Cerebral asymmetry

The cerebral asymmetry is expressed in cognitive Science like an unequal distribution of the functions according to the cerebral hemispheres.

This difference is not given any more in doubt, but in the attribution of the assigned roles to each hemisphere, more the greatest caution is essential.

Lighting

The cerebral cartography is in the beginning surface, in particular with the cerebral lobes, but one also differentiates three layers from the interior towards outside, reptilien (oldest, near to that of the reptiles), limbic and neocortex (litéralement new cortex).

If the brain reptilien does not have lateralization, the limbic brain, and especially the neocortex distinct and complementary actions according to the events have.

One generally admits the evolution " concentrique" and it is supposed that the passage of physical symmetry to dissymmetry functional is due to the increasing complexity of information to treat.

The dyslexic disorder was described for the 1st time by BERKLAN in 1881. Pringle MORGAN had qualified it congenital word blindness and called upon at the origin of the dyslexia a disgenesis of the angular gyrus. This thesis is developed in an important work of INSCHELWOOD " Congenital blindness" appeared in 1917. He showed a dysgenesic deterioration affecting the center of the visual memory of the letters. Later on ORTON took into account a disorder of laterality considering that existed a greater frequency of the dyslexia in the left-handeds person or the ambidexters. It estimated that the left-handed person could neglect the hémichamp visual right, which would explain the inversions of the letters and the reading out of mirror But this theory ignores the dynamic character of to some extent comparable visual perception to a photographic projection. On the other hand American authors DEARBORN, SPOIL, SIMPLETON and BLAU see at the origin of the dyslexic disorder a defective orientation of the movements of the glance. For them, the disorder is at the sensorimotor level of the vision and is related to the preference for such or such direction of the ocular movements. In favor of this thesis, let us announce the results collected in 1931 by TINKER and GOODENOUGH (The J. Educ. Psych). They wanted to know if a conflict between a spontaneous orientation of the glance from right to left with an education aiming to the acquisition of an opposite orientation would make it possible to interpret the remarks at the dyslexiacs and particularly the aptitude for the reading out of mirror. These authors thus have compels 4 adults 5 months lasting with reading during 10 minutes per day, a text through a mirror. At all these subjects the word is not perceived overall but requires the recourse to a meticulous analysis of the letters and syllables These authors note the importance of the inversions, either complete, or partial, sometimes even on the word order in the sentence. They show moreover a curious impression of inversion not only horizontal but vertical. These errors are found in the dyslexiacs and for them the aggravating circumstance is added inherent in any training. Remained to show that exists well at dylexic intelligent, without auditive anomaly, without delay of language or word, a preference with the orientation right-hand side-left of the glance. The proof was brought from there in 1949 by a researcher in the Service of Pr Clement Launay (Thesis G.MAHEC PARIS 1951). Whereas the adults read more easily and more quickly from left to right a series of letters separated by 5 ms, for the former dyslexiacs, the reading time is hardly different or even better from right to left. Thus let us have a clear explanation of the aptitude for the reading and the writing out of mirror a gestural preference towards the left being added sometimes to the preference of the glance. ==Historique== This notion is introduced by Paul Broca with the XIXe century into this work of localization of the cerebral functions. He discovers in particular “the center of the word” (future surface of broca). In his studies of the Aphasias, one notes for example Nou a glare of shell in the right hemisphere which prevents it from identifying a known object, whereas it can identify each part which constitutes it.

Starting from the same bases, in particular of localization of disorder of the more specific word (surface of Wernicke), Carl Wernicke will establish more thorough assumptions, with a theorization dissociating more the psychic functions of the physique, but still not specifically related to asymmetry.

For rather fuzzy projections, it is thus necessary to await Sperry in the Années 1980 for the great discoveries on the subject thanks to research which was worth a Nobel Prize to him.

Many interpretations even recovery and taken aside will however remain in the spirits and will continue to discredit the subject.

Space distribution

Each hemisphere is connected to the opposite part of the body. I.e. if something touches the left part of your body information will go to the right brain, and if you catch this thing with your right hand, the order comes from the left brain.

The distribution " psychique" cannot be also formal, the more so as it is about dominant function and which there exists always a " coopération" between the two with dimensions ones.

Left brain

One it known as analytical, logical, mathematical, sequential.
It functions preferably starting from the detail, it makes use of it to go towards complexity.
It is the preferential seat of the language, which is there exclusively in the majority of the cases.

One however finds people at whom it less true, is even reversed (in particular in a small portion of the left-handed ).

Right brain

One it known as analogical, empirical, intuitive.
It functions rather on globality, the experiment and the error, the deduction.
It is the preferential seat of the nonverbal communication and image processing

Interest of the cerebral cutting

The space localization cannot be exact, and it can largely vary from one individual to another, but he comes out from it a cutting of functions which allows a psychic distribution either spaciale but with the setting in opposition of two contradictory and complementary forms of intelligence.

This logical opposition finds in cognitive Psychologie. One can in particular show the table drawn up by Daniel Durand in the which I know? on the Systemic . To arrive at this synthesis, it is based on work of Jean Piaget and Herbert Simon. It superimposes on separation intuitive/reasoned (here called blurs and rigorous) separation addition/suppression (named here generalizing and discriminating):

Analytical intelligence

It is exact by nature and is expressed fully in detail, in the abstraction, the indexing. It is the base of the science, which makes it possible to affirm that 1 + 1 = 2. In theory, it cannot be taken at fault, and makes it possible to reach all the levels of complexity per addition. Temptation is strong to compare it to mathematics, but it is also the base of the language. Its larger defect is than it does not support the gaps. See: verbal Thought | Rene Descartes | Boolean algebra (logical) | Reason

Empirical intelligence

It is intuitive and is expressed better in the stepping, the experiment and thus globality. It intervenes more in the physical address, in complex mathematics, or when the language becomes poetic. It makes it possible to solve a problem without having all the bases of them, but is put up badly with the abstraction, because any contribution must be integrated into the unit. One would compare it to the artistic intelligence, or the intelligence of the image. See: visual Thought | Logical fuzzy | Inference | Systemic.

On eggs

Were attached to cerebral asymmetry (wrongly or rightly):

the epilepsy Can be a surplus of communication between the cerebral hemispheres. The method of surgical cure consists in dividing a zone of connection between the hemispheres.

the Migraine which affect a hemisphere independently of the other and sometimes the half associated with the body by causing a Hémiplégie partial or total.
the Autism According to some, rupture total or partial of connections between the hemispheres. (But it is another form of " découpage" who takes the step: problem of connection between perception - stimuli - and the remainder of the cerebral activity).

the Dyslexia Problem of connection between the hemispheres or lateralized gap. Thesis accepted in the case of traumatic dyslexia resulting from a cerebral accident, but not for " the dyslexie" in general.

See too

Works

Lucien Israel, right Brain, left brain , Plon, 1996.

Bonds

Theory of the multiple intelligences

External

the brain
Critical constructive and documented

Random links: