Abstract: This study investigated the correlation between learning-memory capacity of different month-aged mice and their central synaptic structural parameters.The discrimination learning capacity was tested by Y-maze and memory retention was observed by using one trial passive avoidance response in both 1-month and 6-month aged mice respectively.Then the animals were killed and the hippocampus and sensori-motor areas of the cerebral cortex were prepared for electron microscopy.The electron microphotographs were analysed quantitatively by XY-biological image analysis system.The main results were as follows:(1)The descrimination learning capacity of 1-month aged mice were significantly better than that of the 6-month aged mice(p<0.05),while memory retention of 1-month aged mice was slightly superior to that of the 6-month aged mice.(2)The curvatures of synaptic interface of 6-month aged mice were greater that of the 1-month aged mice(p<0.05 in the sensori-motor areas:p<0.01 in the hippocampus),while the PSDs of 6-month aged mice were less than that of the 1-month aged mice(p<0.01).These results suggested that changes of learning-memory capacity with increasing age may be based on the changes of the structure of synaptic interface in the brain of mice.

Key words: synaptic structural parameters, CA3 area of hippocampus, sensori-motor area of cortex, electron microscopy, mice