Memory in the neonate brain.

Silvia Benavides-Varela,Jacques Mehler,David M Gómez,Isabelle Peretz,Ricardo A H Bion,Francesco Macagno,Christine Jasoni

doi:10.1371/journal.pone.0027497

Abstract

BackgroundThe capacity to memorize speech sounds is crucial for language acquisition. Newborn human infants can discriminate phonetic contrasts and extract rhythm, prosodic information, and simple regularities from speech. Yet, there is scarce evidence that infants can recognize common words from the surrounding language before four months of age.Methodology/Principal FindingsWe studied one hundred and twelve 1-5 day-old infants, using functional near-infrared spectroscopy (fNIRS). We found that newborns tested with a novel bisyllabic word show greater hemodynamic brain response than newborns tested with a familiar bisyllabic word. We showed that newborns recognize the familiar word after two minutes of silence or after hearing music, but not after hearing a different word.Conclusions/SignificanceThe data show that retroactive interference is an important cause of forgetting in the early stages of language acquisition. Moreover, because neonates forget words in the presence of some –but not all– sounds, the results indicate that the interference phenomenon that causes forgetting is selective.

Highlights

After birth, infants are surrounded by a myriad of new sounds
While previous studies on memory in newborns relied on behavioral responses, we looked at brain responses instead. functional near-infrared spectroscopy (fNIRS) is a non-invasive brain imaging technique that measures hemodynamic responses in the cerebral cortex without requiring any overt behavioral response
We found hemodynamic responses correlated with word recognition in the neonate brain

Summary

Introduction

The newborn brain has access to enough acoustic detail to distinguish all words in the surrounding language. Numerous studies indicate that neonates are sensitive to acoustic properties of speech and can recognize familiar sounds. 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]. Newborn human infants can discriminate phonetic contrasts and extract rhythm, prosodic information, and simple regularities from speech. There is scarce evidence that infants can recognize common words from the surrounding language before four months of age

Methods

Results

Conclusion