Family Nurture Intervention in preterm infants alters frontal cortical functional connectivity assessed by EEG coherence.

AIM: To assess the impact of Family Nurture Intervention (FNI) on cortical function in preterm infants at term age. METHODS: Family Nurture Intervention is a NICU-based intervention designed to establish emotional connection between mothers and preterm infants. Infants born at 26-34 weeks postmenstrual age (PMA) were divided into two groups, standard care (SC, N = 49) and FNI (FNI, N = 56). Infants had EEG recordings of ~one hour duration with 124 lead nets between 37 and 44 weeks PMA. Coherence was measured between all pairs of electrodes in ten frequency bands. Data were summarised both within and between 12 regions during two sleep states (active, quiet). RESULTS: Coherence levels were negatively correlated with PMA age in both groups. As compared to SC infants, FNI infants showed significantly lower levels of EEG coherence (1-18 Hz) largely within and between frontal regions. CONCLUSION: Coherence in FNI infants was decreased in regions where we previously found robust increases in EEG power. As coherence decreases with age, results suggest that FNI may accelerate brain maturation particularly in frontal brain regions, which have been shown in research by others to be involved in regulation of attention, cognition and emotion regulation; domains deficient in preterm infants.

Developmental profiles of infant EEG: overlap with transient cortical circuits.

OBJECTIVE: To quantify spectral power in frequency specific bands and commonly observed types of bursting activities in the EEG during early human development. METHODS: An extensive archive of EEG data from human infants from 35 to 52 weeks postmenstrual age obtained in a prior multi-center study was analyzed using power spectrum analyses and a high frequency burst detection algorithm. RESULTS: Low frequency power increased with age; however, high frequency power decreased from 35 to 45 weeks. This unexpected decrease was largely attributable to a rapid decline in the number of high frequency bursts. CONCLUSIONS: The decline in high frequency bursting activity overlaps with a developmental shift in GABA's actions on neurons from depolarizing to hyperpolarizing and the dissolution of the gap junction circuitry of the cortical subplate. SIGNIFICANCE: We postulate that quantitative characterization of features of the EEG unique to early development provide indices for tracking changes in specific neurophysiologic mechanisms that are critical for normal development of brain function.

Reduced functional connectivity in visual evoked potentials in children with autism spectrum disorder.

OBJECTIVE: An analysis of EEG synchrony between homologous early visual areas tested the hypothesis that interhemispheric functional connectivity during visual stimulation is reduced in children with autism compared to controls. METHODS: EEG power and coherence within and between two homologous regions of the occipital cortex were measured during long latency flash visual evoked potentials. Measures were compared between two groups of children (5.5-8.5years), one with autism spectrum disorders and the other with typical development. RESULTS: In and below the theta band, interhemispheric synchrony was reduced in autistic subjects compared to typical controls by as much as 50%. Above the theta band interhemispheric synchrony in autistic children became indistinguishable from what would occur for uncorrelated cortical activity. Interhemispheric synchrony in autistic subjects was decreased in spite of bilaterally increased power. Wavelet power showed autistic children had a more rapid initial response to stimulation, a slower recovery, and more modulation at longer latencies. CONCLUSIONS: Results suggest that the sensory cortices of autistic children are hypersensitive to stimulation with concurrent diminished functional connectivity between hemispheres. SIGNIFICANCE: Simultaneously increased intrahemispheric power and decreased interhemispheric synchronization of elementalvisual information suggests either that power increases cause poor interhemispheric connectivity or that processes, such as thalamocortical regulation, impact power and coherence independently.

Dietary requirements of subjects exposed to hyperbaric He-O2 conditions: effects of various levels of vitamin supplementation.

A 24-d growth study was conducted on rats exposed to ambient air, 11 ATA He-O2, or 21 ATA He-O2 conditions. The rats were fed either a standard diet or the standard diet supplemented with 25, 50, or 100% increase of all vitamins, or the last with an additional 50 or 100% increase of casein. Fat, as cod liver oil was increased 0.5, 1.0, or 2.0% of the diet as the vitamins were increased. The vitamin and fat-supplemented diets, with or without supplemental casein, were adequate to support normal growth of the rats exposed to 11 ATA but not 21 ATA He-O2 conditions. Urine excretion and water consumption were closely related and varied in accordance with the adequacy of the diet. Feed digestibility was not a limiting factor in determining the growth of the rats under the three environments. The composition of the rat carcasses varied minimally.

Dietary requirements of subjects exposed to hyperbaric He-O2 conditions: effects of supplementation with major nutrient groups.

A 4-week growth study was conducted to determine whether changes in the type of diet could adequately compensate for the increased demands made upon the body by the stresses associated with exposure to hyperbaric He-O2 conditions. A normal rat diet (Hegsted-Chang) was used as a standard diet. This diet was also modified by increasing the fat content 25%, mineral mixture 25%, casein 50%, or all vitamins (including cod liver oil) 50%, or by decreasing the casein portion 10% from the standard levels. The corn starch portion was adjusted appropriately to maintain isocaloric properties of the various test diets. Male Sprague-Dawley rats served as the experimental subjects and were exposed to 1 ATA room air, 11 ATA He-O2, or 21 ATA He-O2 environmental conditions. The rats fed fat-supplemented diets grew as well under 11 ATA He-O2--but not under 21 ATA He-O2 conditions--as those fed the standard diet and exposed to 1 ATA room-air conditions. The rats fed protein-supplemented diets grew as well under both hyperbaric conditions as the control rats. Although the rat growth under the hyperbaric conditions equaled that under control conditions, it was less efficient because more food was required to produce each 1 g of gain. Significant differences were also observed in the apparent digestibilities of the various diets and in the protein, fat, and mineral contents of the carcasses.