The brain controls not only what we pay attention to and think, but also automatic activities such as heartbeat, breathing and temperature. It also handles motor skills, movements, and sensorics, sensations and senses (hearing, vision, smell, etc.) Diseases and injuries that affect these functions are usually referred to as neurological diseases and injuries. The brain also handles our mental health, including through various neurotransmitters. It's called the psychiatric disorders. To fully interpret, understand and interact with the world around us requires a working cognition, e.g. you can talk/find words, remember, orient yourself, be caring and social. Different areas of the brain are responsible for different (cognitive) functions and diseases or injuries here result in a cognitive impairment in the same way that failing function in the pumping capacity of the heart leads to heart failure. If it is a disease that is responsible for the cognitive impairment, they are called cognitive disorders or dementias. You can divide the brain's abilities into six overall functions, "abilities", so-called cognitive domains.