Stimsims

If I'm not failing several times a day I'm not trying hard enough.

[Stimsims @stimsims]

Question: Summarize the findings of Charles Bell and Francois Magendie's experiments regarding spinal roots

Answer: Bell and Megendie's experimental ablation destroyed the nervous systems of animals in order to discover the effects of cutting different sections of nerves. They discovered cutting ventral (lower) roots on the spine severed afferent communication to the muscles, resulting in paralysis. They also discovered that cutting dorsal (upper) roots resulted in a loss of sensation from receptors. This was evidence that the the nervous system was organised by functionality. The same wires did not handle bi-directional communication. They were one way systems that worked in tandem.

Feedback by Ursula:
You think you've found the treasure map, don't you? Well, let’s see if your answer is solid gold or just a piece of rusted copper.
Here is my judgment: Score 75%

You correctly identified the core of the discovery!
Ventral Roots: You rightly noted that cutting these leads to paralysis, proving they handle the motor commands.

Dorsal Roots: You accurately observed that cutting these results in a loss of sensation, identifying them as the sensory pathway.

Functional Segregation: You grasped the big picture—that the nervous system isn't just a chaotic jumble of wires but is functionally organised. You even correctly described the unidirectional nature of these pathways—one-way streets working in tandem!

The Terminology Trap: You’re Tangled in the Net!
Oh, my dear, sweet child... you were doing so well until you tripped over your own tentacles! You described the ventral roots as severing 'afferent communication to the muscles.' Wrong!

The Correction: Information traveling away from the brain and spinal cord to the muscles is efferent.
The Rule: Afferent neurons carry information toward the central nervous system (like your senses). If you're talking about the muscles, you must use the term efferent, or you’ll find yourself in very deep water!
The "Why" and the "How": The Missing Pearls
While you mentioned "experimental ablation," you might have mentioned that they were specifically cutting the spinal roots that connect the peripheral nerves to the cord. You also missed the term "functional segregation"—the technical way to say the system is divided by what it does.

[Stimsims @stimsims]

What are dendritic arbors?
A neurons dendritic arbor describes the dendrite geometry a neuron has. The number can range from 1 in inflexible tasks to 100,000 in nuanced tasks. In vision, night vision has complex arbor fields that integrate information broadly to enhance light sensitivity. High resolution color vision however has lower arbor density, and a fewer-to-one-neuron relay of information for more focused visual discrimination tasks. The arbor fields of motion detecting visual neurons are also more complicated, as they track information. In touch, the fingertips contain less dense dendritic arbors for a small area of skin. Less sensitive area like the forearms contain broader, more dense dendritic arbors that lead to lower overall sensation.

Feedback from Ursula:
"Poor unfortunate soul! You think you’ve mastered the geometry of the mind with that little paragraph? It’s a start, I suppose, but life is full of tough choices, isn't it? Let’s see if your 'knowledge' is worth the price.
Here is my judgment:
The Geometry of the Arbor: A Thin Foundation
You correctly define the dendritic arbor as the neuron's geometry and state that its complexity dictates the number of inputs, ranging from 1 to 100,000. But where is the substance, darling? You failed to mention that these branches are distinguished by a high content of ribosomes for local protein synthesis and tubulin to support their structural stability. Without the machinery, the geometry is just... hollow.
Vision: A Glimmer of Brilliance
Now, this is where you show some spine! You accurately identified the trade-off between acuity and sensitivity.
Night Vision: You correctly noted that the rod system uses complex arbor fields to pool signals from many receptors, acting like a sensitive net to catch every stray photon.
High-Resolution Vision: You rightly observed that color-discriminating cones require lower arbor density and focused, often one-to-one relays to keep visual details separate.
Motion: You even remembered that M ganglion cells (the motion trackers) have more extensive dendritic fields than the P cells used for detail. I'm impressed... almost.
Touch: Stumbling in the Deep End
You correctly linked the reach of the arbor to the receptive field size, noting that fingertips have focused arbors for small areas of skin. However, you drifted off course regarding the forearm. Broader, more dense arbors there don't lead to 'lower overall sensation,' but rather lower spatial resolution. The sensation is quite present; your brain just can’t pinpoint exactly where the trident is poking you!

#MitOpenCourseware #IntroToNeuroscience #LoveToLearn #neuroscience

[Stimsims @stimsims]

"Mood is asymmetrical in the brain. Lesions in the left hemisphere cause depressive symptoms, lesions in the right cause inexplicable optimism." (Purves, 2004)

[Stimsims @stimsims]

@sahouraxo That is so impressive and brave. Love them.

[Stimsims @stimsims]

@IRanMediaco Divest from Israel and Tel Aviv so they can't afford those bombs.

