Brain Regions Affected in Rare Tauopathies¶
Learning Objective¶
Identify which brain regions are primarily affected in rare tauopathies and relate regional damage to characteristic symptoms (Bloom Level 2 - Understand).
Overview¶
Pick's disease, corticobasal degeneration (CBD), and progressive supranuclear palsy (PSP) are all tauopathies — rare dementias caused by a toxic buildup of abnormal tau protein inside brain cells. Even though they share the same underlying protein problem, each disease attacks a different set of brain regions. That pattern of damage is why each disease produces its own recognizable set of symptoms. Learning the pattern makes it much easier to tell the three diseases apart.
This interactive diagram shows all three brains side by side. Hover over any numbered marker to learn which region is affected and what symptom it produces.
How to Use This Diagram¶
Explore Mode — Hover over any numbered marker or label to see a description of that affected region and the symptoms it causes.
Quiz Mode — Click "Quiz" to test your knowledge. Read the hint, then click the correct marker on the brain. A celebration plays when you answer all nine questions correctly.
Pick's Disease — Frontotemporal Pattern¶
Pick's disease is one of the frontotemporal dementias. The damage is concentrated in the frontal lobes and the front of the temporal lobes, while the rest of the brain stays relatively spared early on.
- Frontal cortex atrophy → personality changes, poor judgment, and disinhibition (saying or doing things a person would normally filter out)
- Anterior temporal atrophy → language difficulties (primary progressive aphasia), trouble finding words, and difficulty naming familiar things
Memory is often preserved early in Pick's, which is a key clue that helps distinguish it from Alzheimer's disease.
Corticobasal Degeneration — Cortical and Subcortical¶
CBD damages both the surface of the brain (cortex) and the structures deep inside it, and it usually does so asymmetrically — one side of the body is affected first and stays worse than the other.
- Motor and sensory cortex → limb apraxia (inability to carry out learned purposeful movements) and the dramatic "alien limb" phenomenon
- Parietal cortex → trouble coordinating complex movements and using tools
- Basal ganglia → rigidity and bradykinesia (slow movement) that do not respond well to Parkinson's medications
Asymmetric onset is one of the most helpful clinical clues for CBD.
Progressive Supranuclear Palsy — Brain Stem and Basal Ganglia¶
PSP attacks deeper structures first: the midbrain (part of the brain stem) and the basal ganglia. The frontal lobes are also affected, but usually more mildly.
- Midbrain (near the superior colliculus) → vertical gaze palsy, the inability to look up or down voluntarily — the single most specific sign of PSP
- Basal ganglia → rigidity, bradykinesia, and frequent backward falls, often within the first year of symptoms
- Frontal cortex (mild) → executive dysfunction and apathy
On MRI, the shrunken midbrain of PSP produces a famous "hummingbird sign" when viewed from the side.
The Big Picture¶
All three diseases involve abnormal tau protein, but the regional pattern of damage explains the very different symptom profiles. Matching region to symptom is how clinicians tell these rare dementias apart — and it is a powerful framework for understanding every neurodegenerative disease.