Showing papers on "Developmental plasticity published in 1982"

The role of attention in developmental plasticity.

Abstract: The development of suppression amblyopia in strabismic humans suggests that experience-dependent maturation of sensory functions is gated by attentional mechanisms. Evidence from animal experiments is in favour of this interpretation. Retinal signals support the development of normal receptive fields in the visual cortex of kittens only when the kittens are alert and attend to these signals. Lesion and stimulation studies in kittens suggest that ascending projections from the mesencephalic reticular formation and from the medial thalamic nuclei contribute to the gating of developmental plasticity. It is proposed that this gating is achieved through modulatory control of dendritic depolarization. Disfacilitation of those cortical neurones, which relay activity from the deviated eye could thus effectively block experience-dependent modifications in the respective circuits and lead to the amblyopic deficits.

Neural plasticity: Part 2. Postnatal maturation and function-induced plasticity.

Abstract: At birth, the central nervous system has completed most of its early stages of cell division, migration, and specialization. Much of the neural circuitry has been laid down. Neuroblasts are continuing to divide only in limited brain regions. Hence, at birth, most mammals have a nearly full complement of neurons. Nonetheless, the functional capabilities of the central nervous system of the newborn have little resemblance to those of the adult. Postnatal maturation must proceed in the proper sequence and at the proper rate if central nervous system deficits in the adult are to be avoided. Many of the prenatal maturational phenomena described in the previous paper continue well into the postnatal period. The purpose of this paper is to describe some postnatal maturational mechanisms and to show, by selected examples, the important role that function and experience play in central nervous system development.

Neural Plasticity Part 1. Plasticity in the Developing Nervous System: Prenatal Maturation

Abstract: The origin and development of the nervous system is a gradual process of cell division, migration, and specialization. The establishment of neural circuits requires cell-to-cell recognition. Despite an unceasing search, the mechanisms accounting for this cell-to-cell recognition remain unknown. In contrast, the stages in prenatal development from conception to birth and the sequence of events in the formation of the nervous system are known in considerable detail. The major purpose of Part 1 is to review the ontogeny of the spinal nervous system, with emphasis on the continuous remodeling phenomena that occur as a result of changes in neuronal activity or in the biochemical milieu. The underlying rationale for focusing on the details of prenatal maturation is to identify and analyze cell-to-cell interactions and to define their critical periods. This type of information is expected to provide explanations for previously unexplained developmental phenomena, to improve ability to diagnose and prognosticate in newborns with congenital anomalies of the nervous system, and to provide therapists with insights for improving treatment techniques for neonates with neurological deficits.