It's not accurate to say the brain has only four distinct parts. It's much more complex than that! It's more useful to think of the brain in terms of lobes and structures, each with specialized functions.

Here's a simplified breakdown of some key parts and their roles:

1. Cerebrum: This is the largest part of the brain and is responsible for higher-level cognitive functions:

* Frontal Lobe: Planning, decision-making, problem-solving, personality, voluntary movement.

* Parietal Lobe: Processing sensory information (touch, taste, temperature, pain), spatial awareness, navigation.

* Temporal Lobe: Hearing, language comprehension, memory, emotion.

* Occipital Lobe: Vision, processing visual information.

2. Cerebellum: Located at the back of the brain, the cerebellum plays a vital role in:

* Coordination and balance

* Fine motor skills

* Learning motor skills

3. Brainstem: The brainstem connects the brain to the spinal cord and controls many essential functions:

* Midbrain: Controls eye movements, auditory processing, motor control.

* Pons: Relays signals between the cerebrum and cerebellum, regulates breathing, sleep.

* Medulla Oblongata: Controls vital functions like heart rate, breathing, blood pressure, swallowing.

4. Limbic System: A group of interconnected brain structures involved in emotions, memory, and motivation:

* Amygdala: Processes emotions, especially fear and anxiety.

* Hippocampus: Forms new memories.

* Hypothalamus: Regulates basic drives (hunger, thirst, body temperature), controls hormones.

It's important to note: This is a simplified description. The brain is incredibly complex, and each part interacts with the others in intricate ways. There are many more structures within the brain, and their functions are still being researched.