Fruit flies have concussions too

DROSOPHILIA Size-vs-Penny-1024x768
The fruit fly Drosophila Melanogaster is small. The size is not important to demonstrate the points I will introduce. Fruit flies can suffer brain concussions just like people can. Remember in Nature size is a relative scaleable function within compression/tension signalling networks. Let’s zoom in.

drosophala headThe image of a fruit fly head-on is at the Angstrom scale of electron microscopy the scale appearance shifts now tipping the tiny toward looming large transforming into a very different shape. But not really this shape is present we just can’t discriminate the tiny detail but the shape compression/tension is still there. Zoom in zoom out the shape coherence stays the same. Nature builds things this way. It’s like looking at the night sky overhead in our Vermont cabin. Some nights are simply translucent. Then I gaze into a quadrant with my binoculars revealing even greater density packed with sparkling stars. Working with fruit flies is going the other way in terms of shape size. The incredible thing is as you get smaller and smaller the richness just gets more dense on the details despite the shrinking. Everything is connected in this fashion. What a fruit fly can teach us is astonishing about ourselves as a species.

Drosophila Eye Development

All kinds of Frankenstein type of experiments can be performed distorting the very shape of the eyes in this particular comparison of gene substitution. Ethic review committees around the planet do not hesitate for one instant toward approving such robust feature distorting experiments, after all these flies are so tiny. Looking like two hulking helmeted linemen on opposite sides of the gridiron, what happens at the point of impact collision when heads are rammed into each other? Can fruit flies sustain minor brain injury? The same thing that happens to human heads that massive deceleration against head collisions causing brain tissue warping then distorting back inside an elastic rebound of recovery of shape. What mimicking brain concussions fruit flies can reveal to us about acceleration/deceleration brain injury. It all starts with gravity the first sensation at the force of acceleration that is at the core of signalling on our planet inside all manner of creatures small to large in scale. What happens inside a gravity based brain injury?

I will be citing from a remarkable brain injury report from a fruit fly model :

Drosophila model of closed head traumatic brain injury Rebeccah J. KatzenbergeraCarin A. LoewenbDouglas R. WassarmanaAndrew J. PetersenaBarry Ganetzkyb,1, and David A. Wassarmana, published in The Proceedings of the National Academy of Sciences Of The United States of America (PNAS) October 14, 2013 http://www.pnas.org/cgi/doi/10.1073/pnas.1316895110

We share many activities with fruit flies like mating. Essentially all creatures are programmed to procreate by gene passing-on learned survival skills from one generation to the next. One of the remarkable skill capacities of the fruit fly is their ability to fly to navigate within 3 dimensions. This reflex I have termed gravity-space-time (GST) orienting to gravity. A fruit fly flies oriented relative toward the position of the horizon. Somehow the fruit fly has a reflex that us humans call a yawn which is this Einsteinian type of gravity calibrating reflex. When the Drosophila are subjected to impact as in head type impact some don’t fly anymore. Hence a minor traumatic brain injury is first a vestibular injury. That is what fruit flies teach us. But Nature is very frugal- one system also overlaps into another system. Yawning and mating are very close in the organization of central control networks in human brain stems. A brain damaged fruitfly will also not mate following an injury, remember they can’t even orient themselves.

DROSOPHALA MATING 3886269648_5071ac68fa_bBut Nature has done a remarkable job on accomplishing transmission of information with the survival instinct of reproduction. Once that event is accomplished Nature has not evolved an elaborate display of repair especially for brain injury. Basically at that point things become disposable. I’m sorry if I appear brutal but that is the scale of accomplishment, brain injury is not something Nature has resolved in evolution. But let’s profit from these experiments, what are the main events following a brain concussion ?

HELMET HELMET giants_broncos_rainThe impact shakes the very exoskeleton of the Drosophila. The researchers devised a clever device to inflict the sudden deceleration/acceleration of a violent collision energy impacting into the brain substance. Despite the significant size change between Drosophila to humans the mathematical link that determines neuron network design as architecture that encompasses the tensegrity tension/compression integrity exists in a chiral left/right architecture of diverse neurons involving neurotransmitters covered by surface glial cells with a blood-brain-barrier.  “Glial cells are relevant since they incorporate the innate immune system. The fly brain has a similar inelastic hard covering cranium within the exoskeleton surrounding the brain, the cuticle. The cuticle defines the shape of the head to provide protection for the brain.  

