Electrical activity plays a pivotal role in the development of neurons into functional neural networks. Besides changes in synaptic strength, many other processes are activity-dependent. They influence neuronal function and connectivity, on multiple time scales as well as on multiple levels of specificity, both during development and in adulthood. A number of these processes are reviewed here, together with some simulation models. Their relevance for the current thinking about neural networks is discussed. 1 Introduction In the course of development neurons become assembled into functional neural networks. Electrical activity plays a central role in this process, and its effects are not restricted to mere changes in synaptic strength. Many processes that determine connectivity and neuronal function are, on various time scales, modulated by electrical activity: e.g., naturally occurring cell death, trophic factor production and responsiveness, number and effectiveness of transmitter re...

The author reviews reemerging coconstructive conceptions of development and recent empirical findings of developmental plasticity at different levels spanning several fields of developmental and life sciences. A cross-level dynamic biocultural coconstructive framework is endorsed to understand cognitive and behavioral development across the life span. This framework integrates main conceptions of earlier views into a unifying frame, viewing the dynamics of life span development as occurring simultaneously within different time scales (i.e., moment-to-moment microgenesis, life span ontogeny, and human phylogeny) and encompassing multiple levels (i.e., neurobiological, cognitive, behavioral, and sociocultural). Viewed through this metatheoretical framework, new insights of potential interfaces for reciprocal cultural and experiential influences to be integrated with behavioral genetics and cognitive neuroscience research can be more easily prescribed. Metaphorically speaking, two related pendulums, one swinging back and forth from nature to nurture and the other from brain to mind, have been running the clocks of developmental and cognitive inquiries for centuries. Instead of polarizing toward either end, this review of recent advances in life and developmental sciences

neurocomputation involves discrete signals communicated along fixed transmission lines between discrete computational elements. This concept is shown to be inadequate to account for invariance in recognition, as well as for the holistic global aspects of perception identified by Gestalt theory. A Harmonic Resonance theory is presented as an alternative paradigm of neurocomputation, that exhibits both the property of invariance, and the emergent Gestalt properties of perception, not as special mechanisms contrived to achieve those properties, but as natural properties of the resonance itself.