Neural Basis Of Cognitive Development Research Articles

Methodological approaches in developmental neuroimaging studies.

Pediatric neuroimaging is increasingly providing insights into the neural basis of cognitive development. Indeed, we have now arrived at a stage where we can begin to identify optimal methodological and statistical approaches to the acquisition and analysis of developmental imaging data. In this article, we describe a number of these approaches and how their selection impacts the ability to examine and interpret developmental effects. We describe preferred approaches to task selection, definition of age groups, selection of fMRI designs, definition of regions of interest (ROI), optimal baseline measures, and treatment of timecourse data. Consideration of these aspects of developmental neuroimaging reveals that unlike single-group neuroimaging studies, developmental studies pose unique challenges that impact study planning, task design, data analysis, and the interpretation of findings.

Review of Neuroscience of cognitive development: The role of experience and the developing brain.

CHARLES A. NELSON, MICHELLE DE HAAN and KATHLEEN M. THOMAS Neuroscience of Cognitive Development: The Role of Experience and the Developing Brain Hoboken, NJ: John Wiley & Sons, 2006, 224 pages (ISBN: 0-471-74586-0, C$ 97.99, Hardcover) Reviewed by ULRICH MULLER Within the last decade, there has been a surge of interest in the neurobiological bases of behavioural development. For this reason, the book by Nelson, de Haan, and Thomas on the neuroscience of cognitive development is timely. The goal of the book is to provide a state-of-the-art introduction to the neural bases of cognitive development. The authors set up the book by presenting three reasons for why developmental psychologists should be interested in neurobiology. First, psychological models of behaviour become more plausible when considered in the context of neurobiology. second, a neurobiological approach can elucidate the mechanisms underlying behavioural development, thereby carrying the scientific enterprise beyond description toward the level of process. Third, by incorporating brain development into the study of relations between genes and environment, developmental neuroscience opens up the possibility to conceptualize in more detail how specific experience affects neural circuits, which, in turn, affect the expression of particular genes. The first chapter reviews different aspects of brain development such as neural induction and neurulation, prenatal and postnatal neuronal proliferation, neuronal migration, axonal and dendritic development, synaptogenesis, and myelination. The authors also briefly mention the implications of defects in each of these aspects. Given the authors' emphasis on the role of experience in brain development, the coverage of postnatal brain development is surprisingly brief (also, developmental changes in the concentration of neurotransmitters are not discussed in this chapter or anywhere else in the book). Chapter two illustrates how experience induces changes in the developing brain as well as in the adult brain, and addresses the question of similarities and differences between neural plasticity in children and adults. The next chapter introduces different methods (e.g., lesion method, electrophysiological methods, metabolic procedures, optical imaging, and magnetic encephalography) to study the brain and discusses advantages and disadvantages of each method. Unfortunately, some methods (e.g., diffusion tensor imaging) and ways of analyzing imaging data (e.g., conjunction analysis) that are mentioned in later chapters are not covered in this chapter. In Chapters four through eleven, the authors review the current knowledge about the neurological bases in a number of key areas of cognitive development, including speech and language (Chapter four), declarative or explicit memory (Chapter five), implicit memory (Chapter six), spatial cognition (Chapter seven), object recognition (Chapter eight), social cognition (Chapter nine), higher cognitive (executive) functions (Chapter ten) and attention (Chapter eleven). The chapter on object recognition exclusively deals with face recognition and, for some reason, sections of this chapter are repeated verbatim in the chapter on social cognition. The final chapter provides a very brief outlook on the future of developmental neuroscience. In reviewing each content area, the authors skillfully integrate research findings from lesion studies with animals, studies with brain-injured children and adults, neuropsychological research with healthy adults, and neuropsychological research on typically and atypically developing children. They identify areas of the brain that subserve the respective cognitive ability and they detail how changes in connectivity and specialization are associated with the further development of the ability. A number of recurring themes are that cognitive abilities differ in terms of plasticity and the length of time during which experience can affect brain development. …

