The Mind at Work ---- How to make it work better for you By Ellen Lucas (1993) The Millbrook Press, 2 Old New Milford Road, Brookfield, Connecticut 06804 USA
ABSTRACT: A practical guide to how the brain works and how to maximize its potential. Explains what is cognition, thinking, critical thinking and creative thinking.
Summary:
All of us were born with the same amount of nerve cells(100 billion) and brain matter (which can grow to about 3 lb) without any skills for survival. We all learned our survival skills; how to walk, how to eat etc. practically in the same way --- struggling. That being said, why do some of us become great like Albert Einstein and some of us go unnoticed ? This book tries to explore this question.
Let us examine the intellectual infrastructure that we all have in common with all great people. On the top of the spinal cord, the brain stem handles all the automatic responses which keeps us alive; Breathing , Heart rate etc. This is the communication gateway between the body and the brain.
The cerebellum in the brain is a little more advanced structure which handles and coordinates messages between the brain and the muscles in the arms and legs. It handles all normal physical activities without consciously thinking about them; Walking, Riding a bike etc.
There is a group of structures in the brain called the limbic system which regulates the way we feel. One of the structures in this group, hypothalamus, deals with our primitive responses; Eating, Sleeping, Fighting, Mating etc.
Another component within the limbic system is the hippocampus which deals with all the sensory input systems and plays a vital role in memory.
The thalamus, another component, deals with the physical sensations: Pain, Heat, Cold etc.
At the top of the brain is the cerebrum, the most advanced system of the brain compared to the all living creatures. Cerebrum is the one which makes us human while rest of the brain is working to keep us alive. The Cerebrum is where we learn to think and dream.
The cerebrum is divided into two halves, called left and right hemispheres. The right hemisphere controls the left side of the body, and the left hemisphere controls the right side of the body. Thus when we move our right hand, the signals are coming from the left side of our brain.
These hemispheres are connected by a thick band of nerve fibers called the corpus callosum. The entire cerebrum is covered by nerve cells called cerebral cortex. The cerebral cortex is where advanced brain functions occur.
The cerebral cortex is divided into four lobes: parietal, occipital, temporal and frontal. The parietal lobe assembles information from various places in the body. The occipital lobe receives messages from the eyes and controls our vision. The temporal lobe plays a great part in our sense of hearing, language and memory. The frontal lobe's function is to manage and distribute information coming from other parts of the brain.
The Cerebrum and Cerebral Cortex is the place where everything happens that makes us human. We learn, we think , we reason and we conclude. This area is much larger and more developed in humans than in any other animal.
The entire cerebrum is covered by the cerebral cortex, a layer of nerve cells 1/8 inch thick . Nerve cells are also called neurons, sending and receiving information 24 hours a day. They could receive information from thousands of other neurons and also have the capability of sending messages to thousand of other neurons. This feat is accomplished through the neuron components, dendrites to receive messages and axons to send messages. One neuron's dendrites are coupled to other neuron's axons(or vice versa). The place where an axon terminal and the dendrite of another neuron is called synapse. Chemical messengers called neurotransmitters relay messages across the synapses between neurons.
When we were born, the skull is soft to enable us to fit through the birth canal. During the first year of life it triples in size. As cerebrum continues to grow, it quickly runs out of room in the skull and develops wrinkles and folds to increase the surface area as it acquires information and knowledge. By the age of seven it reaches the maximum weight, about 3 pounds.
For the brain to function properly it needs energy which it receives from the food we eat. It needs natural carbohydrates, proteins and vitamins. I stress "natural" because we are biologically equipped to break down natural substances and use them for energy. That is why a well balanced diet with plenty of fresh fruits and vegetables is essential. You can receive someone else's heart or liver and still be you, but not someone else's brain. It is better to take care of it properly in a natural way.
As the brain structure is out of the way, let us examine how it works. The Mind is what encompasses the working brain and the magic word which describes how it works is 'Cognition'. Cognition is a process that includes perception, learning, remembering , and all the things we call thinking.
Perception is the input stage of cognition. It involves all our senses, smell, taste, hearing, touch and seeing. The Brain receives signals from all these senses 24/7 and it may probably ignore some of them if they are continuous, like an unpleasant smell in a barn. Sensory input gives us perception.(For example, a small child sees a four legged creature, hears some sounds and smells something. A perceived package evolves.)
Learning is the process of knowing the description of what the input signals are telling and filing it. Simply put, Learning is receiving sensory input and filing them for later retrieval.(Mother tells the child that creature is a dog. The perceived package is filed as dog.)
Memory is the storage and retrieval of information learned. Scientists think memories are created by neurons forming memory patterns called "memory traces". These memory traces are a combination of electrical impulses and chemical reactions associated with them. (If the child sees the same type of four legged creature, the child remembers it as a dog.)
Thinking is information processing. (If the child sees similar four legged animals and comes out saying 'dogs'. If someone questions what is a dog, describing dog from the package we stored is also thinking.)
The cognitive processes are invisible, we can not see them even if we open the skull. As we know brain does these cognitive processes through chemical and electrical impulses, only way to track them is through the machines which recognize chemical and electrical impulses.
Electroencephalograms(EEG), magnetic resonance imaging (MRI), positron-emission tomography (PET), and computerized axial tomography (CAT) scans are being used for brain imaging. They give us pictures of what is happening and where in the brain. These help us determining and connecting, what thoughts generate what type of pictures and where in the brain, thus giving a glimpse of the mind at work.
The path to thinking is laid out. First we observe things through our senses, we record them in memory and we retrieve them to think about them.
How we record them makes it easy to retrieve them. For example, we record the dog as a four legged animal in our memory, we could retrieve the info in two ways, by seeing a four legged animal or hearing the word dog. suppose if we add sound to the recording, we can retrieve information by just hearing the sound without seeing. The point is the more descriptions you have for an entity the more paths you can create in memory thereby allowing us to retrieve the information in multiple ways. This is the trick in remembering things quickly.
