Brain Facts:
Brain Hemispheres
| Topic | Discussion | Resource |
Amusia |
Damage to the right half of the brain may result in the loss of musical ability, leaving speech unimpaired. This disorder, known as amusia, was most frequently reported in professional musician who suffered from stroke of other brain damage. |
Sally P. Springer and Georg Deutsch |
Brain Construction |
There are two hemispheres (in the cerebrum) and four lobes in each hemisphere: frontal, parietal, occipital, temporal. | Brynie, Faith
Hickman |
Cognitive Neuropsychology |
Cognitive neuropsychology studies the underlying mechanism of the psychological processes that are the basis of our mental life—thinking, reading, speaking, recognizing, remembering—through the effects of brain injury. Its first aim is to relate the patterns of cognitive performance in brain-injured patients to psychological operations that are necessary for normal cognitive function; the second is to actually draw conclusions about normal cognitive processes from observations of the effects of brain injury. Thus, cognitive neuropsychologists not only attempt to explain how brain injury disrupts normal functions, but they also seek to increase our understanding of the way the normal brain and mind are organized by studying deficits that occur following brain injury. |
Sally P. Springer and Georg Deutsch |
Commissure, Callosum
|
The role of the callosum and other commissures can perhaps best seen as that of a conduit through which the hemispheres exchange information and perhaps handle the problems associated with conflicts among independent processing modules. |
Sally P. Springer and Georg Deutsch |
Complementary Specialization |
The idea that each hemisphere is specialized for different functions is known as complementary specialization |
Sally P. Springer and Georg Deutsch |
Cross-Brain Function |
Each hemisphere controls the opposite side of the body in terms of basic movements and sensations. | Sally P. Springer, and Georg Deutsch |
Hemisphere |
Each hemisphere…has its own…private sensations, perceptions, thoughts, and ideas all of which are cut off from the corresponding experiences in the opposite hemisphere. Each left and right hemisphere has its own private chain of memories and learning experiences that are inaccessible to recall by the other hemisphere. In many respects each disconnected hemisphere appears to have a separate “mind of its own.” |
R. W. Sperry |
| Hemispheres | Different areas of the brain respond to an individual’s activities in the world: the frontal cortex lights up in planning; the left or the right hemisphere lights up while reading or painting; the reticular activating system of the brainstem lights up when one receives sensory input (such as sound or taste) and it sends these signals to the cortex. | Ornstein, Robert, PhD. |
Hemisphere, Left |
Most people’s speech is controlled by the left side of the brain, which is also responsible for mathematics and other forms of logical problems solving. Curiously, it is also the source of many misremembered or confabulated details, and it is the home of the “interpreter”…The left side of the brain seems to have an intense need for logic and order—so intense that if something doesn’t make sense, it usually responds by inventing some plausible explanation. |
Sandra Aamodt, PhD and Sam Wang, PhD |
| Hemisphere, Left | The left hemisphere tends to break things into their component parts, and it attends to distinguishing rather than common features. It process the world in a linear sequential manner. | Richard Restak |
| Hemisphere, Left —Language Function |
In most people (97%), both Broca's area (spoken speech) and Wernicke's area (heard speech) are found in only the left hemisphere of the brain. | Chulder, Dr. Eric. The Brain and Communication Think Quest. Article |
Hemisphere, Left —Language Function |
The left hemisphere is specialized in language functions, but these specializations are a consequence of the left hemisphere’s superior analytic skills, of which language is but one manifestation. |
Sally P. Springer and Georg Deutsch |
Hemisphere, Right |
The right side is much more literal and truthful when it reports what happened. It controls spatial perception and the analysis of objects by touch, and excels at visual-motor tasks. Rather than being “artistic” or “emotional,” the right brain is simply more grounded. It’s a Joe Friday type, and if it could talk, it would probably say, “Just facts, Ma’am.” |
Sandra Aamodt, PhD and Sam Wang, PhD |
| Hemisphere, Right | The right hemisphere relies less on words and language; it’s better at perceiving the “whole picture” by synthesizing and attending to general configurations. It engages in parallel processing, which involves operations going on at the same time. | Richard Restak Mozart’s Brain and the Fighter Pilot p. 87 |
Hemisphere, Right —Visuospatial |