An Overview of the Neural Basis of Cognitive Development: Enriching the Environment for an Infant Science

An Overview of the Neural Basis of Cognitive Development: Enriching the Environment for an Infant Science

Comparison of sustained and transient activity in children and adults using a mixed blocked/event-related fMRI design

The ability to make direct comparisons between adult and child neuroimaging data is important to the study of the neural basis of cognitive development. Recent fMRI studies in adults have used mixed blocked/event-related designs to extract activity consistent with separable sustained, task-related processes and transient, trial-related processes. Because brain regions with different time courses of activity may have different roles in cognitive processing, the ability to distinguish between sustained and transient signals would contribute to understanding the functional roles of regions involved in cognitive processing. The developmental profile of such activity would give insight into how cognitive processing develops over time. The purpose of this study was to assess the utility of the mixed design to detect and dissociate sustained and transient activity in children, and to determine if the time courses or magnitudes of the extracted signals differ from those extracted from adults. An fMRI experiment was performed on 10 adults and 10 children (ages 7–8) using counterphase flickering checkerboard stimuli that produced sustained, transient, and a combination of sustained and transient responses in visual cortex. Analyses were performed using the general linear model (GLM) assuming a shape for sustained effects, but not for transient effects. In visual cortex, neither transient nor sustained effects showed significant between-group differences. For both groups, flickering checkerboard stimuli produced robust responses in visual cortex contralateral but not ipsilateral to the stimulus. Results extend the feasibility of direct statistical comparison of adults and children; mixed designs provide a means to examine neural activity in both adults and children related to sustained, task-level processes, likely related to task-level control.

Comparison of functional activation foci in children and adults using a common stereotactic space

The development of methods allowing direct comparisons between child and adult neuroimaging data is an important prerequisite for studying the neural bases of cognitive development. Several issues arise when attempting to make such direct comparisons, including the comparability of anatomical localization of functional responses and the magnitude and time course of the hemodynamic responses themselves. Previous results suggest that, after transformation into a common stereotactic space, anatomical differences between children (ages 7 and 8) and adults are small relative to the resolution of fMRI data. Here, we investigate whether time courses (BOLD responses) and locations of functional activation foci show similarities as well. Event-related fMRI was performed on 16 children (ages 7 and 8) and 16 adults, who pressed buttons in response to a visual stimulus. After transforming images into Talairach space, the coordinates of four consistent activations in each hemisphere were determined for each subject: two foci in the sensorimotor cortex, one focus in the visual cortex, and one focus in the supplementary motor area (eight activations in total). In seven foci, time courses were similar between children and adults, and peak amplitudes of time courses were comparable in all eight foci. There were negligible between-group differences in location of all foci. Variability of activation location was statistically similar in the two groups. In voxelwise group comparison images, minimal differences were found between children and adults in visual and motor cortex regions. The small differences in time courses and locations of activation foci between child and adult brains validate the feasibility of direct statistical comparison of these groups within a common space.

Structural and functional brain development and its relation to cognitive development

Despite significant gains in the fields of pediatric neuroimaging and developmental neurobiology, surprisingly little is known about the developing human brain or the neural bases of cognitive development. This paper addresses MRI studies of structural and functional changes in the developing human brain and their relation to changes in cognitive processes over the first few decades of human life. Based on post-mortem and pediatric neuroimaging studies published to date, the prefrontal cortex appears to be one of the last brain regions to mature. Given the prolonged physiological development and organization of the prefrontal cortex during childhood, tasks believed to involve this region are ideal for investigating the neural bases of cognitive development. A number of normative pediatric fMRI studies examining prefrontal cortical activity in children during memory and attention tasks are reported. These studies, while largely limited to the domain of prefrontal functioning and its development, lend support for continued development of attention and memory both behaviorally and physiologically throughout childhood and adolescence. Specifically, the magnitude of activity observed in these studies was greater and more diffuse in children relative to adults. These findings are consistent with the view that increasing cognitive capacity during childhood may coincide with a gradual loss rather than formation of new synapses and presumably a strengthening of remaining synaptic connections. It is clear that innovative methods like fMRI together with MRI-based morphometry and nonhuman primate studies will transform our current understanding of human brain development and its relation to behavioral development.