Getting information of a four legged animal with a doggy sound is thinking. Once you got information in memory, identifying it as a dog is critical thinking. Possibilities of having different dog sounds is creative thinking. You can go and look for different sounds coming from dog look a likes.
To be good at cognitive process, we have to gather information first (from schooling, observation etc). Second we have to put that in memory. The more descriptors we have for that information, the more easier to retrieve. Brain has to create memory traces and it uses energy which we have to provide by eating healthy food. Once the information is there we have to practice critical thinking and creative thinking to use that information.
Summing up, while all humans are created with identical brain structures, it is the cognitive function which truly illustrates ones greatness. If one wants to be great, one has to perceive a lot of information and store it for easy retrieval. Once you have information stored in your brain, retrieve it, think critically about it, use it, question it, evaluate it and manipulate it creatively using your brain power with your creative thinking.
One tip, without review, about 80 percent of new material learned in a one-hour period will be forgotten within twenty-four hours. So repeat what you've read and heard within 24 hours, to get the maximum for your effort and blast your neurons for maximum synapses to form memory traces.
There you have it; the path to greatness.
Monday, December 21, 2009
Thursday, October 1, 2009
4. Creating Mind ---- How the brain works by John E Dowling
Creating Mind ---- By John E. Dowling (1998)
W. W. Norton & Company Inc., 500 Fifth Avenue, New York, NY 10110 USA
This is a beautiful book on Brain architecture and function with detailed illustrations. Complex neurological systems are explained in simple terms which makes you visualize and understand. The actual clinical stories are interesting and will give an imagery of what is happening. Specially this is the book to read for in depth understanding of optical and audio sensors.
This book presents a beautiful description of the brain formation, its organization levels and their functions. The autonomous system which controls the human system and the non autonomous which is controlled by human senses are well described
ABSTRACT
Among all creatures, the uniqueness of humans is Brain. Whatever we do in our daily life as humans are controlled by brain. We learn, we think, we imagine, we work, we relax, we look for comfort, we try to fulfill our desires, we create things, we feel happy, we cry, we feel disgusted; all these are controlled by our brain. How do we do these things, we do not know. But the uniqueness of humans is to try to find out how it is all happening. How we have that inquisitiveness? we do not know. This books explores all these human brain functions.
SUMMARY
About three weeks after conception, a group of cells (about 125,000) form a flat sheet along the back side of the embryo. This flat plate is called the neural plate and all the cells (neurons,glial) of the nervous system are derived from here. About 250,000 neurons are created per minute. Almost all 100 billion neurons human brains have are created before human birth.
Unfortunately as humans were born with minimal skills for survival,( it is just like getting a bare bones computer with just an operating system), we have to learn all necessary skills for survival as a dependent starting from walking. we have to start forming neural connections as fast as we could because we start loosing them by 10,000 to 100,000 a day after the age of 20. We have to better start learning all our survival skills before age 20.
The formation of neural plate is interesting. Ectodermal cells which cover the embryo causes the formation of skin and the endodermal cells which are inside embryo lining form stomach, intestine and other internal organs. About a two and half weeks of embryo development, a third, intermediate layer of cells called mesoderm forms. The mesoderm differentiates into many tissues , including muscles, skeleton and cardiovascular system, and also is responsible for the formation of neural plate cells.
Between the third and fourth week of development, the neural plate folds inwards and forms the neural tube. All of the central nervous system originates from neural tube. The anterior part of the tube forms brain and the posterior part becomes spinal cord. By about forty days of development, three swellings appear along the anterior part of the neural tube which eventually become forebrain, midbrain and hindbrain. As the neural tube forms, some cells are left behind on either side of the tube. These cells are called neural crest cells. Much of the peripheral nervous system is derived from these neural crest cells.
Brain uses about 50,000 of about 100,000 genes human genome has to generate for necessary proteins(enzymes) for human body functioning. Out of these 50,000 nearly 30,000 are used only for brain function.
W. W. Norton & Company Inc., 500 Fifth Avenue, New York, NY 10110 USA
This is a beautiful book on Brain architecture and function with detailed illustrations. Complex neurological systems are explained in simple terms which makes you visualize and understand. The actual clinical stories are interesting and will give an imagery of what is happening. Specially this is the book to read for in depth understanding of optical and audio sensors.
This book presents a beautiful description of the brain formation, its organization levels and their functions. The autonomous system which controls the human system and the non autonomous which is controlled by human senses are well described
ABSTRACT
Among all creatures, the uniqueness of humans is Brain. Whatever we do in our daily life as humans are controlled by brain. We learn, we think, we imagine, we work, we relax, we look for comfort, we try to fulfill our desires, we create things, we feel happy, we cry, we feel disgusted; all these are controlled by our brain. How do we do these things, we do not know. But the uniqueness of humans is to try to find out how it is all happening. How we have that inquisitiveness? we do not know. This books explores all these human brain functions.
SUMMARY
About three weeks after conception, a group of cells (about 125,000) form a flat sheet along the back side of the embryo. This flat plate is called the neural plate and all the cells (neurons,glial) of the nervous system are derived from here. About 250,000 neurons are created per minute. Almost all 100 billion neurons human brains have are created before human birth.
Unfortunately as humans were born with minimal skills for survival,( it is just like getting a bare bones computer with just an operating system), we have to learn all necessary skills for survival as a dependent starting from walking. we have to start forming neural connections as fast as we could because we start loosing them by 10,000 to 100,000 a day after the age of 20. We have to better start learning all our survival skills before age 20.
The formation of neural plate is interesting. Ectodermal cells which cover the embryo causes the formation of skin and the endodermal cells which are inside embryo lining form stomach, intestine and other internal organs. About a two and half weeks of embryo development, a third, intermediate layer of cells called mesoderm forms. The mesoderm differentiates into many tissues , including muscles, skeleton and cardiovascular system, and also is responsible for the formation of neural plate cells.
