#Reflex Science

[diana-andraste]

Left: photographic capture of the cat righting reflex [Marey 1894] with zero angular momentum. Right: output of our algorithm controlling the cat shape through a skeleton rig with point masses.

Étienne-Jules Marey, animation of animals falling

[biologist4ever]

[fatedroses]

Something silly for the trio as I think about them encountering a cactuar out in the wilds. Well, more specifically a gigantuar. Here we have: Has taken many a needle before and is very afraid, the one who physically can't feel fear but knows exactly what's about to happen, and a freshly prepared tank who is about to get pin cushioned for the first time in his life.

[orgasmictomato]

2010_12_26_7257 (c1) (1)tag rsz s by Jim Via Flickr: Earth's Moon December 26th 2010 5:10am One shot, no stacking.... My new lens works fine. I see three UAP's in this shot traversing the moon.

[biologist4ever]

[alltingfinns]

Had a nap earlier today and I am starting to think I would get a lot more rest from sleeping if my brain didn't think every other dream needed 57 layers of worldbuilding. Had a fantasy dream where I was a prince/knight/general who fought with a sword and had a princess/priestess love interest. The part where I was also a woman in masculine attire didn't reduce the fantasy stereotypes. However, the alien invasion disrupting the ongoing war with the dragon king did a little bit. Even if the aliens referred to their own subsets (a genetically coded class system where larger size meant higher up the hierarchy) by goblins and ogres for some fantasy flavor, I guess. There was a whole lot of intrigue and infiltrating the aliens and finding defectors. And apparently my character learned how to fake being dead from a tough upbringing involving fights for inheritance. Humans were equal with the smallest aliens, both in the hierarchy and size. (During parts of the dream my pov was a midsize alien helping my original character.)

[untypicable]

Grounded Theory: Making It Up As You Go Along (But With Integrity)

This week, in a break from stalking the usual parade of sociological ghosts—Marx, Weber, Bourdieu and the like—I thought we’d do something different. Let’s talk about something alive, terrifyingly current, and capable of causing existential dread in postgraduate students across the globe: methodology. More specifically, Grounded Theory. Now, if you’ve never come across Grounded Theory, count…

[freepassbound]

One of the best pieces of American oration ever. But how many of the people here will actually read it?

Douglass believed in the United States, and demanded that it live up to the ideals it expressed. He lived long enough to see his work succeed with the abolishment of slavery... and fail, in a sense, with the establishment of segregation. He never stopped believing, and he never stopped working.

Read the entire thing. To do anything less would be an insult to one of the greatest Americans in our history.

yearly required reading

[orgasmictomato]

2010_12_26_7257 (c1) (1)tag rsz s by Jim Via Flickr: Earth's Moon December 26th 2010 5:10am One shot, no stacking.... My new lens works fine. I see three UAP's in this shot traversing the moon.

[ravenlofts-rick-and-concerto]

If your muses had familiars what would they be?

{ That is a good question and while most of the 'party' doesn't technically have access to the 'Find Familiar' spell... if they did this is what I think everyone would have. (I also realize that some of these probably don't fit the spell but fuck it. I also added Beth and Morty even though they are technically dead.)

Artificer/Rick- A flying snake

Bard/Concerto- A hella sassy raven or maybe an otter

Cleric/Jerry- A mouse

Ranger/Summer- A crocodile

Rouge/Morty- A grey and white cat

Paladin/Beth- A Pseudo dragon.}

[presswoodterryryan]

🧠 Unlocking the Secrets of the Nervous System: Ariel’s Ultimate Guide!

By Alice My big sister Ariel isn’t just an amazing artist—she’s also a brilliant scientist! 🔬✨ She just wrote an incredible paper all about the brain, spinal cord, and reflexes, inspired by her passion for understanding how the body works and her curiosity about how science helps people recover from neurological injuries. In this fascinating work, she delves deep into the complex interplay…

[drchristophedelongsblog]

Not all movement is a direct response to an external stimulus !

The different sources of movement:

- Voluntary movements:

o Initiated by a conscious intention, often in response to internal stimuli (a thought, a desire) or external stimuli (an object to catch, a sound to follow).

o Involve complex cognitive processes of planning, coordination and execution.

o Example: Deciding to raise a hand to ask a question.

