Final answer:
Degeneration of dopaminergic neurons is a key feature of Parkinson's Disease (PD), leading to movement and cognitive symptoms due to a dopamine deficit in the brain. Treatments like L-DOPA aim to increase dopamine, but the disease progresses over time.
Step-by-step explanation:
The degeneration of dopaminergic neurons is closely associated with Parkinson's Disease (PD), a progressive neurological disorder. PD is characterized by a loss of neurons in the substantia nigra pars compacta (SNc) that leads to a deficit of dopamine within the basal ganglia. This causes the hallmark symptoms of PD, which include tremors, bradykinesia, muscular rigidity, and postural instability. The cognitive decline experienced by patients can include depression, apathy, and anhedonia, among other symptoms. Although the exact mechanisms behind the neurodegeneration are not fully understood, the condition is associated with genetic and environmental factors, such as protein misfolding, oxidative stress, and mitochondrial dysfunction.
The motor symptoms of PD are a result of changes in the basal ganglia circuitry due to dopaminergic denervation of the striatum, and glutamate excitotoxicity is also implicated in the neuropathology of PD. Treatments aim to increase dopamine levels in the brain, with L-DOPA being the most common form. However, as PD progresses, the effectiveness of L-DOPA decreases and can lead to side effects such as psychosis or schizophrenia.