eSagan 🇮🇳 @crackurbones@qoto.org
Joined Nov 2019
New Intelligence on How the Female Brain Works - WSJ
https://www.wsj.com/articles/what-makes-the-female-brain-different-11583528929
The brain regions affected by declines in #estrogen during #menopause include the hypothalamus, which regulates body temperature; the brain stem, which regulates sleep and stress; the hippocampus, or memory center; and the amygdala, which is the emotional center of the brain.
🔸 How do we get the neurotransmitter out of the vesicle and out of the cell and make it able to go and affect another cell?
🔸 There is a cell membrane, but the cell also has a lot of other membranes that are inside. Inside in these things called organelles.
🔸 The fusion between two different membranes happens constitutively. And the challenge for a neuron is to stop that.
We can't have these vesicles fusing with the plasma membrane, with the cell membrane all the time. That would not work.
🔸 What we want to do is we want to make the vesicle fuse to the membrane **only when the action potential arrives** .
🔸 So the key to neurotransmitter release is two things:
1. We're going to suppress constitutive or ongoing release.
2. We are going to link the release that we want in the synaptic terminal to the action potential.
🔸 There is a molecule that suppresses constitutive release within the synaptic terminal.
🔸 When the action potential comes in, the membrane potential increases and it opens a particular type of ion channel that lets in calcium ions.
🔸 These are positively charged ions with two positive charges. And, these calcium ions are going to flood in to the synaptic terminal, and that is going to trigger release.
🔸 The release that happens of vesicles that contain neurotransmitters is only when the calcium concentration increases.
🔸 All that happens when the calcium concentration increases is that the vesicular membrane and the the cell membrane fuse.
And the calcium concentration only increases when the action potential arrives.
🖼️ Image source: screen-grab from https://www.coursera.org/learn/neurobiology/lecture/o4ZMY/neurotransmitter-release
The WALKING WATER Mystery (in SPACE and SLOW MOTION!) - Smarter Every Day 160
https://www.youtube.com/watch?v=KJDEsAy9RyM
🌱 ECO HOME: No Power, Water & Sewer connection in this house.
https://www.youtube.com/watch?v=LB5gzj0bmq0
New model is very good at predicting the charging time of a supercapacitor while also incorporating physics on the micro and nano scales. https://t.co/N7xGGWI81a
https://twitter.com/PhysicsWorld/status/1237389694918250496?s=09
🧫 The synaptic terminal has these entities here, which are called synaptic vesicles, and they're small, little organelles.
🧫 They're little vesicles made of a membrane; just like the cell has a cell membrane, these vesicles have a vesicular membrane.
The neurotransmitters are within the vesicular membrane.
🧫 And, the neurotransmitter can be any number of a number of different molecules — #Glutamate, #GABA, #Serotonin, #Dopamine, #Acetylcholine, #Glycine, #Norepinephrine, #Epinephrine, #Histamine, #ATP.
🧫 The neurotransmitters are packaged in vesicles. The second thing that's important about this is that we can use the synthesis of a #neurotransmitter as a therapeutic tool.
🧫 So, for instance, Dopamine is missing in #ParkinsonsDisease.
It's not that dopamine isn't made per say, that's there's a problem with making it — it's that the cells that make it die.
🧫 There's something called 'Mass Effect', which means that you take the starting chemical (the substrate) and then through a series of enzymatic processes reaction, through a series of enzymatic reactions, we end up with a neurotransmitter.
🧫 In the case of Dopamine, what we do to treat in most people with Parkinson's is that we give them the substrate — and so that (drug) is what is commonly known as #Sinemet or #Parcopa.
🧫 So we flood the system with substrate, and the goal is to get a little bit of that neurotransmitter out of the system.
Image source: https://in.pinterest.com/pin/11962755239342046/?lp=true
Machine learning illuminates material's hidden order
https://phys.org/news/2020-03-machine-illuminates-material-hidden.html
Extreme temperature can do strange things to metals. In severe heat, iron ceases to be magnetic. In devastating cold, lead becomes a superconductor.
The case for an AI that puts nature and ethics first, not humans
https://thenextweb.com/neural/2020/03/07/the-case-for-an-ai-that-puts-nature-and-ethics-first-not-humans-syndication/
Without Facebook and Twitter, This is How Organisms Stayed Connected Billions of Years Ago
https://www.news18.com/news/buzz/without-facebook-and-twitter-this-is-how-organisms-stayed-connected-billions-of-years-ago-2530549.html
⚡ Neurons sit at a resting membrane potential of about -65 mV.
⚡ Small little potential differences — which are on the order of less than one millivolt up to, say, five millivolts — can travel along the neuron.
