Animal models/research 4.1/4.2/4.3 Biological

Claims for animal models

1) Much of what we know about the human body came from studying animals, as we believe that animals exhibit similar behaviours and animal research decreases human suffering

2) Behaviour can be studied under controlled conditions in a way that would be impossible for humans (lifespan, DNA etc)

3) Due to ethics, some research cannot be done with humans.

Claims against animal models

1) Low transferability, as animals have physiological differences

2) Low external validity and researcher bias

3) Ethics of using animal methods

Scopolamine

Used as an antagonist to block acetylcholine receptor sites

Rogers and Kesners (2003) Aim

To determine the role of acetylcholine in the formation of spatial memory.

Rogers and Kesner (2003) Research method

Laboratory experiment

Rogers and Kesner (2003) Participants

30 rats

Rogers and Kesnery (2003) Procedure

Once all rats were acclimated to the maze, they were randomly allocated to one of two conditions.

Injected with scopolamine (Blocks acetylcholine receptor sites)

Injected with a saline solution (Placebo)

Rats were injected directly into the hippocampus ten minutes before running the maze. Encoding of memory was assessed by the average number of errors made on the first five trials of Day 1 compared to the last five of Day 1. Retrieval was assessed by the average number of errors made on the first five trials of Day 2 compared to the last five trials of Day 1.

Rogers and Kesner (2003) Findings

Scopolamine group took longer and made more mistakes in the learning of the maze, however, it did not appear to affect the retrieval of memories that had already been created.

Rogers and Kesner (2003) Conclusion

Acetylcholine may play an important role in the consolidation of spatial memories.

Rosenzweig et al. (1972) Aim

To investigate whether environmental factors, such as a rich or impoverished environment, would affect the development of neurons in the cerebral cortex.

Rosenzweig et al. (1972) Research Method

Laboratory experiment

Rosenzweig et al. (1972) Participants

Rats from a common litter

Rosenzweig et al. (1972) Procedure

Rats from a common litter were placed into one of three conditions.

1) Control Condition with 3 rats

2) Impoverished Condition with individual cages and lack of enrichment

3) Enriched Condition with 10-12 rats with different stimulus and enrichment

The rats typically spent 30 to 60 days in their respective environments before they were killed in order for the researchers to study changes in the brain's anatomy.

Rosenzweig et al. (1972) Findings

There was an increased thickness and higher weight of the cortex in EC rats compared to that of IC rats. The researchers also noted that rats in the EC condition had developed significantly greater activity in the neurons in the cerebral cortex associated with the transmission of acetylcholine, which is an important neurotransmitter for learning and memory. Follow-up to this research indicated that just 30 minutes a day in an enriched environment produced the same changes in the brain in rats as had been observed in the original experiment where rats were exposed to the EC condition for a much longer period of time.

Rosenzweig et al. (1972) Conclusion

Enrichment does have an impact on the development of neurones in the cerebral cortex.