What is Alzheimer's Disease?

9 Brain Regions Affected by Alzheimer's

Dorian Martin Jan 28th, 2015 (updated May 29th, 2015)
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The brain is made up of a number of regions that are responsible for different functions. This slide show is designed to showcase some of the major areas and describe how they may be affected. This will help you understand the underlying brain issues that cause some of the puzzling behaviors that you might see.

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Hippocampus
Hippocampus

This brain region is responsible for forming new memories. A study found that the volume and ratio of this region was reduced by 25% in Alzheimer’s disease, 21% in mixed dementia, 11% in vascular dementia, and 5% in normal pressure hydrocephalus. This part of the brain is where Alzheimer’s begins and is seen in loss of short-term memory. 

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Hypothalamus
Hypothalamus

This part of the brain plays a critical role in the regulation of feeding and the regulation of weight. Researchers have found that the degeneration of this area relates to changes in eating behavior in frontotemporal dementia and are studying if something similar happens with Alzheimer’s disease.

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Amygdala
Amygdala

This brain region is responsible for the experience and expressions of emotion. This area of the brain is linked to fear responses, pleasure, and sexual emotions. Depression is believed to be linked to abnormal functioning of the amygdala.  In Alzheimer’s as well as frontotemporal dementia, this part of the brain is attacked, leading to personality changes. 

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Cerebellum
Cerebellum

This brain area is linked to the coordination of voluntary movement, gait, posture, speech and motor functions.  The cerebellum also is believed to help with control of cognition and behavior. This region is affected in vascular dementia and another study indicated that the cerebellum is affected in later stages of dementia, although it doesn’t specify which type.

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Frontal lobe
Frontal lobe

The frontal lobe handles executive/management function, such as planning, judgment, motivation, impetus and behavior. This section of the brain is often damaged by Alzheimer’s disease, leading a person to becoming uninhibited, lethargic. A person may become “stuck” on a situation or word, causing them to repeat the action. This area also is often destroyed in frontotemporal dementia. 

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Parietal lobe
Parietal lobe

The parietal lobe handles spatial relationships, perception and magnitude. In addition, this part of the brain is responsible for the sense of one’s body. When this part of the brain is attacked in Alzheimer’s disease, the person may forget how to do common movements (such as those that are necessary to get dressed) and may not recognize objects, faces or surroundings. 

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Occipital lobe
Occipital lobe

This area of the brain helps interpret what the eyes are seeing. When this area is damaged by dementia, people may misinterpret their environment through illusions, misperceptions and misidentification. Damage to this region also may result in hallucinations, which are often seen in dementia with Lewy bodies, Parkinson’s disease dementia, and Alzheimer’s disease. 

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Corpus Callosum
Corpus Callosum

This region helps transfer information between the brain’s left and right hemispheres. This area is often attacked in Alzheimer’s disease, frontotemporal dementia and dementia associated with amyotrophic lateral sclerosis (ALS), resulting in the disruption of the connectivity between the two hemispheres. This leads to loss of processing speed and impairment of motor function.

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Thalamus
Thalamus

The thalamus, located just above the brain stem, is responsible for relaying motor and sensory signals to the cerebral cortex and regulates sleep and alertness. This area often is attacked in thalamic dementia and vascular dementia. Destruction of this brain area may alter consciousness and impair memory, attention and motivation.