2.3 The Zoo of Ion Channels. Next: 2.4 SynapsesUp: 2. Detailed Neuron Models Previous: 2.2 Hodgkin-Huxley Model Subsections The equations of Hodgkin and Huxley provide a good description of the electro-physiological properties of the giant axon of the squid. These equations capture the essence of spike generation by sodium and potassium ion channels. In this section we give an overview of some of the ion channels encountered in different neurons. Here, C is the membrane capacity, Isyn the synaptic input current, and Ik is the current through ion channel k. With being the maximum conductance of ion channel k, Ek is the reversal potential, and m and h are activation and inactivation variables, respectively. 2.3.1 Sodium Channels Apart from fast sodium ion channels, which are qualitatively similar to those of the Hodgkin-Huxley model and denoted by INa, some neurons contain a `persistent' or `non-inactivating' sodium current INaP. 2.3.2 Potassium Channels 200...2000 ms); cf. 2.3.2.1 Example: Slowly firing neurons 0); cf.
Neuro Illusions. Biology Archives. Yale Research Shows People with a Mental Illness are More Likely to Smoke New research from Yale University shows that people with a mental illness are much more likely to smoke cigarettes and are less likely to quit smoking than those without mental illness. Those in the United States with a mental illness diagnosis are much more likely to smoke cigarettes and smoke more heavily, and are less […] Continue reading... New Study Presents “Water World” Theory for the Emergence of Life A new study describes how electrical energy naturally produced at the sea floor might have given rise to life, assembling decades of field, laboratory and theoretical research into a grand, unified picture.
Continue reading... Neurobiologists Block the Effects of Stress By deleting the REDD1 gene in mice, researchers from Yale University were able to block the synaptic and behavioral deficits caused by stress. Continue reading... New Research Tests Theory that Life Originated at Deep Sea Vents Continue reading... Kimball's Biology Pages. Ways to Search These Pages Search Engine. Enter desired term(s) in box above right and click on "GO". (Advantage: finds all occurrences; disadvantages: may return trivial hits, your choice of term may not match mine).
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About These Pages The pages represent an online biology textbook. It has always seemed to me that the many parts that make up the subject of biology are related to each other more like the nodes of a web than as a linear collection of independent topics. About the Author John W. The HOPES Brain Tutorial (Text Version) « HOPES. Base mass refined range nucleus basic control CNS ganglia Welcome Introduction^ The brain is a complex organ with many components. These multiple components work together to maintain basic life processes, like breathing, body temperature and blood pressure, as well as higher functions like creative thought and emotions.
This is an introduction to some of the basic terms used when describing the brain and its major parts. Central Nervous System^ The brain is a part of the central nervous system (CNS). Brain Cells^ The brain is made up of two types of cells: neurons and glial cells. Directions^ The top of the brain is called the superior side, and the bottom is called the inferior side. Protection^ The brain is surrounded and protected by the rigid, bony skull and three membranes, or meninges. Cerebral Cortex^ The outermost and top layer of the brain is the cerebral cortex. Brain Hemispheres^ The cerebral cortex is divided down the middle, from front to back, into hemispheres, or halves. Putamen^ Contents. Review of Clinical and Functional Neuroscience. Enkephalin Interneurons Spinal Cord Wikipedia. Propagation of the Action Potential (Section 1, Chapter 3) Neuroscience Online. 3.1 Changes in the Spatial Distribution of Charge Once an action potential is initiated at one point in the nerve cell, how does it propagate to the synaptic terminal region in an all-or-nothing fashion?
Figure 3.1 shows a schematic diagram of an axon and the charge distributions that would be expected to occur along the membrane of that axon. Positive charges exist on the outside of the axon and negative charges on the inside. Now consider the consequences of delivering some stimulus to a point in the middle of the axon. If the depolarization is sufficiently large, voltage-dependent sodium channels will be opened, and an action potential will be initiated. Consider for the moment "freezing" the action potential at its peak value. Its peak value now will be about +40 mV inside with respect to the outside. 3.2 Determinants of Propagation Velocity A great variability is found in the velocity of the propagation of action potentials. Time Constant. Space Constant. Propagation Velocity. Neurons and Support Cells. Please note that this guide is intended to complement, NOT to replace, textbook readings (i.e., Kandel et al.).
Histology textbooks are NOT recommended for the study of nervous tissue. Most histology textbooks begin with relatively insignificant, and often misleading, details rather than emphasizing features important for understanding nervous tissue function. Recommended are selected chapters in in Kandel, Schwartz and Jessell, Principles of Neural Science. Kandel's classic text is remarkable. The extended table of contents can be read, just as if it were a "capsule" textbook. In about two dozen pages following immediately after the chapter listing, all of the subheadings from every chapter are presented, each as a complete sentence.
Senior author Eric Kandel received the 2000 Nobel Prize for Physiology and Medicine for work on "signal transduction in the nervous system" (Kandel's Nobel Prize lecture). Choose: 5th edition, 2013, 4th edition, 2000, or 3rd. edition, 1991. The Opposite Side of Dopamine: The D2 Receptor. When most people think of dopamine, they think of things that can get you high. Things that feel good. Cocaine. Sex. Food. We imagine floods of dopamine in our brains as the pleasurable feelings take hold. And sure, sometimes it does. This current paper looks at the way we look at D2 receptor function. Bello, et al. In order to understand how the D2 receptors these authors are looking at work, we're going to have to go back to the basics of neurotransmission (for a more detailed explanation, see my SCIENCE 101 post here). (Source) What we're looking at here is a synapse, the space between one neuron and another where a signal has to get passed along. You can also see the little pink flip things on the presynaptic neuron.
But there's something missing in this charming picture, where it's been left out for simplification. Of course, we THINK that's what happens. But that was then. But what does it mean behaviorally? It means these Dopamine neuron D2 knockout mice like to move it move it! The Resting Membrane Potential. “Go” and “NoGo”