Fetal eye movements in response to a visual stimulus

INTRODUCTION

In 2D ultrasound, the lens of the fetal eye can be distinguished as white circles within the hypoechoic eyeball, and eye movements can be visualized from about 15 weeks' gestation. It has been shown that from 31 weeks gestational age the fetal sensory system is capable of directed vision if enough light is available.

METHODS

We have developed a light source for delivering visual stimuli to be seen by the fetal eye, using laser dot diodes emitting at 650 nm. The 2D component of 94 fetal ultrasound scans (mean gestational age 240 days), where the light stimulus was presented, was coded to determine whether the eyes moved in response to the stimuli independent of any head movement.

RESULTS

The light stimulus significantly provoked head and eye movements, but after the light was withdrawn the head stopped moving, yet the eyes continued to move.

CONCLUSION

This provides evidence for visual attention mechanisms that can be controlled through eye movements that are independent of head movements prior to birth.

Clinical study of fetal neurobehavior by the KANET test

Fetal neurology is evolving as an area of great interest in prenatal diagnosis and fetal medicine. The identification and diagnosis of brain damage prenatally has been a great challenge in obstetrics for many years. Investigations of fetal behavior in comparison with morphological studies led to the conclusion that fetal behavioral patterns directly reflect developmental and maturational processes of the fetal central nervous system (CNS). Four-dimensional (4D) ultrasound has greatly improved the assessment of the quality of the fetal spontaneous movements, and enabled a better evaluation of fetal behavior. The assessment of normal neurobehavioral development by 4D ultrasound provided the opportunity to investigate functional characteristics of the fetus that could predict neurological developmental dysfunction. Some studies have already been carried out to evaluate this new methodology in the observation of fetal behavior during different stages of gestation, in an attempt to better understand the relationships between the maturation of the CNS of the fetus and its implications on its behavior pattern. We present a review of literature on fetal behavior by 4D ultrasound.

Antenatal and Postnatal Assessment of Neurobehavior: Which One should be used?

It is obvious that this environment is quite different from one man is experiencing after birth, but, although different, intrauterine environment is ideal at that stage of human development. There is a question of the environmental discontinuity between intrauterine conditions characterized by existence of microgravity (baby astronaut hypothesis), and extrauterine life with gravity as developmental condition sine qua non. The human brain is one of the organs which is very sensitive to environmental changes affecting its growth and development. The brain of very tiny prematurely born babies is unable to follow the genetically determined growth pattern in extrauterine environment, even when postnatal nutrition and nurturing of the babies according to our best knowledge are appropriate. Is this fact of any significance to make distinction between normal and abnormal neurodevelopment pre- and postnatally is still unclear?

Kurjak antenatal neurodevelopmental test (KANET) using four-dimensional ultrasound (4D US) has been introduced using ten parameters and after attempt of standardization only eight parameters remained for neurodevelopmental assessment of low- and high-risk fetuses. We believe that at present level of knowledge, KANET test could be considered as a good test for the detection of fetuses with high neurological risk, without the possibility to define reliable long-term neurodevelopmental outcome. This is also hardly possible based on postnatal neurological assessment with 27 different postnatal tests. They were primarily neurobehavioral or neuromotor assessments that were suitable for use with preterm infants, and were discriminative, predictive or evaluative.

There was a high willingness of clinician to find postnatal neurodevelopmental test which could be predictive for short- term and long-term outcome of low and high-risk infants.

Although, there are many tests available for prenatal and postnatal assessment of neurodevelopment, none of them is reliable in the prediction of neurodevelopmental outcome in low-risk population, while many could be used with fairly acceptable predictivity in high-risk population. Although, many studies have been conducted in order to solve this problem, still there is a space for improvement. In postnatal period we are dealing with infant in front of the clinician with direct observation, while pretnatally we are dealing with quite different environment and less mature brain.

How to cite this article

Stanojevic M. Antenatal and Postnatal Assessment of Neurobehavior: Which One should be used? Donald School J Ultrasound Obstet Gynecol 2015;9(1):67-74.

