synaptic transmission

• neurons communicate with each other within groups called neural networks. Each neuron is separated by the synapse.
• Signale within neurons are transmitted electrically however signals between neurons are transmitted chemically across the synapse
• when the electrical impulse reaches the end of the neuron (presynaptic terminal) it triggers the release of neurotransmitter from synaptic vesicles
• once a neurotransmitter crosses the gap it is taken up by a postsynaptic receptor site on the dendrites of the next neuron. chemical message converted back into an electrical impulse
• direction of travel can only be one way. Neurotransmitters are released from presynaptic terminal and received by post synaptic terminal
• several dozen types of neurotransmitter have been identified in the brain. Each has its own specific molecular structure that fits perfectly into a postsynaptic receptor site
• neurotransmitters have either an excitatory or inhibitory effect on the neighbouring neuron: serotonin causes inhibition in the receiving neuron resulting in the neuron becoming negatively charged and less likely to fire
• summation decided whether a postsynaptic neuron fires. excitatory and inhibitory influences are summed: if the net effect on the post synaptic neuron is inhibitory then it is less likely to fire