Between the third and fourth week of development, the neural plate folds inwards and forms the neural tube. All of the central nervous system originates from neural tube. The anterior part of the tube forms brain and the posterior part becomes spinal cord. By about forty days of development, three swellings appear along the anterior part of the neural tube which eventually become forebrain, midbrain and hindbrain. As the neural tube forms, some cells are left behind on either side of the tube. These cells are called neural crest cells. Much of the peripheral nervous system is derived from these neural crest cells.
Brain uses about 50,000 of about 100,000 genes human genome has to generate for necessary proteins(enzymes) for human body functioning. Out of these 50,000 nearly 30,000 are used only for brain function.
Wednesday, September 9, 2009
3. Human Brain Abnormalities
This post is an addendum to my earlier post on the book Your Brain by Tabitha M. Powledge.
Anencephaly and spina bifida.
These abnormalities develop because the ends of the neural tube in the embryo are not closed properly. The result may be a miscarriage. These abnormalities are as a result of not having folic acid, one of B vitamins. Folic acid is essential in pregnancy.
Hydrocephalus.
Caused because of a blockage of cerebrospinal fluid flowing freely in the brain. The cerebrum gets compressed causing the skull expand; making the head very big. Could be corrected by draining the fluid.
Kallmann Syndrome.
Because of the lack of the special tropic factor that guides fetal neurons to two particular areas of the brain. Genitals of these children are much smaller than usual and they have no sense of smell. Could be treated by hormone therapy.
Sex.
The basic design of all mammalian fetuses is female. If we want male fetus, the neural system has to switch on and off genes to produce right amount of male fetal hormones at the right time. That type of hormonal control is not achieved yet by external means.
These abnormalities develop because the ends of the neural tube in the embryo are not closed properly. The result may be a miscarriage. These abnormalities are as a result of not having folic acid, one of B vitamins. Folic acid is essential in pregnancy.
Hydrocephalus.
Caused because of a blockage of cerebrospinal fluid flowing freely in the brain. The cerebrum gets compressed causing the skull expand; making the head very big. Could be corrected by draining the fluid.
Kallmann Syndrome.
Because of the lack of the special tropic factor that guides fetal neurons to two particular areas of the brain. Genitals of these children are much smaller than usual and they have no sense of smell. Could be treated by hormone therapy.
Sex.
The basic design of all mammalian fetuses is female. If we want male fetus, the neural system has to switch on and off genes to produce right amount of male fetal hormones at the right time. That type of hormonal control is not achieved yet by external means.
Parkinson's Disease
It is a brain disease affecting parts of the motor control system in the body.
It is a brain disease affecting parts of the motor control system in the body.
It produces special kind of involuntary movements: rhythmic tremors, slow twitching hand movements, jerking movements of the arms, legs, and face muscles, and distorted posture. Usually affects over forty people. The basal ganglia neurons which regulate movement in the body and produce neurotransmitter dopamine slowly die in case of this disease. Basal ganglia neurons surround thalamus. Taking drugs that increase dopamine may improve in some cases.
Alzheimer's disease
In this disease the neurons degenerate. This may not be because of aging. One theory is a kind of amyloid protein opens up ion channels in the neural cell membranes allowing excessive amounts of calcium ions causing damage to the cell.
Dementia
It is not a disease but occurs because of a physical disease that affects brain. some causes are drug intoxication, overactive thyroid, bleeding in the brain, and non malignant tumors; can be treated successfully and dementia disappears.
Motion Sickness
This happens because of brain receiving contradictory signals from its sensors. Suppose you are reading a book while travelling, your body says you are moving but your eyes say that you are reading a stationary book. The result is dizziness, sweating, and sometimes severe nausea. Only way to avoid the contradictory signals is to unify the signals. Stop reading the book and look at the moving scenery.
Brain Tumors
Neurons can not multiply after they are matured but the glial cells, which are neuron supportive cells can divide and cause tumors.
Stroke
Blood flow to the brain is interrupted in a stroke and neurons die because of the lack of oxygen.
Since neurons can not be regenerated, partial recovery may occur because of the functional take our by the nearby neurons.
There are two prominent brain related crippling abnormalities.
(The Brain Trust Program ---- By Larry McCleary M.D. (2007)Penguin Group (USA) Inc., 375 Hudson Street, New York, NY 10014, USA)
Hot-Flashes.
For the women at the beginning of menopause, inadequate estrogen leads to fewer sugar shuttles for energy conversion in the brain cells. This leads to an energy crisis which leads to a surge of norepinephtine(NE) in the hypothalamus. This is the cause of hot flashes, which is a simple body reaction to raise the low sugar level and brain starvation. This results in an accumulation of the brain chemical glutamate. This brain chemical excites the cells, putting an added energy demand on an already strained system.
The way to avoid this problem is to get the estrogen to optimal level or bypass this system and provide energy alternate means with ketogenic diet providing ketone bodies (which do not require shuttles) as an alternate fuel source to blood sugar.
Ketone bodies, or simply ketones, are the natural by-products of fat burning; they are basically partially burned fats. They are produced if we go without eating for a prolonged period or when we restrict dietary carbohydrates.
Migraine Headaches: A migraine originates entirely within the brain itself, painlessly, with a burst of unusual firing from one or more small clusters of brain cells. This is caused by the buildup of calcium and sodium within the cells. The cause of this buildup is found out to be an energy-production deficit. (The calcium and sodium ions movement is crucial in the case of synaptic message transportation.)
This abnormal firing activity releases an array of compounds which may cause inflammation or a cause of opening or narrowing arteries. The current thinking is the irritation of the pain sensors on the surface of the blood vessels and brain coverings by these compounds causes migraine headache pain.
A low magnesium levels were found in brains of migraine patients. Supplementing with magnesium can help prevent migraines and can make them less painful and of shorter duration.
