Developmental trajectory of face processing revealed by integrative dynamics.

Given their unique connectivity, a primary function of brain networks must be to transfer and integrate information. Therefore, the way in which information is integrated by individual nodes of the network may be an informative aspect of cognitive processing. Here we present a method inspired by telecommunications research that utilizes time-frequency fluctuations of neural activity to infer how information is integrated by individual nodes of the network.

MEG measures of covert orienting and gaze processing in children.

We investigated developmental differences in the cortical attention processing network using magnetoencephalography (MEG) and a spatial cueing task in 7-8 and 12-13 year old children. The cueing paradigm consisted of a centrally presented face with left or right averted eye-gaze in the gaze cue condition, and a central face with straight gaze presented with a cue stimulus to the left or right of the face in the peripheral cue condition. Cue congruency was 50 %.

Techniques for detection and localization of weak hippocampal and medial frontal sources using beamformers in MEG.

Magnetoencephalography provides precise information about the temporal dynamics of brain activation and is an ideal tool for investigating rapid cognitive processing. However, in many cognitive paradigms visual stimuli are used, which evoke strong brain responses (typically 40-100 nAm in V1) that may impede the detection of weaker activations of interest. This is particularly a concern when beamformer algorithms are used for source analysis, due to artefacts such as "leakage" of activation from the primary visual sources into other regions.

Response inhibition in adults and teenagers: spatiotemporal differences in the prefrontal cortex.

Inhibition is a core executive function reliant on the frontal lobes that shows protracted maturation through to adulthood. We investigated the spatiotemporal characteristics of response inhibition during a visual go/no-go task in 14 teenagers and 14 adults using magnetoencephalography (MEG) and a contrast between two no-go experimental conditions designed to eliminate a common confound in earlier studies comparing go with no-go trials. Source analyses were performed using an event-related beamformer algorithm with co-registered individual structural MRIs.

Spatio-temporal localisation of attentional orienting to gaze and peripheral cues.

Another person's eye gaze often triggers our attention such that we follow their direction of gaze. We investigated how the neural mechanisms for processing eye-gaze and spatial attention interact using magnetoencephalography (MEG) in young adults. In a cueing paradigm, a face was presented centrally with left or right averted eye-gaze serving as the directional cue in the eye-gaze condition.

Characterizing the normal developmental trajectory of expressive language lateralization using magnetoencephalography.

To characterize the developmental trajectory for expressive language representation and to test competing explanations for the relative neuroplasticity of language in childhood, we studied 28 healthy children and adolescents (aged 5-19 years) participating in a covert verb generation task in magnetoencephalography. Lateralization of neuromagnetic responses in the frontal lobe was quantified using a bootstrap statistical thresholding procedure for differential beamformer analyses. We observed a significant positive correlation between left hemisphere lateralization and age.

The development of face recognition; hippocampal and frontal lobe contributions determined with MEG.

Face recognition skills improve steadily across childhood, yet few studies have investigated the development of the neural sources underlying these processes. We investigated the developmental changes in brain activity related specifically to face recognition, using magnetoencephalography (MEG). We studied 70 children (6-19 years) and 20 young adults.

Detection and localization of hippocampal activity using beamformers with MEG: a detailed investigation using simulations and empirical data.

The ability to detect neuronal activity emanating from deep brain structures such as the hippocampus using magnetoencephalography has been debated in the literature. While a significant number of recent publications reported activations from deep brain structures, others reported their inability to detect such activity even when other detection modalities confirmed its presence. In this article, we relied on realistic simulations to show that both sides of this debate are correct and that these findings are reconcilable.

Brain noise is task dependent and region specific.

The emerging organization of anatomical and functional connections during human brain development is thought to facilitate global integration of information. Recent empirical and computational studies have shown that this enhanced capacity for information processing enables a diversified dynamic repertoire that manifests in neural activity as irregularity and noise. However, transient functional networks unfold over multiple time, scales and the embedding of a particular region depends not only on development, but also on the manner in which sensory and cognitive systems are engaged.

Feature-space-based FMRI analysis using the optimal linear transformation.

The optimal linear transformation (OLT), an image analysis technique of feature space, was first presented in the field of MRI. This paper proposes a method of extending OLT from MRI to functional MRI (fMRI) to improve the activation-detection performance over conventional approaches of fMRI analysis. In this method, first, ideal hemodynamic response time series for different stimuli were generated by convolving the theoretical hemodynamic response model with the stimulus timing.

Unattended emotional faces elicit early lateralized amygdala-frontal and fusiform activations.

Human adaptive behaviour to potential threats involves specialized brain responses allowing rapid and reflexive processing of the sensory input and a more directed processing for later evaluation of the nature of the threat. The amygdalae are known to play a key role in emotion processing. It is suggested that the amygdalae process threat-related information through a fast subcortical route and slower cortical feedback.