Maturation of the central nervous system (CNS) is reflected in fetal behavior. Modern technology, such as four-dimensional (4D) sonography improved assessment of fetal behavior in all three trimesters of pregnancy. After summing our own experiences and experiences of the leading authors in the field of fetal and neonatal neurology, new prenatal screening test for assessment of fetal behavior has been suggested. Test was named Kurjak antenatal neurodevelopmental test (KANET). Up to now results of KANET are encouraging and they have been published in several prominent journals. Nevertheless, potential of KANET in the assessment of integrity of the fetal central nervous system needs to be confirmed by studies that are in progress in several world university centers.Keywords: Fetal brain development, Four-dimensional ultrasound, Neurological deficit, Perinatal neurological assessment.
PRENATAL MORPHOLOGICAL AND FUNCTIONAL DEVELOPMENT OF THE FETAL CENTRAL NERVOUS SYSTEMDevelopment of the human central nervous system (CNS) begins in the early embryonic period and proceeds through a sequence of very complicated processes long after delivery. Early embryonic development is characterized by its immobility. Important prerequisite for fetal movements is the existence of the interneuronal and neuromuscular connections. The earliest interneuronal connections, the synapses, can be detected in the spinal cord shortly before the onset of embryonic motility, at 6 to 7 weeks of gestation.1 Therefore, the neural activity leading to the first detectable movements is considered to originate from the spinal motoneurons.2 As mentioned, another important prerequisite for the motility is the development and innervation of muscle fibers. It is well known that primitive muscle fibers (myotubes) are able to contract as soon as they are innervated by motor neurons.3 Between 6 and 8 weeks of gestation, muscle fibers have formed by fusion of myoblasts, efferent and afferent neuromuscular connections have developed, and spontaneous neural activity causing motility can begin. The first spontaneous embryonic movements are gross body movements and they can be observed at the 7 to 7.5th week of gestation. They consist of slow flexion and extension of the fetal trunk, accompanied by the passive displacement of arms and legs. These so-called vermicular movements appear in irregular sequences. Simultaneously with the onset of spontaneous movements, at the 7.5th week of gestation, the earliest motor reflex activity can be observed, indicating the existence of the first afferentefferent circuits in the spinal cord. The first reflex movements are massive and indicate a limited number of synapses in a reflex pathway. General movements are the first complex, wellorganized movement pattern, which involve head, trunk and limb movements. This pattern has been interpreted as the first sign of a supraspinal control on motor activity and can be recognized from 8 to 9 weeks of gestation onwards. 4 The brainstem is fashioned around the 7th week of gestati...