Brain and Functions   Leave a comment

We each have something approaching 100 billion nerve cells – neurons – in the human brain (more than the number of stars in the Milky Way). Each of them can be connected directly with maybe 10,000 others, totaling some 100 trillion nerve connections. The almost instantaneous transmission of electrical impulses from one region of the body to another along specialized nerve cells called neurons.

Our Brain weighing in an average about three pounds, is a complex biological computer hardware, capable of far superior inherent ability. The brain and spine are vital to keep the body alive and functioning.  Everything we do depends on the messages (nerve impulses) that are sent from the brain, along the spinal cord and on to the rest of the body.  The brain is made up of as many as 100 billion neurons or brain cells but only weighs 3 pounds.  It contains billions of nerve cells or neurons, and it coordinates thought, emotion, behavior, movement and sensation. It is surrounded by a fluid called cerebrospinal fluid (CSF). The main functions of CSF are to protect the brain (it acts as a shock absorber), to carry nutrients to the brain and remove waste from it. It is an energy-intensive organ, making up around 2 percent of a person’s weight but using a huge 20 percent of the body’s energy. Theoretically, the manner in which brain composition can evolve is limited, ranging from highly modular (“mosaic evolution”) to coordinated changes in brain structure size (“concerted evolution”) or anything between these two extremes.

1. Hemisphere Brain System

The left and right sides of the brain are interconnected by a great number of nerve fibers. In a healthy brain, the two sides communicate with one another. According to the left brain vs. right brain system, their dominant active brain determines their personality, thoughts, and behavior.

 Left-Brained people are said to be more:

  • Language
  • analytical
  • logical
  • detail- and fact-oriented
  • numerical
  • likely to think in words

Right-Brained people are said to be more:

  • Creative
  • Emotion
  • Imaginative
  • free-thinking
  • able to see the big picture
  • intuitive
  • likely to visualize more than think in word

The corpus callosum is composed of 200 million axons (nerve fibers) that allows the two sides of your brain to communicate and create a useful view of the world. An intelligent person has a very good use of corpus callosum. It has a bundle of neural wires like a computer data transfer wire. It transfers motor, sensory and cognitive information between two hemispheres. The corpus callosum is the largest collection of white matter within the brain, and it has a high myelin content. Myelin is a fatty, protective coating around nerves that facilitates quicker transmission of information. White matter should not be confused with gray matter. The brain uses gray matter for computation, thinking, memory storage, and more. White matter, like the corpus callosum, allows different parts of the brain to communicate with each other. Myelin sheath is a biological hardware that is added to improve data transfer.

2. Major Brain System

THINKING BRAIN (NEO-CORTEX): NEO Brain, is the most advanced brain and each time we challenge our thinking brain to understand why we feel upset, we also become smarter in the way we act and respond to stress. Each coping success brings greater confidence that tells us we can get over our next upset more easily. It gives a known and name of what emotional experience. The neocortex first assumed importance in primates and culminated in the human brain with its two large cerebral hemispheres that play such a dominant role. These hemispheres have been responsible for the development of human language, abstract thought, imagination, and consciousness. The neocortex is flexible and has almost infinite learning abilities. The neocortex is also what has enabled human cultures to develop. The evolutionary expansion of the cerebral cortex, indeed, is among the most distinctive morphological features of mammalian brains.

EMOTIONAL BRAIN (Mammalian Brain): EMO Brain is small in size, but very important into emotional attachments to others. Compassion, Forgiveness stands here.  We need EMO brain to our judgement, attitude, preferences. The limbic brain emerged in the first mammals. It can record memories of behaviours that produced agreeable and disagreeable experiences, so it is responsible for what are called emotions in human beings. The main structures of the limbic brain are the hippocampus, the amygdala, and the hypothalamus. The limbic brain is the seat of the value judgments that we make, often unconsciously, that exert such a strong influence on our behaviour.

REPTILIAN BRAIN (SURVIVAL Brain):  REP Brain is a primitive, powerful brain structure and present in all forms of life reptiles, mammals, even in human. The reptilian brain, the oldest of the three, controls the body’s vital functions such as heart rate, breathing, body temperature and balance. Our reptilian brain includes the main structures found in a reptile’s brain: the brainstem and the cerebellum. Without it, we would not survive. To a threat, it’s instinctive nature, always decides to fight or take a flight, a very survival brain. The primal brain is also in charge of, what are often referred to as, the four Fs: Feeding, Fighting, Fleeing, and Reproduction (well, we won’t use that other f-word here!). Notable behavior patterns include defense of self, family, and personal property, physical communication, and socially approved actions, such as handshakes, head nods, and bowing. The term, ‘reptilian brain’ (or ‘reptilian complex’) is derived from a longstanding belief within the field of neuroanatomy that the forebrains of reptiles, and other small animals, were dominated by these structures. Paul MacLean suggested, within the Triune brain model, that the basal ganglia and a number of the surrounding structures within the base of the forebrain are responsible for ‘species-typical’ behaviors, which are present in aggression, dominance, territoriality, and ritual displays. We might not be living in the same world as primitive man, but we are still met with threatening and potentially dangerous situations. The brainstem is responsible for keeping us safe now, as it was for early man. The health and functioning of this brain region largely determine our ability to detect and respond to threats. At the most basic level, the brainstem helps us identify familiar and unfamiliar things. Familiar things are usually seen as safe and preferable, while unfamiliar things are treated with suspicion until we have assessed them and the context in which they appear. For this reason, designers, advertisers, and anyone else involved in selling products tend to use familiarity as a means of evoking positive emotions.  One of the major functions of the primal brain is to help us distinguish between threatening and non-threatening stimuli. At its most basic form, this function is represented in our ability to distinguish between familiar objects, things, people, scenarios, etc. and unfamiliar objects, etc. immediately. Designing according to the primal brain can encompass all of the basic drives we have, but one of the most effective ways of targeting the primal brain is to make new things seem familiar.

