Dendritic Spines From Shape To Function

One fundamental requisite for a comprehensive view on brain function and cognition is the understanding of the neuronal network activity of the brain. Neurons are organized into complex networks, interconnected through synapses. The main sites for excitatory synapses in the brain are thin protrusions called dendritic spines that emerge from dendrites. Dendritic spines have a distinct morphology with a specific molecular organization. They are considered as subcellular compartments that constrain diffusion and influence signal processing by the neuron and, hence, spines are functional integrative units for which morphology and function are tightly coupled. The density of spines along the dendrite reflects the levels of connectivity within the neuronal network. Furthermore, the relevance of studying dendritic spines is emphasized by the observation that their morphology changes with synaptic plasticity and is altered in many psychiatric disorders. The present Research Topic deals with some of the most recent findings concerning dendritic spine structure and function, showing that, in order to understand how brain neuronal activity operates, these two factors should be regarded as being intrinsically linked.

This reference provides detailed coverage of dendritic spines, the fascinating neuronal components that modulate synaptic transmission, development, strength, and plasticity and are involved in the function of multiple areas of the nervous system. The density, shape, and function of spines may indicate the cellular connectivity and synaptic plasticity in normal and pathological conditions. This field has undergone dramatic advances in terms of techniques and experimental findings from in vitro to in vivo data, from animal models to human neurons, and computational models using artificial intelligence. To address these cutting-edge findings, the book provides state-of-the-art, comprehensive coverage with chapters written by the leading international researchers in the field. The authors consider the multiple implications for the study of dendritic spines with broad implications in the neurosciences and related areas.

Thirty years ago, the group of Baulieu and colleagues discovered that certain steroid hormones were present in higher amounts in the brain than in the plasma, and also found that suppression of circulating steroids by adrenalectomy and castration did not affect the concentration of pregnenolone, dehydroepiandrosterone and their sulfate esters in the rat brain. These seminal observations led to the concept that the brain, in very much the same way as the adrenal cortex, testis, ovary and placenta, was capable of synthesizing steroids. These brain born steroids, called neurosteroids, have been found to exert a vast array of biological activities. A number of steroidogenic enzymes have now been identified in the central nervous system by immunohistochemistry and in situ hybridization, and the neuronal and hormonal mechanisms regulating the biosynthesis of neurosteroids have been partially elucidated. The aim of this Research Topic is to celebrate three decades of research on neurosteroids by gathering a bouquet of review papers and original articles from leading scientists in the flourishing field of neurosteroids.

Studies in human patients and animal models of disease suggest a strong correlation between defects in dendrite development and common neurological disorders such as autism. Much of this book is thus dedicated toward highlighting recent advances in our understanding of the cellular and molecular mechanisms that regulate the development and maintenance of dendrites, a crucial component of neurons. The book begins by presenting the current state of knowledge on the building blocks or cell biology of dendrites. Mechanisms that sculpt the stereotypic architecture of dendritic arbors and shape their connectivity are also discussed, along with recent work describing how dendritic organization and connectivity are perturbed in disease. A unique aspect of the book is its exploration of diverse neuronal cell types across vertebrates and invertebrates, allowing a comparison of mechanisms across distinct circuits and species. The book comprises six parts, which cover the major advances in the field: Part 1, Introduction; Part 2, Basic Biology of Dendrites; Part 3, Patterning Dendritic Architecture of Neurons and Their Populations; Part 4, Cellular and Molecular Control of Dendrite Development and Maintenance; Part 5, Synapse Formation onto Dendrites; and Part 6, Dendrites in Disease. The book offers an excellent point of entry for students interested in neuroscience, as well as for clinicians.

A leading neurobiologist explores the fundamental function of dendritic spines in neural circuits by analyzing different aspects of their biology, including structure, development, motility, and plasticity. Most neurons in the brain are covered by dendritic spines, small protrusions that arise from dendrites, covering them like leaves on a tree. But a hundred and twenty years after spines were first described by Ramón y Cajal, their function is still unclear. Dozens of different functions have been proposed, from Cajal's idea that they enhance neuronal interconnectivity to hypotheses that spines serve as plasticity machines, neuroprotective devices, or even digital logic elements. In Dendritic Spines, leading neurobiologist Rafael Yuste attempts to solve the “spine problem,” searching for the fundamental function of spines. He does this by examining many aspects of spine biology that have fascinated him over the years, including their structure, development, motility, plasticity, biophysical properties, and calcium compartmentalization. Yuste argues that we may never understand how the brain works without understanding the specific function of spines. In this book, he offers a synthesis of the information that has been gathered on spines (much of which comes from his own studies of the mammalian cortex), linking their function with the computational logic of the neuronal circuits that use them. He argues that once viewed from the circuit perspective, all the pieces of the spine puzzle fit together nicely into a single, overarching function. Yuste connects these two topics, integrating current knowledge of spines with that of key features of the circuits in which they operate. He concludes with a speculative chapter on the computational function of spines, searching for the ultimate logic of their existence in the brain and offering a proposal that is sure to stimulate discussions and drive future research.

This collection of fifteen previously published papers, some of them not widely available, have been carefully chosen and annotated by Rall's colleagues and other leading neuroscientists.