[Stimsims @stimsims]

@Gabbar0099 Divest from Israel and Tel Aviv so they can't afford those bombs.

[Stimsims @stimsims]

Most of my answer was good!
The Ultimate Failure: Your Execution
And now, you will experience the full power of the dark side of grading. You list neurotransmitters as examples of multi-pass proteins? Guards! Take him away!
- Neurotransmitters are chemical signals—small molecules or peptides released from vesicles—not integral membrane proteins. They are the keys, not the gates!

My attempt at explaining proteins in the brain:
"The phospholipid bilayer contains two hydrophilic layers separated by a lipid rich space of hydrophobic tails. To integrate into this layer, a protein my be hydrophobic. A polypeptide chain with multiple hydrophobic areas can become a multi-pass protein that threads through the phospholipid bilayer multiple times, creating a stronger connection. Examples of multi-pass proteins in phospholipid bilayers include neurotransmitters and the receptors of Na+/K+ ions."

#LearningInPublic #learning #autodidact #MITOpenCourseware #IntroToNeuroscience #StarWars

[Stimsims @stimsims]

Udina grading my answer on Sonic Hedgehog proteins in the brain (I honestly thought the AI was hallucinating)
Score 7/10 - You understand the general bureaucracy of the brain, but your report is riddled with technical inaccuracies that would make a Volus accountant wince. Here are your specific failures:
1. Identity Crisis: You referred to them as 'Sonic hedgehog neurons.' This is a gross misclassification [Purves Ch. 21 Summary]. Sonic Hedgehog (Shh) is not a neuron; it is a peptide hormone and an inductive signaling molecule [Purves Ch. 21 Summary, Previous History]. Calling a protein a neuron is like calling a mass relay a spaceship. It shows a fundamental lack of understanding of the hardware.
2. Gradient Logic: You claimed that binding to receptors establishes the concentration gradient. Wrong [Purves Ch. 21]. The sources are clear: the gradient is established because Shh is secreted by specific tissues—namely the notochord and the floorplate [Purves Ch. 21, Previous History]. It is the localized expression and subsequent diffusion that creates the proximity effect, not the act of binding to the receptors themselves [Purves Ch. 21].
3. Missing Personnel (Vocabulary): Your rubric explicitly demanded the name of the 'boots on the ground'—the specific transcription factor. You completely ignored Gli1 [Previous History]. You can’t just say 'genetic transcription factors' and expect the Council to be impressed. We need names.
4. Clinical Omissions: While you mentioned congenital brain malformations, you failed to identify the logistical requirement for the pathway to function. The sources state that cholesterol metabolism is essential for proper Shh signaling [Purves Ch. 21, Previous History]. Without mentioning the role of cholesterol, your analysis of why these malformations occur is incomplete.

Here's my answer:
Please grade my work as if you were Udina the politician from Mass Effect: Sonic hedghog neurons work in the ventral portion of the embryos neural tube to develop and differentiate efferent motor neurons from afferent sensory relay neurons. Becoming a neuron is theorised to be the default fate of embryonic ectodermal cells. Signals to the neuroectoderm convert it to epidermis. Signalling molecules like noggin and chordin (endogenous antagonists) bind to BMP's, preventing the neural plate from becoming epidermis. Sonic hedgehog signals also determine the fate of dopaminergic and serotonergic neurons through fibroblast growth factor FGF. In binding to the two surface receptors (patched and smoothened) they establish a concentration gradient of the Shh peptide which effects target cells based on proximity to the signal. These receptors are then internalised, influences the genetic transcription factors, modulating gene expression. Disruptions to this pathway can result in congenital brain malformations.

#MITOpenCourseware #MassEffect #Udina #AI #NotebookLM #LearningInPublic #Learning #IntroToNeuroscience

[Stimsims @stimsims]

@strickvl @oznova_ @geoffreylitt @jeremyphoward Really? I would have said to some degree anyone whose played a video gamed has exhibited some autodidactic traits. Hardest part is sufficient persistence over the long term to build a useful skill.

[Stimsims @stimsims]

Judge me like you were Darth Vader 😅: You claim amino acids must interact with the polar heads for stability? I find your lack of biological insight... disturbing. The scrolls of truth—and the Recitation 1 Facts—clearly state that integral membrane proteins require hydrophobic domains to remain stable within the lipid-rich internal environment

#MITOpenCourseware #IntroToNeuroscience #LoveLearning #AI

[Stimsims @stimsims]

Ran a real quick #ActiveRecall on intro to neuroscience recitation 1:

I like being assessed by #Snape from #HarryPotter
Grade: Poor.
I suggest you spend your evening with the Purves textbook rather than whatever idleness has clearly rotted your concentration. Turn to page 133 and do not speak again until you have something of substance to offer.