From the front (ventral according to the neuraxis). Indicated are the superior lateral and superior medial protocerebra (s l pr, s m pr), the left and right protocerebra divided by the pars intercerebralis (pars in). Visible components of the olfactory pathways are the antennal lobes (ant lo), the mushroom body alpha lobe and beta, gamma lobe complex. Su oes g = suboesophageal ganglion. Dr. Xuejun Sun, Department of Psychology, Dalhousie University,

From the front (ventral according to the neuraxis). Indicated are the superior lateral and superior medial protocerebra (s l pr, s m pr), the left and right protocerebra divided by the pars intercerebralis (pars in). Visible components of the olfactory pathways are the antennal lobes (ant lo), the mushroom body alpha lobe and beta, gamma lobe complex. Su oes g = suboesophageal ganglion. Dr. Xuejun Sun, Department of Psychology, Dalhousie University,

The fly brain is organized into three regions, the protocerebrum, deutocerebrum and triocerebrum, which are homologous to the forebrain, midbrain and hindbrain, respectively of humans. The Drosophila has a fluid hemolymph acting as a blood-like carrier system for macrophages and nutrients separating the brain from the cuticle. Other researchers have used the fruit fly to study a variety of neurodegenerative disorders, effects on memory and sleep patterns. ” ….fly and human brains have common architectural, cellular and molecular features. The fly brain is bilaterally symmetrical and is joined to the ventral ganglion that innervates the body, similar to the way that the spinal cord innervates the human body.

The researchers managed to mimic the contusion contortion behaviour of a brain rattled so-to-speak during the violent contact between brain  against the hardened exoskeleton cuticle. The Wisconsin-Madison group described the similarities as: ” Using the brain inducing damage model, we found that fundamental characteristics of human traumatic brain injury (TBI) also occur within the brains of Drosophila. We also found that primary injuries exacerbate the normal age-related decline in flies. This may explain why human TBI is associated with cognitive and neurodegenerative disorders that are typical of older individuals and why TBI outcomes are worse in older individuals.” In other words traumatic brain injury may contribute to accelerated aging within the fruit  fly brain’s structures.

How do you give a concussion to a fruit fly? It’s called a HIT (high [head]  impact trauma) device. Looking somewhat lie a Jack-in-the-box, a standard screw top plastic vial holding un-anesthetized fruit flies in the bottom under a cotton ball plug attached to the free end of a spring is pulled onto the side then released in a horizontal sweep. Essentially the conditions inside the plastic vial are a miniature version of a violent bus accident careening over a precipice abruptly accelerating then brutally colliding, fruit fly bodies flying everywhere in all manner of horrible contact against the inside surfaces.

Jack__in_the_box___Skulljester_by_WillemXSMThe attached vial to the spring hits a polyurethane pad nearby. The randomness of impact injuries to the fruit fly occupants in terms of location and strength is the same type occurring with of falls, sports collisions and automobile crashes that produce brain trauma injuries that happen with people with variable force primary injuries. Let’s get back to the bus crash for fruit flies.Let’s examine the sequence of brain trauma. What are the genes  that trigger following minor head trauma following a HIT to their brain zone ?

Minor traumatic brain injury in humans affects the brain as potential neurodegeneration occurring over time passing by affecting memory capacity and sleep cycles. That is the reason that these researchers opted to study as if miniature bus crashes of fruit flies together since fruit flies and human brains have common architectural with cellular and molecular features. But the transition also points out the features important how Nature measure’s gravity itself within such small organisms. The pointing finger is how does the sensing of gravity work for a fruit fly? What it reveals is that like Einstein with his warping of space with gravity at the scale of stars, we have Nature warping gravity at the sensing of information. Gravity sensing becomes intelligence at the scale of the fruit fly as it breaks contact into the atmosphere with a flying organism. This marvel happens in ways we still do not comprehend.

wing tensegrity fruit fly

Gravity warping as command structure of architectural design with a flying fruit fly defying gravity itself. The design of the wings of the fruit fly is the mathematical design of floating tension/compression of tensegrity in motion a la Snelson. Recall that tensegrity can support structure without gravity. Mass is suspended in the accomplishment of the design as a distributed field space capable of vibrating at 200 beats per second.

