HL BLOA - Animal Studies Flashcards
Animal Models - Ethical Considerations/Brain & Behavior
What two studies
Rosenzweig et al (1974), Rogers and Kesner (2003)
Animal Models - Hormones and Pheromones
What studies?
Meaney (1988) and Sapolsky (1990, 2003)
Animal Models - Genetics
What 2 studies
Farooqi and Rahilly (2006), Cases et al (1995)
Rogers and Kesner (2003)
Aim and Procedure:
Aim: To study the role of acetylcholine in the formation of spatial memories. This is important to study acetylcholine and memory because many people with alzehiemiers have been shown to have lower levels of acetylcholine in the hippocampus.
30 rats in a Hebb Williams maze with a piece of food on the end. The rats were briefly introduced into the maze and once they were familiarised with the new setting, the experiment began.
10 minutes begin experiment the rats were either injected with an antagonist of scolapomine, which aims to block AcH acetylcholine receptor sites) or a saline salt solution, which acted as a placebo condition to establish a baseline of the rat’s performance
Roger and Kesner procedure
After 5 trials over 2 days each, encoding of memory and access retrieval in the number of errors was measured. Results found the scolapomine group made more mistakes and took longer to complete the maze, but no effect on memory retrieval was established.
The results
Evaluation of Rogers and Kesner (2003)
↑ placebo condition gave researchers a baseline of the rates spatial memory formation and memory encoding without an extraneous variable
↑ relevant study for people with dementia and Alzheimers to study how low levels of acetylcholine can impact memory encoding and spatial memory
↓ however, hard to generalise on people with dementia/alzheimers as they do not have higher levels of the antagonist of acetylcholine (scolapomine) injected into them, but only low levels of acetylcholine
↓ hard to generalise on animals
↓ indirect and reductionist approach using scolapomine
↓ artificial way to measure a physiological process, not representative of how hormones usually occur (extraneous agents inserted into the brain)
Cons of Rosenzweig et al (1974)
↓ ethical considerations of harming and killing animals (cost-benefit analysis needed)
↓ hard to determine whether it was the social company or the toys in the enriched condition that led to higher neural density/increased neuroplasticity and high levels of acetylcholine
Pros of Rosenzweig (1974)
↑ shows the cognitive impacts of impoverished conditions on one’s neural density and greater neurons in the transmission of acetylcholine
↑ establishes a cause and effect with the use of two variables
Meaney (1988) - Hormones and animals - intro and procedure
Meaney (1988) studied the role of stress hormones on memory in rats and how gene expression in young rats helps the regulation of stress throughout the rat’s lifetime. The experiment used an independent samples design with 2 conditions.
The experimental condition took newborn rats and placed them in a plastic container and were handled by researchers for the first 3 weeks of their live, and were intensely groomed to stimulate the grooming sensation by a mother rat for 15 minutes each day.
The control group were also placed in a controlled, plastic container but were not groomed or engaged for the first 3 weeks of life.
What did Meaney do with the 2 yr old rats and what were the results
The rats were tested over their lifetime as mature rats when they were 2 yrs old. The 2yr rates were placed in a pool with a platform in the middle and researches tracked the path the rats took to reach the platform. The groomed rats took a straight and simply path while the ungroomed took a longer and more convoluted path to reach the platform.
Researchers found a more scrambled path in the ungroomed rats, higher hippocampal atrophy and spatial memory deficits and higher levels of stress glucocorticoids or stress hormones.
Meaney conclusion
The study drew on epigenetics where conditions in the environment influence the expression of genes in one’s DNA. The grooming of the rats led to the young newborns leading to coping better with stress and as a result, the brain chemistry with levels of glucocorticoids was less than the ungroomed rates.
Sapolsky (1990, 2003) - Hormones
What are Sapolsky’s aims and sample?
baboon troops in Kenya for 30 years, higher levels of basal cortisol in subordinate baboons due to social stressors like competition for food, mating, grooming, space, etc.
