HL Animal: Hormones

Question 1

Topic of Meaney

Answer 1

Hormone

Question 2

Aim of Meaney + context

Answer 2

To investigate the role of stress hormones on memory

Specifically, it studies the effect of a mother’s touch or grooming on her offspring and because it leads to gene expression which helps their regulation of stress. This leads to lower lifetime cortisol levels meaning less memory impairment later in life

Question 3

Method of Meaney

Answer 3

Used a rat model, there short lifespans makes it possible for this study
* New-born rats handled daily by researchers
* During the time, they were taken away for 15 minutes and brushed to stimulate the grooming of a mother rat
* Rats in the control group was also taken away but not brushed
* 2 year old rats were put into a pool of milky water with a platform in the pool
The researchers tracked the route of the rats as they sought out the platform based on rats’ memories of previous attempts to escape the water

Question 4

Findings of Meaney

Answer 4

• Rats taken away from their mothers and were not brushed took a longer route to get to the platform
• High levels of glucocorticoids (stress hormones) in the early life of a rat resulted in changes that affected the rats in old age
• Increased exposure to stress hormones accelerated hippocampal neuron loss and cognitive impairments in aging

Question 5

Conclusion of Meaney

Answer 5

Loss of hippocampal cells correlates with lower levels of acetylcholine and the ability to create memory. Research shows that there is a correlation between high levels of glucocorticoids, low levels of acetylcholine and Alzheimer’s.

Question 6

Aim of Romero + context

Answer 6

To investigate the role oxytocin plays in animal relationship behavior, specifically social bonding.

Hormones - specifically oxytocin Produced in hypothalamus and released into blood stream by pituitary gland. It has a role in sexual reproduction, childbirth and social bonding. Known as the “the cuddle hormone”.

Question 7

Method of Romero

Answer 7

• Repeated measures design, double-blind study
• 16 dogs sprayed intra-nasally with placebo or oxytocin
• Placed in a room with owner and other dog (behavior recorded for an hour)
• Owner told not to interact with dog, video viewed later for dog interaction patterns

Question 8

Findings of Romero

Answer 8

• Dog sprayed with oxytocin demonstrated significantly more affectionate behavior with both owner and the other dog
• The affection created a bi-directional response, where the owner and the other dog also experienced higher oxytocin levels in their blood resulting from the interaction

Question 9

Conclusion of Romero

Answer 9

• Oxytocin promotes social bonding and maintenance through implicit and explicit prosocial behavior in dogs (research conclude mammals)
• Presented prosocial behavior between animals and animals and between animals and humans