![]() ![]() Both near infra-red spectroscopy (NIRS) and electroencephalography (EEG) can measure neural responses during cognitive tasks in pediatric populations. Most of the major approaches to direct measurement of cortical activity (e.g., positron emission tomography, functional magnetic resonance imaging) cannot be used with human infant participants because of ethical and/or practical concerns. 12 Instead, Richards and colleagues 13,14 suggest that integrating direct physiological measures of brain activity provides a fuller picture of the development of attention. These are behavioural tasks for which the brain areas involved have been firmly established, thus they can be used to indirectly study brain development in infants and children. Traditionally, infant visual attention and brain development have been measured using looking time and eye tracking measures during “marker tasks”. 9-11 From six months on, the anterior attention network (or executive attention system) becomes functional, as areas within the prefrontal cortex and the anterior cingulate cortex begin to play a significant role in maintaining visual attention while inhibiting shifts of attention to distractors. ![]() This network includes areas within the parietal and temporal cortices and the frontal eye fields and is involved in the ability to voluntarily shift visual attention from one stimulus to another. Between three and six months of age, a voluntary orienting network becomes functionally mature. Thus, eye movements and visual attention are generally reflexive in early infancy. In infants from birth to two months of age, it is proposed that eye movements are primarily driven by a “reflexive system” largely under the influence of primitive brain areas located beneath the cerebral cortex (i.e., subcortical). 1-7 Many of these models are influenced by Schiller’s research 8 on eye movement systems in non-human primates. Models of attention in early development are based upon behavioural findings in human infants, integrated with findings on changes in brain function of non-human and human adults, or clinical populations. In infants, attention is thought to change with age concurrently with changes in brain function. These aspects of attention show major developmental change throughout infancy. Additionally, while attention is focused on one object, shifts in attention to distractors are inhibited. It selects certain events or objects in the environment to focus on and maintains focus on the object of interest while information provided by that object is processed.
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