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Biomedical subjects

O H Stanley

Publications and source records attributed to O H Stanley.

5 recordsLinked to original sources
PubMed1991

Development of visual evoked potentials following intrauterine growth retardation.

Visual evoked potentials to flash (FVEP) were recorded in 23 symmetrically growth retarded newborns of between 32 and 39 weeks gestational age and 41 normally grown controls. At 9 months post term FVEP recordings were repeated in 14 of the growth retarded and 26 of the control infants. The development of two long latency negative components of the wave form of the neonatal FVEP was delayed in the growth retarded infants. The amplitude of a long latency negative peak in the 9 month post term FVEP was reduced in the growth retarded infants. We suggest that intrauterine growth retardation may affect the development of secondary activity in the visual cortex.

Cerebral Cortex↗
PubMed1991

Cortical development and visual function.

Hypotheses are advanced regarding some of the processes underlying the development of an accurate retinotopic map in striate cortex, and the development of cortical magnification. In the first case it is suggested that competitive pruning of afferent synapses may be important in the increase in grating acuity seen in infancy, and that this process may be disrupted in anisometropic amblyopia. In the second it is argued that the development of vernier acuity in infancy may reflect changes in cortical magnification, and that this may be due to increasing functional independence of the columnar units in striate cortex.

Humans↗
PubMed1989

Abnormal development of visual function following intrauterine growth retardation.

Vernier acuity was measured at 40 weeks post term in 18 infants born with symmetric intrauterine growth retardation (IUGR) and 32 normal (N) infants. Grating acuity was also measured in 12 IUGR and 26 N infants. The mean vernier detection threshold (V.min) was 0.4 octaves higher in the IUGR than in the N infants (P less than 0.04). The mean grating detection threshold (S.min) was 0.2 octaves lower in the IUGR infants (NS). The mean ratio of S.min to V.min was significantly lower in the IUGR infants (1.5 IUGR, 2.7 N, P less than 0.05). V.min was significantly negatively correlated with the head circumference of the IUGR infants at 40 weeks post term. Vernier acuity depends on visual processing at a cortical level. The normal grating acuity in the IUGR infants implies that cortical, rather than optical or retinal factors, underlie the reduced vernier acuity (high V.min). We suggest that the cortical representation of visual space is affected by IUGR.

Female↗
PubMed1987

Developmental wave form analysis of the neonatal flash evoked potential.

A multiple regression technique was used to describe the wave form of the flash evoked potential (VEP) in 64 neonates born between 28 and 39 weeks of gestation. The successive appearance of new features in the VEP with increasing gestational age at birth was used to define 5 components, of which specimens were obtained by averaging VEPs of 18 selected infants. The VEPs of the other 46 infants were expressed as linear sums of the components, each multiplied by a weighting coefficient. The method accounted for 74 +/- 11% (mean +/- 1 S.D.) of the rms power of the observed VEPs and was used to demonstrate significant effects on wave form maturation from fetal growth retardation and maternal smoking in pregnancy.

Electrophysiology↗