Field of Research
Fetal magnetoencephalography (fMEG) is a unique application of highly sensitive magnetic sensors, which allows for the detection of fetal brain signals and therefore the non-invasive investigation of functional brain development in human fetuses. To achieve this goal, we use a biomagnetic device including 156 primary SQUID (superconducting quantum interference device) sensors distributed over a concave shell to allow the recording of biomagnetic signals generated in the maternal abdomen. The recorded signal contains information from the maternal and the fetal heart, fetal brain, uterine muscles, other biological tissue and environmental noise. The different signal types can be separated by their temporal and spatial activity distribution. In this respect the biomagnetic device, besides recording of the fetal brain, also allows for the investigation of maternal and fetal heart and uterine activity. With respect to the fetal brain we are interested in stimulus evoked fields and spontaneous activity.
Stimulus evoked fields
The visual and auditory system of the fetus is functional in the last trimester of gestation. Auditory stimuli can be delivered to the fetus by sound sources attached to the maternal abdomen and visual stimuli by red light, which is transmitted through the abdomen and perceived by the fetus.
From a developmental neuroscientific point of view we are interested in the development of basic auditory features including auditory discrimination of pure tones and syllables, which are the precursors of general language abilities. In addition we use amplitude-modulated tones to investigate transient evoked fields and steady state responses. This type of stimulus can help to increase the signal to noise ratio of signals in the fetal brain and increase the detection rate of evoked fields.
Moreover we have been able to show that fetuses show simple cognitive functions such as: habituation and basic numerical discrimination capabilities. (Collaborators Prof. Landerl, former CIN member Prof. Graz, CIN members Prof. Born, Prof. Birbaumer, Prof. Kraegeloh-Mann.)
In the fetal brain the output of spontaneous activity generally larger than that of stimulus evoked fields, which is similar to the adult brain. However, it is harder to extract these spontaneous signals than it is to detect fields that have been evoked, because what the features of spontaneous activity in fetuses are is a question that is still being debated. Currently we use an approach that combines expert scoring and automatic extraction of spontaneous activity to extract and characterize fetal spontaneous activity. Based on this we have been able to show distinct changes in spontaneous activity during gestation. Our future focus (in collaboration with CIN member Prof. Born) will be on questions related to sleep development in fetuses and newborns.
Ayoub, A, Mölle, M, Preissl, H, Born, J. (2012) Grouping of MEG gamma oscillations by EEG sleep spindles. Neuroimage. 59(2): 1491-500.
Haddad, N, Govindan, RB, Vairavan, S, Siegel, E, Temple, J, Preissl, H, Lowery, CL, Eswaran H. (2011) Correlation between Fetal Brain Activity Patterns and Behavioral States: An exploratory fetal magnetoencephalography study. Exp Neurol. 228(2):200-5.
Sheridan, C.J., Matuz, T., Draganova, R., Eswaran, H., Preissl, H. (2010) Fetal Magnetoencephalography – Achievements and Challenges in the Study of Prenatal and Early Postnatal Brain Responses: A Review. Infant and child development. 19(1): 80-93.
Micheli, C., McCubbin, J., Murphy, P., Eswaran, H., Lowery, C.L., Ortiz, E., Preissl, H. (2010) Verification of fetal brain responses by coregistration of fetal ultrasound and fetal magnetoencephalography data. Neuroimage. 49: 1469-1478.