A Developmental Framework of Brain and Cognition from Infancy to Old Age

Abstract

The interest in lifespan studies has grown tremendously in recent years with awareness of the possible parallels between development and ageing processes, and also with the increasing knowledge of the malleability of the brain even into old age and the continuing opportunities for ongoing learning and interventions across the lifetime. Our conceptualization of brain changes and brain function across the lifespan has evolved from the vision of two distinct and separate processes, an initial development till maturity, and a later decline through ageing processes (Fig. 1a), to a much more dynamic, life-long vision in which processes evolve and influence each other across the entire lifespan (Fig. 1b). There is growing awareness in the neurosciences of the importance of understanding brain development from infancy (and even in utero) through childhood and then the continuing evolution of brain structure and function in adult and then ageing populations. To fully appreciate a mature or ageing system, it is important to understand the processes underlying and contributing to its maturation, and how related processes continue to shape brain structure and function until death. We have developed the appreciation that there is no period when the brain and its functions are static; changes are continuous throughout the lifespan. The nature, extent and the rates of change vary by region and function assessed and are influenced by genetic and well as environmental factors, both due to physiologic influences and by diseasesrelated pathological processes. This special issue offers an array of papers, which incorporate literature reviews for those not as familiar with the field of brain lifespan studies, with their empirical data. The studies included are exceptional in their application of complex protocols that assess the neuroplasticity and agerelated changes in structure and/or function from infants through to our most senior citizens, and highlight the value of different methodological techniques and approaches. Starting this special issue are two letters addressing the topic of measures of brain maturity and providing commentary on Dosenbach et al. (2010). Brandeis et al. (2011) raise the point that estimation of brain maturity has a long history, as it has been assessed for many decades using electrophysiological measures. Dosenbach et al. (2010) agree with the suggestion that neuroimaging approaches be combined. These letters raise the intriguing questions of commonalities across imaging modalities that should be kept in mind for all of the papers in this special issue. We have organized the reports from early to late in the lifespan. The topic of the first paper is on the youngest of participants—4-month-old infants. Trainor and colleagues (2011) presented young infants with one of two types of musical stimuli over the course of a week. After only about 160 min of listening experience, event-related potential (ERP) responses in the infants from the two different groups reflected the musical exposure of the infant. This very interesting paper demonstrates the early and rapid plasticity in the infant brain. The following study by Gordon and colleagues (2011) also investigated the neuroplasticity of brain function; in this case in infants and This is the Introduction to the Special Issue: Brain function across the lifespan.