Brain Circuitry

The human brain is an immensely complicated organ, capable of everything from motor control and facial recognition to emotion and rational thought. The brain is composed of billions of neurons and trillions of nerve connections, along with many other factors such as glial cells and myelinated axons. All of these components work together to create complex circuitry, or pathways, that control and regulate most brain functions. The brain is divided into two hemispheres, the larger left hemisphere and the smaller right hemisphere. While they are connected by a dense bundle of nerve fibers referred to as the “corpus callosum”, the left hemisphere is responsible for language and logical thinking, while the right hemisphere specializes in artistic abilities and empathy. Inside each hemisphere, an intricate network of neural pathways transmits signals between neurons. This network is called the "cortical or brain circuit". The cortical circuits are composed of “neurotransmitter systems” which are specialized nerve fibres that connect neurons and transmit signals from one neuron to another. Examples of neurotransmitter systems include dopamine, serotonin and norepinephrine. The layout of these neurotransmitter systems follows a particular 3-part design. It consists of two layers of neurons, an upper layer called the cortex and a lower layer known as the thalamus. The cortex is responsible for the majority of higher brain functions such as reasoning, memory and language. The thalamus is an essential brain area that serves as an interface between the cortex and the lower brain. It relays sensory information such as touch and smell to the cortex and coordinates the activity of various brain regions. Together, these three layers form the basis of brain circuitry. Neurons in the cortex produce electrical signals when they are exposed to a stimulus, such as a mental image or sound. These signals are transmitted through the thalamus to the areas of the brain that are specialized in processing them. This neural network of connections and signals functions as the foundation of almost all higher mental processes. In addition to providing complex “circuitry”, this network of neurons also enables high-level cognitive tasks like reasoning and decision-making. It is this network which makes the human brain so unique and capable of withstanding almost any cognitive challenge. By studying and manipulating these circuitry pathways, scientists are uncovering more about the mystery of the brain and its many functions.