I. The Thalamus of Primates (E.G. Jones). 1. Introduction. Basic subdivisions of the thalamus. 3. Nuclear parcellation of the thalamus in respresentative primates. 4. Histochemistry of the monkey and human thalamus. 5. The cell types of the primate thalamus. 6. Chemical identities of relay neurons. 7. Basic circuitry of the primate thalamus. 8. Neurotransmitters and their receptors in the thalamus. 9. Regional projections of the thalamus. 10. Thalamic nuclei as components of defined functional systems. 11. Summary. 12. Acknowledgments. Abbreviations. 14. References. II. Visual Cortex (J.H. Morrison, P.R. Hof and G.W. Huntley). 1. Introduction. 2. General organization of primate visual cortex. 3. Neurotransmitter links to cortical circuits: overview. 4. Excitatory circuits. 5. Inhibitory circuits: GABAergic interneurons. 6. Monoaminergic and cholinergic innervation of primate visual cortex. 7. Activity-dependent plasticity of neurotransmitters, receptors and other neurochemicals in adult monkey area V1. 8. Chemoarchitectonics: chemical markers of regional heterogeneity. 9. Relationships between neurochemical phenotype, connectivity and human neuropathology: the visual cortex in Alzheimer's disease. 10. Acknowledgments. 11. References. 12. Abbreviations. Subject Index.