Finally the book is very interesting to read and easy to follow the guidelines for optimum brain health. There are exercises for the brain. There are recommended recipes for cocktails to follow and eliminate the uncomfort of Hot Flashes and Migraine Headaches, Ketogenic Cocktail, Anti-Excitatory Cocktail and Antimigraine Cocktail.
Motion Sickness
This happens because of brain receiving contradictory signals from its sensors. Suppose you are reading a book while travelling, your body says you are moving but your eyes say that you are reading a stationary book. The result is dizziness, sweating, and sometimes severe nausea. Only way to avoid the contradictory signals is to unify the signals. Stop reading the book and look at the moving scenery.
Brain Tumors
Neurons can not multiply after they are matured but the glial cells, which are neuron supportive cells can divide and cause tumors.
Stroke
Blood flow to the brain is interrupted in a stroke and neurons die because of the lack of oxygen.
Since neurons can not be regenerated, partial recovery may occur because of the functional take our by the nearby neurons.
There are two prominent brain related crippling abnormalities.
(The Brain Trust Program ---- By Larry McCleary M.D. (2007)Penguin Group (USA) Inc., 375 Hudson Street, New York, NY 10014, USA)
Hot-Flashes.
For the women at the beginning of menopause, inadequate estrogen leads to fewer sugar shuttles for energy conversion in the brain cells. This leads to an energy crisis which leads to a surge of norepinephtine(NE) in the hypothalamus. This is the cause of hot flashes, which is a simple body reaction to raise the low sugar level and brain starvation. This results in an accumulation of the brain chemical glutamate. This brain chemical excites the cells, putting an added energy demand on an already strained system.
The way to avoid this problem is to get the estrogen to optimal level or bypass this system and provide energy alternate means with ketogenic diet providing ketone bodies (which do not require shuttles) as an alternate fuel source to blood sugar.
Ketone bodies, or simply ketones, are the natural by-products of fat burning; they are basically partially burned fats. They are produced if we go without eating for a prolonged period or when we restrict dietary carbohydrates.
Migraine Headaches: A migraine originates entirely within the brain itself, painlessly, with a burst of unusual firing from one or more small clusters of brain cells. This is caused by the buildup of calcium and sodium within the cells. The cause of this buildup is found out to be an energy-production deficit. (The calcium and sodium ions movement is crucial in the case of synaptic message transportation.)
This abnormal firing activity releases an array of compounds which may cause inflammation or a cause of opening or narrowing arteries. The current thinking is the irritation of the pain sensors on the surface of the blood vessels and brain coverings by these compounds causes migraine headache pain.
A low magnesium levels were found in brains of migraine patients. Supplementing with magnesium can help prevent migraines and can make them less painful and of shorter duration.
Finally the book is very interesting to read and easy to follow the guidelines for optimum brain health. There are exercises for the brain. There are recommended recipes for cocktails to follow and eliminate the uncomfort of Hot Flashes and Migraine Headaches, Ketogenic Cocktail, Anti-Excitatory Cocktail and Antimigraine Cocktail.
Tuesday, September 1, 2009
2. Your Brain ... Tabitha M. Prowledge
Macmillan Publishing company, 866 Third Avenue, New York, NY 10022 USA
This is an intermediate level book on Brain and Neurophysiology. A very nice readable book with information presented in a way be understood by a novice or an expert. The book introduces brain beautifully but not inspirational or challenging to the reader. The following summary of the book presents the information hopefully to spark an interest in Neurons and neural systems.
ABSTRACT
Neurons are generated at the center of the brain and travel to different locations in the brain. While traveling to their destination, they pickup information of the neurons in their path way for possible synaptic connections. After reaching their destination, they change their shape and structure depending upon their location. They make synaptic connections as necessary. The synaptic connections could be; between cells and neurons, dendrites and dendrites, dendrites and axons or between axons.
The receptors at our five senses create action potentials (electrical pulses) which in turn emit chemical neurotransmitters. They swim the synaptic path way and gets attached to receptors of the dendrites of the other neuron. The receptors in turn generate second messages which in turn generate some more second messages. The action potential travels like a wave through the neuron-synaptic pathway and reach its ultimate destination in the cerebral cortex of the brain. The message is analyzed and brain responds.The action message travels through the neural pathway and reaches the destination( a muscle cell, a hormone making site etc).
How these neurons make choice synaptic connections, how they store information , how they retrieve information; these are all questions to be answered. The players are action potentials, neurotransmitters, second messages and yet to be discovered unknowns.
Summary
For all existing organisms the name of the game is survival and improving survival skills as the mantra of nature is survival of the fittest. when the survival skills are not adequate they become extinct. We are surrounded by lot of information of organisms which survived and the ones which did not survive. From this information, obtained from fossils, we try to understand how the evolution is evolving.
When uni-cellular organisms appeared on the planet billions of years ago one single cell took care of all the survival skills. They do not have any built in thinking system for survival. They started improving their existence by evolving into multi cellular organisms where different cells do different things at the same time, action coordination became critical. Nerve Cell(neuron) appeared in evolution whose sole purpose is coordination between cells in the organism.
Neuron's basic function is to communicate and exchange information between various parts of the organism for survival coordination. So it has dendrites to receive information and axons to transmit information to other cells. When two neurons are communicating, the neural message moves through the gap between an axon of one neuron to the dendrite of other neuron. This gap is called the synapse. This basic synaptic communication system called nerve net, which we find in Jelly fish and corals is the precursor of our human nervous system, .
As the organisms started improving their survival skills, sensual receptors started appearing in multi cellular organisms. Rapid communication between cells became a necessity and basic Nerve net's simple system is inadequate. The existing Nerve net's communicating channel was tapped at different points for information sharing. The simple nerve net became a nerve cord running along the front of the body with swelling of neuron structures for information exchange. Such a swelling is called a nerve ganglion. The nerve cord is the precursor to spinal cord in humans. An earth worm has a nerve cord with a ganglion in each of its body segments so that it can move in one direction. The ganglion in its head - the cerebral ganglion - is connected to its mouth so as to coordinate its movement in one direction for food.
