Neurotransmission

• Neurons are the BUILDING BLOCKS of behaviour
• Neurons send electrochemical messages to the brain so that we can respond to stimuli - Both from the environment, or a body’s internal changes
• The process by which these electrochemical messages are sent is known as neurotransmission
• Electrical impulses that travel along the body are known as action potentials - Action potentials release neurotransmitters down the axon of the neuron, the neurotransmitters are then released into the gap between neurons known as a synapse
• Neurotransmitters are the body’s natural chemical messengers that transmit information from one neuron to another neuron
• After crossing synapses, the neurotransmitters fit into receptor sites on the synapse, like an enzyme and it’s substrate.
• Once the message has been given to the synapse, enzymes will actually come and break it down, or the body will reabsorb it

Neurotransmitters have been shown to have a range of different effects on human behavior. In fact, neurotransmission underlies behavior as varied as mood, sleep, learning and memory, sexual arousal, and mental illness. The table below, which highlights just a few neurotransmitters, gives an idea of the variety of behaviors that are influenced by these neurochemicals.

Neurotransmitters

Inhibitory or excitatory?

When discussing neurotransmitters, we categorize them by how they affect a neuron.

• Excitatory neurotransmitters increase the likelihood of a neuron firing by depolarizing the neuron. Excitatory neurotransmitters include acetylcholine.
• Inhibitory neurotransmitters decrease the likelihood of a neuron firing by hyperpolarizing the neuron. Inhibitory neurotransmitters include GABA.

Because neurotransmitters fit tightly into receptor sites, like a key in a lock, drugs have been developed to either simulate the neurotransmitter if there is not enough of a specific neurotransmitter or to block the site if it is excessive. The application of such research has improved the lives of many people.

There has been criticism of reducing the explanation of behavior to the workings of neurotransmitters alone. It is said to be reductionist. Can a complex human behavior like falling in love with someone be attributed to a simple “love cocktail” of dopamine and norepinephrine? Can your mood during the summer holidays be attributed simply to serotonin levels? Once again, most psychologists consider that neurotransmitters play a role, but do not rely solely on neurotransmission to explain behavior.

IMPORTANT NEUROTRANSMITTERS

1. Acetylcholine - Plays a role in the consolidation of memory localised in the hippocampus
2. Dopamine - The body’s reward and pleasure centers - Plays a key role in motivation - Low levels are linked to addictive behaviour