The Corpus Callosum is the largest commissure, which facilitates communication between the right and left hemispheres of the brain. The views on the value of the Corpus Callosum are varied: from the most "useless" to those defining the higher cognitive functions of human brain structure. According to modern concept, the role of Corpus Callosum is not limited to the transfer of information. This commissure enables meta-control of the information in both hemispheres, as one of them must establish the function of its processing (Banich, 1995). Corpus Callosum not only transmits sensory information, ensuring its double representation in every hemisphere, but it reveals the consistency of the information received, therefore its agenesis can have very grave consequences (Ottoson, 1987).
Of particular interest is the dependence of human behavior on the quality of hemispheric interaction, mediated primarily by Corpus Callosum. G. O’Brien, in the test of the hypothesis of the absence of any behavioral disorders in case of Corpus Callosum pathology, examined 47 children and described their behavior (O’Brien, 1994). Parents of children with Agenesis of the Corpus Callosum reported poor social skills of their children and a poor ability to understand the essence of the situation, which particularly affects their daily lives (Brown and Paul, 2000), (O’Brien, 1994), (Stickles, Schilmoeller, and Schilmoeller, 2002). This was expressed in an emotional immaturity and poor emotional communication, a lack of social skills, planning deficiencies. For example, the participants of the study preferred much younger friends, had difficulties in initiating conversations and maintaining it, understood everything literally, could not get the point of view of another person, were not able to effectively plan and carry out their daily activities such as housework, taking a shower, the payment of bills and so on (Stickles, Schilmoeller and Schilmoeller, 2002). As a result, the study revealed impoverished and superficial social relations, conflicts at home and at work due to errors in the interpretation of the communicative information. In general, there was a social and emotional isolation, leading to a depletion of self-understanding. In a study of people with normal intelligence, who nonetheless suffer from Agenesis of the Corpus Callosum, their performance in tests of reasoning and concept formation was worse than what was expected based on the index of their IQ test (Brown and Paul, 2000). It was evident that the illness has led to a significant reduction of their performance in social understanding, interpretation of proverbs, social logic, self-perception and interpretation of ambiguous stimuli, behavioral abnormalities or even psychopathology.
Scholars have concluded that the poor hemispheric integration of composite material leads to disturbances in social cognition, manifesting itself in short supply of complex cognitive operations (concept formation, definition, reasoning, problem-solving). For people with this disease, it is difficult to imagine the chain of events, scenes and understand the meaning of a specific thought, no easier is it to express an idea themselves. Upon presentation of provocative social themes (pictures with distortion), these patients misunderstood emotional valence, and the emotional intensity of the images, especially negatively stained.
Evaluation of their social behavior demonstrated that 44% of children cannot, and 42.5% can interact with strangers. They are not prone to the appearance of shyness or psychological defenses (47.5%). On the other hand, only 21.8% can effectively communicate with their peers in the group, for the rest, it is easier to interact with adults or with children of a younger age. 21.5% of the children demonstrated aggressive behavior, 25.4% had frequent temper tantrums, 16.6% deliberately spoiled things. In some cases, scholars observed emotional insensitivity (17.4%), mood swings (22, 0%), or inappropriate expression of emotions (11.7%) (Doherty et al., 2006), (Stickles, Schilmoeller, and Schilmoeller, 2002). In general, children with Agenesis of the Corpus Callosum were evaluated as happy, outgoing, but having problems in social contact with peers as well as anger issues. This though is directly related to the nervous system (Banich, 1995).
The main and specific function of the central nervous system (CNS) is the implementation of simple and complex highly differentiated reflective responses, called reflexes. The lower and middle section of the central nervous system – the spinal cord, the medulla oblongata, the midbrain and cerebellum – regulate the activity of individual organs and systems of the highly developed organism, facilitate communication and interaction between them, provide the unity of the body and the integrity of its operations (Banich, 1995). The upper section part of the CNS – the cortex of the cerebral hemispheres and immediate subcortical structures – mainly regulate communication and relationships of the organism as a whole with the environment (Banich, 1995).
The peripheral nervous system (PNS) is basically a link between the CNS and sensory organs. It consists of nerves which are formed by the motor, sensory and vegetative fibers. Motor fibers are long processes (axons) of neurons, the body of which are in the spinal cord and in parts of the brain, which they then follow to the striated muscle fibers of the body (Banich, 1995). Sensory fibers are processes of the homonymous neurons whose bodies are arranged in the form of clusters (sensitive nodes) in close proximity to the nerves of the CNS, they carry the information to the centers of the brain and spinal cord. Vegetative fibers come out of the CNS and, subsequently leaving the main nerve trunks, through the autonomic system nodes regulate the function of internal organs (Banich, 1995). Such relationship of the PNS and the CNS is evidence enough about their functional and structural unity.
Reference
Banich M.T. (1995). “Interhemispheric interaction: Mechanisms of unified processing.” In Kitterle F.L. (ed.) Hemispheric communication: Mechanisms and models. Hillsdale: Laurence Erlbaum, pp. 271–300.
Brown W.S., and Paul L.K. (2000). “Cognitive and psychosocial deficits in agenesis of the corpus callosum with normal intelligence.” Cognit. Neuropsychiatry. Vol. 5(2). pp. 135–157.
Doherty D., Tu S., Schilmoeller K. and Schilmoelle G. (2006). “Health-related issues in individuals with agenesis of the corpus callosum.” Child: Care, Health and Development. Vol.3(3). pp. 333–342.
O’Brien G. (1994). “The behavioral and developmental consequences of agenesis of the corpus callosum.” In Lassonde M., Jeeves M.A. (eds). Callosal agenesis: A natural split brain? L.: Plenum Press, pp. 235–246.
Ottoson, D. (1987). Duality and Unity of the Brain : Unified Functioning and Specialisation of the Hemispheres. Boston, MA: Springer US.
Stickles J.L., Schilmoeller G.L., Schilmoeller K.J. (2002). “A 23year review of communication development in an individual with agenesis of the corpus callosum.” Intern. J. Disability, Devel. and Educat. Vol. 9. pp. 367–383.
