Carthage Neuroscience Lab
The Neuroscience Laboratory at Carthage is used by psychology and neuroscience faculty and students. The lab is equipped with a rodent colony, complex environment housing, operant chambers, 17-arm radial maze, water maze, object recognition chambers, and equipment for surgery and histology.
In this lab, Professor Daniel Miller leads students in researching post-traumatic stress disorder in an animal model: Researchers study the behavioral effects of manipulating the brain through lesions or drugs. Professor Penny Seymoure leads students in studying the lifespan consequences of neonatal intervention on the development of gonadal and stress hormone systems in rodents. Currently she and her students have been engaged in lifespan studies on the cognitive effects of neonatal exposure to the commonly used antidepressant fluoxetine (Prozac).
Students can use the following equipment in their research:
The signaled barpress uses a standard operant conditioning chamber; a rat presses a lever to receive food pellet reinforcement. A speaker directly above the cage delivers a one-second tone, on average every 25 seconds. A bar press that occurs during the tone results in food pellet delivery. A bar press that occurs at other times is not reinforced. On average, rats reach asymptotic learning levels in six days, making this an ideal task for undergraduate behavioral neuroscience research.
Carthage’s rodent colony includes enriched environment, or complex environment, housing. In this type of housing, rodents are grouped with 10 to 12 other rats of the same sex in large stainless steel cages. Toys and other items in the cage are changed on a weekly basis, allowing the rats to interact with each other and the objects. The environment gives the animals more stimulation, explains Professor Penny Seymoure: “They interact with their environment. They move all of their items around, they pick favorite things and sleep in them.” When the cages are cleaned, new items are added. “Within 30 minutes, the rats have reorganized it,” Dr. Seymoure says. “Animals who live in these cages, we know from a multitude of research, are smarter, learn faster, have better memory, are more flexible in their thinking, and adopt alternate strategies quite rapidly.”
17-arm Radial Maze
The 17-arm radial maze is a very challenging task, requiring the hippocampus and related brain structures for success in learning the task. Professor Penny Seymoure has used the 17-arm radial maze to study rearing environment and gender differences (Seymoure, P., Dou, H., and Juraska, J.M. 1996 Psychobiol., 24, 33-37) and lifespan spatial cognition (Seymoure, P., 2003, Spatial memory for the 17-arm-radial maze improves over the lifespan of rats living in a complex environment presented at the Society for Neuroscience conference) in hooded rats. In the 2003 study Dr. Seymoure tested Long-Evans hooded rats in the 17-arm radial maze four times, from before puberty to early old age. She found that spatial memory for the 17-arm radial maze significantly improves over the lifespan of rats living in a complex environment.
The Morris water maze task is a well-established method to examine both acquisition and memory in rodents. Rats are natural swimmers and can find the hidden underwater escape platform through using cues, which are either spatial cues arranged around the testing room or a local cue that signals the exact placement of the platform. An advantage of the water maze method is that animals are motivated to escape from the water, so that food or drinking restrictions are not used for the task.
Professor Seymoure has used the water maze to examine the effects of naturally cycling gonadal hormones, environmental housing conditions, neonatal stress through decreases or increases in tactile stimulation, and through neonatal exposure to fluoxetine.