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The ability to bind together the contextual details associated with an event undergoes dramatic improvement during childhood. However, few studies have examined the neural correlates of memory binding encoding and retrieval during middle childhood. We examined age‐related encoding and retrieval differences using continuous electroencephalogram (EEG) measures in a sample of 6‐ and 8‐year‐olds. For the memory binding task, children were tested on memory for individual items (i.e., objects and backgrounds only) and combined object–backgrounds pairings (combination condition). Memory for individual item information was comparable across both age groups. However, younger children experienced greater difficulty (i.e., higher false alarm rate) in the combination condition. Theta (4–7 Hz) neuronal oscillations were analyzed to compare memory encoding and retrieval processes. Widespread retrieval‐related increases in theta band EEG power (compared with baseline and encoding‐related activation) were evident in both 6‐ and 8‐year‐olds. Regression analyses revealed that parietal theta EEG power during retrieval accounted for variability in memory binding performance. These findings suggest that theta rhythms are intricately linked to memory binding processes during middle childhood. [ABSTRACT FROM AUTHOR]

Physiological stress systems and the brain rapidly develop through infancy. While the roles of caregiving and environmental factors have been studied, implications of maternal physiological stress are unclear. We assessed maternal and infant diurnal cortisol when infants were 6 and 12 months. We measured 12-month infant electroencephalography (EEG) 6-9 Hz power during a social interaction. Steeper 6-month maternal slope predicted steeper 12-month infant slope controlling for 6-month infant slope and breastfeeding. Steeper 6-month maternal slope predicted lower 6-9 Hz power. Six-month maternal area under the cuve (AUCg) was unrelated to 12-month infant AUCg and 6-9 Hz power. Psychosocial, caregiving, and breastfeeding variables did not explain results. At 6 months, maternal and infant slopes correlated, as did maternal and infant AUCg. Twelve-month maternal and infant cortisol were unrelated. Results indicate maternal slope is an informative predictor of infant physiology and suggest the importance of maternal physiological stress in this developmental period. [ABSTRACT FROM AUTHOR]

A novel quantitative method for coding epochs of active and quiet sleep in infants using respiration is reported. The approach uses the variance of the instantaneous breathing rate within brief epochs of sleep. Variances are normalized within subject by dividing by the 75th percentile variance across epochs. Then, a normalized variance active sleep threshold of 0.29 was determined to produce the highest concordance with a method based on visual inspection of respiratory variability (100% and 90% for quiet and active sleep, respectively). The method was independently validated by comparing to standard polysomnographic state coding (87% and 80% concordance for quiet and active sleep) as well as with behavioral state coding (92% and 78% for quiet and active sleep). Validity was also demonstrated by showing that sleep states identified by the method resulted in the expected state differences in infant heart rate variability and electrocortical activity. [ABSTRACT FROM AUTHOR]