Value of Animal Models - brain+beh (LOF + Neuroplasticity)- Rosenweig / weiskranz - human | LUBY

Ethical Considerations

• animal welfare (rosenzweig) - euthanized animals to see brains

Critical thinking Animal Models

Strengths

• Allows for a longitudinal study across whole lifespan

• Can rigorously control environment allowing for less extranious variables

• Human study to support - luby

Limitation

• Animals are different to humans in their cognitive levels meaning the results might not be generalised to the human population

Generalisability

• similarities may be insufficient to generalise to humans. metabolic + cellular differences between humans/animals

• Key symptoms may not be modelled in lab animals - depression cannot be modelled as its unknown if animals will feel the same of humans.

• animals do not have culture and cognition while humans do so that is another major difference between animals and humans

Aim of Rosenweig

to investigate whether environmental factors like rich or impoverished environments would affect the development of neurons in the cerebral cortex

Method of Rosenweig

• 3 male rats were randomly allocated to one of three environments

• control condition had 3 rats in the cage

• 2 conditions: impoverished condition, enriched condition

• enriched condition had 10-12 rats in a cage with different objects to explore and play with and had access to food and water

• impoverished condition had no toys or maze but access to food and water

• rats spent 30-60 days in environments before they were killed to study brain changes

Results of Rosenweig

the findings were that there was an increased thickness and heavier cortex in the enriched condition compared to the impoverished rats

Conclusion of Rosenweig

in conclusion, the environmental factors that differ their stimulus affect the development of neurons in the cortex because the rats in the enriched condition had a thicker and heavier cortex than the rats in the impoverished condition

Aim of weiskranz

to investigate if the amygdala was associated with fear in monkeys

method of weiskranz

• behaviour of monkeys was observed before and after the damaging of their amygdala in surgery

• measured how fearful they were before and after the surgery

• a control group was with a different part of temporal lobe damaged to specify which part of brain would affect the fear

results of weiskranz

the findings were that the monkeys with amygdala lesioned were tame and lost fearful reactions to humans while the control group would still display pre-surgery levels of fear to humans

conclusion of weiskranz

in conclusion, the amygdala does affect fear because the monkeys with lesions to their amygdala, showed less fearful reactions to humans while the control condition with lesions to a different part of their brain showed no change in fearful reactions.

Localisation of Function

certain functions of the brain happen in certain locations or areas within the brain and influence specific behaviours

Luby - human study support

• This study aimed to investigate whether poverty experienced in early childhood affects the brain development at school age.

• This relates to the animal study rosenweig because the poverty acted as the impoverished condition with less stimuli. Luby found that poverty was accociated with less grey brain matter and smaller hippocampus which correlates with the results of rosenweig.

• Thus the use of this animal study is a strength as it is supported by the human study luby.

Neuroplasticity

the ability of the brain to change as a result of one’s experiences

Animal models

used in research to understand humans without risk of causing harm to a human during the process, however there are still some ethical considerations that must be followed even with animal studies.