malberigi's blog

Rod and cone cells are proven photoreceptors of the eye, and responsible for scotopic and photopic vision.  Natural circadian rhythms are physical, mental, and behavioral changes that follows a daily cycle.  This rhythm is tuned to environmental influence and can be reset with exposure to light.  Mice and people that lack rods and cones still posses the ability to reset their circadian clock, meaning rods and cones are not the only way to perceive light.  Retinal ganlion cells (RGCs) are specialized neurons that receive visual information from photoreceptive neurons (rods and cones) on the retina and project into the brain.  Melanopsin has been identified with green flourescent protein (GFP) labeling to be present in RGCs which were previously thought to act only as output cells from rods and cones.  Melanopsin is a protein that, according to the amino acid sequence, is very similar to proteins found in rod and cone cells such as rhodopsin and color opsins.    Circadian rhythm experiments have concluded that eyeless mice are unable reset their circadian clock, but mice genetically modified to lack rods and cones can reset their circadian clocks.  This means that the mechanism for setting this circadian clock lies within the retina and is still photosensitive in blind animals.  Recent experiments tested if melanopsin could act as the mechanism to set circadian rhythm, modify pupil size, and influence conscious visual perception.

Rod and cone cells are proven photoreceptors of the eye, and responsible for scotopic and photopic vision.  The natural circadian cycle is tuned to environmental influence and can be reset with exposure to light.  Mice and people that lack rods and cones still posses the ability to reset their circadian clock, meaning rods and cones are not the only way to perceive light.  Melanopsin is a protein that, according to the amino acid sequence, is very similar to proteins found in rod and cone cells such as rhodopsin and color opsins.  Melanopsin has been found to be present in retinal ganglion cells, which were previously thought to act only as output cells from rods and cones to the rest of the brain.  Circadian rhythm experiments have concluded that eyeless mice are unable reset their circadian clock, but mice genetically modified to lack rods and cones can reset their circadian clocks.  This means that the mechanism for setting this circadian clock lies within the retina and is still photosensitive in blind animals.  Recent experiments tested if melanopsin could act as the mechanism to set circadian rhythm, modify pupil size, and influence conscious visual perception.

Even if the brain is not bombarded with high amounts of sensory information, neuronal activity does not cease to occur.  There are high amounts of synaptic transmission that are non-random, and this non-random activity is hypothesised to influence the creation of engrams, the physical representation of memories. Optogenetics involves the use of light to control the synaptic transmission of neurons genetically modified to express light sensitive ion channels.  The Clozapine N-oxide (CNO) injections in mice take at least an hour to stimulate neuronal activity and is not a realistic depiction of real-time memory processing.  Running neuronal labeling, training, and retrieval tests with mice using optogenetics might depict formation of engrams more accuratly.  Scientists could include female mice in a separate experimental group that undergoes the same synthetic memory generation.   Male mice were tested in order to rule out any discrepancies resulting from a difference in hormones, and the subsequent affect on memory retrieval.  It would be interesting, however, to prove if there is a difference associated with hormones and memory.  This difference might explain why some sexes are more predisposed to certain neurological conditions associated with memory, such as women experiencing Alzheimer’s at higher rates.

There are many ideas for downstream experiements that could be utilized in order to delve into remaining questions resulting from this study.  Potential utilization of the more modern idea of optogenetics, which involves the use of light to control the synaptic transmission of neurons that have been genetically modified to express light sensitive ion channels.  The CNO injections used in this experiement take at least an hour to stimulate neuronal activity, which is not a realistic depiction of how memory processes work in real life.  Running the same labeling, training, and retrieval tests using a more realistic method of generating synthetic memories might depict more accurate and applicable results.  Another idea would be to include female mice in a totally separate experimental group that undergoes the same synthetic memory generation.  All male mice were utilized in these experiments in order to rule out any discrepancies that might result from a difference in hormones, and the subsequent affect on memory retrieval.  It would be interesting, however, to actually prove if there is a difference associated with hormones and memory.  This difference might explain why some sexes are more predisposed to experience certain neurological conditions associated with memory, such as women being more likely to experience Alzheimer’s.  

Travel is a constant part of any day, and is an important way to get to and from activities in a timely manner.  Even when there is no reason to leave the house, there are still methods of moving the body from one room to the next or up the stairs that constitute movement no matter how small the distance.  On a typical school day, the forms of travel may vary from walking to longboarding to driving. Each type of movement from point A to point B are carefully selected upon depending on the distance being traveled and time constraints.  I normally being my school day by walking out of my house and to my car.  I then drive the distance to campus from my house off campus, which is long and driving is normally necessary.  After I have parked my car I normally remove my longboard from the trunk in order to travel to class and on time because I have to park far away.  I will occasionally walk to class if the conditions do not permit longboarding.  I finish my day by driving home, parking my car, and walking into my house.  Each day I use about three modes of transportation which are specifically tailored to the distance and time needed to arrive where I need to be punctually.

