Rapamycin-sensitive signalling in long-term consolidation of auditory cortex-dependent memory

Area of Science:

• Neuroscience
• Molecular Biology
• Memory Research

Background:

• Newly formed memories are initially unstable and require protein synthesis for consolidation into long-term storage.
• Previous research demonstrated that protein synthesis inhibitors in the auditory cortex disrupt long-term memory in gerbils trained with frequency-modulated tones (FMs).

Purpose of the Study:

• To investigate the role of target of rapamycin (TOR)-mediated pathways in protein synthesis required for persistent memory storage.
• To elucidate the specific signalling pathways involved in long-term memory consolidation using rapamycin.

Main Methods:

• Utilizing differential conditioning with linearly frequency-modulated tones (FMs) in Mongolian gerbils.
• Administering rapamycin bilaterally into the auditory cortex post-training.
• Employing FK506 as an antagonist in control experiments.

Main Results:

• Rapamycin infusions did not affect memory maintenance at 24 hours post-injection.
• Profound retention deficits were observed at 48 hours after rapamycin administration.
• The amnesic effect was confirmed to be rapamycin-dependent and specific to memory formation, being blocked by FK506.

Conclusions:

• Activation of rapamycin-sensitive signalling pathways is crucial for the long-term consolidation of auditory cortex-dependent memories in mammals.
• The findings suggest at least two distinct protein synthesis-dependent processes govern memory formation after learning.
• One process supports initial memory maintenance for approximately one day, while a second process regulates long-lasting memory persistence.