Contents -- 1: Introduction -- A Walk in the Neuronal Forest -- Historical Roots: Nuts and Bolts of a Neuronal Machine -- Great Victories of Cajal's "Rational Psychology" Paradigm -- The Janus-Face of Order and Variability, and the Dangers of Typology -- Back to the Future: Early Notions on Variability -- Defining Interneurons -- 2: Developmental Origins of Interneuronal Heterogeneity -- Ontogenetic Differences between Glutamatergic Neurons versus Interneurons -- Molecular Carrots and Sticks for Interneuronal Migration -- Distinct Interneurons from Different Sources? -- A Case Study: Migration of Interneurons Toward the Hippocampus -- Long Road to Tipperary: Consequences of Distant Progenitor Zones for Interneuronal Specification -- When Things Go Wrong: Interneuron Migrations and Neurological Disorders -- 3: Order in Diversity: From Phenomenology to Function -- Diversity at Multiple Levels of Neuronal Organization -- Linnean Order in Diversity: A Modern Compendium of Interneuronal Species -- Cogwheels of Understanding: Functions of Interneuronal Subtypes -- Basket Cells: Division of Labor -- Canonical Microcircuits, Cortical Columns, and Their Stereotyped Inhabitants -- Crusade for the Great Synthesis and the End of Neuroscience -- 4: Cracks in the Crystal: Elusive Neurospecies and the Great Correlation Hunt -- Neuronal Species: Can't Live with Them, Can't Live without Them -- Getting Lost in Parameter Space: The Mirage of Blind Phenotypic Correlations -- Imperfect Correlations: Experimenter's Errors or Reality? -- The Other Extreme: Each Interneuron as an Unclassifiable Individual -- 5: Functions of Heterogeneity: Meaning of Means and Variability of Variances -- Reconciling Order and Variability: Distinct Subtypes and Cell-to-Cell Heterogeneity as Simultaneously Existing Reality -- Definitions: Heterogeneity, Variance and Diversity.

First Look at Variability and Function: Interneuronal Covering of Principal Cells Both in Space and Time -- Simulations of Interneuronal Variance and Synchrony -- Toward Rules that Underlie the Modulation of Postsynaptic Behavior by Interneuronal Variability -- 6: Interneuronal Variability: Plasticity and Regulation -- Dynamic Clamp-Down on Interneuronal Variance -- Alterations in Variance: Neuromodulators, Neurological Diseases, and Development -- Statistical Methods of Measuring Changes in Variance -- Transfer of Interneuronal Variability to Principal Cells: Potential for More Functional States? -- Heterogeneity in the Outside World and Its Reflection in the Circuit -- Variations for the Advanced Age: Intra-Species Variance in Interneuronal Populations through Somatic Mutations? -- 7: Diversity Beyond Variance -- Species Number and Relative Abundance: Entropy-Based Measures of Diversity -- Plasticity of Interneuronal Diversity: Birth and Loss of Cellular Species -- Effects of Changed Diversity on Firing Rates -- Modulation of Synchrony by Alterations in Diversity -- Equitability, and Alpha, Beta and Gamma Diversity -- Molecular Dragnets Cast Wide: Interneuronal Species from Unsupervised Clustering -- Emerging Order in the Molecular Pandora's Box -- Ontogenetic Cladistics for Interneurons -- Interneuronal Diversity and Evolution -- Constraints on Interneuronal Diversity -- 8: Fifty Ways to Be a Basket Cell: Self-Tuning Interneurons with Multiple Solutions for Their Tasks -- The "Ideal" Basket Cell -- Unbearable Multiplicity of Being a Specialized Neuron -- Failure of Averaging -- Homeostatic Regulation and Activity Sensors -- Homeostasis in GABAergic Systems -- Wanted, Alive: Interneuronal Heterogeneity in Naturalistic Environments -- 9: Interneuronal Diversity and Small World Neuronal Networks -- Building Complex Machines with Minimal Wiring.

Real-World Small Worlds: Worming Up to the Hippocampus -- Attack Tolerance of Small World Networks: Hippocampal Sclerosis as a Natural Experiment -- Scale-Free Networks: Interneurons as Hubs -- Interneuronal Heterogeneity in Small-World Networks -- 10: Closing Thoughts: The Stucture of Cortical Microcircuit Theory -- Resolution of the Diversity Debate -- Building a Complex Machine from Variable Parts -- Phenogenetic Perspective for Interneuronal Research and the Role of Chance -- Cajal's Functional Neuroanatomy in the 21st Century -- Bibliography -- Index -- A -- B -- C -- D -- E -- F -- G -- H -- I -- J -- K -- L -- M -- N -- O -- P -- R -- S -- T -- U -- V -- W.