Antenatal study of the Heschl’s gyrus: The first step to understanding prenatal learning

Fetal MR Imaging Anatomy of the Transverse Temporal Gyrus (Heschl Gyrus)

BACKGROUND AND PURPOSE

The human auditory system develops early in fetal life. This retrospective MR imaging study describes the in vivo prenatal anatomic development of the transverse temporal gyrus (Heschl gyrus) site of the primary auditory cortex.

MATERIALS AND METHODS

Two hundred seventy-two MR imaging studies of the fetal brain (19-39 weeks' gestational age) acquired from a single institution's 1.5T scanner were retrospectively examined by 2 neuroradiologists. MR imaging with pathologic findings and extreme motion artifacts was excluded. Postnatal Heschl gyrus landmarks were used as a reference on T2-weighted ssFSE sequences in the 3 orthogonal planes. The frequency of the Heschl gyrus was reported for gestational age, hemisphere, and planes. Descriptive statistics and a McNemar test were performed.

RESULTS

Two hundred thirty MR imaging studies were finally included. Fetal brains were divided by gestational age (in weeks) into 8 groups (parentheses indicate the number of observations): 19-21 (29), 22-23 (32), 24-25 (21), 26-27 (18), 28-29 (35), 30-31 (30), 32-33 (33) and >34 (32). The Heschl gyrus appeared on MR imaging between 24 and 25 weeks' gestational age (14/21 fetuses, 67%) and was visible in all fetuses after the 28th week of gestation. By its appearance (24-28 weeks' gestational age), the sagittal plane was the most sensitive in its detectability. After 28-29 weeks' gestational age, the Heschl gyrus was evident in all acquisition planes and fetuses. Results did not differ between hemispheres.

CONCLUSIONS

The Heschl gyrus appears on MR imaging at 24-25 weeks' gestational age, paralleling the functional activation of the auditory system. We propose the Heschl gyrus as an early additional MR imaging marker of fetal brain development.

Effect of Musical Stimulation on Placental Programming and Neurodevelopment Outcome of Preterm Infants: A Systematic Review

BACKGROUND

The fetal environment is modulated by the placenta, which integrates and transduces information from the maternal environment to the fetal developmental program and adapts rapidly to changes through epigenetic mechanisms that respond to internal (hereditary) and external (environmental and social) signals. Consequently, the fetus corrects the trajectory of own development. During the last trimester of gestation, plasticity shapes the fetal brain, and prematurity can alter the typical developmental trajectories. In this period, prevention through activity-inducing (e.g., music stimulation) interventions are currently tested. The purpose of this review is to describe the potentialities of music exposure on fetus, and on preterm newborns in the Neonatal Intensive Care Unit evaluating its influence on neurobehavioral development.

METHODS

Databases were searched from 2010 to 2022 for studies investigating mechanisms of placental epigenetic regulation and effects of music exposure on the fetus and pre-term neonates.

RESULTS

In this case, 28 selected papers were distributed into three research lines: studies on placental epigenetic regulation (13 papers), experimental studies of music stimulation on fetus or newborns (6 papers), and clinical studies on premature babies (9 papers). Placental epigenetic changes of the genes involved in the cortisol and serotonin response resulted associated with different neurobehavioral phenotypes in newborns. Prenatal music stimulation had positive effects on fetus, newborn, and pregnant mother while post-natal exposure affected the neurodevelopment of the preterm infants and parental interaction.

CONCLUSIONS

The results testify the relevance of environmental stimuli for brain development during the pre- and perinatal periods and the beneficial effects of musical stimulation that can handle the fetal programming and the main neurobehavioral disorders.

The prenatal brain readiness for speech processing: A review on foetal development of auditory and primordial language networks

Despite consolidated evidence for the prenatal ability to elaborate and respond to sounds and speech stimuli, the ontogenetic functional brain maturation of language responsiveness in the foetus is still poorly understood. Recent advances in in-vivo foetal neuroimaging have contributed to a finely detailed picture of the anatomo-functional hallmarks that define the prenatal neurodevelopment of auditory and language-related networks. Here, we first outline available evidence for the prenatal development of auditory and language-related brain structures and of their anatomical connections. Second, we focus on functional connectivity data showing the emergence of auditory and primordial language networks in the foetal brain. Third, we recapitulate functional neuroimaging studies assessing the prenatal readiness for sound processing, as a crucial prerequisite for the foetus to experientially respond to spoken language. In conclusion, we suggest that the state of the art has reached sufficient maturity to directly assess the neural mechanisms underlying the prenatal readiness for speech processing and to evaluate whether foetal neuromarkers can predict the postnatal development of language acquisition abilities and disabilities.