Brain activity refers to the electrical impulses and chemical signals that occur within the brain as it processes information. Neurons, the brain's nerve cells, communicate with each other through synapses, creating networks that enable functions such as thinking, memory, and movement. This activity can be measured using techniques like EEG (electroencephalography) and fMRI (functional magnetic resonance imaging), which help researchers understand how different areas of the brain respond to various stimuli. Different types of brain activity are associated with specific mental states. For example, alpha waves are linked to relaxation, while beta waves are associated with alertness and concentration. The brain is constantly active, even during sleep, as it processes information and consolidates memories. Understanding brain activity is crucial for fields like neuroscience and psychology, as it provides insights into how the brain functions and how it can be affected by various factors.