Aim
Investigate role of acetylcholine in spatial memory encoding using scopolamine.
Examine hippocampal activation during spatial memory task.
Procedure
20 healthy male adults (mean age 28 years).
Double-blind study; randomly assigned to scopolamine or placebo.
Participants underwent fMRI while playing "Arena task" to assess spatial memory.
Task involved navigating to a pole in a virtual arena, then mentally rehearsing after a blank screen, starting from a new position.
Brain activity measured across six trials.
Follow-up session 3-4 weeks later with reversed treatment condition (placebo or scopolamine).
Results
Scopolamine group showed significantly reduced hippocampal activation compared to placebo.
Acetylcholine likely plays a crucial role in human spatial memory encoding.
Conclusion
Scopolamine impacts hippocampal function, affecting spatial memory encoding.
Findings align with similar studies in rodents, suggesting a conserved role of acetylcholine in memory processes.
Strengths
Double-blind design minimizes bias.
Repeated measures design controls for participant variability.
Counterbalancing treatment order reduces practice effects.
Limitations
Small sample size (20 participants) limits generalizability.
Participants reported stress during the study, potentially affecting hippocampal function and memory performance.
Task design may not have effectively measured performance differences despite significant biological findings.