Discussion in 'News and Current Events' started by DeathHamster, May 15, 2011.
Not enough detail for you? Here is another table showing more brain structures and their associated divisions. The roman numerals (I through XII) refer to the cranial nerves.
Divisions of the Brain
Major NucleiMajor Fiber TractsVentricles
Gyri and sulci
Olfactory Nerve (I)
Optic Nerve (II)
Oculomotor Nerve (III)
Trochlear Nerve (IV)
Crus Cerebri Cerebral Aqueduct
Trigeminal Nerve (V)
Abducens Nerve (VI)
Facial Nerve (VII)
Vestibulocochlear Nerve (VIII)
Deep Cerebellar Nuclei
Glossopharyngeal Nerve (IX)
Vagus Nerve (X)
Spinal Accessory Nerve (XI)
Hypoglossal Nerve (XII)
Inferior Olive Pyramids
Neuroscience For Kids
Lobes of the Brain
The average human brain weighs about 1,400 grams (3 lb). When the brain is removed from the skull, it looks a bit like a large pinkish-gray walnut. The brain can be divided down the middle lengthwise into two halves called the cerebral hemispheres. Each hemisphere of the cerebral cortex is divided into four lobes by various sulci and gyri. The sulci (or fissures) are the grooves and the gyri are the "bumps" that can be seen on the surface of the brain. The folding of the cerebral cortex produced by these bumps and grooves increases the amount of cerebral cortex that can fit in the skull. (In fact, the total surface area of the cerebral cortex is about 324 square inches - about the size of a full page of newspaper!). Although most people have the same patterns of gyri and sulci on the cerebral cortex, no two brains are exactly alike.
Located in front of the central sulcus.
Concerned with reasoning, planning, parts of speech and movement (motor cortex), emotions, and problem-solving.
Find out more about the frontal lobe with the story of an unlucky worker in 1848 who survived an iron rod that went through his head!! Read about Mr. Gage and the frontal lobe in a GREAT multimedia slide show. If you are interested in a book about Phineas Gage, try Phineas Gage: A Gruesome but True Story About Brain Science by John Fleischman (Boston: Houghton Mifflin Co., 2002).
Located behind the central sulcus.
Concerned with perception of stimuli related to touch, pressure, temperature and pain.
Located below the lateral fissure.
Concerned with perception and recognition of auditory stimuli (hearing) and memory (hippocampus).
Located at the back of the brain, behind the parietal lobe and temporal lobe.
Concerned with many aspects of vision.
Images used with permission of the Slice of Life.
Gyri | Gyrus | Sulcus | Sulci | Frontal | Occipital | Parietal | Temporal
Did you know?
September 13, 1998 marked the 150th Anniversary of the injury to Mr. Phineas Gage. Find out more about poor Mr. Gage.
The skull of Phineas Gage.
(Image courtesy of the National Library of Medicine, History of Medicine Collection.)
Take a short review quiz about the lobes of the brain.
Review the lobes of the brain with this online coloring page.
Review the lobes of the brain with this online puzzle.
Review the lobes of the brain with a SHOCKWAVE GAME! For this Build a Brain Game, you must have the Shockwave plug-in for your browser. Get the Shockwave plug-in.
Neuroscience For Kids
Functional Divisions of the Cerebral Cortex
The cerebral cortex is responsible for many "higher-order" functions like language and information processing. Language centers are usually found only in the left cerebral hemisphere. For more information on language and differences between the right and left cerebral hemisphere, read about split brain experiments.
Cortical Area Function
Prefrontal Cortex Problem Solving, Emotion, Complex Thought
Motor Association Cortex Coordination of complex movement
Primary Motor Cortex Initiation of voluntary movement
Primary Somatosensory Cortex Receives tactile information from the body
Sensory Association Area Processing of multisensory information
Visual Association Area Complex processing of visual information
Visual Cortex Detection of simple visual stimuli
Wernicke's Area Language comprehension
Auditory Association Area Complex processing of auditory information
Auditory Cortex Detection of sound quality (loudness, tone)
Broca's Area Speech production and articulation
Images courtesy of Slice of Life.
Take the Cerebral Cortex Review Test. Requires the Adobe Acrobat Reader.
Answers to the test.
See: Mind Projection Fallacy
Also see: Argumentum ad populum
See: Contrast effect
Neuroscience For Kids
The Brain: Right Down the Middle
Although some people may think that the brain is like a bowl of Jell-O, the brain is NOT a bowl of jell-O. Unlike a bowl of Jell-O, the brain is not a uniform material. Rather, the brain is made up of many different areas, each having a particular structure and function. The "midsagittal plane" separates the brain into right and left hemispheres.
