Maternal prenatal depressive symptoms and child brain responses to affective touch at two years of age.

Background: Touch is an essential form of mother-child interaction, instigating better social bonding and emotional stability.

Methods: We used diffuse optical tomography to explore the relationship between total haemoglobin (HbT) responses to affective touch in the child's brain at two years of age and maternal self-reported prenatal depressive symptoms (EPDS). Affective touch was implemented via slow brushing of the child's right forearm at 3 cm/s and non-affective touch via fast brushing at 30 cm/s and HbT responses were recorded on the left hemisphere.

Imaging affective and non-affective touch processing in two-year-old children.

Touch is an important component of early parent-child interaction and plays a critical role in the socio-emotional development of children. However, there are limited studies on touch processing amongst children in the age range from one to three years. The present study used frequency-domain diffuse optical tomography (DOT) to investigate the processing of affective and non-affective touch over left frontotemporal brain areas contralateral to the stimulated forearm in two-year-old children.

Relationship between maternal pregnancy-related anxiety and infant brain responses to emotional speech - a pilot study.

Background: Maternal pregnancy-related anxiety (PRA) is reportedly related to neurodevelopmental outcomes of infants. However, the relationship between maternal PRA and the processing of emotions in the infant brain has not been extensively studied with neuroimaging. The objective of the present pilot study is to investigate the relationship between maternal PRA and infant hemodynamic responses to emotional speech at two months of age.

Hemodynamic responses to emotional speech in two-month-old infants imaged using diffuse optical tomography.

Emotional speech is one of the principal forms of social communication in humans. In this study, we investigated neural processing of emotional speech (happy, angry, sad and neutral) in the left hemisphere of 21 two-month-old infants using diffuse optical tomography. Reconstructed total hemoglobin (HbT) images were analysed using adaptive voxel-based clustering and region-of-interest (ROI) analysis.

Emotional Processing in the First 2 Years of Life: A Review of Near-Infrared Spectroscopy Studies.

Emotional stimuli processing during childhood helps us to detect salient cues in our environment and prepares us for our social life. In early childhood, the emotional valences of auditory and visual input are salient and relevant cues of social aspects of the environment, and it is of special interest to understand how exactly the processing of emotional stimuli develops. Near-infrared spectroscopy (NIRS) is a noninvasive neuroimaging tool that has proven valuable in studying emotional processing in children.

Affective and non-affective touch evoke differential brain responses in 2-month-old infants.

Caressing touch is an effective way to communicate emotions and to create social bonds. It is also one of the key mediators of early parental bonding. The caresses are generally thought to represent a social form of touching and indeed, slow, gentle brushing is encoded in specialized peripheral nerve fibers, the C-tactile (CT) afferents.

Effect of task-related extracerebral circulation on diffuse optical tomography: experimental data and simulations on the forehead.

The effect of task-related extracerebral circulatory changes on diffuse optical tomography (DOT) of brain activation was evaluated using experimental data from 14 healthy human subjects and computer simulations. Total hemoglobin responses to weekday-recitation, verbal-fluency, and hand-motor tasks were measured with a high-density optode grid placed on the forehead. The tasks caused varying levels of mental and physical stress, eliciting extracerebral circulatory changes that the reconstruction algorithm was unable to fully distinguish from cerebral hemodynamic changes, resulting in artifacts in the brain activation images.

Accelerometer-based method for correcting signal baseline changes caused by motion artifacts in medical near-infrared spectroscopy.

In medical near-infrared spectroscopy (NIRS), movements of the subject often cause large step changes in the baselines of the measured light attenuation signals. This prevents comparison of hemoglobin concentration levels before and after movement. We present an accelerometer-based motion artifact removal (ABAMAR) algorithm for correcting such baseline motion artifacts (BMAs).

Magnetic-stimulation-related physiological artifacts in hemodynamic near-infrared spectroscopy signals.

Hemodynamic responses evoked by transcranial magnetic stimulation (TMS) can be measured with near-infrared spectroscopy (NIRS). This study demonstrates that cerebral neuronal activity is not their sole contributor. We compared bilateral NIRS responses following brain stimulation to those from the shoulders evoked by shoulder stimulation and contrasted them with changes in circulatory parameters.

Correlation of visual-evoked hemodynamic responses and potentials in human brain.

The interaction of brain hemodynamics and neuronal activity has been intensively studied in recent years to yield better understanding of brain function. We investigated the relationship between visual-evoked hemodynamic responses (HDRs), measured with near-infrared spectroscopy (NIRS), and neuronal activity in humans, approximated with the stimulus train duration or with visual-evoked potentials (VEPs). Concentration changes of oxyhemoglobin (HbO(2)) and deoxyhemoglobin (HbR) in tissue and VEPs were recorded simultaneously over the occipital lobe of ten healthy subjects to 3, 6, and 12 s pattern-reversing checkerboard stimulus trains having a reversal frequency of 2 Hz.

Hemodynamic responses to speech and music in newborn infants.

We used near-infrared spectroscopy (NIRS) to study responses to speech and music on the auditory cortices of 13 healthy full-term newborn infants during natural sleep. The purpose of the study was to investigate the lateralization of speech and music responses at this stage of development. NIRS data was recorded from eight positions on both hemispheres simultaneously with electroencephalography, electrooculography, electrocardiography, pulse oximetry, and inclinometry.

An application of perturbation Monte Carlo in optical tomography.

Haemodynamic changes related to activation of the human visual cortex were studied using optical imaging. The change in oxyhaemoglobin concentration in the visual cortex was estimated using a perturbation Monte Carlo (pMC) method. Comparison to a topographic map obtained using the modified Beer-Lambert law and interpolation is given.

Comparison between a time-domain and a frequency-domain system for optical tomography.

The quality of phase and amplitude data from two medical optical tomography systems were compared. The two systems are a 32-channel time-domain system developed at University College London (UCL) and a 16-channel frequency-domain system developed at Helsinki University of Technology (HUT). Difference data measured from an inhomogeneous and a homogeneous phantom were compared with a finite-element method (diffusion equation) and images of scattering and absorption were reconstructed based on it.

Bilateral hemodynamic responses to auditory stimulation in newborn infants.

We studied hemodynamic auditory evoked responses of 20 healthy full-term neonates with near-infrared spectroscopy. The instrument used allows the measurements to be performed simultaneously above both auditory cortices. The stimulation consisted of 5-s trains of sound (700-ms interstimulus interval) with a 25-s silent interval.