As the new kind of animals appeared, the head end of an animal became a prominent organ. Improvements in survival skills are developed around the mouth (eyes, ears) to hunt for food. Visual skills, hearing skills, smelling skills, touching skills, tasting skills started to appear in organisms. These new skill system were melded with the existing spinal neural network as they appear. As a result we see organisms with unique specialized skills, like Bats with sonar system(sound) , dogs for olfactory(smell) etc.
In evolution, incorporating multiple specialized skills started with the African ape line (Chimpanzees and Gorilla) and led to the human line. Brain development took place to coordinate all the messages coming from the senses. There are two classes of cells in brain, neurons and glial. Neurons do the neural message processing and glial cells do the structural supportive work for neurons.
Neural development in humans is interesting. Three weeks after conception, the embryo is about 1/10 of an inch and has a hollow channel called neural tube running the back of the embryo. At one end of the neural tube is a small bulge. The neural tube grows up to be the spinal cord and the bulge transforms into 3 bulges which eventually become 3 important parts of the brain, Hind brain, Mid brain and Fore brain. One of the bulges which eventually become fore brain divides into three fluid-filled spaces in the cerebrum, known as ventricles. Ventricles lie at the center of the brain. The cerebral cortex neural cells are created by the cell division at ventricles.
The neurons created at the center of the brain travel to the various areas of the brain through the help of glial (glue in Greek) cells. while on their way to reach their destinations they pickup information from the settled neurons in their path, probably to make connections (synapses) later. Once they reach their final destination, neurons get bigger, axons lengthen and dendrites branch out seeking synaptic connections with other cells.
Hind brain is the one closest to the spinal cord. It controls many automatic functions, such as breathing and heartbeat. It has Cerebellum and Medulla oblongata.
The fore brain is involved in thinking, planning, language and problem solving. It consists of Hippo campus, Amygdala , Hypothalamus, Thalamus and Cerebrum.
Hippo campus processes memories. Amygdala is involved in our emotions. Hypothalamus governs the system of hormones in the body. Thalamus is the brain's central message relay station; almost all information passes through here on its way to other parts of the brain. Cerebrum is the top most part of the brain where we think and plan. It has the Cerebral cortex where all the signals from the senses are stored and analyzed.
The work in the brain is performed by the neurons. There are 100 billion neurons actively participating in the transmission and storing of information in the body. Neurons tirelessly work from the time we were born to the time we die. About 250,000 neurons are created every minute during pregnancy so as to reach its limit 100 billion towards the end of pregnancy.
After the baby is born, it has to struggle to acquire skills for survival in the world, like struggling to walk and talk. The more struggle in repetitive tasks the more intense are the synaptic connections it makes and the more ease of performing them throughout their life. That is how our walk and talk became almost automatic. We never pause to think that we struggled to acquire those skills for months when we are babies.
Human body senses are triggered by physical stimulus occurring outside the brain. These physical stimuli act upon the specialized receptor cells. These receptor cells in turn generate nerve impulses. These nerve impulses are partly chemical and partly electrical. The main function of the neurons is to receive and transmit these impulses. The nerve impulse travels from the dendrite to axon for transmission to the next neuron through a synapse.
The transmission of nerve impulses is well written in the book but I will make my humble attempt to describe.
Cell membranes have perforations for ion transportation. These are called ion channels. These channels control the movement of ions in and out of the cell. The cell has a stable charge configuration and because of the movement of charged ions in message transmission, parts of the cell charges are altered. Immediately a counter migration of ions are initiated to counteract the altered charge. For example it is slightly negative inside a cell but when positive ions get into the cell it becomes more positive and immediately some positive ions are allowed to get out of the cell membrane ion channels for restoring the negative charge. This process generates a tiny electrical impulse called action potential. These action potentials have about 1/10 of a volt and travel like waves with speed around 100 miles per hour. Potassium and Sodium ions participate in impulse transmission.
The nerve impulse after reaching the axon's terminus, forces it to eject what are called neurotransmitters thereby transforming an electrical signal to a chemical signal. The chemical signal travels in the synapse and attaches to a receptor on the dendrites of the neighbouring cell. The signal changes to an electrical signal in the next neuron. The travel continues until it reaches the destination. Some of the neurotransmitters are Glutamate, Aspartate, Dopamine, Serotonin, Nitric Oxide.
When a neurotransmitter attaches itself to a receptor on a dendrite, it initiates the release of chemicals within the cell called second messengers. They carry the message to the interior of the cell and trigger reactions. These reactions could change the cell behavior or may produce additional second messages some of them may reside in the cell permanently.
Axons and dendrites branch out like trees. An average Neuron forms thousand synapses. Some neurons have 200,000 synapses where they can exchange neurotransmitter messages with thousands of other neurons. Synapses are the gaps where either chemical or electrical impulse information is exchanged between neurons or neurons and cells .
We have five senses, seeing, hearing, smelling, tasting and touching. There are specific receptors for specific senses spread all over body. They produce electrical impulses called action potentials. First destination for all these impulses is the thalamus, which is in the middle of the brain. Thalamus is the central processing unit for sensory impulses where they were analyzed and sent to proper locations on cerebral cortex. Visual Cortex takes care of Optical signals coming from the eye, auditory cortex for hearing, somatic sensory cortex for identifying and locating touching signals. Final signal analysis was made at the cerebral cortex and response signal was sent to the appropriate area through the neural network.
For example you are walking and suddenly saw your friend whom you want to meet going in the other way. Signals in your cortex know your location, optical and auditory signals sending all about traffic on the street, brain knows your intention to move, signals sent to your muscles so that you can cross the street safely and meet your friend. Your optical system, auditory system, muscular system coordinated your street crossing and your lips are there ready to greet your friend.
