2 Week Neuroscience Lecture Notes PDF

신경과학원리 화 6교시, 목 4교시, 캠B146 정수영 교수 뇌∙인지과학부 Introduction • “Neurophilosophy” • • No separation of mind and brain Glia and neurons • Glia insulate, support, and nourish neurons. • Neurons • • • • Process information Sense environmental changes Communicate changes to other n...

신경과학원리 화 6교시, 목 4교시, 캠B146 정수영 교수 뇌∙인지과학부 Introduction • “Neurophilosophy” • • No separation of mind and brain Glia and neurons • Glia insulate, support, and nourish neurons. • Neurons • • • • Process information Sense environmental changes Communicate changes to other neurons Command body response Copyright © 2016 Wolters Kluwer • All Rights Reserved The Neuron Doctrine • Histology • Microscopic study of tissue structure • Nissl stain • Facilitates the study of cytoarchitect ure in the CNS 출처: https://pathologycenter.jp/method-e/nissl.html Copyright © 2016 Wolters Kluwer • All Rights Reserved The Neuron Doctrine—(cont.) • Golgi stain (developed by Camillo Golgi) revealed two parts of neurons: • Soma and perikaryon • Neurites: axons and dendrites Copyright © 2016 Wolters Kluwer • All Rights Reserved Basic Parts of a Neuron Copyright © 2016 Wolters Kluwer • All Rights Reserved The Neuron Doctrine—(cont.) • Cajal’s contribution • Neural circuitry • Neurons communicate by contact, not continuity. • Neuron doctrine • Neurons adhere to cell theory. • Use of Golgi stain Copyright © 2016 Wolters Kluwer • All Rights Reserved Neurites in Contact, Not Continuity Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron • The soma • Cytosol: watery fluid inside the cell • Organelles: membrane-enclosed structures within the soma • Cytoplasm: contents within a cell membrane (e.g., organelles, excluding the nucleus) Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron—(cont.) • The nucleus • Gene expression • Transcription • RNA processing Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron • Neuronal genes, genetic variation, and ge netic engineering • Neurons differ from other cells because of specific genes. • Sequencing of human genome • Genetic basis of many diseases of the ner vous system • Role of genetic engineering and gene targe ting Copyright © 2016 Wolters Kluwer • All Rights Reserved Gene targeting in mice Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron • The soma—(cont.) • Ribosomes the major site for protein synthesis • Rough endoplasmic reticulum Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron • The soma—(cont.) • Protein synthesis also on free ribosomes; polyribosomes Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron • The soma—(cont.) • Smooth ER and Golgi apparatus • Sites for preparing/sorting proteins for delivery to different cell regions (trafficking) and regulating substances Copyright © 2016 Wolters Kluwer • All Rights Reserved Khan, 2022, Mol Neurobiol 59:1 The Prototypical Neuron • The soma—(cont.) • Mitochondria • Site of cellular respiration (inhale and exhale) • Krebs cycle • ATP is cell’s energy source. Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron • The neuronal membrane • Barrier that encloses cytoplasm • ~5 nm thick • Protein concentration in membrane varies. • Structure of discrete membrane regions influences neuronal function. Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron • The cytoskeleton • Not static • Internal scaffolding of neuronal membrane • Three structures • Microtubules • Microfilaments • Neurofilaments Copyright © 2016 Wolters Kluwer • All Rights Reserved Alzheimer’s disease and the neuronal cytoskeleton • Neurons in a human brain w ith Alzheimer’s disease. • (a) neuronal neurofilaments • (b) tau within neurofibrillary tangles • (c) superimposition Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron • The axon • Axon hillock (beginning) • Axon proper (middle) • Axon terminal (end) • Differences between axon and soma • Rough ER does not extend into axon. • Protein composition: unique Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron—(cont.) • The axon terminal • Differences between the cytoplasm of axon terminal and axon • No microtubules in terminal • Presence of synaptic vesicles • Abundance of membrane proteins • Large number of mitochondria Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron • The synapse • Synaptic transmission • Electrical-to-chemical-to-electrical transformation • Synaptic transmission dysfunction leads to mental disorders. Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron • Axoplasmic transport • Anterograde (soma to terminal) vs. retrograde (terminal to soma) transport Copyright © 2016 Wolters Kluwer • All Rights Reserved Copyright © 2016 Wolters Kluwer • All Rights Reserved The Prototypical Neuron • Dendrites • “Antennae” of neurons • Dendritic tree • Synapse—receptors • Dendritic spines • Postsynaptic (receives signals from axon terminal) Copyright © 2016 Wolters Kluwer • All Rights Reserved Copyright © 2016 Wolters Kluwer • All Rights Reserved Classifying Neurons • Classification based on number of neurites • Single neurite • Unipolar • Two or more neurites • Bipolar: two • Multipolar: more than two Copyright © 2016 Wolters Kluwer • All Rights Reserved Classifying Neurons • Classification based on dendritic and somatic morphology • Stellate cells (star-shaped) and pyramidal cells (pyramid-shaped) • Spiny or aspinous Copyright © 2016 Wolters Kluwer • All Rights Reserved Classifying Neurons • Classification by connections within the CNS • Primary sensory neurons, motor neurons, interneurons • Classification based on axonal length • Golgi type I • Golgi type II Copyright © 2016 Wolters Kluwer • All Rights Reserved Classifying Neurons • Classification based on gene expression • Creation of transgenic mice • Example of “ChAT-Cre mice” • Green fluorescent protein • Classification based on neurotransmitter type Copyright © 2016 Wolters Kluwer • All Rights Reserved Copyright © 2016 Wolters Kluwer • All Rights Reserved Glia • Function of glia • Support neuronal functions • Astrocytes • Most numerous glia in the brain • Fill spaces between neurons • Influence neurite growth • Regulate chemical content of extracellular space Copyright © 2016 Wolters Kluwer • All Rights Reserved Glia • Myelinating glia • Oligodendroglia (in CNS) • Schwann cells (in PNS) • Insulate axons Cross section of myelinated nerve fibers Copyright © 2016 Wolters Kluwer • All Rights Reserved Glia • Myelinating glia—(cont.) • Oligodendroglial cells • Node of Ranvier • Region where axonal membr ane is exposed Copyright © 2016 Wolters Kluwer • All Rights Reserved Other Non-Neuronal Cells • Ependymal cells • Microglia as phagocytes (immune function) • Vasculature Copyright © 2016 Wolters Kluwer • All Rights Reserved Concluding Remarks • Structural characteristics of the neuron provide insight into how neu rons and their different parts work. • Structure correlates with function. Copyright © 2016 Wolters Kluwer • All Rights Reserved