Researchers at the University of Washington used an array of high-speed video cameras operating at 7,500 frames a second to capture the wing and body motion of flies after they encountered a looming image of an approaching predator.

“Although they have been described as swimming through the air, tiny flies actually roll their bodies just like aircraft in a banked turn to maneuver away from impending threats,” said Michael Dickinson,  UW professor of biology and co-author of a paper on the findings in the April 11 issue of Science. “We discovered that fruit flies alter course in less than one one-hundredth of a second, 50 times faster than we blink our eyes, and which is faster than we ever imagined.”

Eight images of fly show banked turn

In the midst of a banked turn, the flies can roll on their sides 90 degrees or more, almost flying upside down at times, said Florian Muijres,  a UW postdoctoral researcher and lead author of the paper.

“These flies normally flap their wings 200 times a second and, in almost a single wing beat, the animal can reorient its body to generate a force away from the threatening stimulus and then continues to accelerate,” he said.

“The brain of the fly performs a very sophisticated calculation, in a very short amount of time, to determine where the danger lies and exactly how to bank for the best escape, doing something different if the threat is to the side, straight ahead or behind,” Dickinson said.

“How can such a small brain generate so many remarkable behaviors? A fly with a brain the size of a salt grain has the behavioral repertoire nearly as complex as a much larger animal such as a mouse. That’s a super interesting problem from an engineering perspective,” Dickinson said.

Here in the elegant words of John Bender and Mark Frey are the ways Nature measures and senses gravity in insects : Invertebrate solutions for sensing gravity/ Current Biology Vol 19 No 5 R186 -R190. “In the absence of wind, an animal standing at rest is acted upon only by the force of gravity. An animal might not explicitly calculate the global gravitational vector per se, but rather may actively modulate local joint angles and torques to implicitly compensate for gravity’s pull. In many instances, insects and crustaceans measure the angles of their appendages’ joints using clusters of mechanosensitive hairs, called hair plates.  drosophila_suzukii08 SEM In one such cluster, the prosternal organ of insects, a grove of hairs sprout from the forward part of the thorax. As the animal’s head moves, it brushes against these hairs. By monitoring the deformation of each hair, the animal can precisely determine the orientation of its head relative to its thorax. The prosternal organs are especially well-developed in highly visual animals such as flies and mantids — animals for which the body-centered location of visual stimuli is very important. Hair plates also serve similar roles on leg, wing, and body joints.”

In addition to measuring joint position, invertebrates also have  specializations for measuring joint load. Whereas our bones have no active sensory capacity and instead our sensors are imbedded in surrounding, soft tissues, many invertebrates are equipped with sensory arrays embedded in the exoskeleton at strategic points and with specific orientations. Called campaniform sensilla in insects, lyriform organs in arachnids and centipedes, and cuticular stress detectors in crustaceans, these are similar in mechanism to the stretch and pressure sensors in human skin. It is not known whether these receptors were inherited from a common ancestor, but they clearly have convergent functions. Each of these invertebrate stretch receptors is composed of an oval-shaped slit which can be deformed by pressure along its short axis.”

drosophola Formation of the cephalic furrow in the anterior end of a developing

Drosophila- formation of the cephalic furrow in the anterior end of a developing embryo

“This induced deformation leads to ion flux, which is transduced and relayed to the central nervous system by dedicated afferent neurons. Insects possess additional stretch receptors called scolopidial organs. A subset of these, called chordotonal organs, are attached to inflexible connective tissue spanning joints inside the exoskeleton. Scolopidial organs act as strain sensors, measuring the distance between their attachment points as well as its rate of change.

“But then how would an animal determine which stimuli merit a more interactive response? This question is relevant not just to invertebrates, but to humans
as well. Possibly, the answer lies in the fact that gravity is constant, whereas stimuli requiring a change in behavior are likely to be unpredictable or irregular and thus
more salient. Intriguingly, making the distinction between irrelevant and evocative stimuli requires two different neural responses to gravity: postural feedback always needs to account for gravitational pull, but task-level control should be adaptive and ignore such static inputs. The neurobiology of this sort of parallel control architecture has yet to be fully worked out in any animal. Invertebrates display complex
and robust behavioral equilibrium reflexes with extremely limited neural resources, a paradox which serves to experimentally highlight the underlying neural mechanisms.”