- Reflex movements:

o Automatic, rapid responses to external stimuli, without conscious intervention.

o Provide vital functions (protection, balance) and are controlled by simple neural circuits.

o Example: removing hand from heat source.

- Rhythmic movements:

o Repetitive, stereotyped movements, such as walking, running or breathing.

o Often generated by specific neural networks in the spinal cord or brain stem.

o Example: Walking without thinking.

 - Emotional movements:

o Express emotional states (joy, sadness, anger) and can be voluntary or involuntary.

o Involve complex interactions between the limbic and motor systems.

o Example: clenching one's fists in anger.

Stimuli and movement: a complex relationship

While all reflex movements are responses to stimuli, the same cannot be said of voluntary, rhythmic movements. The latter can be triggered by internal stimuli (thoughts, memories, emotions) or by conscious intentions, without the need for an external stimulus.

In short, human movement is a complex phenomenon resulting from the interaction of many factors:

- Stimuli: internal or external, conscious or unconscious.

- The nervous system: central and peripheral, which integrates sensory information and generates motor commands.

- Muscles: which execute movements.

- Cognitive factors: attention, motivation, emotions, which influence the planning and execution of movements.

 To find out more:

- Movement disorders: Diseases such as Parkinson's disease and Huntington's chorea demonstrate the importance of a harmoniously functioning motor system.

- Cerebral plasticity: The brain is capable of reorganizing itself in response to experience, enabling the acquisition of new motor skills and recovery from injury.

- Brain-machine interfaces: These technologies enable external devices to be controlled by thought, opening up new prospects for the rehabilitation and enhancement of human capabilities.

Go further

[myrawjcsmicasereports]

Myocardial ischemia due to oculocardiac reflex in patient with myocardial hypertrophy undergoing upper blepharoplasty by Andrew Albokrinov in Journal of Clinical Case Reports Medical Images and Health Sciences

Abstract

Oculocardiac reflex (OCR) is caused by pressure or traction of intraorbital structures and results in bradycardia. Patients with myocardial hypertrophy can suffer myocardial ischemia due to reduced coronary vascular reserve. In this case report we describe patient who developed myocardial ischemia as a result of OCR induced by traction of intraorbital soft tissue structures during upper blepharoplasty.

Keywords: Oculocardiac reflex, Myocardial ischemia, Myocardial hypertrophy

Introduction

The oculocardiac reflex (OCR) is a reflex afferent limb of which is trigeminal nerve and efferent limb is vagus nerve. OCR is usually caused by pressure on the oculus, traction of ocular muscles, or traction of the conjunctiva resulting in bradycardia and hemodynamic compromise in severe cases [1].

The incidence of OCR in eyelid surgery ranges between 20 and 25% [2, 3].

Patients with myocardial hypertrophy are prone to myocardial ischemia due to mismatch of myocardial mass and its vascularization or reduced coronary vascular reserve [4]. The incidence of myocardial ischemia in patients undergoing cosmetic surgery is unknown.

Treatment of OCR includes immediate cessation of the stimuli and atropine administration [1].

Case report

A 52-year-old female patient with no history of angina pectoris, normal physical exercise tolerance (>6 MET), normal ECG had upper blepharoplasty under local anesthesia. From her history was known that she had apical hypertrophic cardiomyopathy with no clinical manifestation.

Ten minutes after beginning of surgery during traction of medial hernia sac (Figure 1) patient felt bad and complained of severe retrosternal burning pain radiating to left hand. Standard monitoring (2-lead ECG, NIBP, SpO2) was set up and showed severe sinus bradycardia and hypotension (HR 32 bpm, BP 65/28 mmHg) and ST segment depression >2 mm in V5 lead. Surgery was stopped. Treatment included epinephrine to restore normal HR and BP (4 boluses 10 mcg each) and then phenylephrine to restore diastolic BP and hence coronary perfusion pressure (3 boluses 25 mcg each). Acetylsalicylic acid 300 mg was administered to chew by patient. Twelve-lead ECG showed ST segment depression in leads V3-V5. Twelve minutes later normal HR and BP were achieved (MAP > 80 mm Hg) and ischemic ECG changes and patient’s complaints disappeared. Fentanyl 50 mcg was administered after stabilization. Additional local anesthesia of intraorbital soft tissue structures was advised and fulfilled by the surgeon. Then surgery was finished uneventfully. Troponin I (CITO Test) two hours after surgery was negative. Twelve-lead ECG two hours after surgery and next day were normal. The postoperative course was uneventful and the patient was discharged on the next day.

