Dyscalculia The human brain appears fairly symmetrical anatomically between the left and right hemisphere and many basic sensory and motor. functions in the brain are distributed symmetrically. Homologous regions of cerebral coex on either side of the brain are connected to each other long association ,fibres carried by the corpus collosum. For some unknown reasons, however there are marked asvmmetry in several brain functions. The most obvious asymmetry in the cerebral function is the language. In most individuals the language function depends predominantly on the left hemisphere. The left hemisphere is dominant for the language in over 95% of right handers and in over 60-70% of left handers therefore it is called the dominant hemisphere. The core structures associated with language situated in the left hemisphere are Wernicke's areaQ and Broca's area. Other impoant .functions associated with the dominant hemispheredeg (left) are detailed analytical abilities and complex motor planning activities (praxias) The right hemisphere is the non dominant hemisphere of the brain as it does not play dominant role in language. The non-dominant hemisphere is specialized .for ceain nonverbal function and appears to be generally, more impoant for complex visual spatial skills, for impaing emotional significance to events and for music perception. However now the concept of cerebral dominance and a dominant and non-dominant hemisphere has been replaced by a concept of complementary specialization of the hemispheres. Because the hemisphere that is not concerned with language is not simply less developed or "non-dominant" instead, it is specialized in the area of spatiotemporal relations. It is this hemisphere that is concerned, for example with the identification of objects by their form and the recognition of musical themes. It also plays a primary role in the recognition of faces. So, the cerebral hemispheres are now divided by the concept of :- Categorical hemisphere Representational hemisphere Lesions in: Categorical hemisphere - Representational hemisphere --a One .for sequential analytical process and language One .for visuospatial relations Produce language clisorderQ AstereognosisQ, AgnosiaQ The language disorder produced due to lesion in the categorical hemisphere depends upon the areas involved in the categorical hemisphere Wernicke's aphasia - Empty meaningless' and full of nonsensical paraphasic errors (&t of Wernicke 's area) Normal fluency Broca 'saphasia -4 Decreased Fluency and spared comprehension, (d/t Broca's area) Function of left Functions of the right hemisphere (categorical) hemisphere (representative) . Right handed control . Visuospatial orientation Spoken language . Left hand control . Written language . Music awareness Mathematical skills . Three dimensional awareness Scientific skills . A awareness . Reasoning .Insight . Imagination Symptoms of the catego Symptom's in the representation rial or left hemisphere hemisphere (right hemisphere) - Aphasia - Astereognosis (inability to - Dyscalculia recognize objects by feeling them) - Agnosias - Unilateral inattention and neglect - Patient unconcerned and euphoric - Anosgnosia - Dysgraphia or agraphia