Electrophysiological Evaluation of Human Brain Development

Abstract

The complex development of the human brain during infancy can only be understood by convergent structural, functional, and behavioral measurements. The evaluation of event-related potentials (ERPs) is the most effective current way to look at infant brain function. ERP paradigms can be used to examine the simple transmission of sensory information to the cortex and the discrimination of this information within the cortex. The main developmental changes involve localization of function as the brain becomes tuned to the experienced world (related to synaptic pruning) and a speeding up of transmission as pathways become efficient (related to myelination). ERPs that occur in relation to different temporal aspects of a stimulus (onset-responses, offset-responses, sustained potentials and steady-state responses) and ERPs recorded at different stimulus rates may help track perceptual development from a temporal perspective. Particularly important in human development are the ERP changes that occur in the processing of speech sounds and human faces. At present, ERP studies can show differences between groups of subjects that can demonstrate developmental disorders or elucidate mechanisms of development. However, because of their variability, ERPs are less helpful in determining whether an individual infant is developing abnormally. Where possible, ERP measurements should be used in conjunction with behavioral tests so as to relate performance to mechanism, and with anatomical brain measurements to relate mechanism to structure.

Functional and time-course changes in single word production from childhood to adulthood

“…Latency changes across age have also been described (Allison et al, 1984;Zemon et al, 1995). Shorter P1 peak latency in adults than in children may reflect the increase in processing speed due to myelinisation (Picton and Taylor, 2007). Several studies have reported that P100 latency stabilizes around 20 years of age (Shaw and Cant, 1981;Allison et al, 1984;Emmerson-Hanover et al, 1994).…”

“…A decrease in the amplitudes of VEP with age has been repeatedly described using different kinds of visual stimuli (Allison et al, 1984;Brecelj et al, 2002;Hoffmann et al, 2001;Holcomb, Coffey and Neville, 1992;Mahajan and McArtur, 2012;Taylor et al, 2004). Larger amplitudes in children have been attributed to less thick skulls or to generators being closer to the surface electrode in smaller brains (Chauveau et al, 2004;Picton and Taylor, 2007). Alternatively, amplitude decreases may result from increasing automaticity; the same processes require fewer resources, leading to a decrease in cerebral activation, a phenomenon that has been described in many developmental brain imaging studies (Durston and Casey, 2006).…”

Variations in theTNF-α Gene (TNF-α -308G→A) Affect Attention and Action Selection Mechanisms in a Dissociated Fashion

“…It is known that TNF alpha affects oligodendrocytes that in course can effect myelination (e.g., Huang et al 2002), which could lead to differences in ERP latencies and response times. In fact, ERPs have been used as a measure to infer the status of myelination (Lippe et al 2007;Picton and Taylor 2007).…”

Practical Aspects of Running Developmental Studies in the MEG

“…While numerous developmental studies have used electrophysiological techniques (namely, EEG and event-related potentials; for reviews, see [1,38,43]), structural MRI (for reviews, see [29,42]), and functional MRI (for examples, see [15,50]), the use of MEG offers the unprecedented opportunity to apply its exquisite spatio-temporal resolution to examining the complexities and intricacies of typical development and, as a consequence, atypical development. The availability of whole head MEG systems, with more than 300 recording sensors, attests to the maturity of MEG instrumentation.…”