First Experience in Clinical Application of KANET

Introduction of three- and four-dimensional ultrasound into clinical practice enabled qualitative and quantitative assessment of fetal movements, including the analysis of fetal face expression which is considered to be the mirror of the maturational processes of upper motor neuron. Since, prenatal fetal behavioral patterns are reflections of developmental and maturational processes within the fetal central nervous system, the findings about changes in fetal movements and behavior could leed to the prenatal diagnosis of neurological impairment. Kurjak's antenatal neurodevelopment test (KANET) is the first prenatal test based on the three- and four-dimensional ultrasound examination of the fetus that could be used for the evaluation and prediction of the fetal neurologic status.

How to cite this article

Luetic AT. First Experience in Clinical Application of KANET. Donald School J Ultrasound Obstet Gynecol 2015;9(1):96-99.

Fetal Neurology: Past, Present and Future

Neurological failure is the most apprehension complication of pregnancy, labor and the neonatal period. The origin and outcome correlation is frequently doubtful. The arrival of four-dimensional ultrasonography (4D US) and its function to study fetal behavior patterns have initiated to offer insight into the structural and functional fetal brain development. Although many fetal behavioral studies have been conducted, it is still questionable whether the assessment of continuity from fetal to neonatal behavior could improve our ability of early detection of brain pathology. Neurological assessment of fetus in utero is extremely difficult even having such sophisticated equipment like 4D ultrasound. As it is well known that quantity of GMs is not so informative and predictive for neurological impairment, their quality should be assessed. Gestalt perception of premature GMs we are dealing with in utero and several weeks postnatally are not as predictive for the detection of neurologically abnormal fetuses or newborns as fidgety GMs. Therefore, some additional parameters should be added to the prenatal neurological examination in order to improve our ability to make the distinction between normal and abnormal fetuses.

How to cite this article

Kurjak A, Antsaklis P, Stanojevic M. Fetal Neurology: Past, Present and Future. Donald School J Ultrasound Obstet Gynecol 2015;9(1):6-29.

Recent Results of the Clinical Application of Kanet Test

Many investigations led to the conclusion that fetal behavioral patterns directly reflect developmental and maturational processes of fetal central nervous system (CNS), and may make possible to distinguish between normal and abnormal brain development as well as prenatal diagnosis of neurological impairment. The arrival of three- and four-dimensional ultrasound (3D/4D US) made possible to study fetal behavioral patterns. Kurjak's antenatal neurodevelopmental test (KANET) is the first prenatal test based on 3D/4D ultrasound examination of the fetus, that could be used for the evaluation and prediction of fetal neurological status. Here, we present our review of literature on KANET around the world and summarized results of this promising prenatal neurological screening test.

How to cite this article

Neto RM, Kurjak A. Recent Results of the Clinical Application of Kanet Test. Donald School J Ultrasound Obstet Gynecol 2015;9(4):420-425.

Modeling the minimal newborn's intersubjective mind: the visuotopic-somatotopic alignment hypothesis in the superior colliculus

The question whether newborns possess inborn social skills is a long debate in developmental psychology. Fetal behavioral and anatomical observations show evidences for the control of eye movements and facial behaviors during the third trimester of pregnancy whereas specific sub-cortical areas, like the superior colliculus (SC) and the striatum appear to be functionally mature to support these behaviors. These observations suggest that the newborn is potentially mature for developing minimal social skills. In this manuscript, we propose that the mechanism of sensory alignment observed in SC is particularly important for enabling the social skills observed at birth such as facial preference and facial mimicry. In a computational simulation of the maturing superior colliculus connected to a simulated facial tissue of a fetus, we model how the incoming tactile information is used to direct visual attention toward faces. We suggest that the unisensory superficial visual layer (eye-centered) and the deep somatopic layer (face-centered) in SC are combined into an intermediate layer for visuo-tactile integration and that multimodal alignment in this third layer allows newborns to have a sensitivity to configuration of eyes and mouth. We show that the visual and tactile maps align through a Hebbian learning stage and and strengthen their synaptic links from each other into the intermediate layer. It results that the global network produces some emergent properties such as sensitivity toward the spatial configuration of face-like patterns and the detection of eyes and mouth movement.