The lateralisation of brain function is a tendency for some nerve function or cognitive processes that are specific to one side of the brain or the other. The medial longitudinal fissure separates the human brain into two different hemispheres, linked by the corpus callosum. Although the macro structures of the two hemispheres seem almost identical, the composition of different neural networks allows different special functions in each hemisphere.
The delays in brain structure are based on general tendencies expressed in healthy patients; However, there are many contradictions for every generalization. Every human brain develops differently leading to a unique lateralization of the individual. This differs from specialization because lateralization refers only to the function of one structure divided between two hemispheres. Specialization is much easier to observe as a trend because it has a stronger anthropological history. The best example of established lateralization is that Broca and Wernicke areas where both are often found exclusively in the left hemisphere. These areas often correspond to handedness, however, meaning that the localization of these areas is regularly found in parts corresponding to the dominant hand (anatomically on the opposite side). Lateralization of functions such as semantics, intonation, accentuation, prosody, etc. has been questioned and has largely been found to have a neuronal basis in both hemispheres. Another example is every hemisphere in the brain tends to represent one side of the body. In the cerebellum this is the same bodyside, but in the forebrain it is dominated by the contralateral side.
Video Lateralization of brain function
Laterized Function
Language
Language functions such as grammar, vocabulary and literal meaning are usually lateralized to the left hemisphere, especially in the individual right hand. While language production is left-lateralized to 90% of right-handers, it's more bilateral, or even right-lateral, in about 50% of the left hand.
Broca's area and Wernicke's area, two areas associated with speech production, are located in the left hemisphere about 95% of the right hand, but about 70% of the left hand.
Auditory and visual processing
The processing of visual and auditory stimuli, spatial manipulation, facial perception, and artistic ability are represented bilaterally. Numerical estimations, comparisons and online calculations depend on bilateral parietal areas while precise calculations and fact-taking are related to the left parietal region, possibly due to their bonding to linguistic processing.
Maps Lateralization of brain function
Clinical interests
Depression associated with hyperactive right hemisphere, with evidence of selective involvement in "processing negative emotions, pessimistic thoughts and unconstructive thinking", as well as vigilance, passion and self-reflection, and relatively hypoactive left hemisphere, "specifically involved in the process of pleasing experience "and" relatively more involved in the decision-making process ". In addition, "left hemisphere lesion produces an omissive response bias or error pattern whereas right hemispheric lesions produce commu- sive response bias or error patterns." Delusional misidentification syndrome, reduplicative parametia and Capgras delusions are also often the result of right hemispheric lesions.
Hemisphere damage
Damage to the right or left hemisphere, and resulting deficit provides insight into the functioning of the damaged area. Right hemisphere damage has many effects on the production and perception of language. Damage or lesions in the right hemisphere can lead to a lack of prosody or emotional intonation when speaking. Right hemisphere damage also has a monumental effect on understanding discourse. People with damage to the right hemisphere have less ability to produce conclusions, understand and produce key concepts and reduced abilities to manage alternative meanings. Furthermore, when engaged in the discourse of people with right hemisphere damage, their discourse is often abrupt and perfunctory or verbose and redundant. They can also have pragmatic deficits in turn-taking situations, topic maintenance and knowledge sharing.
Lateral brain damage can also have an effect on spatial frequency. People with left brain damage are only able to see low frequencies, or large images, part of an image. Right hemisphere damage causes damage to low spatial frequencies, so that people with right hemisphere damage can only see image detail, or high frequency part of an image.
Plasticity
If a particular region of the brain, or even the entire hemisphere, is injured or destroyed, its function can sometimes be assumed by neighboring regions in the same hemisphere or other appropriate areas of the hemisphere, depending on the damaged areas and the patient's age. When injuries disrupt the path from one area to another, an alternative (indirect) connection can develop to communicate information with a separate area, despite inefficiency.
Broca's Broca's Aphasia
Broca's aphasia is a specific type of expressive aphasia and so named because of the aphasia that results from damage or lesions to Broca's brain area, which is most common in the left inferior frontal hemisphere. Thus, the aphasia that develops from Broca's lack of functional areas is expressive and non-expressive aphasia. This is called 'non-current' because the problems that arise because Broca's area is very important for language pronunciation and production. The area controls some of the motor aspects of the production of speech and the articulation of the mind into words and thus the lesion to the area produces a specific non-eloquent aphasia.
aphasia Wernicke
Wernicke's aphasia is the result of damage to the area of ​​the brain that is usually in the left hemisphere above the sylvian fissure. Damage to this area causes a major deficit in language comprehension. While the ability to speak fluently with normal melodic intonation is spared, the language produced by someone with Wernicke's aphasia is full of semantic error, and may sound unreasonable to the listener. Wernicke's aphasia is characterized by phonemic paraphasia, neologism or jargon. Another characteristic of a person with Wernicke's aphasia is that they do not care about the mistakes they make.
