A characteristic pathological feature of Parkinson’s disease is presence of –
**Core Concept**
Parkinson's disease is a neurodegenerative disorder characterized by the loss of dopamine-producing neurons in the substantia nigra, a region of the midbrain involved in motor control. The degeneration of these neurons leads to a decrease in dopamine levels in the striatum, resulting in characteristic motor symptoms such as tremors, rigidity, and bradykinesia.
**Why the Correct Answer is Right**
The correct answer is Lewy bodies, which are abnormal protein clumps composed of alpha-synuclein that accumulate within the neurons of individuals with Parkinson's disease. Lewy bodies are thought to play a key role in the pathogenesis of the disease, contributing to the degeneration and death of dopaminergic neurons. The presence of Lewy bodies is a hallmark pathological feature of Parkinson's disease and is used as a diagnostic criterion in post-mortem examinations.
**Why Each Wrong Option is Incorrect**
* **Option A:** Neurofibrillary tangles are characteristic of Alzheimer's disease, not Parkinson's disease. They are composed of hyperphosphorylated tau protein and are a distinct pathological feature of Alzheimer's pathology.
* **Option B:** Astrocytosis refers to the activation and proliferation of astrocytes, a type of glial cell in the brain. While astrocytosis may occur in various neurological disorders, it is not a characteristic pathological feature of Parkinson's disease.
* **Option C:** Microgliosis refers to the activation and proliferation of microglia, another type of glial cell in the brain. Like astrocytosis, microgliosis may occur in various neurological disorders, but it is not a hallmark pathological feature of Parkinson's disease.
**Clinical Pearl / High-Yield Fact**
Parkinson's disease is a clinical diagnosis, and the presence of Lewy bodies can only be confirmed post-mortem. However, the presence of Lewy body-like inclusions in the brain's substantia nigra pars compacta on a DaTSCAN or PET scan can be a useful diagnostic clue.
**Correct Answer: C. Lewy bodies**