The word "cortex" comes from the Latin word for "bark" (of a tree). This is because the cortex is a sheet of tissue that makes up the outer layer of the brain. The thickness of the cerebral cortex varies from 2 to 6 mm. The right and left sides of the cerebral cortex are connected by a thick band of nerve fibers called the "corpus callosum". In higher mammals like humans, the cerebral cortex looks like it has many bumps and grooves. A bump or bulge on the cortex is called a gyrus (the plural of the word gyrus is "gyri" and a groove is called a sulcus (the plural of the word sulcus is "sulci". Lower mammals like rats and mice have very few gyri and sulci.
The word "cerebellum" comes from the Latin word for "little brain." The cerebellum is located behind the brain stem. In some ways, the cerebellum is a bit like the cerebral cortex: the cerebellum is divided into hemispheres and has a cortex that surrounds these hemispheres.
Brain stem Functions:
The brain stem is a general term for the area of the brain between the thalamus and spinal cord. Structures within the brain stem include the medulla, pons, tectum, reticular formation and tegmentum. Some of these areas are responsible for the most basic functions of life such as breathing, heart rate and blood pressure.
The hypothalamus is composed of several different areas and is located at the base of the brain. It is only the size of a pea (about 1/300 of the total brain weight), but it is responsible for some very important behaviors. One important function of the hypothalamus is the control of body temperature. The hypothalamus acts as like a "thermostat" by sensing changes in body temperature and then sending out signals to adjust the temperature. For example, if you are too hot, the hypothalamus detects this and then sends out a signal to expand the capillaries in your skin. This causes blood to be cooled faster. The hypothalamus also controls the pituitary.
The thalamus receives sensory information and relays this information to the cerebral cortex. The cerebral cortex also sends information to the thalamus which then transmits this information to other areas of the brain and spinal cord.
Hear IT! Cerebellum | Corpus Callosum | Cortex | Hypothalamus | Thalamus
Check out the glossary for definitions of other brain areas.
Neuroscience For Kids
...or "My Brain is Bigger than Your Brain"
As you might imagine, larger animals have larger brains. However, this does not mean that animals with larger brains are smarter than animals with smaller brains. For example, a larger brain is necessary to control larger muscles in larger animals and a larger brain is necessary to process more sensory information from the skin in larger animals - this has nothing to do with intelligence.
Brain Weight (grams) Species
1,300-1,400 Adult Human
97 Rhesus Monkey
More brain weights
During the course of evolution, the brain areas that show the most changes are the cerebral hemispheres (the red areas in the drawings): the more recently evolved animals have a larger proportion of the brain taken up by the cerebral cortex. In the "higher" animals (especially the higher mammals), the surface of the cerebral cortex becomes folded. This creates grooves on the surface of the brain called sulci (singular = sulcus). The bumps or ridges on the surface of the brain are called gyri (singular = gyrus). The folding of the cortex increases the cortical surface area. The cerebral cortex, made up of four lobes is involved in many complex brain functions including memory, perceptual awareness, thinking, language and consciousness.
Click on a word to hear how it is pronounced:
Gyri | Gyrus | Sulcus | Sulcii
The Primary Somatosensory Cortex
Parts of the cerebral cortex in the parietal lobe are involved with processing information related to touch. One such area is the primary somatosensory cortex which is located behind the central sulcus. Neurons in the primary somatosensory are activated when the skin is touched. However, the body is NOT represented in the cortex in proportion to the amount of skin. A map of the human somatosensory cortex was drawn by Dr. Wilder Penfield, a neurosurgeon, in the 1950s.
After stimulating the cortex of patients undergoing brain surgery for
epilepsy, Dr. Penfield asked the patients what they felt. By observing the location on the brain that caused patients to feel sensations on different parts of their bodies, Dr. Penfield was able to draw a map of the brain. As you can see in this figure above, even though the arms and trunk make up most of your body, they are not given much cortical tissue. However, the face and hands take up a good portion of the primary somatosensory cortex. This is because the amount of primary somatosensory cortex is directly related to the sensitivity of a body area and the density of receptors found in different parts of the body. The areas of skin with the higher density of receptors (like the face, hands and fingers) have more cortical tissue devoted to them. If you were "built" in proportion to the amount of cortex devoted to each part of your body, you would look a bit distorted: you would have a big head and hands and a small torso and tiny legs. This distorted body map is called a homunculus which means "little man."
