3B - Neurotransmission And Neuromodulators Flashcards
Neural Transmission (And Neurons)
- Neurons are individual nerve cells, specialised to receive, process, and transmit information within the nervous system.
- When neurons communicate with each other, this is referred to as neural transmissions, which occurs when a neuron is activated, or fires, sending out an electrical impulse or action potential.
- Electrical = WITHIN the neuron
- Chemical = BETWEEN neurons
Neural Transmission Process
1 - Neural impulse reaches axon terminal of pre-synaptic neuron
2 - This causes vesicles to release NTs into the synaptic gap
3 - The NTs bind to the receptor sites on the dendrite of the post-synaptic neuron
4 - This causes the post-synaptic neuron to
Either-
- more likely fire (excitatory)
less likely fire (inhibitory)
Neurotransmitters
Excitatory - Glutamate
Inhibitory - GABA
Excitatory
Stimulates or activates post-synaptic neurons, increasing their likelihood of firing
Inhibitory
Suppresses or slows down post-synaptic neurons, decreasing their likelihood of firing
Glutamate
Important role in learning and memory
Exitatory effects form and strengthen synaptic connections between neurons that are repeatedly activated during learning
GABA
Important role in regulating post-synaptic activation in neural pathways, preventing the over exitation of neurons
Reduces anxiety and seizures
The Balancing Act
- GABA and glutamate need to be balanced in the brain for optimal functioning in terms of neural transmission
- If there is too much glutamate (excitatory) and not enough GABA (inhibitory) then neural transmission will be out of control
Neuromodulators
- The verb ‘to modulate’ means to adjust or vary or change
- Neuromodulators are chemical molecules that affect multiple post-synaptic neurons at the same time
- They function on a larger scale than neurotransmitters. For example;
- Neurotransmitters are 1:1
- Neuromodulators are 1:multiple - Neuromodulators can influence large areas of the brain at the same time
Neuromodulation (More Like The Process)
- Neuromodulation is the process by which the synaptic transmission between two neurons is either enhanced or decreased through the action of a third substance, called a neuromodulator.
- Neuromodulation can be described as any chemical communication between neurons that:
- enhance the excitatory/inhibitory effects of neurotransmitters
by changing the responsiveness of receptor sites - may not be point-to-point - they can be released diffusely,
- affecting multiple neurons
- enhance the excitatory/inhibitory effects of neurotransmitters
- may not be fast, because they attach to slower kinds of receptor sites
Dopamine/ Serotonin Effect
- Can have excitatory or inhibitory effects on the post-synaptic neurons
- The effect of dopamine/ serotonin depends on the type of receptor sites present at the particular brain location
Dopamine Role Of Functioning
Coordinating voluntary motor movement
Reward-based learning
Motivation
Serotonin Role Of Functioning
Mood regulation and stablisation
Regulating the sleep-wake cycle
Appetite
