Lecture 13: neurotransmitter networks Flashcards
what is the significance of phineas Gage
early evidence that different areas of brain are networked to create our personality
How is the CNS imaged
- Positron Emission Tomography (PET): tracks glucose uptake (tracer)
- Functional Magnetic ResonanceImaging (fMRI): tracks blood flow (deoxyhemoglbin is paramagnetic)
- become apparent with above techniques that areas of activity/function do not always precisely coincide with defined anatomical zones
How are Networks defined?
They sue same neurotransmitter
Explain the Norepinephrine Networks, what it modulates and its psychostimulants
modulates:
- mattentin
- arousal
- slwwp/wake
- learning
- memory
- pain
- anxiety
- mood
Psychostimulants:
- methamphetamine
- Ritalin
- Caffine
Explain the Serotonin Network, what is modulates
modulates:
- pain
sleep/wake
emotion
How do most antidepressatns work?
- increase serotonin levels
What are migraines associated with
Low seratonin levels
What does the Acetylcholine Network modulate
- arousal
- sleep/wake
- learning
- memory
- sensory information
What is alxheimers characterized by
- massive loss of cholinergic neurons
- low acetyl choline levels
- drugs treat by inhibiting cholinesterase (an enzyme that rapidly breaks down ach in the synapse)
- slows the breaking down of acetyl choline
What does the dopamine network modulate
- motor contorl
- reward/pleasure centres
How are dopamine treatments used for patients with parkinsons disease
- dopamine agonists used to increase health span
- PD patients may have decreased sexual activity
- too much dopamine can cause hyper sexuality and problems controlling impluses
Where is the dopamine signal processed into pleasure?
prefontal cortex of brain
How does dopamine work with drugs
- have dopamine neuron, target neuron and GABA neuron
- GABA acts as negative feedback preventing prolonged dopamine
- heroine/morphine blocks release of GABA. prolonged dopamine
- cocain blocks reuptake of dopamine
What is GABA
gamma-amino butyric acid. inhibited by heroin/morphine
- released by GABA neurons and blocks propagation of the dopamine triggered signal in post synaptic neuron
how can you prevent accumulation of a transmitter?
- reuptake of transmitter at presynaptic terminal
- enzymatic degradation of transmitter within synpase
- negative feedback to inhbit further release
