrodotoxin (5 ng/0.6ml in each) were used to temporarily inactivate the AN during retrieval of the passive avoidance task. Control rats were injected with the same volume of saline. Results:The data indicated that bilateral or only right AN 2 and 4 days after training significantly impaired retrieval memory(p<0/01). But in activation of the left AN 6 days after training had no significant effect. Conclusion:The results of this study suggest that the right and left AN has different contribution to the expression of memory and that the contribution of the right AN may be more important to the expression and retention of memory for the passive avoidance task.