3. General Anatomy Of Brain

The hemispheres of the brain are divided into four lobes: the frontal, parietal, occipital, and temporal lobes.

The Frontal lobe governs our personality, character and behaviour. The frontal lobes control thinking, problem solving, planning, short-term memory and movement. It is where we control our body movement and how we express ourselves. This part of the brain allows us to speak. It is also where we solve problems and do most of our learning. It allows us to organise and plan.

The Occipital lobe receives messages from the eyes and recognises shapes, colours and objects. This bit of the brain allows you to tell the difference between a square and a triangle. It also controls your eye movements. The occipital lobes process images and link that information with images stored in memory.

The Parietal lobe gives you a sense of ‘me’. It figures out the messages you receive from the five senses of sight, touch, smell, hearing and taste. This part of the brain tells you what is part of the body and what is part of the outside world. The parietal lobes interpret sensory information, like taste, touch, temperature etc.

You have two Temporal lobes, one behind each ear. They receive and processes incoming messages from the ears so that you can recognize it. This part of the brain also recognizes speech and is how you understand what someone says to you. It also helps your sense of smell. Your short-term memory is also kept here.

The Cerebellum sits at the back of the brain and controls your sense of balance, the motor function. This allows you to stand up, walk in a straight line, and know if you are standing up or sitting down.

The Brain stem controls your lungs and heart and blood pressure. It sits at the top of the spine and receives messages from the rest of the body. In some ways this is the most important part of the brain because it keeps you alive. Hurting this part of the brain is very serious. The brainstem is responsible for keeping us safe now, as it was for early man. At the most basic level, the brainstem helps us identify familiar and unfamiliar things. Familiar things are usually seen as safe and preferable, while unfamiliar things are treated with suspicion until we have assessed them and the context in which they appear.

In Thalamus, there are lots of interesting things that go on in the very middle of the brain, which is made of smaller parts known as the limbic system. The hypothalamus and pituitary gland control things like your body temperature, how fast you grow and tells you when you are thirsty. The suprachiasmatic nucleus (SCN) of the hypothalamus is the principal circadian pacemaker in the mammalian brain and, as such, it generates circadian rhythms in rest and activity, core body temperature, neuroendocrine function, autonomic function, memory and psychomotor performance, and a host of other behavioral and physiological processes. The SCN is the central player in an important neural system, the circadian timing system (CTS).

4. The Nervous System

The brain is connected to the rest of the body via the spinal cord and the nerves.

The central nervous system, together, the brain and spinal cord make up the central nervous system. Messages (nerve impulses) from the brain travel along the spinal cord and control the activities of the body, such as the movement of the arms and legs, sensory functions like touch and temperature, and things we don’t think about that go on in the background, like the function of the organs.  The spine is made up of the backbone and the spinal cord. The backbone is made of vertebrae (spinal bones). Some of the muscles in the back-form part of the structure of the spine, to hold it all together. The spinal cord extends from the brain to the lumbar section of the spine. The backbone continues beyond the lumbar section to the coccyx (tail bone). Like the brain, the spinal cord is surrounded and protected by cerebrospinal fluid (CSF). The dura mater (dura) is the tough, fibrous membrane which forms the outer covering of the brain and spinal cord and keeps the CSF in place. Different sections of the spinal cord are responsible for different movements and functions of the body.

The peripheral nervous system, Nerves branch out from the spinal cord through the dura and vertebrae and become part of the peripheral nervous system. The peripheral nervous system is the network of nerves outside the central nervous system. It carries messages between the central nervous system and the rest of the body as Somatic Nervous system and Autonomic Nervous system. The autonomic nervous system is controlled mainly by the hypothalamus and is in turn divided into two sets of nerves: the sympathetic and parasympathetic nervous systems. Each of these two systems has a distinct anatomical location and communicates with its target organs through other neurons located in ganglia.

The Sympathetic nervous system goes into action to prepare the organism for physical or mental activity. When the organism faces a major stressor, it is the sympathetic nervous system that orchestrates the fight-or-flight response. It dilates the bronchi and the pupils, accelerates heart rate and respiration, and increases perspiration and arterial blood pressure, but reduces digestive activity. Two neurotransmitters are primarily associated with this system: epinephrine and norepinephrine.