On theory and modelling

Parisi, D., & Plunkett, K. (1996). Rethinking innateness: A connectionist perspective on development. Cambridge, Mass.: MIT Press. Goldman-Rakic, P. S. (1988). Topography of cognition: Parallel distributed networks in primate association cortex. Annual Review of Neuroscience, 11, 137–156. Kojima, S., & and, G.-R. P. S. (1982). Delay-related activity of prefrontal neurons in rhesus monkeys performing delayed response. Brain Research, 248, 43–49. Montague, P. R., Dayan, P., & Sejnowski, T. J. (1996). A framework for mesencephalic dopamine systems based on predictive Hebbian learning. Journal of Neuroscience, 16, 1936–1947. Munakata. (1997). Infant perseveration and implications for object permanence theories: A PDP model of the A-not-B task. Developmental Science, this issue. Niki, H., & Watanabe, M. (1976). Prefrontal unit activity and delayed response: relation to cue location versus direction of response. Brain Research, 105, 79–88. Quartz, S. R., & Sejnowski, T. J. (in press). The neural basis of cognitive development: A constructivist manifesto. Behavioral and Brain Sciences. 196€Commentaries

The neural basis of cognitive development: a constructivist manifesto.

How do minds emerge from developing brains? According to "neural constructivism," the representational features of cortex are built from the dynamic interaction between neural growth mechanisms and environmentally derived neural activity. Contrary to popular selectionist models that emphasize regressive mechanisms, the neurobiological evidence suggests that this growth is a progressive increase in the representational properties of cortex. The interaction between the environment and neural growth results in a flexible type of learning: "constructive learning" minimizes the need for prespecification in accordance with recent neurobiological evidence that the developing cerebral cortex is largely free of domain-specific structure. Instead, the representational properties of cortex are built by the nature of the problem domain confronting it. This uniquely powerful and general learning strategy undermines the central assumption of classical learnability theory, that the learning properties of a system can be deduced from a fixed computational architecture. Neural constructivism suggests that the evolutionary emergence of neocortex in mammals is a progression toward more flexible representational structures, in contrast to the popular view of cortical evolution as an increase in innate, specialized circuits. Human cortical postnatal development is also more extensive and protracted than generally supposed, suggesting that cortex has evolved so as to maximize the capacity of environmental structure to shape its structure and function through constructive learning.

Maturation of prefrontal cortex in the monkey revealed by local reversible cryogenic depression

THE emergence of increasingly complex cognitive functions with age is widely assumed to reflect in part the maturation of connections within the central nervous system, but the neural bases of cognitive development have resisted identification. There is some evidence to indicate that the dorsolateral prefrontal association cortex in monkeys acquires its adult functional capacities over a protracted span of postnatal development1–3. Most of this evidence, however, has come from studies involving surgical ablation. The study of cerebral development in brain-damaged subjects is complicated by anterograde and retrograde degenerative changes, as well as by the possibility of compensatory neural reorganisation which could occur during the weeks or months between surgical ablation and assessment of behavioural performance4. It is now possible to study the functions of specific brain sites without producing permanent brain damage by localised cortical cooling, a method which allows reversible inactivation of restricted regions of cortex in otherwise normal animals. The latter are able to serve as their own controls before and after the episodes of cortical hypothermia5–7. This method has previously been used only in research on mature animals. In this study, local hypothermia was produced for the first time in the dorsolateral prefrontal cortex of young, developing rhesus monkeys during repeated assessment of their performance on a delayed-response task. Such performance in adult monkeys is known to be dependent on the integrity of that region8. Our findings provide direct evidence that part of the dorsolateral prefrontal association cortex does not become functionally mature until at least 34–36 month of age, that is, close to sexual maturity in this species.