Cerebral Cortex : Further Aspects of Cortical Function, Including Hippocampus

Volume 6 of Cerebral Cortex is in some respects a continuation of Volume 2, which dealt with the functional aspects of cortical neurons from the physiological and pharmacological points of view. In the current volume, chapters are devoted to the catecholamines, which for a number of reasons were not represented in the earlier volume, and to acetylcholine and the neuropeptides, about which much new information has recently appeared. Volume 6 deals in part with the structure and function of cholinergic and catecholaminergic neuronal systems in the cerebral cortex and with new aspects of the cortical peptidergic neurons, notably the almost universal propensity of the known cortical peptides for being colocalized with classical transmitters and with one another. It thus completes our coverage of the major cortical neuro­ transmitter and neuromodulatory systems. Other chapters in this volume deal with data pertaining to the proportions of different types of cells and synapses in the neocortex and the physiology of the cortical neuroglial cells. These latter are topics that rarely receive separate treatment and the current chapters serve again to continue discussions of subjects that were introduced in Volume 2. The previous volumes have all been devoted to the neocortex but the present one introduces the subject of the archicortex. To this end, separate chapters are devoted to the physiology and anatomy of the hippocampal formation.

1 Functions of Glial Cells in the Cerebral Corte.- 1. Introduction.- 2. The Electrophysiology of Cortical Glial Cells.- 2.1. Ion Distribution and Membrane Potential.- 2.2. Ion Channels of Glial Membranes.- 2.3. Responses of the Membrane Potential of Glial Cells.- 2.4. Contribution by Glia to Electrocorticographic Signals.- 3. Neuroglia and Ion Homeostasis.- 3.1. The Role of Glial Cells in the Regulation of Potassium Levels.- 3.2. Glia and pH.- 4. Glia and Transmitter Substances.- 4.1. Amino Acid Transmitters.- 4.2. Other Transmitters and Glial Cells.- 5. Pathophysiology of Cortical Glia.- 5.1. Seizures.- 5.2. Glia and Spreading Depression of Leão.- 6. Closing Remarks.- 7. References.- 2 Monoamine Innervation of Cerebral Cortex and a Theory of the Role of Monoamines in Cerebral Cortex and Basal Ganglia.- 1. Introduction.- 2. Synthesis of Monoamines.- 3. Techniques of Study.- 4. Dopamine.- 4.1. Introduction.- 4.2. Anatomical Studies.- 4.3. Functional Studies.- 5. Norepinephrine.- 5.1. Introduction.- 5.2. Anatomical Studies.- 5.3. Functional Studies.- 6. Serotonin.- 6.1. Introduction.- 6.2. Anatomical Studies.- 6.3. Functional Studies.- 7. Theoretical Note on the Functions of Monoamines in Cortex and Basal Ganglia.- 7.1. Introduction.- 7.2. Corticostriatopallidal Systems: Overview.- 7.3. Unique Organization of the Prefrontal System with Regard to Monoamine Input and Corticostriatopallidal Circuitry.- 7.4. Unique Organization of the Prefrontal System with Regard to Body Representation in the SN-VTA.- 7.5. Unique Organization of the Prefrontal System with Regard to Corticosubcortical Loops in the SN-VTA.- 8. References.- 3 Cholinergic Innervation in Cerebral Cortex.- 1. Introduction.- 2. The Specificity of Markers for Cholinergic Neurons.- 3. The Anatomical Characterization of Cholinergic Innervation in Cortex.- 3.1. The Cholinergic Projection from Magnocellular Forebrain Nuclei to Cerebral Cortex.- 3.2. The Cholinergic Projection from Midbrain to Frontal Cerebral Cortex.- 3.3. Intrinsic Cholinergic Neurons in Cerebral Cortex.- 4. Discussion.- 5. Alzheimer’s Disease and Cortical Cholinergic Function.- 6. References.- 4 The Cholinergic Modulation of Cortical Function.- 1. Introduction.- 2. The Cholinergic Innervation of Neocortex.- 3. Mechanisms of Action of ACh at the Cellular Level.- 4. Mechanisms of Action at the Level of System Function.- 5. Interactions with VIP and the Other Extrinsic Modulatory Systems.