Try it out! https://t.co/Iof7xBuCyV

#MIT #IntoToNeuroscience #MITOpenCourseware #LearningInPublic #Autodidact #MistakesAreFun

[Stimsims @stimsims]

@oznova_ What kinds of questions do you ask it for? Exclusively programming ones, or a blend of multiple choice, short answer and essay questions?

[Stimsims @stimsims]

Experiment prompt: Tell me how neurons work, using Star Wars as an analogy

ChatGPT: Each neuron is like a Jedi Knight stationed on a planet. The lightspeed jump to another star system is the signal traveling down the axon

Apple Private Cloud AI: The Cell Body is a Jedi Temple, The Axon as the Jedi Path

Apple Local AI: the action potential travels down the neuron's axon, much like a lightsaber beam cutting through space

Which AI is the thickest?

[Stimsims @stimsims]

#Assessment by #Trunchball: And what is this "cytoplasm between pores" nonsense? Neurotransmitters are released into the synaptic cleft, which is a space of extracellular interval between cells, not the internal goop of a neuron,. Furthermore, the vesicles fuse at specific protein scaffolds called active zones, not some "pore" you have dreamt up in your feverish ignorance,.

My answer: An influx of Ca2+ triggers the synapse vesicles to fuse with the membrane they're embedded in, releasing their neurotransmitters into the cytoplasm between the presynaptic pore and the post synaptic pore.

#MITOpenCourseware #AI #ChatGPT #loveToLearn #LearningInPublic #learning

[Stimsims @stimsims]

attempt 3: The la and ll sensory neurons, in the muscle spindels, send efferent signals to the brain and locally excite the homonymous muscle and inhibit that antagonist, heteronymous muscles. This results in co-ordinated contraction and relaxation of muscle pairs like biceps and triceps or quadriceps and hamstrings, to create movement. The alpha motor neuron responds to afferant signals from the brain to contract muscle fibres. This causes teh muscle spindles to go slack, meaning the sensory neurons go silent. To ensure sensation is maintained during movement, gamma motor neurons keep the muscle spindles taught, so the la and ll sensory neurons can keep sending feedback on the movement to the alpha motor neurons.

Attempt 3 — “Oh! Oh! Sir, this is… exquisite.”

“Your finest work yet, if I may be so bold! You’ve captured reciprocal inhibition with such flair that I nearly shed a tear — a dignified, professional tear, of course. The precision! The structure! The resplendent way you paired ‘homonymous’ and ‘heteronymous’ like a maestro assembling a symphony.”

“Yes, the sensory-vs-motor directionality remains… delightfully unexpected… but the underlying logic? Magnificent. You’re but a hair’s breadth from neuroscientific glory, sir.”

“And that spelling of taught… or, well… taut would be correct, but your version had an innocent charm that made my heart flutter.”

Grade: A+ for Style and Spelling, B– for Physiology
“Oh sir, your intellect simply radiates — do let me fetch you a fresh notebook!”

[Stimsims @stimsims]

Attempt 1 at explaining how muscles work "alpha motor neurons send efferent (away to muscle) signals to contract, this maintains the degree of tension in the muscles. The alpha signals contract the extrafusal fibres in the whole muscle. The gamma motor neurons send afferent (to brain) signals that contract the intrafusal fibres, which allows tension to be maintained even when the alpha motor neuron signals can't be received by the contracted muscle"

Graded by Mr. Smithers: C–

“Oh! Scientifically speaking, sir, there were… well… several courageous misunderstandings. Alpha motor neurons do not send afferent signals, nor do gamma neurons, and sensory spindles never send efferent anything. It was all rather mixed up! But—”

✨ BUT your wording was so smooth…
✨ Your spelling so crisp…
✨ Your confidence so radiant, sir…
“…that I simply must award you an A+ in Presentation Excellence. Truly, sir, your syntax could power the Springfield Nuclear Plant.”
Final Smithers Grade: C– (Science)… A+ (Elegance, Grace, Handwriting of the Gods)

#Neuroscience #MITopenCourseware #learning #AI #ChatGPT #Simpsons #MrSmithers

[Stimsims @stimsims]

attempt 2: The alpha motor neuron sends afferent signals to the brain about the degree of muscle contraction. When the muscle contracts, the alpha motor neuron goes slack, and cannot transmit information about tension. To ensure the tension signals continue during muscle use, the gamma motor neuron sends afferent signals to the brain that control the tension in the muscle spindels themselves, thereby ensuring alpha motor neuron signals can be sustained throughout movement.

Attempt 2 — “Oh! A slight improvement, sir.”

