Neurons communicate through a combination of electrical and chemical signals, enabling rapid and precise transmission of information in the nervous system.
Electrical Communication Within a Neuron
- Communication starts inside a neuron with electrical signals called action potentials. These are rapid changes in the electrical charge across the neuron's membrane caused by the movement of ions (charged particles) through ion channels.
- The inside of a resting neuron is negatively charged relative to the outside (around -70 mV). When stimulated, ion channels open, allowing positive ions to flow in, changing the charge and generating an action potential.
- This electrical impulse travels along the neuron's axon from the cell body toward the axon terminals
Chemical Communication Between Neurons
- Neurons do not physically touch but communicate across tiny gaps called synapses.
- When an action potential reaches the axon terminal of the presynaptic neuron, it triggers the release of chemical messengers called neurotransmitters into the synaptic cleft (the gap between neurons).
- These neurotransmitters bind to specialized receptor proteins on the postsynaptic neuron's membrane.
- Binding to receptors can open ion channels or initiate chemical signaling inside the postsynaptic neuron, influencing its electrical state.
- This can either excite (promote firing of an action potential) or inhibit (prevent firing) the postsynaptic neuron, depending on the type of neurotransmitter and receptor involved
Integration and Signal Propagation
- A single neuron receives hundreds of inputs on its dendrites and cell body, integrating excitatory and inhibitory signals.
- If the net input reaches a threshold, the neuron fires its own action potential, continuing the communication chain.
- This process of synaptic integration and plasticity underlies learning and adaptation in the brain
In summary, neurons communicate by converting electrical signals within the cell into chemical signals at synapses, which then influence the electrical activity of connected neurons, allowing complex information processing in the brain
