الفهرس 
ACKNOWLEDGMENTOnly 14 pages are availabe for public view
 |  | from | 194 |  |  |
| | | from | 194 | | |
Abstract
Brain asymmetry has been observed in humans and animals structurally, functionally, and histologically. This lateralization is thought to originate from hereditary, developmental, hormonal, genetic, experiential and pathological factors. The most prominent observations of structural brain asymmetry are protrusions of the right frontal and left occipital lobes leaving an inner impression in the skull, which is known as petalias. The associated extension of these lobes across the inter-hemispheric midline referred to as the Yakovlevian anticlockwise torque. At its posterior limit, the right Sylvian fissure curves upward more anteriorly than the left, and the left has a gentler slope. PT shows marked leftward volume asymmetry, whereas PP shows rightward areal asymmetry. Broca’s speech area (in the left frontal lobe) is also larger in volume than its homolog in the right hemisphere. Asymmetry in the sulci of the brain was reported including an increase in the depth of the CS in dominant hemisphere and increase in surface area of parieto-occipital fissure in the right hemisphere. The paracingulate sulcus occurred more frequently in the left hemisphere. The white matter fibres as uncinate fasciculi, cingulate fasciculi and subinsular white matter show left greater than right anisotropy. Deep nucli such as hippocampus, amygdaliod nuclus and globus pallidus show rightward asymmetry. However, there is little normative asymmetry in the thalamus and other basal ganglia structures. There are significant rightward asymmetries in most cerebellar lobules and leftward asymmetries in the medial parts of cerebellar posterior lobe. Dextral humans has greater cerebellar torque (right anterior, left posterior lobe of the cerebellum) than non dextral. The two cerebral hemispheres are different functionally. The left hemisphere is known to be specialized in linguistic, analytic, mathematical and sequential processing, whereas the right hemisphere is superior in processing emotional and musical functions as well as non-verbal and holistic information.