Figure 1.

Experimental conditions (A) and behavioral results (B).(A) Experimental conditions under which neurophysiological recordings were conducted. In the Alone condition (left, Alone), a subject rat (white) was exposed to an auditory conditioned stimulus (CS) without the presence of an associate. In the Social condition (right, Social), a subject rat was exposed to the CS in the presence of an conspecific rat (gray). Two wire mesh walls (dotted lines) were installed in order to prevent physical contact between the rats. (B) Comparison of the freezing duration between the conditions on each day of the fear-expression test. ^***P < 0.001, Student's t-test.