Social Interaction Test

A three-chamber social interaction test was performed on PND 22 as previously described.21) Subjects were habituated in the middle compartment with doors closed for five minutes before the test. In the first session, subjects were placed in the middle of the compartment. Then strange animal (same age and strain) was placed into the wired cage of either the left or the right compartment. This new rat represented the stranger zone 1 while the other wired cage remained empty as an empty zone. The rats were left for a 10-minute sociability test. The time spent in the stranger zone 1 with interaction to the new rat versus time spent in the empty zone were measured and are expressed as a ratio. The social preference test was conducted for another 10 minutes period after termination of the sociability test. Another new animal was introduced into the wired cage in place of the empty zone and was consider as stranger zone 2. The same parameters were measured to define preference of the subjected animal to choose interaction with the familiar animal or the novel one. The tracking of movement was recorded using the video recorder. Sociability and social preference indices were calculated followed by the formulas described early.21) Controls (n=10) and VPA treated group (n=9) were used for this analysis.