The brain is made up of billions of neurons, which are the basic units of information processing. Neurons receive input from other neurons through synapses, which are specialized junctions that allow electrical signals to pass from one neuron to another.

2. The Action Potential

When a neuron receives enough input from other neurons, it fires an action potential, which is a self-propagating electrical signal that travels along the neuron's axon. Action potentials are the primary means by which neurons communicate with each other.

3. Neurotransmitters

When an action potential reaches the end of an axon, it causes the release of neurotransmitters, which are chemical messengers that can bind to receptors on other neurons, causing them to fire action potentials.

4. The Central Nervous System and the Peripheral Nervous System

The central nervous system (CNS) consists of the brain and the spinal cord, while the peripheral nervous system (PNS) consists of all the nerves that connect the CNS to the rest of the body.

5. The Limbic System

The limbic system is a complex network of brain structures that is involved in emotion, memory, and motivation. The limbic system includes the amygdala, hippocampus, and hypothalamus.

6. The Cerebral Cortex

The cerebral cortex is the outermost layer of the brain and is responsible for higher-level cognitive functions such as language, thought, and consciousness. The cerebral cortex is divided into two hemispheres, the left and right hemispheres, which are connected by the corpus callosum.

7. Plasticity

The brain is capable of changing and adapting over time in response to experience, a process known as plasticity. Plasticity is the basis for learning and memory.

By understanding how the brain works, we can better understand ourselves and our interactions with the world around us.