Notes
A collection of fragments of understanding in the pursuit of deeper questions.
Contents
- Computational Vision
- Introduction to Data Science
- Translational Neuromodeling
- Deep Learning in Artificial & Biological Neuronal Networks
- Introduction to Neuroinformatics
- Intro to Neuroscience
- Systems Neuroscience
- Readings in Neuroinformatics
- Neurobiology of Consciousness
- Econometrics
- Principles of Finance
- Big Data & Databases
- Game Theory
- Intro to Blockchain
- Marketing Analytics
- Financial Accounting
- Fundamentals of Computer Science
- Foundamentals of Information Technology Law
- Statistics
- Computer Programming
- Macroeconomics
- EU Information Law & Data Economy
- Advanced Mathematics & Statistics
- Principles of Management
- Mathematics
- Microeconomics
Action Potential & Ion Channels
Ion Channels and the AP Ion channels are "digital", they are either open or closed. The amplitude of single channel current (i) depends on single-channel conductance (g) and "driving force" (). The probability of a V-gated Channel is dependent on the voltage (Na+, K+). The whole-cell current depends on single-channel conductance, driving force, number of open channels (n), and open probability ():
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Ion Channels Requirements & Design Challenges
- Selectivity: Ion filter mimics hydration of ion
- High Conductivity (Speed): approx. speed of diffusion in H2O but as a purely passive process.
- Na+ ions/channel = 10,000,000/s
- Ions/channel = 1000/ms - 10,000/ms
- More than 1000 times faster than membrane transporters and pumps. (Na+/K+ pump/ATPase = 100/s).
- Gating: Voltage gating involves V-dependent movement of charged channel structures.
- Inactivation vs. Closure: during inactivation the channel does not conduct during the stimulus. The inactivation of V-gated ion channels involves charged channel structures (ball).
- Specificity (>90%): K+ channels 99.99% versus Na+ (Ionic Radius: K+ 152pm, Na+ 116pm).
The Action Potential
The action potential propagation: 
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How can we increase conduction speed?
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High-Frequency Transmission Short AP duration is required for high-frequency firing and transmission. This characteristic is very important to perform Rate Coding.
Examples (Physiology & Pathology) Hyperexcitability in ALS patient-derived iPS motoneurons due to decreased K+ current. In this experiment, sample of skin from patients with sclerosis were taken. Based on these samples, they made stem cells and transdifferentiated them in motoneurons. They did current clamps to analyze spiking patterns in these cells, which highlighted that these cells presented hyperexcitability compared to control ones. And voltage clamps highlighted a decrease of potassium currents over sodium currents. Hence, one of the problems of these cells may be related to a decreased number of potassium channels.
