Learning, Explicitly, About Parkinson's Disease

The five million cases of Parkinson’s Disease worldwide (Willingham) drives researchers to actively seek better treatments, and eventually a cure. Emily Willingham, the author of the recently published article on Parkinson’s, talks about the finding of a new gene that might be related to inherited PD. This is particularly exciting for researchers, because with the further understanding of how this gene plays a role in the progression of PD, the mechanisms can contribute to developing new drugs to help slow down or even stop the progression. The mutated form of this gene, leucine-rich repeat kinase 2(LRRK2), interacts with proteins in a way that causes an overproduction of the protein-associated kinase. This led to the research on how the LRRK2 activity affects the dopaminergic neurons, to try to biochemically understand the mechanisms in which this gene is involved with this disease. Researchers are starting to explore whether the LRRK2 protein is involved in non-inherited forms of PD. With this new knowledge, we are able to make a greater impact on the goal of finding better treatment and a cure for Parkinson’s Disease. 

In another study published in 2013, Eric Gobel et al examined the effects of PD on implicit skill learning. Gobel tested subjects using the Serial Interception Sequence Learning (SISL) task and compared the performance of PD and MCI patients to healthy adults. This task required the use of implicit memory, by forcing the subjects to make quick, motor responses. The findings were particularly interesting. While both MCI and PD patients were not able to both complete the task in a short time, and maintain a score between 75% and 92% correct, some of the PD patients were able to complete the task with high accuracy if given more time. The MCI patients were not. The PD patients were somehow able to compensate for their loss of implicit skills by using their explicit memory. These findings raise the question of how PD differs from MCI, on a biochemical level. Besides the determination of which brain areas are affected between the two, how, on a biochemical level, are proteins and kinases responsible for which brain areas are affected by a disease like dementia, versus Parkinson’s? Could a specific kinase, like [from] LRRK2, be responsible for dopaminergic cell loss? Could it be localized in a way that it does not affect the regions of the brain required for explicit learning? 

It is important to study the cellular biology and genetics disease, in attempt to better understand the primary cause, and therefore seek a better prevention plan. Like both Willingham’s article on LRRK2 and Eric Gobel’s study, PD is evidently a problem. Researchers are already moving forward with the finding of the LRRK2 gene. Roberto Di Maio, a research professor involved in the study with the LRRK2 gene, states that this finding might be an opportunity to test people for pre-symptomatic states of PD, by marking high levels of LRRK2 to be a sign for an individual's’ high risk for PD. Gobel also stated that dopamine treatments for PD might actually be harming the implicit - perceptual skill learning, rather benefit. All additional knowledge regarding Parkinson’s is essential to understanding the mechanisms in which the disease is progressed, and it will continue to be a topic of interest for researchers until the best possible treatment, and hopefully cure, is found. 

Willingham, Emily. “Parkinson's Drugs Aimed at Rare Gene Mutation Show Promise for Other Sufferers, Too.” Scientific American, 6 Aug. 2018, www.scientificamerican.com/article/parkinson-rsquo-s-drugs-aimed-at-rare-gene-mutation-show-promise-for-other-sufferers-too/. 

Gobel EW, Blomeke K, Zadikoff C, Simuni T, Weintraub S, Reber PJ. Implicit Perceptual-Motor Skill Learning in Mild Cognitive Impairment and Parkinson’s Disease. Neuropsychology. 2013;27(3):314-321. doi:10.1037/a0032305.