Acetylcholine pathways are more important in the making of memories than in their consolidation or recall.

Although acetylcholine is known to be important in memory, its exact role is unclear. To gain a clearer picture, Dr Boyer Winters, Dr Lisa Saksida and Dr Tim Bussey at the University of Cambridge turned to scopolamine, a 'truth serum', date-rape drug and cure for seasickness that blocks the acetylcholine receptor.

Broadly speaking, memory involves three key stages: the initial making of the memory (encoding), creation of long-term memories (storage/consolidation) and recall (retrieval). When scopolamine was infused into the rat perirhinal cortex – an area critical for memory – it inhibited the first stage, memory encoding. It had no effect when given during the retrieval stage, and actually enhanced memory retrieval when given after encoding, during the period when the memory would be normally stored or consolidated.

The results suggest that acetylcholine pathways are important in memory encoding, but not consolidation or retrieval. The authors suggest that scopolamine given after encoding probably blocks the acquisition of unwanted, interfering memories, indirectly enhancing memory performance.

Image courtesy of Heidi Cartwright.

External links

• Winters BD et al. Paradoxical facilitation of object recognition memory after infusion of scopolamine into perirhinal cortex: implications for cholinergic system function. J Neurosci 2006;26(37):9520–9.