Trace and contextual fear conditioning are impaired following unilateral microinjection of muscimol in the ventral hippocampus or amygdala, but not the medial prefrontal cortex

► Trace fear conditioning requires bilateral participation of the ventral hippocampus. ► The amygdala is necessary for both trace and delay fear learning. ► Trace conditioning is more sensitive than delay to unilateral amygdala disruption.