neurotransmitter networks

Question 1

what happened to Phineas P. Gage? why was it so important in research?

Answer 1

Phineas P. Gage had an accident that resulted in a mental rod puncturing through his right cheek and protruding out of the left of his skull. most of his left frontal lobe was damaged, resulting in a personality change - quicker to anger.
this helped develop early evidence that different parts of the brain are networked to create our personality.

Question 2

what is PET?

Answer 2

• positron emission tomography
• tracks glucose uptake
• glucose tracer

Question 3

what is fMRI?

Answer 3

• functional magnetic resonance imaging
• tracks blood flow
• deoxyhemoglobin is paramagnetic

Question 4

why are the imaging techniques not always precise?

Answer 4

• do not always coincide with defined anatomical zones
• they can stretch across different brain regions

Question 5

what are the neurotransmitter-driven networks?

Answer 5

• norepinephrine
• serotonin
• acetylcholine
• dopamine

Question 6

what does the norepinephrine network modulate?

Answer 6

• attention
• arousal
• sleep-wake
• learning
• memory
• pain
• anxiety
• mood

Question 7

what are the psychostimulants of the norepinephrine network?

Answer 7

• methamphetamine
• caffeine
• Ritalin (ADHD treatment)

Question 8

what does the serotonin network modulate?

Answer 8

• pain
• sleep-wake
• emotion - contributor to feelings of well-being and happiness
• most antidepressants work by increasing serotonin levels
• low serotonin levels are associated with migraines

Question 9

what are some facts about the acetylcholine network?

Answer 9

• various drugs are available in Canada to treat Alzheimer’s symptoms such as cholinesterase inhibitors
• cholinesterase is the enzyme that rapidly breaks down acetylcholine in the synapse

Question 10

what does the acetylcholine network modulate?

Answer 10

• arousal
• sleep-wake
• learning
• memory
• sensory info

Question 11

what does the dopamine network modulate?

Answer 11

• motor control
• reward and pleasure centers
• advancing Parkinson’s disease has a loss of dopamine - dopamine agonists are used to increase healthspan in patients.

Question 12

how do dopamine levels affect the body?

Answer 12

• too much can cause hypersexuality and problems controlling impulses
• typically associated with addictions
• can be increased by various drugs (cocaine, etc)
• can be increased by natural endorphins (exercise, food, etc)
• note that cocaine works differently than heroin/morphine

Question 13

what are the characteristics of the phenylalanine hydroxylase pathway?

Answer 13

• normally converts phenylalanine to tyrosine - removes excess phenylalanine and enables production of tyrosine
• excess phenylalanine results in decreased dopamine and serotonin in the brain

Question 14

what are the possible health implications of altering the PAH pathway?

Answer 14

• hyperactivity (ADHD)
• anxiety
• impulsivity
• mental illness
• low motivation/self-esteem
• low dopamine and low serotonin

Question 15

what are the effects of phenylketonuria (PKU)?

Answer 15

• PKU affects 1 in 12,000 people
• a mutation in the PAH gene reduces the amount of the enzyme that converts phenylalanine to tyrosine

Question 16

how is PKU treated?

Answer 16

lifetime diet with minimal intake of foods containing phenylalanine