The human brain, a large mass of nerve tissue that’s protected within the skull is one of the most complex systems on the earth. Every component of the brain works together to keep the body functioning. Some of the main functions of the brain are processing sensory information, regulating blood pressure and breathing, releasing hormones etc. The injured brain has the potential to affect every aspect of life as almost everything we do, say and think is controlled by our brain. As there are hundreds of conditions that can affect the brain so we need to be aware of the brain functioning. In the direction of keeping the brain in good health and reducing the risk of certain brain conditions, Brain Awareness Week (BAW) is organized every year in March. BAW is the global campaign to increase public awareness of the progress and benefits of brain research. The activities include open days at neuroscience labs, exhibitions about the brain, lectures on brain-related topics, social media campaigns, displays at libraries and community centers, classroom workshops, and many more. A scientific grand challenge known as the BRAIN Initiative (Brain Research through Advancing Innovative Neurotechnologies) was announced by Mr. Barack Obama in April 2013. This $100-million-plus project aimed to develop new technologies that will produce a dynamic picture of the human brain, from the level of individual cells to complex circuits.
The human brain develops from three sections known as the forebrain, midbrain, and hindbrain and each of these contains fluid-filled cavities called ventricles. The forebrain develops into the cerebrum and underlying structures; the midbrain becomes part of the brainstem, and the hindbrain gives rise to regions of the brainstem and the cerebellum. The brain is a part of the nervous system which can be divided into several connected systems that function together. The nervous system has two parts central nervous system and peripheral nervous system. The central nervous system has the brain and the spinal cord. The average adult human brain approximately 3 pounds and contains about 86 billion neurons, also called nerve cells and trillions of “support cells” called glia. The brain is divided into 3 main areas: the cerebrum, which is responsible for higher brain functions including thinking and emotions, the cerebellum, responsible for balance and muscular coordination and the brain stem, responsible for basic body functions such as heartbeat regulation. The cerebrum is the largest part of the brain with a thickness varying from 2 to 6 mm. It is also called as “cortex” which comes from the Latin word for “bark” (of a tree), as the cortex is a sheet of tissue that makes up the outer layer of the brain. Human cerebral cortex has many bumps and grooves called as gyrus and sulcus respectively. It has two hemispheres, the left and right, connected by a bundle of nerve fibers called the corpus callosum. Regions involved in speech and language (called the Broca’s area and Wernicke’s area, respectively) and mathematical calculation are found in the left side. Whereas, the visual and auditory processing, spatial skills and artistic ability/creative things fall under right brain. Although these functions involve both hemispheres. The left brain controls all the muscles on the right-hand side of the body and the right brain controls the left side. Each hemisphere are divided into four lobes, which are associated with different functions. Frontal lobes are the largest of the lobes and are located in the front part of the brain coordinating motor skills, problem solving, judgment, planning, attention, emotions and impulse control. Just behind frontal are parietal lobes involved in organizing and interpreting sensory information from other parts of the brain. Located on the either side of the head on the same level as the ears are temporal lobes which coordinate visual memory (such as facial recognition), verbal memory (such as understanding language), and interpreting the emotions and reactions of others. The back of the brain has occipital lobes and are involved in the ability to read and recognize printed words, along with other aspects of vision. The 2nd part of the brain Cerebellum, is located just below the occipital lobes. The word “cerebellum” is derived from the Latin word for “little brain.” Located behind the brain stem, the cerebellum is similar to the cerebral cortex because it has hemispheres and a cortex that surrounds the hemispheres. It is involved in coordination of smaller, or finer, movements, especially those involving the hands and feet. Body maintain its posture, equilibrium, and balance with cerebellum. The brain stem refers to the area of the brain between the thalamus and spinal cord. Structures of the brain stem include the midbrain, pons, and, medulla oblongata. The brain stem is located in front of the cerebellum and connects to the spinal cord. Midbrain helps to control eye movement and processes visual and auditory information. Pons, the largest part of the brain stem located below the midbrain, is a group of nerves that help connect different parts of the brain. The pons also contains the start of some of the cranial nerves which are involved in facial movements and transmitting sensory information. The medulla oblongata is the lowest part of the brain, acting as the control center for the function of the heart and lungs. It helps regulate many important functions, including breathing, sneezing, and swallowing. The brain stem is important for maintaining basic life functions such as breathing, heart rate and blood pressure.
Other important parts are thalamus acting as a kind of relay station for signals coming into the brain. It’s also involved in consciousness, sleep, and sensory processing, movement. Epithalamus which serves as a connection between the limbic system and other parts of the brain. The limbic system (or the limbic areas) is a group of structures that includes the amygdala, the hippocampus, mammillary bodies, and cingulate gyrus and is involved with emotion, long-term memory, and behavior. Hippocampus, a part of the limbic system and is important for memory and learning. The hypothalamus helps maintain homeostasis i.e. the balance of all bodily functions by detecting changes in body temperature and sending commands to adjust the temperature.
A brain disorder can affect anyone and long-term effects vary depending on the person and the type of brain disorder (1). The damage can be permanent or temporary where treatments such as surgery, medicines, or physical therapy can correct the source of the problem or improve symptoms. In a brain disorders intelligence is usually not affected, although cognitive changes such as problems with memory, concentration, and attention occur. Cognitive functions are the mental processes that allow us to understand and to relate to the world more effectively (2). Traumatic brain injury are caused by a blow to the head which may include motor vehicle accidents, assault, falls, sports accidents, domestic violence, and young babies being shaken. In this type of injury the brain tissues get torn, stretched, penetrated, bruised and swollen and as a result, oxygen doesn’t reach to the brain cells. Brain tumors restrict blood supply to other cells through exerting physical pressure upon cells. The brain swells (encephalitis) or the tissue surrounding the brain swells (meningitis), or may kill cells through direct infection. In multiple sclerosis, nerve cells die when the myelin is removed from the neurons. Parkinson’s disease results from the loss of cells in various parts of the brain, including an area that creates dopamine leaving people less able to direct or control their movement. It affects movement, rigidity, tremors and balance problems. Alzheimer’s disease where Plaques and tangles in the brain usually develop later in life and lead to problems with short-term memory, disorientation, mood swings, and behavioral issues. Stroke is caused due to lack of blood supply within the brain and the same lack of blood supply in the heart is called a heart attack. Meningitis is an inflammation of the protective membranes covering the brain and spinal cord by viruses, bacteria, fungi, and protozoa. It leads to high fever, headaches, sensitivity to light, confusion, and occasionally seizures. Encephalitis is a swelling of the brain due to infection by viruses or bacteria. Epilepsy involves recurring brief episodes of abnormal electrical activity in the brain leading to uncontrolled convulsions and unconsciousness, or just a momentary loss of awareness.
Neuroscientists have observed in recent years that new dendrites actually sprout to make connections with other neurons, and this is how learning takes place in the connections between the neurons. This is very encouraging as it indicates that as long as neurons exist learning continues even into very old age. However, to make these connections occur, we should continue to have new experiences, so that new connections can form in the brain (3).
- D Richards, T Clark, C Clarke The human brain and its disorders. J Neurol Neurosurg Psychiatry. 2007 Oct; 78(10): 1164.
- Evolution of the brain and Intelligence,” by Gerhard Roth and Ursula Dicke, in Trends in Cognitive Sciences (May 2005).
- Green CS, Bavelier D. Exercising your brain: a review of human brain plasticity and training-induced learning. Psychol Aging. 2008 Dec;23(4):692-701.