BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: neurons

Newly Discovered Neurons and Their Role in Maintaining Normal Body Temperature

The internal body temperature in humans and mammals is maintained at 37℃/96℉, unless disrupted by a force like an illness or heat exhaustion. Regulating the body to stay in the normal range is crucial for survival and for enzyme function.  Our internal body temperature is constantly being regulated by our hypothalamus, located at the base of our brain. The hypothalamus uses sensors from a mediator known as prostaglandin E which is brought about when an infection is present in the body. After PGE2 is present, it signals for the body to raise its temperature and combat the infection. If temperature levels are abnormal, the enzymes in our body have trouble functioning because they need specific temperature conditions to carry out reactions. Therefore, maintaining homeostasis throughout the body by regulating internal temperature is key to human survival.

Prostaglandin E

A team of researchers at Nagoya University in Japan were inspired by this process and decided to focus on the unknown neurons that make up the receptors of PGE2 and how this regulation process functions. The group of professors and colleagues successfully discovered key neurons that work to regulate the body temperature of mammals. This finding can be highly useful for creating future technology that can artificially fix body temperature related conditions such as hypothermia, heat stroke, and obesity.  

Neuron

Neuron

By using rats as a subject for their research, they exposed the rats to cold (4°C), room (24°C) and hot (36°C) temperatures to observe the effect of temperature changes on EP3 neuron response. After conducting the experiment, the researchers were able to conclude that exposure to the hot temperature led to an activation of EP3 neurons and the cold temperatures did not. Once they made this conclusion, they dug deeper into the neurons and analyzed the nerve fibers of the neurons to discover where the signal transmission occurs after sensing an infection. The researchers were able to conclude that the neuron fibers are spread out in different areas of the brain, mainly the dosomedial hypothalmus, which works to activate the sympathetic nervous system. Not only did they discover these fibers, but they also discovered the substance that EP3 neurons utilize to send signals to DMH. By observing the structure and chemical makeup, they found that this substance is a neurotransmitter known as gamma-aminobutyric acid (GABA), which inhibits neuron excitation. 

Finally, their findings support the idea that EP3 neurons are a major component of regulating internal body temperature and that they send out the GABA substance to signal to DMH neurons for a proper response. Their research proves that intiating a neural response decreases body temperature and inhibiting neurons leads to an increase in body temperature. Furthermore, their strong research in this area can support future development of advanced technology that will be capable of artificially adjusting internal body temperature. The anticipated technology could help prevent hypothermia, treat obesity to keep body temperature slightly higher and initiate fat burning, and be a key method of survival in hot environments. 

 

Environmental Cues Can Trigger Planned Movement and Advance Studies of Motor Disorders

A group of scientists from different universities, including Dr. Hidehiko Inagaki, Dr. Susu Chen, and Dr. Karel Svoboda, came together to understand how cues in our environment can trigger planned movement. Neurons in the human brain are active with diverse patterns and timing. The Motor cortex is responsible for the control of movement. The patterns of the motor cortex differ in the phases of movement. The transitions between these phases is a critical part of movement. The brain areas controlling these transitions were a mystery.

To identify the parts of the brain controlling these transitions the group of scientists performed their research on mice.They recorded the activity of neurons in a mouse’s brain when doing a triggered movement task. Researchers found brain activity taking place directly after the go cue and between the stages of movement. This brain activity came from a circuit of neurons in the midbrain, thalamus, and cortex. To determine whether this circuit was a conductor or not the scientists used optogenetics. Through the use of optogenetics Dr. Inagaki and his colleagues were able to identify a neural circuit critical for triggering movement in response to environmental cues. Dr Inagaki says that “We have found a circuit that can change the activity of the motor cortex from motor planning to execution at the appropriate time. This gives us insight into how the brain orchestrates neuronal activity to produce complex behavior.

Figure-1

Not only is this important for the use of knowing more about the brain but it also helps to advance studies of motor disorders, such as Parkinson’s disease. By adding environmental cues to trigger movements it could drastically change the mobility of patients.

