Final answer:
The important chemicals in the brain mentioned are dopamine, norepinephrine, and phenylethylamine (PEA), with dopamine and norepinephrine being crucial for transmitting nerve impulses and influencing mood and behavior. Dopamine is especially significant in reward and addiction processes, while norepinephrine affects alertness and stress responses. These neurotransmitters and their roles in the brain are targeted by psychoactive drugs to produce various effects.
Step-by-step explanation:
According to scientists, the key chemicals within the brain are dopamine, norepinephrine, and phenylethylamine (PEA). These chemicals are neurotransmitters that play crucial roles in the transmission of nerve impulses within the brain. Dopamine is involved in reward and pleasure mechanisms and plays a role in addiction as it is part of the dopaminergic system with specific dopamine receptors. Studies of dopamine action are instrumental in understanding addictive processes, looking at brain function in drug addicts and explaining why activities that stimulate the brain's pleasure center can be addictive. Norepinephrine, also known as noradrenaline, along with epinephrine (adrenaline), is part of the adrenergic neurotransmitter system, working as a hormone when released into the bloodstream by the adrenal gland. These neurotransmitters impact our feelings of well-being and are involved in alertness and response to stress.
Stimulant drugs work by affecting these neurotransmitters, with some blocking the reuptake of dopamine, hence enhancing its effects. The binding of chemicals to dopamine receptors has been observed through PET scans, showing differences between non-addicted and addicted individuals, indicating the relevance of dopamine receptor activity. The complex networks involving dopaminergic neurons in areas such as the substantia nigra and ventral tegmental area illustrate the intricate interplay of neurotransmitters in brain functions, including cognition, affective states, and behavioral patterns. Psychoactive drugs affect the brain's chemistry by acting as either agonists or antagonists to various neurotransmitters, altering mood, perception, and behavior.