How do neurons communicate?
Neurons communicate via dendrites and axons, sending electrical impulses down the axon, converting them to chemical signals at the axon terminal, releasing neurotransmitters (chemical messengers) across synaptic gaps (narrow space between the axon terminal and the dendrite of another neuron), and attaching to the receiving neuron’s receptor site. The dendrite receives the neurotransmitter and converts it back to electrical signals. This process happens between billions of neurons in the brain. Communication between neurons functions to control behavior, cognition, mood, and movement.
How do drugs affect the neuronal communication?
Drugs of abuse, whose chemical structures mimic natural neurotransmitters, interfere with normal neuronal processing, releasing neurotransmitters in excessive amounts, providing greater pleasure than naturally pleasing survival activities (e.g., eating or sex) and preventing normal chemical reuptake, meaning that an excessive amount of neurotransmitters are left in the synapse, ultimately affecting the behavior of other communicating neurons, which subjectively alters our mood.
Brain reward system and addiction
The brain’s reward system is activated when an individual engages in survival activities, providing euphoric feelings and reinforcing behavior. When activated, information travels from the ventral tegmental area (VTA) to the nucleus accumbens and then to the prefrontal cortex.