⚡ They might travel, but they're going to peter out pretty quickly. So, it's not going to work to simply rely on these small potential changes if we have to go long distances.
⚡ The longest neuron that we possess is a cell that has a cell body right at the base of the spine. And it sends one process all the way down to the toe, and it sends another process all the way up to the medulla.
⚡ Because neurons are so long, we use something called the Action Potential. And the Action Potential goes really far up and comes back down in height. So, it's about 100 mV.
⚡ So from the resting memory potential (-65mV) to the top of the Action Potential — which happens at around, say, 20mVs or so — we're talking about roughly 100 millivolts of difference. And that can get communicated all the way up. That's not going to get lost.
⚡ And what carries that Action Potential is: —
We looked at potassium being in very high concentration in a cell and much lower outside a cell. The reverse is true for sodium.
And so, the sodium comes flooding in, and because it's positively charged, that's what takes the cell up to this very high membrane potential.
⚡ Now the ability for a neuron to communicate using an Action Potential is a slow process unless we add one more thing, and that is an insulator —essentially a very nice insulator —called myelin.
⚡ Electrical language of cells ⚡
⚛️ In a living organism, we don't use electrons. Instead, we use molecules that have a charge, and those molecules are called ions.
⚛️ So these ions are present within the context of cells. And all cells have what are called cellular membranes, which are made up mostly of fat. It's important to understand that most of a membrane is fat. And this is like a layer of oil surrounded by a couple layers of water.
⚛️ Let's consider an ion that's positively charged, and let's consider one to be potassium ion (K+).
⚛️ This potassium ion is very happy in water, but it can't get through oil. It's not gonna pass through there. So it's gonna bounce off this membrane. And the only way for it to get through is via a special place which we're gonna call an ion channel.
⚛️ The physical force for this potassium ion is to leave the cell because of lower concentration of ions outside the cell than in the cell (osmosis).
But, on the other hand, the cell is actually negatively charged. And outside the cell is grounded.
⚛️ The potassium ion is positive and so there's an electrical force that attracts it into the cell.
⚛️ The potential at which the physical (osmotic) force and the electrical force will be equal is where the membrane is gonna sit.
⚛️ And we have to worry about three ions -- the potassium ion, the sodium ion, which is also positively charged, and chloride ion. And once we take into consideration each of these ions, what we see is that this cell is going to sit at rest at about -70 to -60 millivolts (with respect to the potential outside the cell).
🔸 Motor neurons are a very special type of neuron. If they die, you can no longer move muscles.
🔸 The motor neurons are contained either in the brain stem or in the spinal cord. But, there are no motor neurons in the forebrain.
🔸 So the motor neurons in the brain stem move the face, move the mouth, move the larynx, and are responsible for speech and swallowing, facial expressions, things like that.
🔸 The motor neurons in the spinal cord are responsible for movements of all the arms, our legs, our trunk. All of our movement that we do with our body happens through the spinal cord.
I forgot to add the source to the original image. Here it is: https://www.reddit.com/r/IncredibleIndia/comments/fabyvd/meghalaya/
Meghalaya, #India Just in case you're not aware of: Meghalayan Age, named after #Meghalaya, is the latest age or uppermost stage of the Qua...
Physicists take snapshots of quantum measurement – Physics World
https://physicsworld.com/a/physicists-take-snapshots-of-quantum-measurement/
What #philosophy and #travel have in common: They both push boundaries to unlock new worlds
https://scroll.in/article/955225/where-philosophy-and-travel-meet-they-both-push-boundaries-to-unlock-new-worlds
Measuring iron in the brain can point to dementia
https://www.medicalnewstoday.com/articles/measuring-iron-in-the-brain-can-point-to-dementia
Anatomy 101: The Brain Science Behind Meditation | Yoga Journal
https://www.yogajournal.com/meditation/science-behind-being-present
Rainmaker1973Climate (@Rainmaker1973c@twitter.com) Tweeted:
In the search to find an environmentally friendly alternative for fossil fuels, scientists from the #TokyoUniversity developed a new technique for safely & efficiently producing 25 times more hydrogen fuel by using a specific type of rust and light source https://t.co/oKgzo0VyhP https://t.co/ALBFXt6SSZ https://twitter.com/Rainmaker1973c/status/1236556526212571136?s=20
#Astronomy Magazine (@AstronomyMag@twitter.com) Tweeted:
70,000 years ago, a nomadic star came within a light-year of the Sun, shaking up our solar system. https://t.co/WYdHYljkHH https://twitter.com/AstronomyMag/status/1236494398013276160?s=20
Joined Nov 2019
