ABSTRACT
A bilateral cytotoxic lesion of the caudal hippocampus (about 1/3 of the whole hippocampus, which is insufficiently studied) influences learning of bank voles (Clethrionomys glareolus) in the Morris water maze. This effect has been estimated in this paper. A version of the test intended to measure long-term spatial memory was used. The lesion was shown to exert an influence on the learning dynamics by slowing it down, as well as to reduce the accuracy of platform location memorizing at early stages of training. The data obtained indicate the involvement of this area in control of spatial learning in rodents.
Subject(s)
Arvicolinae/physiology , Hippocampus/physiopathology , Memory, Long-Term/physiology , Space Perception/physiology , Animals , Arvicolinae/surgery , Hippocampus/surgery , Male , Maze Learning/physiologyABSTRACT
Open field behavior is well known to depend on physical characteristics of the apparatus. However many of such effects are poorly described especially with using of modern methods of behavioral registration and analysis. The previous results of experiments on the effect of arena size on behavior are not numerous and contradictory. We compared the behavioral scores of four groups of C57BL/6 mice in round open field arenas of four different sizes (diameter 35, 75, 150 and 220 cm). The behavior was registered and analyzed using Noldus EthoVision, WinTrack and SegmentAnalyzer software. A significant effect of arena size was found. Traveled distance and velocity increased, but not in proportion to increase of arena size. Moreover a significant effect on segment characteristics of the trajectory was revealed. Detailed behavior analysis revealed drastic differences in trajectory structure and number of rears between smaller (35 and 75 cm) and bigger (150 and 220 cm) arenas. We conclude, that the character of exploration in smaller and bigger arenas depends on relative size of central open zone in arena. Apparently its extension increases the motivational heterogeneity of space, that requires another than in smaller arenas, strategy of exploration.