Discussion

Treatment of OCR involves immediate cessation of the stimuli and atropine administration. In cases of hemodynamic depression epinephrine administration is needed [1].

In cases of myocardial ischemia and hypotension coronary perfusion pressure must be restored to break the vicious circle when hypotension leads to coronary hypoperfusion, which leads to myocardial ischemia and depression, which leads to hypotension. Besides, myocardial depression leads to increased left ventricle diastolic pressure, which decreases subendocardial circulation and worsens myocardial ischemia. So, in this case atropine was not considered as it does not act as a pressor and promptly enough to restore coronary perfusion pressure and normal circulation. We used epinephrine as the initial agent as it acts as a pressor and chronotropic agent. When HR established > 60/min, boluses of phenylephrine were used to achieve MAP > 80 mm Hg and not to provoke tachycardia.

Optimal intraoperative BP for noncardiac surgical patients remains controversial. But MAP 65 mm Hg is considered as a threshold for intervention [5]. Taking into consideration the fact that patients with reduced coronary vascular reserve can require higher coronary perfusion pressures we chose MAP 80 mm Hg as a hemodynamic target.

ECG changes showed apical (but not another) myocardial ischemia, which corresponded with zone of myocardial hypertrophy. This suggests that perfusion of hypertrophic myocardium is highly dependent on coronary perfusion pressure.

OCR prophylaxis includes premedication with atropine and retrobulbar block [1]. In this case surgery under local anesthesia was planned and no preoperative anesthesiologist’s consultation was obtained. Premedication by surgeon is impractical in our clinic. The practice and incidence of premedication by surgeon is not described in literature. Besides, premedication with atropine can lead to tachycardia and myocardial ischemia in cardiac patients [1], thus it should be used as a case-based approach. Retrobulbar block is not safe enough and is not used in this type of surgery [6].

Conclusion

Oculocardiac reflex can occur due to traction of intraorbital soft tissue structures. Patients with myocardial hypertrophy can develop myocardial ischemia due to oculocardiac reflex. Circulation in hypertrophic myocardium is highly dependent on coronary perfusion pressure.

[riddlesandlies]

I keep seeing people say "play Outer Wilds, no, I can't tell you anything about it". Bitch. It's an exploration game about astronauts fucking around in space, doing archeology, astrology astronomy and science, with the gameplay itself consisting mostly of navigation in various 3D spaces with your legs or your trusty spaceship. There are interesting characters and tantalizing mysteries. It will require a fair bit of reading and thinking, it will sometimes test your speed, reflexes and precision. The story is about curiosity, courage, compassion, music, death, rebirth, and the terrifying vastness of space. The game can induce agoraphobia, claustrophobia, fear of heights, fear of depths and that which is unseen or hidden. Your character has four eyes and can roast marshmallows on any bonfire. Bitch.

[littleflorablr]

I believe the Norton books - I want to say specifically The Borrowers Afield, but don't quote me on that - mention that borrowers' hands and feet are proportionately a little larger than humans', which could translate to improved gripping ability.

Incidentally, if you want to, I'd be interested in seeing the scope of the vitamin D examination post expanded; it recently occurred to me that most house borrowers are unlikely to get much access to protein or fresh produce, due to those being refrigerated and/or bulky

We already know the borrowers’ size puts them at a slight disadvantage when it comes to survival, but how does their size positively impact them? (scientific/biology answer)

Hi everyone! This post is going to be a little continuation of the previous post I did about borrowers’ fall damage. If you haven’t read it, I recommend checking it out (here)! In this post, I will talk about some scientifically proven advantages that borrowers have. BTW word count is like 1000.