The main function of the brain is to be aware of the body's location and what is happening around it and respond appropriately. The continuous routine functions like breathing, heart beat, temperature monitoring etc are handled by the brain stem. The sensual signals coming from receptors have all the necessary information, like location of the sending receptor(eye); location of the object, color, shape, texture etc. ( from taste buds sweet or sour etc.; from nose type of smell etc; from ear what type of sound and where it is coming from etc; from touch texture of the object, temperature etc.). The signals take two paths to the brain. One goes there directly and the other visits the spinal cord on the way. Spinal cord takes care of the emergency signals by sending reflexive signals and informs brain later ( We take away our hands after touching a hot plate).
All signals go to their respective areas on the cerebral cortex through the controlling area on the thalamus. Some signals my be stopped at the thalamus level if they are just routine signals. For example you get used to ocean sound and do not here at all after a while; the sensory signals being sent by the rubbing of your clothes to the skin, you will not be aware of it; the perfume smell we ware, we will not be aware of it after a while; Sometimes conflicting signals reach the brain and brain gets confused resulting in dizziness, or seasickness etc. In almost all these cases you will be doing two opposite things at the same time, you are moving and yet you are sitting stationary ( going in a plane, traveling on a ship, whirl around and stop etc).
Brain will analyze all these signals reaching the cortex and responds by sending action signals to the proper location. We do not know how it makes this analysis but it happens all the time. There are so many mysteries in our own body. May be sometime someday in the evolutionary cycle there comes a super human who will solve all the mysteries.
This is an intermediate level book on Brain and Neurophysiology. A very nice readable book with information presented in a way be understood by a novice or an expert. The book introduces brain beautifully but not inspirational or challenging to the reader. The following summary of the book presents the information hopefully to spark an interest in Neurons and neural systems.
ABSTRACT
Neurons are generated at the center of the brain and travel to different locations in the brain. While traveling to their destination, they pickup information of the neurons in their path way for possible synaptic connections. After reaching their destination, they change their shape and structure depending upon their location. They make synaptic connections as necessary. The synaptic connections could be; between cells and neurons, dendrites and dendrites, dendrites and axons or between axons.
The receptors at our five senses create action potentials (electrical pulses) which in turn emit chemical neurotransmitters. They swim the synaptic path way and gets attached to receptors of the dendrites of the other neuron. The receptors in turn generate second messages which in turn generate some more second messages. The action potential travels like a wave through the neuron-synaptic pathway and reach its ultimate destination in the cerebral cortex of the brain. The message is analyzed and brain responds.The action message travels through the neural pathway and reaches the destination( a muscle cell, a hormone making site etc).
How these neurons make choice synaptic connections, how they store information , how they retrieve information; these are all questions to be answered. The players are action potentials, neurotransmitters, second messages and yet to be discovered unknowns.
Summary
For all existing organisms the name of the game is survival and improving survival skills as the mantra of nature is survival of the fittest. when the survival skills are not adequate they become extinct. We are surrounded by lot of information of organisms which survived and the ones which did not survive. From this information, obtained from fossils, we try to understand how the evolution is evolving.
When uni-cellular organisms appeared on the planet billions of years ago one single cell took care of all the survival skills. They do not have any built in thinking system for survival. They started improving their existence by evolving into multi cellular organisms where different cells do different things at the same time, action coordination became critical. Nerve Cell(neuron) appeared in evolution whose sole purpose is coordination between cells in the organism.
Neuron's basic function is to communicate and exchange information between various parts of the organism for survival coordination. So it has dendrites to receive information and axons to transmit information to other cells. When two neurons are communicating, the neural message moves through the gap between an axon of one neuron to the dendrite of other neuron. This gap is called the synapse. This basic synaptic communication system called nerve net, which we find in Jelly fish and corals is the precursor of our human nervous system, .
As the organisms started improving their survival skills, sensual receptors started appearing in multi cellular organisms. Rapid communication between cells became a necessity and basic Nerve net's simple system is inadequate. The existing Nerve net's communicating channel was tapped at different points for information sharing. The simple nerve net became a nerve cord running along the front of the body with swelling of neuron structures for information exchange. Such a swelling is called a nerve ganglion. The nerve cord is the precursor to spinal cord in humans. An earth worm has a nerve cord with a ganglion in each of its body segments so that it can move in one direction. The ganglion in its head - the cerebral ganglion - is connected to its mouth so as to coordinate its movement in one direction for food.
As the new kind of animals appeared, the head end of an animal became a prominent organ. Improvements in survival skills are developed around the mouth (eyes, ears) to hunt for food. Visual skills, hearing skills, smelling skills, touching skills, tasting skills started to appear in organisms. These new skill system were melded with the existing spinal neural network as they appear. As a result we see organisms with unique specialized skills, like Bats with sonar system(sound) , dogs for olfactory(smell) etc.
In evolution, incorporating multiple specialized skills started with the African ape line (Chimpanzees and Gorilla) and led to the human line. Brain development took place to coordinate all the messages coming from the senses. There are two classes of cells in brain, neurons and glial. Neurons do the neural message processing and glial cells do the structural supportive work for neurons.
Neural development in humans is interesting. Three weeks after conception, the embryo is about 1/10 of an inch and has a hollow channel called neural tube running the back of the embryo. At one end of the neural tube is a small bulge. The neural tube grows up to be the spinal cord and the bulge transforms into 3 bulges which eventually become 3 important parts of the brain, Hind brain, Mid brain and Fore brain. One of the bulges which eventually become fore brain divides into three fluid-filled spaces in the cerebrum, known as ventricles. Ventricles lie at the center of the brain. The cerebral cortex neural cells are created by the cell division at ventricles.
The neurons created at the center of the brain travel to the various areas of the brain through the help of glial (glue in Greek) cells. while on their way to reach their destinations they pickup information from the settled neurons in their path, probably to make connections (synapses) later. Once they reach their final destination, neurons get bigger, axons lengthen and dendrites branch out seeking synaptic connections with other cells.
