Time of conditioning selectively influences contextual fear conditioning: further support for a multiple-memory systems view of fear conditioning

J Exp Psychol Anim Behav Process. 1998 Jul;24(3):316-24. doi: 10.1037//0097-7403.24.3.316.


Time of conditioning influences long-term retention of contextual but not auditory-cue fear conditioning. Long-Evans rats (Rattus norvegicus) conditioned at 12 noon displayed reduced contextual fear conditioning compared to rats conditioned at 8 a.m. or 4 p.m. This effect was eliminated by exposure to the context 24 hr prior to conditioning and by a posttrial injection of corticosterone (1.0 mg/kg). Time of conditioning did not influence short-term retention of contextual fear. These results suggest that time of conditioning influences the posttrial processes that construct a memory representation of the context. They also support the view that contextual and auditory-cue fear conditioning depend on different processes. These results are discussed in relation to the concept of memory storage modulators.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Conditioning, Psychological*
  • Fear*
  • Female
  • Male
  • Memory / physiology*
  • Rats
  • Retention, Psychology
  • Time Factors