Training-dependent biphasic effects of corticosterone in memory formation for a passive avoidance task in chicks

Area of Science:

• Neuroscience
• Animal Behavior
• Endocrinology

Background:

• Corticosterone is a key stress hormone involved in memory processes.
• Its precise role in memory consolidation, particularly its concentration-dependent effects, remains incompletely understood.

Purpose of the Study:

• To investigate the functional role of corticosterone in memory formation using a passive avoidance task in day-old chicks.
• To explore the concentration-dependent effects of corticosterone on memory retention under varying training intensities.

Main Methods:

• Day-old chicks were trained using passive avoidance tasks with either strong or weak aversive stimuli.
• Intracerebral administration of varying corticosterone concentrations was performed.
• Plasma corticosterone levels and memory retention were measured post-training.

Main Results:

• Chicks trained with a strong aversant showed increased plasma corticosterone and impaired long-term memory with corticosterone administration.
• Memory for a weak aversant was facilitated by low-dose corticosterone but not by higher doses.
• Chicks trained on the weak task did not show elevated post-training corticosterone levels.

Conclusions:

• Corticosterone plays a biphasic role in memory formation, facilitating short-term memory and impairing long-term memory depending on training intensity and hormone concentration.
• These findings highlight corticosterone's crucial role in the transition from short- to long-term memory and offer a model for studying its mechanisms of action.