Excitation and inhibition

• Neurons contain many different types of neurotransmitters such as serotonin, dopamine, glutamate, GABA and acetycholine
• Different neurotransmitters can either have excitatory or inhibitory effects
• Excitatory: Increase the likelihood of the neuron firing
• Inhibitory: Decrease the likelihood of the neuron firing
• For example, serotonin has a generally inhibitory effect
• When serotonin binds to the receptor of a neuron, it increases the negative charge of that neuron, making it less likely to fire
• Glutamate has an excitatory effect
• So, if glutamate outweighs serotonin in a neuron, the net effect is increased likelihood of that neuron firing
• When a neuron is in a resting state the inside of the cell is negatively charged compared to the outside
• When a neuron is activated, the inside of the cell becomes positively charged for a split second causing an action potential to occur
• The action potential causes an electrical impulse that travels down the axon towards the end of the neuron