To mark Brain Awareness Week, a global campaign to increase public awareness of the progress and benefits of brain research, which runs from 11-17 March 2019, I will be posting a series of articles on the nature of the brain.
Your brain is a multilayered web of billions of nerve cells arranged in patterns that coordinate thought, emotion, behaviour, movement and sensation.
A complicated highway system of nerves connects your brain to the rest of your body so communication can occur in split seconds. Think about how fast you pull your hand back from a hot stove.
The outermost layer, the cerebral cortex (the “gray matter” of the brain), is a fraction of an inch thick but contains 70 percent of all neurons. Deep folds and wrinkles in the brain increase the surface area of the gray matter, so more information can be processed.
Your brain’s hemispheres are divided into four lobes.
- The frontal lobes control thinking, planning, organizing, problem-solving, short-term memory and movement.
- The parietal lobes interpret sensory information, such as taste, temperature and touch.
- The occipital lobes process images from your eyes and link that information with images stored in memory.
- The temporal lobes process information from your senses of smell, taste and sound. They also play a role in memory storage.
The cerebrum is divided into two halves (hemispheres) by a deep fissure. The hemispheres communicate with each other through a thick tract of nerves, called the corpus callosum, at the base of the fissure. In fact, messages to and from one side of the body are usually handled by the opposite side of the brain.
Beneath the cortex are areas such as the basal ganglia, which controls movement; the limbic system, central to emotion; and the hippocampus, a keystone of memory.
The primitive brainstem regulates balance, coordination and life-sustaining processes such as breathing and heartbeat.
Throughout the brain, nerve cells (neurons) communicate with one another through interlocking circuits. Neurons have two main types of branches coming off their cell bodies. Dendrites receive incoming messages from other nerve cells. Axons carry outgoing signals from the cell body to other cells — such as a nearby neuron or muscle cell.
Interconnected with each other, neurons are able to provide efficient, lightning-fast communication. When a neuron is stimulated, it generates a tiny electrical current, which passes down a fiber, or axon. The end of the axon releases neurotransmitters —chemicals that cross a microscopic gap, or synapse — to stimulate other neurons nearby.
Neurotransmitters pass through the synapse, the gap between two nerve cells, and attach to receptors on the receiving cell. This process repeats from neuron to neuron, as the impulse travels to its destination — a web of communication that allows you to move, think, feel and communicate.
While all the parts of your brain work together, each part is responsible for a specific function — controlling everything from your heart rate to your mood.