Sharks are well adapted to the marine environment and habit all latitudes from shallow water to the abyssal pit.  There are several adaptations that allow them to swim without expending too much energy and enable them to maneuver quickly and with agility. The bodies of most shark species taper to points at both the snout and the tail, increasing their hydrodynamics as they chase after prey.  They also have a type of scale known as a denticle, which controls the flow of water over the skin’s surface leading to a reduction in drag and more efficient swimming.    All sharks have a skeleton composed entirely of cartilage, which prevents it from sinking due to its lack of a swim bladder.  Unlike most vertebrates, they do not rely on their internal skeleton to provide them with firm sites for muscle attachment.  Instead, sharks have a thick skin composed of a meshwork of strong and flexible collagen fibers.  This woven layer acts as a receptacle for swimming muscles to attach directly to their armor-like skin.  From a mechanical perspective, having muscle directly attached to an external skeleton is a very efficient arrangement, resulting in very little waste of muscular energy.  Sharks use low energy and mechanically complicated movement, which allows for continued existence as an apex predator.  The study of shark swimming adaptations, which have allowed them to be evolutionarily unchanged from millions of years, could be implemented in future boats and submarines.  

Sharks are amazingly well adapted to their ever-changing marine environment.  They possess several adaptations that help them swim without expending too much energy, and enable them to maneuver quickly and with agility. The bodies of all sharks taper to points at both the snout and the tail, increasing their hydrodynamics as they chase after prey.  They also have a type of scale known as a denticle, which controls the flow of water over the skin’s surface leading to a reduction in drag.  Most importantly, sharks are known for possessing a skeleton entirely composed of cartilage.  Unlike most vertebrates, they do not rely on their internal skeleton to provide them with firm sites for muscle attachment.  Instead sharks have a thick skin composed of a meshwork of strong and flexible collagen fibers.  This woven layer acts as a receptacle for swimming muscles to attach directly to their armor-like skin.  From a mechanical perspective, having muscle directly attached to an external skeleton is a very efficient arrangement, resulting in very little waste of muscular energy.  In general, sharks use low energy and mechanically complicated movement, which allows for continued existence as an apex predator. 

An unknown organism is presented in a small pertri dish for discriptional observation over a 30-minute period.  The organism appears to be a bilaterally symmetrical insect larva of some sort.  It possesses a tan coloration, with translucent dorsal and ventral sides causing the insides to be slightly visible.  This coloration might have something to do with the environment it inhabits, which may be subterranean, therefore providing camouflage.  The tail is much darker than that of the rest of the body and the very tip of the tail is completely black.  The 13mm long tail is roughly the same length as the 14mm body.  This comparison between tail and body length raises the question of the tail's significance to the organism's survival. There appears to be 8 nubby legs that provide little traction for movement and two black spots that exist close to the rostral end of the body.  There exist slight ridges along the circumference of the body.  These ridges expand and contract during movement, allowing the organism to extend its body forwards in an inching fashion similar to that of a caterpillar.  This organism appears to be blind, as obstruction of its potential viewpoint with a pen has no effect on its reaction.  The organism, however, is very shy and will cease all movement and act dead if touched.  There still exist many questions about this organism that cannot be answered only through observation in a petri dish.  What does this organism consume, and what may consume this organism?  What type of environment does this organism inhabit?  And is this organism at one certain stage of its lifecycle?  These questions have potential answers with more in depth observation.

The organism appears to be a bilaterally symmetrical insect larvae of some sort.  It possesses a tan coloration, with translucent dorsal and ventral sides causing the insides to be slightly visible.  This coloration might have something to do with the environment it inhabits, which may be subterranean. There exist slight ridges along the circumference of the body.  These ridges expand and contract during movement, allowing the organism to extend its body forwards in an inching fashion similar to that of a caterpillar. There appears to be 8 nubby legs that provide little traction for movement and two black spots that exist close to the rostral end of the body. The tail is much darker than that of the rest of the body and the very tip of the tail is completely black.  The 13mm long tail is roughly the same length as the 14mm body.  This comparison between tail and body length raises the question of the tail's significance to the organism's survival.  This organism appears to be blind, as obstruction of its potential viewpoint with a pen has no effect on its reaction.  The organism, however, is very shy and will cease all movement and act dead if moved or touched.  There still exist many questions about this organism that cannot be answered only through observation.  What does this organism consume, and what may consume this organism?  What type of environment does this organism inhabit?  And is this organism at one certain stage of its lifecycle?  These questions have potential answers with more in depth observation.