As the transition from boneless insects occurs within the continuum of evolution capacity to use architectural design to solve problems, sensing gravity is a highly coordinated neural activity. A brain concussion is essentially first sensed within  vestibular systems as a motion detected within the force of deceleration. The fruit fly as a member of the invertebrates suffers concussion like effects that evoke a secondary immune response coupled with an accelerated aging effect within the longevity of this organism.

The fruit fly has exquisite vision capacity to evade predators. Attempting to mimic that visual scene unfolding has opened the field of virtual reality goggles. In the latest understanding of how to accomplish merging virtual reality for vision goggles that immerse the participant into experiencing seamless vision with no disturbing vestibular effects that produce dizzying nausea. One company the upstart Oculus Rift described in WIRED magazine by author Peter Rubin reveals the jumps of understanding that inventor Palmer Luckey used to create the sensation of what the engineers call ‘presence’ for the brain’s interaction of the fake reality. Listen to what the device describes in its design, “The biggest challenge in creating realistic VR is getting the image to change with your head movements, precisely and without any perceptible lag. The Rift fuses readings from a gyroscope, accelerometer, and magnetometer to evaluate head motion. Even better, it takes 1,000 readings a second, allowing it to predict motion and pre-­render images, shaving away precious milliseconds of latency.” What this device begins to accomplish is the critical importance of fusing the visual images with head movement using a gyroscope with an accelerometer to orient the projected visual field without delay of processing for our brain to interpret at the rate of 1000 verification per second. Its like the transition of watching movie frames once transforming at the critical speed to reduce any flicker so that the images fuse as one continuum. What Luckey and software engineer John Carmack have matched is how the head facing forward uses a camera to orient the dimensions of an external wall as what are termed fiducial markers to calibrate the interaction of the viewers spatial information to the viewers position upon the virtual reality scene. Let’s take a step back here. Neither of these men are brain scientists they are virtual reality problem solvers.

Inside Oculus rift virtual reality googles with individual eye lenses creating 'presence' within the viewers own brian seamless to the visual experience

Inside Oculus rift virtual reality googles with individual eye lenses creating ‘presence’ within the viewers own brian seamless to the visual experience

But the gist of their VR goggles highlights the significance of head position as facing forward to the perceived image related to the translation as either the image shifts or the head shifts with a moving body. In other words our world is like this virtual world that drives the smooth image over our perception is dependant on a matrix of space being created around us as we experience ordinary scenes of life.  Even a fruit fly at the scale of this organism can perform this kind of 3 D interaction within its neural network to evade predators. The critical aspect is the sensing of gravity within a matrix of space for the organism to live and thrive. Even for a fruit fly concussion this effect deteriorates the creatures ability to perform since its own accelerometer gyroscope shape sensing is perturbed which affects the very length of its lifespan. When a fruit fly suffers a concussion the interaction within the perceived matrix of X-Y-Z space is unfused from the flawed positioning of its mechanosensitive foot plates. 3D navigation is lost yet everything is linked to this acute vestibular perception including the post secondary effected genes that react to the vestibular injury. Vestibular signalling is at the apex of signal interpretation. Vestibular sensing is gravity based shape sensing at the core of hierarchies that Nature has established during the advance of evolution. Injure this primary system degrades the entire harmony. The predator wins.

We as vertebrates also actively sense the position and direction of gravity as a primary vestibular system that coordinates to our autonomic systems. This gravity sensing system takes a specific hit of vulnerability with traumatic head injury. We will also age prematurely with concussive head deceleration affecting a more rapid cognitive decline which the professional football players are already revealing with their life shortening chronic encephalopathy deficits.

 

 

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Montreal Grandmother, Agnes Kent was saved by Raul Wallenberg from certain death, when he provided papers for her and her Mom to escape away from the Nazis. Today when asked what that escape meant, she replied,"Remind people, that while statesmen and whole countries remained silent and did nothing, a single individual chose to act, with ramifications that proved enormous. Similar choices confront us today. Write that simple truth she said, it can never be repeated often enough because the world keeps forgetting it."
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