Society and culture
Misapplication
Terence Hines states that research on lateralization of the brain serves as a research program, although commercial promoters have applied it to promote subjects and products far beyond the research implications. For example, the research implications have nothing to do with psychological interventions such as EMDR and neurolinguistic programming, brain training equipment, or management training.
Psikologi pop
Some popularization overly simplifies the science of lateralization, presenting the functional distinction between hemispheres as more absolute than is actually the case.
Gender differences
In the 19th century and at the lower 20th level, it was estimated that each side of the brain was associated with a particular sex: the left associated with masculinity and rights with femininity and each section could function independently. The right side of the brain is seen as inferior and is considered prominent in women, barbarians, children, criminals, and madmen. A prime example of this in fictitious literature can be seen in Robert Louis Stevenson's Robert Jane case. Dr. Jekyll and Mr. Hyde .
Evolutionary advantages
The widespread publication of many vertebrate animals demonstrates the evolutionary advantages associated with the specialization of each hemisphere.
History
Broca
One of the first indications of lateralisation of brain function resulted from the research of French physician Pierre Paul Broca, in 1861. His research involved male patients nicknamed "Tan", who suffered from speech deficits (aphasia); "tan" is one of the few words he can express, then his nickname. In Tan's autopsy, Broca decides she has a syphilis lesion in the left hemisphere. This left frontal lobe brain region (Broca's area) is an important speech producing region. The motor aspect of the speech production deficit caused by damage to Broca's area is known as expressive apasia. In this aphasia clinical assessment, it should be noted that the patient can not clearly articulate the language used.
Wernicke
German physician Karl Wernicke continued in Broca's vein of research by studying language deficits unlike expressive aphasia. Wernicke notes that not every deficit in speech production; there is a linguistic. He found that damage to the left posterior, superior temporal gyrus (Wernicke area) led to a deficit of language comprehension rather than a speech production deficit, a syndrome known as receptive aphasia.
Imaging
This seminal work on hemispheric specialization is performed on the patient or postmortem brain, raising questions about the potential pathological impacts on the research findings. The new method allows inward in vivo hemispheric comparisons on healthy subjects. In particular, magnetic resonance imaging (MRI) and positron emission tomography (PET) are important because of their high spatial resolution and ability to describe subcortical brain structures.
Movement and sensation
In the 1940s, neurosurgeon Wilder Penfield and his neurologist Herbert Jasper developed a technique of brain mapping to help reduce the side-effects caused by surgery to treat epilepsy. They stimulate the motor cortex and brain somatosensory with a small electric current to activate discrete brain regions. They found that stimulation in the motor cortex of one hemisphere produces muscle contraction on the opposite side of the body. In addition, the functional maps of motor and sensory cortex are fairly consistent from person to person; Penfield and Jasper's famous image of motor and homunculi sensory are the result.
Brain-split patients
Research by Michael Gazzaniga and Roger Wolcott Sperry in the 1960s on split brain patients led to a greater understanding of functional lateralities. Split-brain patients are patients who have undergone corpus callosotomy (usually as a treatment for severe epilepsy), termination of most corpus callosum. The corpus callosum connects the two hemispheres of the brain and allows them to communicate. When this connection is interrupted, both parts of the brain have a reduced capacity to communicate with each other. This led to many interesting behavior phenomena that allowed Gazzaniga and Sperry to study the contribution of each hemisphere to various cognitive and perceptual processes. One of their main findings is that the right hemisphere is capable of processing imperfect language, but often lacks lexical or grammatical capabilities. Eran Zaidel also studied such patients and found some evidence for the right hemisphere that has at least some syntactic ability.
Language is mainly localized in the left hemisphere. One experiment conducted by Gazzaniga involves a male-split male patient who sits in front of a computer screen while having words and images presented on both sides of the screen and visual stimuli will go into the visual field right or left, and thus the left hemisphere or right, respectively. Observed that if the patient is presented with the image to the left visual field (right brain), he will report not seeing anything. If he can feel around for a particular object, he can accurately pick the right object, even though it does not have the ability to say what he sees. This leads to confirmation that the left brain is localized to the language while the right brain does not have this ability, and when the corpus callosum is cut, the two hemispheres can not communicate in speech relating to the situation to be generated.
Additional images
See also
- Foreign hand syndrome
- Ambidexterity
- Bicameralism
- Brain Asymmetry
- Truth
- The contralateral brain
- Cross-dominance
- Awareness is divided
- Double brain theory
- Dual awareness
- Emotional Thermalization
- Handedness
- Hemispherectomy
- Delay
- Left brain interpreter
- My Stroke of Insight
- Parallel computing
- Psychoneuroimmunology
- Right hemisphere brain damage
- Ten percent of the brain myth
- The master and his envoy
- Wada Test
- Yakovlevian Torque
References
Further reading
Source of the article : Wikipedia
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