Hind brain is the one closest to the spinal cord. It controls many automatic functions, such as breathing and heartbeat. It has Cerebellum and Medulla oblongata.
The fore brain is involved in thinking, planning, language and problem solving. It consists of Hippo campus, Amygdala , Hypothalamus, Thalamus and Cerebrum.
Hippo campus processes memories. Amygdala is involved in our emotions. Hypothalamus governs the system of hormones in the body. Thalamus is the brain's central message relay station; almost all information passes through here on its way to other parts of the brain. Cerebrum is the top most part of the brain where we think and plan. It has the Cerebral cortex where all the signals from the senses are stored and analyzed.
The work in the brain is performed by the neurons. There are 100 billion neurons actively participating in the transmission and storing of information in the body. Neurons tirelessly work from the time we were born to the time we die. About 250,000 neurons are created every minute during pregnancy so as to reach its limit 100 billion towards the end of pregnancy.
After the baby is born, it has to struggle to acquire skills for survival in the world, like struggling to walk and talk. The more struggle in repetitive tasks the more intense are the synaptic connections it makes and the more ease of performing them throughout their life. That is how our walk and talk became almost automatic. We never pause to think that we struggled to acquire those skills for months when we are babies.
Human body senses are triggered by physical stimulus occurring outside the brain. These physical stimuli act upon the specialized receptor cells. These receptor cells in turn generate nerve impulses. These nerve impulses are partly chemical and partly electrical. The main function of the neurons is to receive and transmit these impulses. The nerve impulse travels from the dendrite to axon for transmission to the next neuron through a synapse.
The transmission of nerve impulses is well written in the book but I will make my humble attempt to describe.
Cell membranes have perforations for ion transportation. These are called ion channels. These channels control the movement of ions in and out of the cell. The cell has a stable charge configuration and because of the movement of charged ions in message transmission, parts of the cell charges are altered. Immediately a counter migration of ions are initiated to counteract the altered charge. For example it is slightly negative inside a cell but when positive ions get into the cell it becomes more positive and immediately some positive ions are allowed to get out of the cell membrane ion channels for restoring the negative charge. This process generates a tiny electrical impulse called action potential. These action potentials have about 1/10 of a volt and travel like waves with speed around 100 miles per hour. Potassium and Sodium ions participate in impulse transmission.
The nerve impulse after reaching the axon's terminus, forces it to eject what are called neurotransmitters thereby transforming an electrical signal to a chemical signal. The chemical signal travels in the synapse and attaches to a receptor on the dendrites of the neighbouring cell. The signal changes to an electrical signal in the next neuron. The travel continues until it reaches the destination. Some of the neurotransmitters are Glutamate, Aspartate, Dopamine, Serotonin, Nitric Oxide.
When a neurotransmitter attaches itself to a receptor on a dendrite, it initiates the release of chemicals within the cell called second messengers. They carry the message to the interior of the cell and trigger reactions. These reactions could change the cell behavior or may produce additional second messages some of them may reside in the cell permanently.
Axons and dendrites branch out like trees. An average Neuron forms thousand synapses. Some neurons have 200,000 synapses where they can exchange neurotransmitter messages with thousands of other neurons. Synapses are the gaps where either chemical or electrical impulse information is exchanged between neurons or neurons and cells .
We have five senses, seeing, hearing, smelling, tasting and touching. There are specific receptors for specific senses spread all over body. They produce electrical impulses called action potentials. First destination for all these impulses is the thalamus, which is in the middle of the brain. Thalamus is the central processing unit for sensory impulses where they were analyzed and sent to proper locations on cerebral cortex. Visual Cortex takes care of Optical signals coming from the eye, auditory cortex for hearing, somatic sensory cortex for identifying and locating touching signals. Final signal analysis was made at the cerebral cortex and response signal was sent to the appropriate area through the neural network.
For example you are walking and suddenly saw your friend whom you want to meet going in the other way. Signals in your cortex know your location, optical and auditory signals sending all about traffic on the street, brain knows your intention to move, signals sent to your muscles so that you can cross the street safely and meet your friend. Your optical system, auditory system, muscular system coordinated your street crossing and your lips are there ready to greet your friend.
The main function of the brain is to be aware of the body's location and what is happening around it and respond appropriately. The continuous routine functions like breathing, heart beat, temperature monitoring etc are handled by the brain stem. The sensual signals coming from receptors have all the necessary information, like location of the sending receptor(eye); location of the object, color, shape, texture etc. ( from taste buds sweet or sour etc.; from nose type of smell etc; from ear what type of sound and where it is coming from etc; from touch texture of the object, temperature etc.). The signals take two paths to the brain. One goes there directly and the other visits the spinal cord on the way. Spinal cord takes care of the emergency signals by sending reflexive signals and informs brain later ( We take away our hands after touching a hot plate).
All signals go to their respective areas on the cerebral cortex through the controlling area on the thalamus. Some signals my be stopped at the thalamus level if they are just routine signals. For example you get used to ocean sound and do not here at all after a while; the sensory signals being sent by the rubbing of your clothes to the skin, you will not be aware of it; the perfume smell we ware, we will not be aware of it after a while; Sometimes conflicting signals reach the brain and brain gets confused resulting in dizziness, or seasickness etc. In almost all these cases you will be doing two opposite things at the same time, you are moving and yet you are sitting stationary ( going in a plane, traveling on a ship, whirl around and stop etc).
Brain will analyze all these signals reaching the cortex and responds by sending action signals to the proper location. We do not know how it makes this analysis but it happens all the time. There are so many mysteries in our own body. May be sometime someday in the evolutionary cycle there comes a super human who will solve all the mysteries.
Saturday, August 1, 2009
1. Look At Your Body ... Brain and Nerves by Steve Parker
Copper Beech Books, Brookfield, Cunnecticut, USA
This is an excellent children's book giving a basic understanding of Brain and nervous system. The complex concepts are supplemented with beautiful illustrations. The following is the summary.
