Synaptic Transmission and Neurotransmitters

Synaptic transmission is the process by which signals are transmitted between neurons. While signals within neurons are transmitted electrically, the communication between neurons occurs chemically across the synapse.

The process of synaptic transmission involves several steps:

1. An electrical impulse reaches the presynaptic terminal.
2. This triggers the release of neurotransmitters from synaptic vesicles.
3. Neurotransmitters diffuse across the synaptic cleft.
4. They bind to postsynaptic receptor sites on the next neuron.
5. The chemical signal is converted back into an electrical impulse in the postsynaptic neuron.

Example: Neurotransmitters such as dopamine, serotonin, and acetylcholine play crucial roles in various bodily functions and mental processes.

Excitation and Inhibition in Neural Communication

Neurotransmitters can have either an excitatory or inhibitory effect on the neighboring neuron:

• Excitation: Neurotransmitters like adrenaline increase the positive charge of the postsynaptic neuron, making it more likely to fire and pass on the electrical impulse.
• Inhibition: Neurotransmitters such as serotonin increase the negative charge of the postsynaptic neuron, decreasing the likelihood of it firing and passing on the electrical impulse.

Highlight: The balance between excitatory and inhibitory signals determines whether a postsynaptic neuron will fire or not, a process known as summation.

Summation Process

Summation is the process that decides whether a postsynaptic neuron fires:

• If the inputs are mainly inhibitory, the postsynaptic neuron is less likely to fire.
• If the inputs are mainly excitatory, the postsynaptic neuron is more likely to fire.

Vocabulary: Excitatory postsynaptic potential (EPSP) increases the likelihood of a neuron firing, while inhibitory postsynaptic potential (IPSP) decreases this likelihood.

Understanding these processes is crucial for comprehending how the nervous system functions and how various psychological and physiological phenomena occur.