Fundamentals of Neuroscience by Prof. David Cox - 1

Ayyy, it's me again. Wonder what's new? I have completed the first part of my course "Fundamentals of Neuroscience" delivered by Prf. David Cox of Harvard University. It is a MOOCs course and you can easily find it online. Hmmm, I'm planning to share with you what I've learnt and my experiences for enrolling in this course, but covering everything in a single post would be tedious to read, so I will split it into 4 parts. My knowledge may not be correct since I'm only a high school student, so forgive me if I made some mistakes and I would derive great pleasure out of hearing your ideas. And let me use present tenses for conveniences.

Alright, let's get straight to the pointtt! Part 1 allows me to study The electrical properties of the neurons. This part is split into 4 smaller parts, let's call them 4 lessons. I will quickly go through the content of each lesson to give all of you an idea what's to expect in this course (in case some of you are thinking of taking the same course, hehe)

• Lesson 1: The Resting Potential

• Lessons 2: Passive Membrane Properties

• Lesson 3: The Action Potential

• Lesson 4: Action Potential Propagation

In lesson 1, we gain an insight into the basis of electricity in neurons. Some of you may have already known that neurons communicate with each other by sending out electrical signals, and there are elaborate mechanisms behind this seemingly simple idea. When at rest, neurons also have electricity in itself, this is called the resting potential. Take note that when measuring the membrane potential, neuroscientists always use the outside of the cell as "ground" or reference point, so the value of the resting potential is around - 75mV. Then we are introduced to two forces that cause the resting potential: diffusion and electrostatic forces. There are even illustrations and animations to aid us in understanding the activities of these two forces. The process is quite hard to explain in limited words so you can search for it online. Then we come to study the Nernst potential equation, which allows us to calculate an individual ion's potential at equilibrium. Again, take note that equilibrium does not mean that there is no movement of ions, it's just the movement of ions in and out of the cell are equal. The other formula is the GHK equation, which is kinda similar to the Nernst equation but allows us to calculate resting potential of various ions in the neurons, and is named after three prominent scientists in field: David Goldman, Alan Hodgkin and Bernard Katz. Hmm, but how can neurons allow for the passing of one particular kind of ions to create the resting potential? It is the work of ion filters. Nature has a lot to surprise us, and one of which is ion filters. For ions with opposite charges like Cloride and Sodium, it would be an easy work (same charges repel, opposite charges attract) but how about Sodium and Potassium, they are both positive and their sizes are incredible small, so how can we filter them? In fact, in aquatic solution, there are a myriad of water molecules roaming in the solution, when an ion comes into contact with water, these water molecules would be attracted to that ion (since water molecule is polarised, the positive end of it will go away from the Sodium ion (as an example) while the negative end of it surrounds that ion). This happen in a way that form a solvation shell around the given ion, and each ion has its unique solvation shell. Thanks to this, ion channels (made up of protein) would replicate the shape of the solvation shell and therefore, while one ion can flow through with ease, the others wouldn't. Fascinating, isn't it? We also learn about the active Na+/K+ bumps, which is already covered in Biology classes at school. After each lesson, we are taken to a field trip and for lesson 1, we are allowed to join the virtual visit of the Museum of Science to understand more about interaction between charges and we attend a class about human brain dissection. Although the content of the course is quite academic, it is in fact enjoyable since the layout is user-friendly and the explanations are straightforward and comprehensible. I don't wanna spoil the fun so I skipped through all of the academic features, if you want to know more, just contact, I'm willing to guide you through this ^x^.

Thank you for taking a look at my website. Hope you will enjoy your day. I will come back soon.

Here are some displays for you to know more about it (they are copied from my own writing so they would not be at best quality, sorry for that ^^)

Here is the structure of a neuron, as you can see, a neuron is mainly made up of a cell body, pendrites and an axon. The outer surface of the neuron is the bilayers of lipids. In the axon, we can see the myelin sheath, the is a wonder of nature and I will go into details later.

Here is the solvation shell of Sodium, it looks kinda like this, this is just a simple drawing for you to understand with ease.