Figure 5.

Locomotion, thigmotaxis, and Morris Water Maze behavioral tests of control and mutant mice. (A) Open field test assesses animal exploratory behavior. Mutants exhibit hyperactivity as a function of increased locomotor activity; however, mutants do not appear to have altered anxiety levels as measured by thigmotatic behavior. (B) Hippocampal dependent contextual fear tasks show a severe reduction of long term memory in the mutants, consistent with the loss of the hippocampal structure in mutants. Re-exposure to the fear conditioning chamber (7 day) elicited no fear response in mutant animals, akin to the lack of freezing seen in hippocampal lesioned animals. (C) Morris water maze testing the ability of mice to recall spatial navigation is a hippocampal specific learning and memory task. Over continuous learning trial days, mutants do not improve in finding the hidden platform, nor do they exhibit a learning curve for the task of locating the platform. (D) Conditional mutants score below chance (25%) in probe trials after a 14-day learning protocol, indicative of poor spatial memory in the mutants. For each category of mice, more than 11 adult mice/genotype around the age of 6 months were used in behavioral tests.