‘What is consciousness?’ The question has compelled Tyler Rhind ’18 to think about the relationship between the brain, behavior and awareness since taking courses in neuroscience and consciousness last year. While so far little is known about the links between them, Rhind hopes to further the understanding of consciousness through studying the effects of marijuana on short-term memory and how they relate to schizophrenia.
This summer Tyler Rhind joined a research group from Yale University and VA Medical Center in West Haven, Conn., to conduct related research. THC in marijuana causes similar symptoms to schizophrenia and the researchers sought to discover if short-term memory was impacted by marijuana accordingly.
Many claims have been made about marijuana’s negative impact on short-term memory, but researchers hope to substantiate some of them in this experiment. The location at which marijuana causes short-term memory deficiency should be clearer after completing the experiment.
The research group administers the test on control subjects, schizophrenics, and marijuana users, with about 10 people in each group. The short-term memory task involves the recall of 15 words. They analyzed the number of words correctly remembered and the number of intrusions (errors) each subject reported. As the subject was doing the Rey Auditory Verbal Learning Test (RAVLT), an EEG (electroencephalogram) recorded the electrical activity of the brain to see which areas were stimulated during correctly remembered words compared to the intrusions. The EEG data for healthy subjects will be measured against that of marijuana users and schizophrenics to discover the location of short-term memory deficits in the brain.
The research group analyzes EEG data through the software called Brain Analyzer. The analyzer helps filter EEG waves to remove the interference of muscle movement and other disruptive electrical signals. Then they are able to observe which spikes in brain activity correlate with correct responses. These spikes are from action potentials firing in localized memory regions such as hippocampus. The group believes that repeating the process for marijuana users and schizophrenics would lead to a greater understanding of short-term memory deficits, as they are going to do so for the next step.
The researchers have discovered that memory encoding begins in the frontal cortex. Marijuana indeed causes a decline in short-term memory, but the exact location of this deficit has yet to be identified. They predict the hippocampus and the entorhinal cortex, associated with memory, might be affected, but it is not known for sure until the EEG analysis is completed.
Rhind is planning to take more courses involving neuroscience and consciousness as he is fascinated by both topics. He said that the research experience has only increased his interest in psychology and opened the eyes to the world of science outside of the classroom. After Hamilton, he may pursue a master degree in psychology.
