What is Parkinson’s Disease?
Parkinson’s Disease (PD) is a neurological condition caused by the neurodegeneration (degradation) of specific neurons (cells) in the brain. To be precise the neurons affected are within an area of the brain called the basal ganglia (BG), specifically a set of neurons which release dopamine. These dopaminergic neurons form the basis of a ‘pro-movement’ signaling pathway and allow us to perform many voluntary movements. Therefore, when degraded we simply loose most of this ability, resulting in akinesia (a lack of movement), rigidity and a resting tremor (although this list is not exhaustive).
A Generalised Overview of its formation
From the figures below the magnitude of each arrow is representative of the intensity of that output. In a healthy individual (figure 1) the number of dopaminergic neurons arising from the SNc is large, meaning large numbers of D1 and D2 receptors are activated in the striatum. Overall, this results in limited amounts of GABAergic inhibitory drive being elicited on the Thalamus and so we see large amounts of cortical excitation. However, a PD patient will have a reduced number of dopaminergic neurons projecting to the striatum (figure 2), this results in large amounts of inhibitory drive acting on the thalamus and as a result reduced cortical excitation, ultimately affecting their motor function ability[3].
Traditional treatments for Parkinson’s disease include the prescription of L-dopa, Carbidopa and Selegiline however these only combat the symptoms of the disease and don’t halt disease progression. Therefore, there is a major clinical need to solve this issue in order to improve our ability to treat patients[4].
In the Images below, the thickness of each arrow represents the size/intensity of that input/output.
