About The Brain

The human brain is a unique and amazing organ. It is probably the most complex structure in the universe. It gives you the power to think, plan, speak, imagine. The brain carries out a remarkable number of tasks which include the following:

• It is responsible for controlling body temperature, blood pressure, heart rate and breathing.
• It absorbs tremendous amount of information about the world around through various senses (vision, hearing, smell, taste and touch).
• It takes care of physical motion while walking, talking, standing or sitting.
• It lets you think, dream, reason and experience emotions.

Parts of the brain

The brain is made of three main segments:

• forebrain
• midbrain
• hindbrain.

Each of these segments is made up of different mutually dependant parts. The forebrain is the largest segment of the brain and consists of the cerebrum, thalamus, and hypothalamus (parts of the limbic system). The midbrain consists of the tectum, tegmentum and cerebral peduncles. The hindbrain consists of the cerebellum, pons and medulla. Often the midbrain, pons, and medulla are together referred as the brainstem. (More information about brain anatomy)

A specialized function of cerebrum

In the brain, the neurons connect the sensory inputs and motor outputs with cortical centers in the various lobes of the cerebral cortex. There are also connections between these cortical centers and other parts of the brain. These connections form a map of the body's surface on the parietal lobe. This map is called a homunculus.

The homunculus looks bizarre because the representation of each area is related to the number of sensory neuronal connections, not to the physical size of the area. The homunculus usually describes the distorted human figure that is drawn to reflect the relative space human body parts occupy on the somatosensory cortex (sensory homunculus) and the motor cortex (motor homunculus). The lips, hands, feet and sex organs have more sensory neurons than other parts of the body, so the homunculus has likewise distortedly large lips, hands, feet, and genitals. Homunculus is also commonly known as 'the little man inside the brain'.

Blood supply of the brain

The brain receives one fifth of the resting cardiac output. The blood supply of the brain is carried by the two internal carotid arteries and the two vertebral arteries that come together at the base of the brain to form the circle of Willis.

The carotid arteries and their branches supply the front portion of the brain, whilst the vertebrobasilar system supplies the rear portion of the brain. (More information on blood supply to the brain)

Introduction to brain mapping

EEG or electroencephalogram is a recording of brainwave activity. QEEG (Quantitative EEG), widely known as brain mapping, refers to a wide-ranging analysis of brainwave frequency bandwidths that make up the raw EEG. Whilst QEEG is recorded in the same way as EEG, the output is different in that color-coded topographic maps are created showing the electrical activity occurring in the cerebral cortex.

It basically attempts to relate the brain's structure to its function, or finding what parts give us certain abilities. This is called localization of function.

Brain mapping aims to give us a comprehensive picture of our brain's structure. A complete structural map of our brain can show us all regions of the brain including functional lobes, specialized centers, thick neuron bundles connecting brain parts, neuron circuits, single neurons, neuronal junctions and even neuron parts.

While other brain imaging techniques such as CT, MRI, PET, and SPECT measure properties such as cerebral blood flow, metabolism or structural integrity; QEEG is known to measure the electrical activity of the brain. It provides complex analysis of brainwave characteristics. In fact, slight disruptions of electrical connectivity and flow in the brain sometimes may be the only or the early signs of a developing problem.

Brain mapping looks from the outside in too by examining how our environment changes our brain's structure by activities such as studying and how physical changes occur in the brain through the learning and aging processes.

Brain Plasticity

Neuroplasticity or brain plasticity refers to the ability of brain to transform itself throughout life.

The brain has the remarkable capability to reorganize itself by forming new connections between brain cells. It is thus described as an adjustment in the strength of synaptic connections between brain cells. 

Whilst study of brain plasticity has been moving forward quickly in the last decade, there is much more research to be done. It is thought that neuroplasticity is enabled by neurogenesis (the birth of new neuronal cells). These new cells facilitate the brain in adapting to environmental changes and also in learning and memory on an ongoing basis . In addition to genetic factors, the environment in which a person lives as well as the actions of that person, play a role in plasticity.

The brain responds with change to following types of stimuli

• developmental such as in the newly formed and ever evolving brain of a child
• activity dependent such as in cases of lost senses
• learning and memory in which the brain respond to a particular experience
• injury induced arising from any damages in the brain, as it occurs in a stroke.