Lecture 13

Question 1

Why is Parkinson’s disease caused?

Answer 1

Due to a loss of dopaminergic cells in the substantia nigra.

Question 2

What kinds of environmental and genetic factors cause Parkinson’s?

Answer 2

Environmental-pesticide exposure, head injury, heavy metal exposure
Genes: LRRK2, PRKN, SNCA

Question 3

What are the 2 ways you can treat (NOT CURE) Parkinsons?

Answer 3

Dopamine replacement treatment-L-Dopa

Deep Brain Stimulation

Question 4

How does our body make dopamine?

Answer 4

The dietary amino acid Tyrosine is turned into L-Dopa with tyrosine hydroxalase (which we don’t have much of). Because of this, DOPA decarboxylase (which we have a lot of) converts L-Dopa into dopamine.

Question 5

Why don’t we just inject dopamine? Why L-Dopa?

Answer 5

Dopamine doesn’t get past the blood-brain barrier, but L-Dopa can. By injecting L-Dopa directly, we bypass the tyrosine hydroxylase phase so we can get more dopamine out of L-Dopa.

Question 6

Who discovered the L-Dopa cure and how did he do it?

Answer 6

Oliver Sacks-supervised people with influenza in the 20s who developed Parkinson’s symptoms-all went into comas. He then tried L-Dopa on a hunch and the patient woke up!

Question 7

What did Oliver Sack’s experiment show?

Answer 7

A neurological condition can be treated by a drug that replaces neurotransmitters.

Question 8

What are some of the side effects of too much dopamine?

Answer 8

Hypotension, arrhythmias, nausea, confusion, anxiety, vivid dreams, insomnia, auditory/visual hallucinations, psychosis.

Question 9

What is deep brain stimulation?

Answer 9

Microelectrodes that are chronically implanted into the brain-stimulation of a specific area is provided via a pulse generator.

Question 10

How does deep brain stimulation work for someone with Parkinson’s?

Answer 10

Bypasses the substantia nigra to target network responsible for movement-not a cure, but there are less side effects than L-Dopa.

Question 11

What are some other ways to slow the symptoms of Parkinsons?

Answer 11

Activities with large movements (Boxing), singing (improves speech and swallowing).

Question 12

What is neuroplasticity?

Answer 12

Modification at the synapse-how does our experience modify information flow at the level of the synapse.

Question 13

Who was Donald Hebb?

Answer 13

First person to theorize about neuroplasticity-cells that fire together, wire together.

Question 14

Who was Erik Kandel?

Answer 14

Awarded Nobel prize in physiology and medicine for his work on memory in Aplysia (sea slug)- great simple system to work on!

Question 15

What are the 2 types of behaviour that Erik Kandel studied?

Answer 15

Habituation-Learning behaviour in which response to a stimuli weakens with repeated presentation
Sensitization- Response to a stimulus strengthens with repeated presentation- because the stimulus is novel, or stronger than normal.

Question 16

How can we tell if an Aplysia has learned?

Answer 16

In response to a shock, it keeps itself contracted for a longer period of time.

Question 17

What happens at the synapse with habituation?

Answer 17

Influx of calcium ions in response to an action potential decreases-less neurotransmitters are released at the presynaptic membrane, less depolarization of post synaptic membrane.

Question 18

What happens at the synapse with sensitization?

Answer 18

Interneuron added which releases serotonin-reduces K+ efflux through potassium channels, prolonging an action potential. Prolonged action potential results in greater calcium influx, leading to increased neurotransmitter release and greater depolarization.

Question 19

How does the neuron change in response to short-term learning versus long term?

Answer 19

Short-term- changes in neurotransmitter release

Long-term- actually changes connections between neurons.