A Typical Feeding Enhances Memory for Spoken Words in Healthy 2- to 3-Day-Old Newborns

Abstract

OBJECTIVE. The objective of this study was to determine whether healthy 2-to 3-day-old newborns have better memory of a spoken word after a typical feeding (breast milk or formula) than before a feeding and, if so, whether memory is related to blood glucose. METHODS.A naturalistic study was conducted in which delayed recognition memory of a spoken word was examined in 60 healthy 2-to 3-day-old newborns either 120 minutes after their previous feeding (preprandial) or 30 minutes after their last feeding (postprandial). In this procedure, infants initially turn their head toward a novel word (orientation) and with repeated presentations cease turning toward it (habituation). Mean number of trials to reach orientation and habituation criteria provides measures of attention and rate of learning, respectively. After a 100-second delay, the word is presented again. Infants either turn toward it, indicating that they have forgotten it, or remain habituated, indicating that they remembered the word. Percentage of trials with head turns toward the word after the delay is the principal dependent measure.RESULTS. The postprandial group was split at the median for blood glucose to define high-and low-glucose groups. All 3 groups showed similar rates of orientation and habituation. On reexposure to the word during postdelay trials, the preprandial group displayed less retention than the postprandial high and low groups. No correlation was found between memory and blood glucose levels. The postprandial high blood glucose level differed statistically from the preprandial level, whereas the postprandial low level did not.CONCLUSIONS. Memory for spoken words in newborns is better after a typical milk feeding than before a feeding. This feeding effect is specific to memory and does not include attention or rate of learning. Also, it is not necessarily associated with increased blood glucose. It remains to be seen whether feeding enhances memory for other types of stimuli and what implications this may have for development. T HE INTAKE OF food affects memory in both wellnourished human and non-human animals across different ages. In adult and preweanling infant rats, subcutaneous injections of the carbohydrate glucose (versus saline) enhance memory storage and retrieval. [1][2][3] In humans, ingestion of a glucose drink, compared with placebo, improves declarative verbal memory as well as storage and retrieval processes in healthy young adults, 4 the elderly, 5,6 and populations that are known to exhibit memory deficits, such as patients with mild Alzheimer's disease. 7,8 This may explain why eating breakfast as opposed to missing breakfast leads to improved performance on memory and learning tasks in well-nourished school-aged children and university students. 9 Altogether, these data suggest an important role of nutrient intake on memory across different ages and raise the question of whether fluctuations in memory with acute nutritional intake are present from birth.We recently assessed whether ingestion of a glucose sol...

Memory in the Neonate Brain

“…Exposure for over half an hour -or over two hundred repetitions of the words- was used in previous studies looking at memory in newborns [12], [13]. The familiarization phase of our experiment was much shorter (six minutes in total, including more than four minutes of silent pauses) and with fewer instances of the familiarization word, providing evidence that newborns do not require protracted experience to remember a word.…”

“…In laboratory studies, newborns can retain the sounds of words [12], [13], but there is no evidence in the literature showing that infants younger than 4 months of age can remember words from their surrounding language. In this work, we found hemodynamic responses correlated with word recognition in the neonate brain.…”

“…However, it is unlikely that fetuses remember details about the sound forms of words (hereafter referred to as word or words ), because the properties of the uterus render many phonemic differences imperceptible [11]. There is some evidence that newborns retain a word over a brief delay [12], and even over a day [13], but it is not clear how newborns succeeded in these experiments given that no other study has demonstrated that infants remember common words from the surrounding language before four months of age [14].…”

On the edge of language acquisition: inherent constraints on encoding multisyllabic sequences in the neonate brain

“…Hurlstone et al ., ), less research has investigated how sequential information is encoded early in development and whether there are constraints on sequential processing in infancy that might influence early language acquisition. Existing research on early memory capabilities suggests that newborns are capable of remembering the rhythmic patterns of stories the mother read out loud during the last trimester of pregnancy (DeCasper & Spence, ), or short bisyllabic words they heard shortly after birth (Benavides‐Varela, Gómez, Macagno, Bion, Peretz et al ., ; Valiante, Barr, Zelazo, Papageorgiou & Young, ). These findings suggest that humans are born with the ability to extract and remember information that is potentially useful for language acquisition.…”

Brain regions and functional interactions supporting early word recognition in the face of input variability

“…Developmental studies in the language domain have uncovered basic perceptual (4-6), discrimination (7,8), and mnemonic capacities (9)(10)(11)(12)(13)(14) in newborns and fetuses, supporting the hypothesis that memories for sounds begin to be established very early in life. However, infants' memory for specific words seems to be highly vulnerable to interference.…”