The right hemisphere’s superior Visuospatial performance is assumed to be derived from its synthetic, holistic manner of dealing with information. |
Sally P. Springer and Georg Deutsch |
Hemispheres |
Some investigators have speculated that there is a delicate balance between hemispheres, with one or the other taking over, depending on the task and other as yet unspecified factors. In this view, the corpus callosum and other commissures play an important role in achieving interhemispheric harmony in the normal brain, serving to integrate the specialized functions of the left and right hemispheres into unified behaviors. |
Sally P. Springer and Georg Deutsch |
History |
Franz Gall, a late eighteenth century German anatomist, was the first to propose that the brain is not a uniform mass and that various mental faculties can be localized to difference part of the brain. The faculty of speech, he believed, is located in the frontal lobes, the part of each hemisphere closest to the front of the head. Unfortunately, Gall also claimed that the shape of the skull reflects the under lying brain tissues and that an individual’s mental and emotional characteristics can be determined through a careful study of bumps on the head. |
Sally P. Springer and Georg Deutsch |
History |
In 1864 the great British neurologist John Hughlings Jackson wrote. “Not long ago, few doubted the brain to be double in function as well as physically bilateral; but not that it is certain from the research of Dax, Broca, and others, that damage to one lateral half can make a man entirely speechless, the former view is disrupted. |
Sally P. Springer and Georg Deutsch |
History |
11 years later (1876) Jackson argued that the lobes at the rear of the brain are the seat of visual ideation or thought and that “the right posterior lobe is the leading side, the left the more automatic.” Jackson based this proposal on his observation of a patient who had a tumor in the right hemisphere and experienced difficulty recognizing objects, persons, and places. |
Sally P. Springer and Georg Deutsch |
History |
The test known as the Wada Test after its inventor, Juhn Wada, has been very valuable in localizing functions across hemispheres. In the Wada test, the neurosurgeon temporarily anesthetizes one hemisphere at a time on separate days before surgery so that it can be determined which side of the brain normally controls the ability to speak. |
Sally P. Springer and Georg Deutsch |
History |
By 1870, other investigators began to realize that many types of language disorders could result from damage to the left hemisphere…Karl Werncike, a German neurologist, is credited with showing that damage to the back part of the temporal lobe of the left hemisphere could produce difficulties in understanding speech. |
Sally P. Springer and Georg Deutsch |
History |
By 1864 Broca had become convinced of the importance of the left hemisphere in speech…Although Broca is often credited with being the first to see the relationship between damage to the left hemisphere and loss of speech, the association had in fact been noted almost 30 years earlier by Marc Dax, a French country doctor. |
Sally P. Springer and Georg Deutsch |
Music |
Damage to the right half of the brain may result in the loss of musical ability, leaving speech unimpaired. This disorder, known as amusia, was most frequently reported in professional musicians who suffered from stroke of other brain damage. |
Sally P. Springer and Georg Deutsch, Left Brain Right Brain: Perspectives from Cognitive Neuroscience Fifth Edition |
Split-Brain Studies |
On the basis of split-brain studies, the most general statement that can be made about right-hemisphere specialization is that they are nonlinguistic functions that seem to involve complex visual and spatial process. The perception of part-whole relations, for examples, seems to be superior in the right hemisphere. |
Sally P. Springer and Georg Deutsch, Left Brain Right Brain: Perspectives from Cognitive Neuroscience Fifth Editionp. 45-6 |
Split-Brain |
Split-brain research has dramatically confirmed that, in most persons, control of speech is localized to the left hemisphere. |
Sally P. Springer and Georg Deutsch |
Synchrony |
When two cellists play the same bit of music, the rhythms of neuronal firing in their right hemisphere are extraordinarily close. The synchrony of these zones for musical abilities is far greater across brains of the two than in the care of the left and height hemispheres within each brain. |
Daniel Goleman, PhD |
Whole Brain Use |
In reality, you use your whole brain every day. If big chunk of brain were never used, damaging them would not cause noticeable problems. This is emphatically not the case! Functional imaging methods that allow the measurement of brain activity also show that simple tasks are sufficient to produce activity throughout the entire brain. |
Sandra Aamodt, PhD and Sam Wang, PhD |
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