The neurobiology of dementia

The Neurobiology of Dementia

Final Project for Peggy Mason’s Coursera Course

Understanding the Brain

Submitted by Christy LyonsJuly 18, 2014

Introduction Dementia is a name for progressive

brain syndromes which affect memory, thinking, behaviour and emotion.

Symptoms may include:- loss of memory- difficulty in finding the right words or understanding what people are saying- difficulty in performing previously routine tasks- personality and mood changes

Introduction (cont.)

Dr. Mason discussed Alzheimer’s, a major type of Dementia in a Lab during Week 4.

Dementia is a disease that affected 44.4 million people worldwide in 2013[1].

There is a new case of dementia somewhere in the world every 4 seconds [1].

The number of patients with dementia are expected to triple by 2050 [1].

Relevant Parts of the Nervous System

- Dementia involves the loss of nerve cells.- Since there are nerve cells throughout the brain, the loss of nerve cells in different areas of the brain will affect individuals differently.- This presentation will focus only a couple of areas: the temporal lobe and the hippocampus.

http://www.today.colostate.edu/story.aspx?id=9857

Relevant Parts of the Nervous System: Nerve Cells

There are approximately 100 billion nerve cells or neurons in the brain.

http://www.geek.com/geek-cetera/our-brains-forget-information-at-a-

rate-of-1-bit-per-second-per-neuron-1308566/

http://www.alzheimers.org.uk/braintour

Relevant Parts of the Nervous System: Temporal Lobe

The temporal lobe is the portion of the cerebral cortex that:- recognizes faces- perceives (hearing, vision, smell)- understands language- has emotional reactions

http://www.drzukiwski.com/brain-function/

Relevant Parts of the Nervous System: The Hippocampus

The hippocampus is the part of the brain that allows us to make new, declarative memories: both semantic and episodic. Healthy Hippocampus

(From Dr. Mason’s Week 4 Video)

Impaired Functions

Describe the functions of the nervous system that are apparent or impaired in your example.

Impaired Nerve Cells

Brain cells are generally not replaced.

As more and more brain cells die, the brain starts to shrink.

Impaired or Degenerated Temporal Lobe

Impairments in the temporal lobe have been traced to Alzheimer’s.

People with damage to the temporal lobe suffer difficulties in face recognition and object recognition.

Long- and short-term memory loss.

Aggression

The Temporal Lobe of a Dementia Patient

(Week 4 – Peggy Mason)

Impaired or Degenerated Hippocampus

Damage to the hippocampus causes:- severe memory impairment- disorientation- it may also cause depression

Healthy Hippocampus(Week 4)

Hippocampus of DementiaPatient (Week 4)

Perforant Path

The stream of information from the entorhinal cortex, through the dentate gyrus to the hippocampus is called the perforant path.

The entorhinal cortex is one of the first areas of the brain to show signs of Alzheimer’s disease.

The entorhinal cortex is associated with self-localization as well as declarative memory.

The Everyday Living of NeurobiologyExplain in detail the ways in which this course has allowed you to better analyze the events and phenomena around you.

The Everyday Living of Neurobiology: Dementia

My 97-year-old grandmother has had dementia for at least the last 7 years.

She was a bookkeeper with an excellent memory.

The Everyday Living of Neurobiology: Dementia

Watching her deteriorate has had a profound impact on our family; particularly my mother.

She has periods where she cannot recognize my sister-in-law or cousin’s boyfriend who’ve been around for the last 10 and 4 years, respectively.

Less frequently, she doesn’t know who me, my brother or even my mother and uncle are.

The Everyday Living of Neurobiology: Dementia

She will ask a question and 3 minutes later ask the same question and then 5 minutes later, repeat it again. (Short-term memory loss)

While at the cottage, she will be angry that the family is there, because she is expecting company, but when she’s queried on who the company is she won’t recall. She’s forgotten that she sold the cottage to my mom and uncle 15 years ago. (Aggression and long-term memory loss)

The Everyday Living of Neurobiology: Dementia

One time, I was visiting with Nana and she asked me if my husband was stationed in St. John and if I’d taken the trolley to see her. (Prosopagnosia) Explanation: She met my grandfather during WWII and they lived on the east coast.

This course has helped me to understand more clearly the physiological changes occurring in my grandmother, why she is behaving the way she is, and hopefully be more empathetic.

References

[1] Dementia Statistics. Alzheimer’s Disease International. Retrieved from: http://www.alz.co.uk/research/statistics

[2] 3D Brain Ap produced by Cold Spring Harbor Laboratory DNA Learning Center.

[3] Peggy Mason’s The Neurobiology of Everyday Living Videos.