Quantitative analysis of rat behavior patterns in a residential maze.

A method for monitoring spontaneous locomotor patterns of rats during one day is described. The animals' locomotion is registered in a residential maze by 18 optical gates connected to a computer. Status changes of each optical gate are stored on a disk file and can be retrieved for complete session reconstruction and data analysis. The general features of a rat's behavior in the maze are discussed. Quantitative analyses and statistical comparisons between two sessions spaced two weeks apart and between a group of 4 control animals and 4 rats treated in utero with methylmercury chloride are performed. Following parameters are analysed as functions of time and maze location: locomotor and local activity, occupational duration and time per visit in the maze compartments. Angular dependences of path decisions and regional preferences of crossing at the alley bifurcations are observed. No changes of the measured parameters can be observed between the first and second sessions. Methylmercury treatment results in a consistently lower local activity during the night period and in differences of path preferences.