Martinez and Kesner 1991

Martinez & Kesner (1991) Aim

To investigate the role of the neurotransmitter acetylcholine (ACh) in spatial memory formation.

Martinez & Kesner (1991) Participants

Laboratory rats trained to run a maze.

Martinez & Kesner (1991) Procedure

Rats were divided into three groups: Group 1 received scopolamine (blocks ACh receptors), Group 2 received physostigmine (increases ACh availability), and Group 3 was a control group with no injections. All rats then ran a maze.

Martinez & Kesner (1991) Results

Group 1 (less ACh) made more mistakes and ran slower than control. Group 2 (more ACh) ran faster and made fewer mistakes than control.

Martinez & Kesner (1991) Conclusion

Acetylcholine plays an important role in spatial memory; increasing ACh improves memory performance while reducing it impairs memory.

Strength: Experimental control

The study used a lab experiment with precise control over variables, allowing cause-and-effect conclusions.

Strength: Clear operationalization

Memory performance was measured objectively by speed and number of errors in the maze.

Strength: Biological insight

The study provided evidence for the role of ACh in spatial memory, supporting the biological basis of memory.

Limitation: Animal study

Findings may not fully generalize to humans because rats' brains are different and humans have more complex memory systems.

Limitation: Ethical considerations

Use of invasive injections raises ethical concerns about harm to animals.

Limitation: Maze learning may not reflect all types of memory

The task measured spatial memory, so results may not apply to other memory types like verbal or episodic memory.

Overall evaluation

The study strongly supports a role for ACh in memory using a controlled experiment, but generalizability to humans is limited and ethical issues must be considered.