Think about how sensitive your fingertips are compared to your leg. For a demonstration of the sensitivity of different body areas, test your two point discrimination.
Try the REALLY WEIRD BODY MAP animation to learn more about the homunculus.
Why don't you probe the motor cortex with this science odyssey activity from PBS?
Neuroscience For Kids
One Brain...or Two?
How many brains do you have - one or two? Actually, this is quite easy to answer...you have only one brain. However, the cerebral hemispheres are divided right down the middle into a right hemisphere and a left hemisphere. Each hemisphere appears to be specialized for some behaviors. The hemispheres communicate with each other through a thick band of 200-250 million nerve fibers called the corpus callosum. (A smaller band of nerve fibers called the anterior commissure also connects parts of the cerebral hemispheres.)
Are you right-handed or left-handed? As you probably know, most people (about 90% of the population) are right-handed - they prefer to use their right hand to write, eat and throw a ball. Another way to refer to people who use their right hand is to say that they are dominant. It follows that most of the other 10% of the population is left-handed or "left hand dominant." There are few people who use each hand equally; they are "ambidextrous." (Most people also have a dominant eye and dominant ear...test your "sidedness" here.)
Exactly why people are right-handed or left-handed is somewhat of a mystery. Dr. William Calvin has developed a fascinating theory about the origin of handedness and has written an essay called The Throwing Madonna to explain it.
Right Side - Left Side
The right side of the brain controls muscles on the left side of the body and the left side of the brain controls muscles on the right side of the body. Also, in general, sensory information from the left side of the body crosses over to the right side of the brain and information from the right side of the body crosses over to the left side of the brain. Therefore, damage to one side of the brain will affect the opposite side of the body.
In 95% of right-handers, the left side of the brain is dominant for language. Even in 60-70% of left-handers, the left side of brain is used for language. Back in the 1860s and 1870s, two neurologists (Paul Broca and Karl Wernicke) observed that people who had damage to a particular area on the left side of the brain had speech and language problems. People with damage to these areas on the right side usually did not have any language problems. The two language areas of the brain that are important for language now bear their names: Broca's area and Wernicke's area.
Images courtesy of Slice of Life.
Each hemisphere of the brain is dominant for other behaviors. For example, it appears that the right brain is dominant for spatial abilities, face recognition, visual imagery and music. The left brain may be more dominant for calculations, math and logical abilities. Of course, these are generalizations and in normal people, the two hemispheres work together, are connected, and share information through the corpus callosum. Much of what we know about the right and left hemispheres comes from studies in people who have had the corpus callosum split - this surgical operation isolates most of the right hemisphere from the left hemisphere. This type of surgery is performed in patients suffering from epilepsy. The corpus callosum is cut to prevent the spread of the "epileptic seizure" from one hemisphere to the other.
Roger Sperry (who won the Nobel prize in 1981) and Michael Gazzaniga are two neuroscientists who studied patients who had surgery to cut the corpus callosum. These studies are called "Split-Brain Experiments". After surgery, these people appeared quite "normal" - they could walk, read, talk, play sports and do all the everyday things they did before surgery. Only after careful experiments that isolated information from reaching one hemisphere, could the real effects of the surgery be determined.
Dr. Sperry used a tachistoscope to present visual information to one hemisphere or the other. The tachistoscope requires people to focus on a point in the center of their visual field. Because each half of the visual field projects to the opposite site of the brain (crossing in the optic chiasm), it is possible to project a picture to either the right hemisphere OR the left hemisphere.
So, say a "typical" (language in the LEFT hemisphere) split-brain patient is sitting down, looking straight ahead and is focusing on a dot in the middle of a screen. Then a picture of a spoon is flashed to the right of the dot. The visual information about the spoon crosses in the optic chiasm and ends up in the LEFT HEMISPHERE. When the person is asked what the picture was, the person has no problem identifying the spoon and says "Spoon." However, if the spoon had been flashed to the left of the dot (see the picture), then the visual information would have traveled to the RIGHT HEMISPHERE. Now if the person is asked what the picture was, the person will say that nothing was seen!! But, when this same person is asked to pick out an object using only the LEFT hand, this person will correctly pick out the spoon. This is because touch information from the left hand crosses over to the right hemisphere - the side that "saw" the spoon. However, if the person is again asked what the object is, even when it is in the person's hand, the person will NOT be able to say what it is because the right hemisphere cannot "talk." So, the right hemisphere is not stupid, it just has little ability for language - it is "non-verbal."
