Large-scale sprouting of cortical connections after peripheral injury in adult macaque monkeys.

Distributions of thalamic and cortical connections were investigated in four macaque monkeys with long-standing, accidental trauma to a forelimb, to determine whether the growth of new connections plays a role in the reorganization of somatosensory cortex that occurs after major alterations in peripheral somatosensory inputs. In each monkey, microelectrode recordings of cortical areas 3b and 1 demonstrated massive reorganizations of the cortex related to the affected limb. Injections of tracers in area 1 of these monkeys revealed normal patterns of thalamocortical connections, but markedly expanded lateral connections in areas 3b and 1. Thus, the growth of intracortical but not thalamocortical connections could account for much of the reorganization of the sensory maps in cortex.

The effects of prenatal and perinatal complications on development at one year of age.

35 variables descriptive of birth and obstetric complications, prematurity, maternal discomfort, and demographic status were studied for a sample of 322 infants. Factor analyses of these variables resulted in 7 major factors that were used to predict developmental status at 1 year of age for 233 of the subjects. Factors identified as "prematurity," "delivery and related variables," "ethnicity," and "complications" made significant independent contributions to Cattell DQ at 1 year. When Cattell DQs were corrected for the effects of gestational age, only delivery and related variables remained critical, confirming the importance of this factor for later development.

Toward a modification of the indices of neonatal prematurity.

In a study of 233 infants, traditional indices of neonatal prematurity were excessively high for predicting developmental lag at 1 yr., and alternative cut-off scores were suggested. Prematurity indices were especially important for infants with below-average development.