Psych Animal Research Quiz

Rogers and Kesner (2003) Aim

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

Rogers and Kesner (2003) Procedures

1. 30 rats were familiarized with a Hebb-Williams maze.

2. Rats were randomly assigned to two groups:

   • Scopolamine group: Received an injection to block acetylcholine receptor sites.

   • Placebo group: Received a saline injection as a control.

3. Memory encoding was measured by comparing errors in early and later trials on Day 1. Memory retrieval was assessed by comparing errors from Day 2 to the end of Day 1.

Rogers and Kesner (2003) Findings

The scopolamine group made more errors and took longer to learn the maze, showing that acetylcholine is important for memory consolidation. However, it did not affect the retrieval of existing memories.

Rogers and Kesner (2003) Conclusion

Acetylcholine is essential for the consolidation of spatial memory but does not significantly impact memory retrieval.

Rosenzweig, Bennet & Diamond (1972) Aim

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

Rosenzweig, Bennet & Diamond (1972) Procedures

• Three male rats from the same litter were randomly assigned to:

  • Control condition (CC): Standard cage with no stimuli.

  • Impoverished condition (IC): Individual cages without toys or a maze.

  • Enriched condition (EC): Group cages with toys and a maze for exploration.

• Rats lived in their environments for 30–60 days before being euthanized to analyze brain anatomy.

Rosenzweig, Bennet & Diamond (1972) Findings

Rats in enriched environments had thicker cortices, heavier brains, and greater neuron activity linked to learning and memory compared to those in impoverished conditions.

Rosenzweig, Bennet & Diamond (1972) Conclusion

The study demonstrates that environmental stimulation can lead to physical brain changes, highlighting the role of neuroplasticity in cognitive development.

Meaney et al (1988) Aim

To determine the effect of glucocorticoids (stress hormones) on memory.

Meaney et al (1988) Procedures

• Newborn rats were assigned to two groups:

  • Treatment group: Handled daily and groomed by researchers.

  • Control group: Separated from mothers with no handling.

• At two years old, rats' memory was tested by tracking their routes to a hidden platform in a water pool.

Meaney et al (1988) Findings

Rats in the control group showed greater hippocampal neuron loss and memory deficits, while groomed rats had better memory and less hippocampal damage due to lower cortisol levels and gene activation.

Meaney et al (1988) Conclusion

Maternal grooming activates stress-regulating genes, improving memory and reducing hippocampal damage in rats.

Cases et al (1995) Aim

To investigate the genetic origins of aggression by studying the effect of a variation in the MAOA gene on behavior.

Cases et al (1995) Procedures

Transgenic mice were genetically modified to lack the MAOA gene. The mice were observed for aggressive behaviors such as frantic running, shaking during sleep, and biting. "Resident-intruder" tests were conducted to observe aggressive interactions with other mice.

Cases et al (1995) Findings

Mice with the MAOA deficiency exhibited increased aggression, including offensive behavior toward intruders, and elevated levels of serotonin, dopamine, and norepinephrine.

Cases et al (1995) Conclusion

The lack of the MAOA gene in mice led to aggression, suggesting that a genetic predisposition may contribute to aggressive behavior in humans, influenced by gene-environment interactions.

Rogers & Kesner (2003) Link to Human Behavior

This study on acetylcholine and memory consolidation in rats is directly relevant to understanding human memory. It emphasizes how neurotransmitters like acetylcholine play a key role in learning and memory processes, potentially influencing treatments for memory-related conditions such as Alzheimer's disease in humans.

Rosenzweig, Bennett, & Diamond (1972) Link to Human Behavior

The study on environmental enrichment and brain development in rats suggests that cognitive abilities in humans can be enhanced by environmental factors. It has implications for understanding how social and intellectual stimulation in early childhood can improve cognitive development, potentially influencing educational policies and interventions for children in impoverished environments.

Meaney et al. (1988) Link to Human Behavior

Meaney's research on the effects of early maternal care and stress regulation in rats provides insight into how early life experiences, particularly maternal care, can influence human stress responses. It helps explain how childhood neglect or trauma might contribute to mental health issues like PTSD, anxiety, and depression in humans later in life.

Cases et al. (1995) Link to Human Behavior

The study on knockout mice with a mutation in the MAOA gene sheds light on the genetic basis of aggressive behavior, potentially explaining human aggression linked to the same gene. The research suggests that genetic predispositions could influence aggressive behavior in humans, helping to inform the development of treatments or interventions for violent behaviors, particularly in individuals with the "warrior gene."