Another type of experiment performed with split brain patients uses chimeric figures, like this one to the right. In this figure, the face on the left is a woman and the face on the right is a man. Therefore, if the patient focuses on the dot in the middle of the forehead, the visual information about the woman's face will go to the right cerebral hemisphere and information about the man's face will go to the left hemisphere. When a split brain patient is asked to point to a whole, normal picture of the face that was just seen, the patient will usually pick out the woman's picture (remember, the information about the woman's face went to the RIGHT cerebral hemisphere). However, if the patient is required to say whether the picture was a man or a woman, the patient will SAY that the picture was of a man. Therefore, depending on what the patient is required to do, either the right or left hemisphere will dominate. In this case, when speech is not required, the right hemisphere will dominate for recognition of faces.
Before different types of brain surgery, it is important to identify which cerebral hemisphere is dominant for language so that the neurosurgeon can avoid damaging speech areas. One way to test which hemisphere is dominant for language is with a procedure called the Wada Test. During this test, a fast acting anesthetic called sodium amytal (amobarbital) is injected into the right or left carotid artery. The right artery supplies the right cerebral hemisphere and the left artery supplies the left cerebral hemisphere. Therefore, either the right or left hemisphere can be "put to sleep" temporarily. If the left hemisphere is put to sleep in people who have language ability in the left hemisphere, then when asked to speak, they cannot. However, if the right hemisphere is put to sleep, then these people will be able to speak and answer questions. (Remember too that because the right hemisphere controls muscles on the left side, people will not be able to move the left side of their bodies.)
Another way to test for language representation in the brain is to electrically stimulate the cerebral cortex. A neurosurgeon can place an electrode on various areas of the exposed brain of an awake patient during surgery. The patient can say what he or she feels and thinks. Placement of the electrode on the brain does NOT hurt because the brain itself does not have any receptors for pain. In people who have left side dominance for language, electrical stimulation of various locations on the left cerebral cortex will interfere with speech.
Handedness and brain lateralization.
Play the Split Brain Experiments Game from Nobelprize.org.
Are you a left hander? If you are, then you have something in common with some famous people such as Barack Obama, Bill Clinton, Jimmy Connors, Angelina Jolie, Ronald Reagan, Kurt Cobain and Marilyn Monroe.
9.01 Introduction to Neuroscience
As taught in: Fall 2007
Cortical area 17 also known as the primary visual cortex of the brain shown for both human and monkey. (Figure by MIT OpenCourseWare. After figure 10.12 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the Brain. 2nd ed. Baltimore, MD: Lippincott Williams & Wilkins, 2001. ISBN: 9780683305968.)
Prof. Mark Bear
Prof. Sebastian Seung
This course is an introduction to the mammalian nervous system, with emphasis on the structure and function of the human brain. Topics include the function of nerve cells, sensory systems, control of movement, learning and memory, and diseases of the brain.
Introduction to neuroscience
By Gary G. Matthews
John Frederick Stein, C. J. Stoodley
Wiley, 2006 - 471 pages
This engaging book will serve as an introductory text in neuroscience. It conveys important ideas in neuroscience without overburdening the student with unnecessary detail. Drawing from his 35 years of teaching experience of teaching at Oxford University, the author concentrates on concepts and observations that students find difficult, amusing, interesting or exciting.
Starting with a brief history of neuroscience, it covers cellular and biophysical aspects, sensory systems, motor systems, the hypothalamus, the automatic nervous system, learning and memory and speech and reading.
Understanding Yourself: An Introduction To Neuroscience
By Lowell E. White
Human learning: biology, brain, and neuroscience
edited by Aaron S. Benjamin
Neuroscience: exploring the brain
By Mark F. Bear, Barry W. Connors, Michael A. Paradiso
Nope. It's all been debunked because L. Ron says the brain is a time machine. What more proof do you need? Sorry. Hundreds of years of research down the tubes.
Neurons and networks:
an introduction to neuroscience, Part 747
John E. Dowling
Introduction to Neuroscience I
By Donald C. Cooper Ph.D.
Nerve cells and nervous systems: an introduction to neuroscience
By Alan Geoffrey Brown
By Jon H. Kaas
Knowledge is power. Arm yourself.
SHUT UP SHUT UP SHUT UP
Please let ScnTO continue spewing copypasta
Nope. Wrong again, since knowledge isn't stored in the brain. It's stored in the ether and the brain is just a switchboard between the meat between your legs ears and your past life. Duh!
I know it's true because I observed Scientologists telling me this, and they learned it from L. Ron Hubbard, and he couldn't possibly be wrong or full of shit.
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