Sample response

In the biological approach, animals are often used instead of humans to study the brain and behaviour. There are several reasons for this. First, it is possible to do research with animals that would be unethical to do with humans. Secondly, it is possible to study several generations of animals (like rats) over a shorter period of time than humans. And finally, animals are said to have a similar physiology of their brains to humans. But the question is are animal models really valid in the study of humans?

One study with animals was done by Rogers and Kesner. They wanted to study the role of acetylcholine in the creation of memories. This is important because there are many acetylcholine receptors on the hippocampus – and we also know that there are lower levels of acetylcholine in people with Alzheimer’s. In their study, they first taught a group of mice a maze. The rats were then randomly allocated to one of two conditions. The rats were either injected with scopolamine (which blocks AcH receptor sites) or with a saline solution to act as a placebo. The injections were made directly into the hippocampus. The results were that when acetylcholine was blocked, new memories could not be created.

This study lacked ecological validity because it was done in a lab. In addition, we have to consider the ethics of injecting mice with a drug. It is not possible for the animals to give consent and they cannot withdraw. Finally, it is difficult to generalize this study because it was done on rats. The human brain is more complex than the brains of rats.

Another study with animals was done by Rosenzweig et al. In this study, they also looked at the role of acetylcholine. In this study, rats were put into one of three conditions. They were either put into an enriched environment (with other rats, a maze and stimulating toys), an impoverished environment (alone with no stimulation or maze) or a control condition (no maze or toys, but other rats). All conditions received the same level of food and water. After 60 days the rats were killed and their cerebral cortex was measured. The researchers found that there was more great matter in the brains of the stimulated rats and that they had denser neural networks. This shows that environmental stimulation can lead to neuroplasticity.

This study has been linked to studies of abused and neglected children who have smaller hippocampi. But we can only see this difference with MRIs, we cannot kill people and check the mass of their hippocampus. This is why animal models are important. The problem, however, is that the behaviours that we see in animals are not the same as what we see in human beings. So, what may be stimulating to a rat may not be stimulating to a human being. In addition, since the rats in both of these studies were raised in laboratories, it is difficult to know if the results are valid.

There have been many links between animal studies and human studies, leading us to believe that animals may be a good model for the study of the human brain. However, there are many questions. In the case of drug research, many drugs that have been tested in animals – which change the level of neurotransmission – do not work in humans. So, maybe the models are not very good after all.

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