- 6. Cholinergic Influences in Plasticity, Memory, and the Potential Cholinergic Deficit in Alzheimer’s Disease.- 7. Overview.- 8. References.- 5 Acetylcholinesterase in the Corte.- 1. Introduction.- 2. Biochemistry of AChE.- 3. Histochemistry of AChE.- 4. Organization of the Neocortex.- 5. Biochemistry of Cholinergic and Cholinesterase-Rich Cortical Circuitry.- 6. Pharmacology and Physiology of Cholinergic Cortical Circuitry.- 7. General Enzymotectonics of Neocortex.- 8. Ultrastructural Distribution of AChE.- 9. Sources of Cortical AChE.- 10. Organization of the AChE-Rich Innervation from Basal Forebrain.- 11. Development of AChE Innervation to Neocortex.- 12. Transient AChE in Cortex.- 13. Potential Functional Implications of the AChE-Rich Innervation of Neocortex.- 14. References.- 6 GABA-Peptide Neurons of the Primate Cerebral Cortex: A Limited Cell Class.- 1. Introduction.- 2. Observations.- 2.1. Pyramidal Neurons Are Not Immunoreactive for Known Peptides.- 2.2. GABA Neurons Make Up a Large Proportion of Cortical Neurons.- 2.3. GABA Neurons Belong to Several Varieties of Cortical.- Intrinsic Neuron.- 2.4. All Cortical Neuropeptide Neurons Have a Similar Morphology.- 2.5. Many Peptide-Immunoreactive Cortical Neurons Are Immunoreactive for GABA.- 2.6. All GABA Neurons Are Not Immunoreactive for Known Peptides.- 2.7. Can Different Classes of GABA-Peptide Cortical Neurons Be Identified?.- 3. What Are the Functions of Cortical Peptide Neurons?.- 4. Conclusions.- 5. References.- 7 Number of Neurons and Synapses in Primary Visual Cortex.- 1. Introduction.- 2. Concentration of Neurons.- 2.1. Monkey.- 2.2. Cat.- 2.3. Rabbit.- 2.4. Rat.- 2.5. Mouse.- 2.6. Man.- 2.7. Discussion.- 3. Total Numbers of Neurons.- 4. Pyramidal and Nonpyramidal Cells.- 4.1. Rat Visual Cortex.- 4.2. Other Visual Cortices.- 5. Densities of Synapses.- 5.1. Counts of Total Numbers of Synapses.- 5.2. Symmetric and Asymmetric Synapses.- 5.3. Discussion.- 6. General Discussion.- 7. References.- 8 Electrophysiology of Hippocampal Neurons.- 1. Introduction.- 1.1. Theta Activity.- 1.2. Field Potentials.- 1.3. Functional Role.- 2. Electrotonic Structure.- 3. Membrane Conductances and Action Potentials.- 3.1. Sodium (Na+).- 3.2. Chloride (CI-).- 3.3. Calcium (Ca2+).- 3.4. Potassium (K+).- 4. Local Circuitry and Cellular Interactions.- 4.1. Cell Types and Connections.- 4.2. EPSPs and IPSPs.- 4.3. Population Synchronization.- 5. Neurotransmitters.- 5.1. Acidic Amino Acids.- 5.2. GABA.- 5.3. Acetylcholine.- 5.4. Norepinephrine.- 5.5. Serotonin.- 5.6. Dopamine.- 5.7. Histamine.- 5.8. Adenosine.- 5.9. Peptides.- 6. Plasticity.- 6.1. Paired-Pulse Inhibition.- 6.2. Paired-Pulse Facilitation.- 6.3. Frequency Facilitation.- 6.4. Long-Term Potentiation.- 6.5. Learning and Memory.- 7. Epileptogenesis.- 8. Conclusion.- 9. References.- 9 The Hippocampal Formation of the Primate Brain: A Review of Some Comparative Aspects of Cytoarchitecture and Connections.- 1. Introduction.- 2. Etymology and Nomenclature.- 3. Phylogenetic Considerations.- 4. Comparative Cytoarchitectonics.- 4.1. Longitudinal Levels of the Hippocampal Formation.- 4.2. Cytoarchitecture of the Main Body of the Hippocampal Formation.- 4.3. Cytoarchitecture of the Uncal Hippocampal Formation.- 5. Neurohistochemistry.- 5.1. The Main Body of the Hippocampal Formation.- 5.2. The Uncus and Genu of the Hippocampal Formation.- 6. Connectivity.- 6.1. Extrinsic Afferents.- 6.2. Intrinsic Afferents and Efferents.- 6.3. Commissural Afferents and Efferents.- 6.4. Extrinsic Efferents.- 6.5. Summary and Conclusions.- 7. Fiber Tracts of the Hippocampal Formation.- 7.1. The Alveus.- 7.2. The Fimbria.- 7.3. The Fornix.- 7.4. The Dorsal Fornix.- 7.5. The Callosal Perforating Fibers of the Fornix.- 7.6. The Angular Bundle and Perforant or Temporoammonic Pathway.- 7.7. Superficial Presubicular Pathway.- 7.8. The Hippocampal Commissures.- 8. Immunohistochemistry.- 9. Functional Considerations.- 10. Abbreviations.- 11. References.