Neurological bases of behavioral development in infancy.

This article presents selected psychological competences that emerge in children during the first 2 years, together with correlated structural, biochemical and physiological changes in the brain. Major behavioral events of the 1st year are the disappearance of the neonatal reflexes, the improvement of recognition and working memory and the appearance of the universal fears of strangers and of separation from the caretaker. These behaviors are correlated in time with changes in the brain that allow the increased ability of the cortex to inhibit brainstem reflexes, with processes in the prefrontal cortex and hippocampus that facilitate the formation, storage and retrieval of memories, and with strengthened connections between the cortex and limbic system.

Neurobiological bases of behavioral development in the second year.

We discuss selected psychological competences that develop and become noticeable between one and two years of age and are temporally correlated to structural, biochemical and physiological changes in the brain. The psychological competences are: Language development, a sense of "right" and "wrong", self-awareness, and the ability to make inferences. The accompanying changes in the brain involve the prefrontal cortex, language-related cortical areas, hippocampus, cerebellum, basal ganglia and an increase in the connectivity of the network.

Neurobiological bases of behavioral development in the first year.

This review summarizes the temporal relations between selected psychological milestones in the first year of the human infant and theoretically relevant developmental neurobiological changes in the brain, supplemented where appropriate, with evidence from the non-human primate. The disappearance of the palmar grasp reflex and the decrease in endogenous smiling and spontaneous crying, which occur at 2-3 months, are correlated to emergent cortical inhibition of brainstem circuits. In addition, the improved ability to recognize an event experienced in the immediate past (recognition memory) is related to growth of the hippocampus and adjacent structures at this age.

Structural and neurobehavioral delay in postnatal brain development of preterm infants.

Postnatal brain development of healthy prematurely born infants was assessed to study possible influence of premature birth and early extrauterine environment on structural, biochemical, and functional brain development. Myelination and differentiation of gray and white matter were studied by in vivo magnetic resonance (MR) imaging (MRI), changes in cerebral metabolism by 1HMR spectroscopy (MRS), and changes in early human neurobehavior by the assessment of preterm infant's behavior (APIB). The stage of intrauterine and extrauterine brain development in prematurely born infants at term was compared with the stage of mainly intrauterine brain development in a group of full-term infants.