IB Psychology - Neurotransmission

Neurons

Neurons AKA nerve cells, the building blocks of behavior.

Neurons send electrochemical messages to the brain so that individuals are able to react to stimuli (environmental or internal).

Neurotransmission

The process of transferring information from one neuron to another at a synapse.

Axon

The extension of a neuron.

Action Potential

The electrical impulse that travels down the axon of the neuron.

Synaptic Cleft

Gap between two neurons.

Neurotransmitters

Chemical messengers that transmit information from one neuron to another

Receptor Sites

Located on the post-synaptic membrane. Neurotransmitters fit into the receptors like a key and a lock.

Breaking Down or Reuptake

After the message has been passed on, the neurotransmitter is either broken down by an enzyme or re-absorbed by the pre-synaptic neuron.

Acetylcholine

Plays a role in the consolidation of memory in the hippocampus.

Dopamine

Controls the brain's reward and pleasure centers. Plays a key role in motivation; low levels are linked to addiction.

Norepinerphrine/Noradrenaline

Plays a role in arousal and alertness.

Serotonin

Plays a role in sleep, arousal levels and emotion.

Gamma-Aminobutyric Acid (GABA)

Neurotransmitter that reduces activity across the synaptic cleft and thus inhibits a range of behaviors and emotions, especially generalized anxiety. This inhibition allows for more cognitive load. Low GABA levels may lead to intrusive thoughts that make concentration and the making of new memories difficult.

Excitatory Neurotransmitters

Neurotransmitters increase the likelihood of a neuron firing by depolarizing the neuron.

e.g. acetylcholine

Inhibitory Neurotransmitters

Neurotransmitters decrease the likelihood of a neuron firing by hyperpolarizing the neuron.

e.g. GABA

Metabotropic Neurotransmitters

Neurotransmitters that indirectly affect the neuron; neither excitatory nor inhibitory.

e.g. serotonin, dopamine, norepinephrine/noradrenaline

Agonists

Chemical substances that mimic or enhance the effects of a neurotransmitter on the receptor sites of the next cell, increasing or decreasing the activity of that cell

Endogenous: all neurotransmitters
Exogenous: drugs, e.g. nicotine for acetylcholine

Antagonists

Chemical substances that block or reduce a cell's response to the action of other chemicals or neurotransmitters.

Exogenous: drugs, e.g SSRIs for serotonin, scopolamine for acetylcholine

Endogenous

Produced within the body.

Exogenous

Produced outside the body.

SSRIs

Selective Serotonin Reuptake Inhibitors

Used to block receptor sites in the pre-synaptic neuron to prevent reuptake of serotonin; used as a treatment for depression.

Scopolamine

Antagonist that blocks receptor sites of acetylcholine on the post-synaptic neuron.