All are affected in dementia except –
**Core Concept**
Dementia is a complex neurodegenerative disorder characterized by progressive cognitive decline, affecting memory, thinking, and behavior. It involves multiple pathological processes, including amyloid-beta deposition, tau protein hyperphosphorylation, and neuroinflammation.
**Why the Correct Answer is Right**
The correct answer is **Cholinergic neurons**. Cholinergic neurons, which utilize the neurotransmitter acetylcholine, play a crucial role in cognitive function, particularly in memory formation and retrieval. In dementia, especially Alzheimer's disease, cholinergic neurons are significantly affected, leading to a decline in cognitive abilities. This is due to the degeneration of cholinergic neurons in the basal forebrain, a region critical for cognitive processing.
**Why Each Wrong Option is Incorrect**
**Option A:** The correct answer is not **Glutamatergic neurons**, although they are also affected in dementia, particularly in the context of excitotoxicity and neuroinflammation. However, the primary issue in dementia is not the loss of glutamatergic neurons but rather the disruption of their function and the subsequent excitotoxicity.
**Option B:** **Serotonin** is indeed affected in dementia, particularly in the context of depression, which is a common comorbidity in patients with dementia. However, the primary issue in dementia is not the serotonergic system but rather the cholinergic system.
**Option C:** **Dopaminergic neurons** are also affected in dementia, particularly in the context of parkinsonian symptoms, which are a common feature of dementia with Lewy bodies. However, the primary issue in dementia is not the dopaminergic system but rather the cholinergic system.
**Clinical Pearl / High-Yield Fact**
A key aspect of dementia pathophysiology is the interplay between amyloid-beta deposition and tau protein hyperphosphorylation, leading to neurofibrillary tangles and synaptic loss. This interplay is a critical area of research in understanding the underlying mechanisms of dementia.
**Correct Answer:** None of the above (Cholinergic neurons)