The activation of the Parasympathetic nervous system causes a general slowdown in the body’s functions in order to conserve energy. Whatever was dilated, accelerated, or increased by the sympathetic nervous system is contracted, decelerated, or decreased by the parasympathetic nervous system. The only things that the parasympathetic nervous system augments are digestive functions and sexual appetite. One neurotransmitter is primarily associated with this system: acetylcholine.

Brain Power

The average human brain weighs about three pounds and comprises the hefty cerebrum, which is the largest portion and performs all higher cognitive functions; the cerebellum, responsible for motor functions, such as the coordination of movement and balance; and the brain stem, dedicated to involuntary functions like breathing. The majority of the energy consumed by the brain powers the rapid firing of millions of neurons communicating with each other. Scientists think it is such neuronal firing and connecting that gives rise to all of the brain’s higher functions. The rest of its energy is used for controlling other activities—both unconscious activities, such as heart rate, and conscious ones, such as driving a car. Even in sleep, areas such as the frontal cortex, which controls things like higher level thinking and self-awareness, or the somatosensory areas, which help people sense their surroundings, are active

The human brain contains about 100 billion neurons, more than 100,000 km of interconnections, and has an estimated storage capacity of 1.25 × 1012 bytes (Cherniak, 1990Hofman, 2012). These impressive numbers have led to the idea that our cognitive capabilities are virtually without limit. The human brain, however, has evolved from a set of underlying structures that constrain its size, and the amount of information it can store and process. If the ability of an organism to process information about its environment is a driving force behind evolution, then the more information a system, such as the brain, receives, and the faster it can process this information, the more adequately it will be able to respond to environmental challenges and the better will be its chances of survival (Macphail and Bolhuis, 2001Roth and Dicke, 2012Hofman, 2014). The limit to any intelligent system therefore lies in its abilities to process and integrate large amounts of sensory information and to compare these signals with as many memory states as possible, and all that in a minimum of time. It implies that the functional capacity of a neuronal structure is inherently limited by its neural architecture and signal processing time (see e.g., Laughlin and Sejnowski, 2003Buzsáki et al., 2013). The object of this review is to present current perspectives on primate brain evolution, especially in humans, and to examine some hypothetical organizing principles that underlie the brain’s complex organization. Some of the design principles and operational modes that underlie the information processing capacity of the cerebral cortex in primates will be explored, and it will be argued that with the evolution of the human brain we have nearly reached the limits of biological intelligence.

The human brain is complex. Along with performing millions of mundane acts, it composes concertos, issues manifestos and comes up with elegant solutions to equations. It’s the wellspring of all human feelings, behaviors, experiences as well as the repository of memory and self-awareness. So, it’s no surprise that the brain remains a mystery unto itself. Adding to that mystery is the contention that humans “only” employ 10 percent of their brain. If only regular folk could tap that other 90 percent, they too could become savants who remember to the twenty-thousandth decimal place or perhaps even have telekinetic powers.

Although it’s true that at any given moment all of the brain’s regions are not concurrently firing, brain researchers using imaging technology have shown that, like the body’s muscles, most are continually active over a 24-hour period. “Evidence would show over a day you use 100 percent of the brain,” says John Henley, a neurologist at the Mayo Clinic in Rochester, Minn. Even in sleep, areas such as the frontal cortex, which controls things like higher level thinking and self-awareness, or the somatosensory areas, which help people sense their surroundings, are active, Henley explains. Take the simple act of pouring coffee in the morning: In walking toward the coffeepot, reaching for it, pouring the brew into the mug, even leaving extra room for cream, the occipital and parietal lobes, motor sensory and sensory motor cortices, basal ganglia, cerebellum and frontal lobes all activate. A lightning storm of neuronal activity occurs almost across the entire brain in the time span of a few seconds.

Being able to map the brain’s various regions and functions is part and parcel of understanding the possible side effects should a given region begin to fail. Experts know that neurons that perform similar functions tend to cluster together. For example, neurons that control the thumb’s movement are arranged next to those that control the forefinger. Thus, when undertaking brain surgery, neurosurgeons carefully avoid neural clusters related to vision, hearing and movement, enabling the brain to retain as many of its functions as possible.

What’s not understood is how clusters of neurons from the diverse regions of the brain collaborate to form consciousness. So far, there’s no evidence that there is one site for consciousness, which leads experts to believe that it is truly a collective neural effort. Another mystery hidden within our crinkled cortices is that out of all the brain’s cells, only 10 percent are neurons; the other 90 percent are glial cells, which encapsulate and support neurons, but whose function remains largely unknown. Ultimately, it’s not that we use 10 percent of our brains, merely that we only understand about 10 percent of how it functions.

If we assume that biological intelligence in higher organisms is the product of processes of complex sensory information processing and mental faculties, responsible for the planning, execution and evaluation of intelligent behavior, variations among species in intelligence must in principle be observable in the neural substrate. In higher organisms, especially in primates, the complexity of the neural circuitry of the cerebral cortex is considered to be the neural correlate of the brain’s coherence and predictive power, and, thus, a measure of intelligence.

Posted January 14, 2020 by arjunlimbu in Uncategorized

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