The Brain in the human body is formed as follows. About 4 weeks into conception, the nerve tissue on the back of embryo forms a tube. The front of this tube enlarges and develops into three bulges which develop into the main three sections of the brain, forebrain, midbrain, and hindbrain. The rear part of the tube develops into spinal cord.
Brain is stationed in the head of every human being and consists of mainly nerve cells for receiving, storing, analyzing and transmitting information for human body function. Nerve cells come in various form and shapes depending upon their local function. Human Brain weighs about 3 lbs. Humans have one of the highest brain to body weight ratio, at 1:50. In comparison, a chimpanzee is 1:120 and a cow is 1:1200.
In an unborn baby 1.25 million brain cells(nerve cells) are produced every minute until it is born at which it will have nearly 500 billion brain cells. After the age of 20 between 10,000 and 100,000 brain cells die each day. while we are learning new things, interconnections between neural cells are formed.
Brain tapers at its base into the spinal cord which runs through Vertebra, the backbones. The brain and spinal cord form the Central Nervous System(CNS). A network of smaller nerves branch from spinal cord and reach every part of the body. These nerves are called Peripheral Nervous System(PNS). Certain parts of brain, spinal cord and Peripheral nervous system, form another system called Autonomic Nervous System(ANS) which is responsible for the automatic functioning of organs (ex: Heart,Intestines etc.).
Our sensory organs in the body(eyes, ears, nose, tongue, skin) send signals to the brain directly and also through the spinal cord. And brain responds by sending action(motor) signals through the nervous system for taking proper action. Sometimes if the action has to be instantaneous (like when touching a hot plate etc.) the signal goes through a reflexive loop at the spinal cord and the danger averted by sending an action signal immediately before informing the brain. These are called body reflexes.
A nerve signal is a tiny pulse of electricity. It is produced by the quick movement of electrically charged chemical particles Sodium and Potassium in the cell and travels along its outer membrane(Skin). Signal transmission occurs by these tiny pulses going from one cell to other. The signal transmission junction between two nerve cells is called a synapse. In synapse a flood of Neurotransmitters are released and they move quickly and reach the Receptors at the signal receiving nerve cell. The signal jumps between cells and finally reaches its destination in the nervous system. Nerve signals travel quickly, about 330 feet(100 meters) per second.
A beautiful example of signal transmission is the False Start in running races. The starting gun sound has to reach the ear of the runner and should go to the brain and get response(run signal) to the leg muscles, which will take tenth of a second. If the runner responded quickly before tenth of a second, it is a False Start and flagged as such in the race.
Most of the Nerve disorders(Depression, Epilepsy, Parkinson's etc) come because of problems in Nerve signal generation or transmission.
This is an excellent children's book giving a basic understanding of Brain and nervous system. The complex concepts are supplemented with beautiful illustrations. The following is the summary.
The Brain in the human body is formed as follows. About 4 weeks into conception, the nerve tissue on the back of embryo forms a tube. The front of this tube enlarges and develops into three bulges which develop into the main three sections of the brain, forebrain, midbrain, and hindbrain. The rear part of the tube develops into spinal cord.
Brain is stationed in the head of every human being and consists of mainly nerve cells for receiving, storing, analyzing and transmitting information for human body function. Nerve cells come in various form and shapes depending upon their local function. Human Brain weighs about 3 lbs. Humans have one of the highest brain to body weight ratio, at 1:50. In comparison, a chimpanzee is 1:120 and a cow is 1:1200.
In an unborn baby 1.25 million brain cells(nerve cells) are produced every minute until it is born at which it will have nearly 500 billion brain cells. After the age of 20 between 10,000 and 100,000 brain cells die each day. while we are learning new things, interconnections between neural cells are formed.
Brain tapers at its base into the spinal cord which runs through Vertebra, the backbones. The brain and spinal cord form the Central Nervous System(CNS). A network of smaller nerves branch from spinal cord and reach every part of the body. These nerves are called Peripheral Nervous System(PNS). Certain parts of brain, spinal cord and Peripheral nervous system, form another system called Autonomic Nervous System(ANS) which is responsible for the automatic functioning of organs (ex: Heart,Intestines etc.).
Our sensory organs in the body(eyes, ears, nose, tongue, skin) send signals to the brain directly and also through the spinal cord. And brain responds by sending action(motor) signals through the nervous system for taking proper action. Sometimes if the action has to be instantaneous (like when touching a hot plate etc.) the signal goes through a reflexive loop at the spinal cord and the danger averted by sending an action signal immediately before informing the brain. These are called body reflexes.
A nerve signal is a tiny pulse of electricity. It is produced by the quick movement of electrically charged chemical particles Sodium and Potassium in the cell and travels along its outer membrane(Skin). Signal transmission occurs by these tiny pulses going from one cell to other. The signal transmission junction between two nerve cells is called a synapse. In synapse a flood of Neurotransmitters are released and they move quickly and reach the Receptors at the signal receiving nerve cell. The signal jumps between cells and finally reaches its destination in the nervous system. Nerve signals travel quickly, about 330 feet(100 meters) per second.
A beautiful example of signal transmission is the False Start in running races. The starting gun sound has to reach the ear of the runner and should go to the brain and get response(run signal) to the leg muscles, which will take tenth of a second. If the runner responded quickly before tenth of a second, it is a False Start and flagged as such in the race.
Most of the Nerve disorders(Depression, Epilepsy, Parkinson's etc) come because of problems in Nerve signal generation or transmission.
Sunday, July 26, 2009
0. Introduction
It is my intention here to review a few books from introductory to advanced on Brain and Nervous System. This is to initiate a thinking process in the reader to generate new ideas on the structure and functionality of Brain and Nervous System. Once we have the knowledge of what happened in the brain research and what is happening now, we can all contribute to the advancements in this field because of our functional brains.
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