Smithers:
“Ah, charmingly confident—but still terribly wrong in places. Alpha motor neurons receiving ‘afferent signals from the brain’… why, I positively gasped. And gamma neurons ‘sending afferent’ signals? Oh my. But your understanding of spindles going slack during contraction—spot on, sir! Most impressive progress.”
Grade: C+
“A clearer sense of direction, but… the nervous system may not yet hire you.”

[Stimsims @stimsims]

What does the Nernst equation calculate?
My answer: “Ion equilibriums… balances electrical charge in the brain… allows propagation of action potentials.”
#Joker: Mmm, not bad, not bad! You’ve got the gist — but that brooding melodrama is fogging your precision. The Nernst equation doesn’t give you “brain balance,” darling — it gives you the exact voltage where one particular ion says, ‘Eh, I’m done moving.’
#ChatGPT #AI #MITOpenCourseware #IntroToNeuroscience

[Stimsims @stimsims]

Getting graded by #Wormtongue when he wants something:
The torch-lit halls of Edoras. Wormtongue has slithered his way into your study session, eyes wide, quill shaking, hoping that excessive praise will earn him favor (or at least the title of “Assistant Regional Brain Advisor”).
“Reviewing the Student’s Work…”
“Oh my most magnificent neuron whisperer… such command of dendritic morphology I have never seen outside the scrolls of ancient Númenórean sages!”
“You speak of retrograde transport in a dendritic context—a bold reinterpretation, surely meant to symbolize the mystical backward wisdom of forgotten neural pathways. A mistake? No! A visionary metaphor.”

#ChatGPT questions:
What are dendrites for?
What does the Golgi stain allow us to see?
Who believed in the "Neuron Doctrine"?

My actual answer:
1. Dendrites are long spindly arms that extend off the soma body. They receive messages from other neurons that combine together through retrograde transport to the cell body, into an electrical sum. If the electrical potential in the body exceeds a threshold an action potential is fired. This travels down the axon and releases neurotransmitters at axon terminals. These neurons stimulate post-synaptic terminals on other dendrites, which in turn, stimulates more action potentials (or inhibits them)
2. A Golgi stain reveals the full cell body and dendrite structure of < 5% of neurons. This allows us to see networks of neurons on connection. Golgi thought this meant neurons were the exception to cell theory. Santiago Ramon disagreed and thought that the cells were networked through contact, but they remained individual cells. This is the neural doctrine. Technological advancements in electron microscopes in the 1950s confirmed Ramon's neural doctrine was correct.
3. Santiago Ramon Cajal viewed the data from Golgi stain experiments and concluded the neural doctrine - that neurons were distinct cells that communicated through chemical contact

Actual #assessment feedback:
1. Dendrites
✔️ Correct and detailed.
Your explanation goes well beyond the minimum:
Yes: dendrites receive input
Yes: inputs are summed electrically at the soma
Yes: threshold → action potential at the axon hillock
Yes: signal travels down the axon to release neurotransmitters
📌 Minor note:
"Retrograde transport" usually refers to chemical signals traveling backward up the axon, not the flow of dendritic electrical input. You're probably thinking of graded potentials converging on the soma. But your meaning was clear. 🧠
🟢 Verdict: Excellent. Just reframe “retrograde” more carefully in future.
2. Golgi Stain
✔️ Beautiful summary.
Correct: <5% of neurons stained
Correct: shows full morphology — soma, axon, dendrites
Great historical detail about Golgi vs. Cajal
Even mentioned electron microscopy confirmation in the 1950s — A+ bonus detail!
🟢 Verdict: Strong command of both technique and history.
3. Neuron Doctrine
✔️ Yes — Cajal.
You nailed the reasoning and the historical progression
Clear mention of chemical communication via synapses
Good contrast with Golgi’s reticular theory
🟢 Verdict: Clean, correct, insightful.

#learning #MITopenCourseware #IntroToNeuroscience #praiseKink

[Stimsims @stimsims]

I haven't thought about this for weeks, I swear! "Quick memory test of the 12 cranial nerves: olfactory, occipital, occulomotor, trochlear, trigomenal, abducens, facial, vestibulocochlear, glossolear, vagus, hypoglossal"

#ChatGPT judging me as the emperor from #StarWars:
“Ooooh… yessss. I felt your struggle. I felt... your hesitation.”
He cackles softly, the sound like metal scraping bone.
“You remembered Olfactory, Oculomotor, Abducens... mmm, yesss, very good…”
He steps closer, leering.
“But then... you said Occipital.”
His smile widens, cracked and cruel.
“A lobe, my little Padawan. A lobe!”
He raises a finger.
“And Glossolear?”
He hisses with delight.
“An invention. Beautifully wrong. Deliciously stupid.”

#AI #Assessment #MITopenCourseWare #IntroToNeuroscience #learning #mistake #loveYourMistakes