Throughout all the borrower stories I have read, I have found some interesting constants: borrowers heal quicker than humans, recover from illness faster than humans, are genetically faster and stronger relative to their body mass, need little to no vitamin D to survive, etc. In fact, the original book by Mary Norton and a few of its adaptations mention a peculiar “borrower sense” that Arrietty and Pod Clock seem to have, which allows them to sense humans before they appear. However, scientific backing and evidence is rarely provided. Here, I will evaluate the legitimacy of many borrower conceptions.

1. Superhuman agility, durability, and strength

Borrowers tend to be depicted as having the superhuman ability to climb up structures relatively the height of skyscrapers with no sweat, but does this have to do with the muscle they built up over time, or does the answer lie in their genetics and body make-up? My non-proven scientific hypothesis is that both of these answers are correct. While yes, the fact that borrowers spend their entire lives exercising definitely plays a role in their off-the-charts abilities, there is also a not-so-talked-about genetic and biology explanation for this, the first reason tying back to my previous physics post.

I explained earlier that bone strength relative to body mass is greater for borrowers than it is for humans, because bone strength is determined by cross-sectional area (length squared) and body mass is determined by volume (length cubed). Therefore, body mass decreases faster than bone strength. This same idea can also be applied to muscle tissue, meaning borrowers’ muscles become stronger relative to their body mass as borrowers are scaled down. For example: a borrower 1/18th the height of a human would have 1/(18x18)th the bone strength and muscle strength, and 1/(18x18x18)th the body mass. This means they are relatively 18 times more durable and stronger than humans. Bone strength correlates to durability and muscle strength correlates to strength. This concept also explains why ants are able to lift 50x their body weight.

This increase in muscle strength, other than increasing borrower’s raw strength, will also allow borrowers to jump higher and move more quickly.

More reasons why real-life borrowers would be comparatively way faster than humans has to do with shorter neural distances, less inertia, and relativity to size. First, the distance between the borrower’s brain to their hand, foot, legs, etc is way smaller than it is for humans. This means that their brain is incredibly more efficient when it comes to sending signals to parts of the body, increasing borrowers’ reflexes and coordination. Also, their legs would be able to move faster because muscle contraction time is less. Muscles work by contracting, and smaller animals’ muscles are able to contract faster relative to their body size because their muscle fibers are shorter and therefore electrical signals and chemical reactions move through them more quickly.

To explain how less inertia helps borrowers move faster, lets reflect on the most basic physics principle: force = mass x acceleration. Mass and acceleration are inversely proportional, therefore someone with a smaller mass needs less force to reach the same acceleration. To put it simply, a greater inertia makes it harder for somebody to overcome momentum. Because borrowers have almost no inertia compared to humans (body mass is directly proportional to inertia), they would have to put in almost no force to accelerate quickly, take sharp turns without losing balance, stop quickly, and jump high. This is because they are able to overcome momentum very easily. Think about how squirrels or mice are able to dart around very quickly.

Almost done! Lastly, I just wanted to mention genetics. While strength and speed are greatly impacted by someone’s own exercise routine and diet, the genetic lottery can also have a say in someone’s athleticism. For example, the way somebody’s fat is distributed after they eat and the efficiency of their metabolism are often hereditary traits. I would assume that after generations upon generations of training in the walls, staying in great physical shape, and an unhealthy/unreliable diet has led borrowers to perfect their metabolism within their genes to suit their needs. I believe they would have a very slow metabolism so they could store their energy for longer and go longer without eating. I also believe their borrower’s fat would naturally be stored in places on their body to keep them warm, for example their joints.

Fun fact: the odd haircut poodles are famous for is a result of competitive swimming. Poodles were often raced in the water, so they were shaved all the way down to make them faster. However, people kept the fluff on their joints to keep poodles warm while leaving the smallest amount of fur as possible.

Okay, I got a little off topic but do with that information as you will. In conclusion, borrowers should be scientifically faster, stronger, more durable, and more agile than humans (comparatively). Imagine a borrower darting around on the floor in a blur, or jumping onto areas taller than them and off ledges ten times their height. I hope this was as interesting to you as it was to me! I appreciate everyone who took the time to read this it makes me feel super good when people like the same stuff as me. If you want to learn more borrower science, please vote below on what I should research next:

[biologist4ever]