In Ap Biology class we learned about cell communication. Neurons communicate with each other by releasing specific molecules in the gap between them, called the synapses. The sending neuron passes on messages through neurotransmitters that are picked up by the receptors of the receiving neuron.

How to Keep Your New Year’s Resolutions: The Making and Breaking of Habits

What is a habit? A habit is “a behavior pattern acquired by frequent repetition or physiologic exposure that shows itself in regularity or increased facility of performance“ (Merriam-Webster). With this being the second month of 2022, New Year’s Resolutions are still in many people’s minds. February is statistically the time when individuals give up on their life-changing aspirations that the new-year inspired, “virtually every study tells us that around 80% of New Year’s resolutions will get abandoned around this month” (This Is The Month When New Year’s Resolutions Fail—Here’s How To Save Them). The “new year, new me” mindset is beginning to seem a little too hard to accomplish. If we can create habits that contribute to our new year’s resolutions, maybe they won’t seem so difficult. So, how can we make these resolutions into good habits and break existing bad ones?

New Years Resolutions

Habits are created through associative learning. Essentially, as you repeat a certain behavior in the same context, it becomes an automatic response rather than a thought-out action and that is when it is a habit. When this switch happens, that behavior/action moves from the intentional mind to the habitual mind. So, if we can intentionally make certain changes as a part of a resolution, we will eventually do them without thinking and maybe accomplish a resolution! 

Brain

Now, let’s look at some interesting science involved in the study of habits! Specifically, the dorsolateral striatum. This is a part of the brain that “experiences a short burst of activity” as the brain begins to create a new habit (Revving habits up and down, new insight into how the brain forms habits). As a habit becomes stronger and harder to break, this burst also intensifies. This was proved in an MIT study where rats were taught how to run in a maze and received a sugar pellet reward at the end. As we have learned in biology, neurons are nerve cells that send and receive signals. In fact, we know all about how these signals are transmitted! In this study, using optogenetics, scientists controlled the neurons in the dorsolateral striatum with light. “A flashing blue light excites the brain cells while a flashing yellow light inhibits the cells and shuts them down” (Science Daily). As the rats were running through the maze, if the neurons were excited, they ran faster and habitually, whereas when the flashing yellow light inhibited the cells, the rats slowed down and no longer knew where to go, making wrong turn after wrong turn. Senior author of the study Kyle S. Smith said, “Our findings illustrate how habits can be controlled in a tiny time window when they are first set in motion. The strength of the brain activity in this window determines whether the full behavior becomes a habit or not”. This shows us, it is fairly easy to form habits if you continue it repeatedly as the action first begins! While this can be good or bad, with the other information you will learn in this blog post, I hope that this is encouraging! 

In a recent study rewards were also shown to help form habits. This study explored how giving individuals in India a reward for washing their hands before dinner created good hand washing habits. “The study involved 2,943 households in 105 villages in the state of West Bengal between August 2015 and March 2017. All participants had access to soap and water. Nearly 80 percent said they knew soap killed germs, but initially only 14 percent reported using soap before eating” (Small bribes may help people build healthy handwashing habits). These households were divided into groups. Those that received a reward for washing their hands before dinner did 62% of the time, whereas those who did not receive a reward only washed their hands 36% of the time. This is a big difference! “Significantly, good habits lingered even after researchers stopped giving out rewards” (Small bribes may help people build healthy handwashing habits). Rewards helped create the habit, but once the habit was formed, it was automatic and even without the reward, the habit still took place! Now you may be wondering, why is this information relevant? Well, reward yourself! If your goal is to do one pull-up everyday, give yourself a piece of chocolate every time you do it and eventually you will not need any chocolate! 

So, based on this information, how can we break bad habits? First off, go to a new environment. Due to the fact that habits form from repeated behaviors in the same context, by changing our surroundings, it is much easier to not participate in that behavior. Secondly, repeat a new, replacement behavior over and over. For example, if your goal is to eat less pears, make it a habit to reach for an apple every time you walk into the kitchen. As we know, repetition forms habits! Lastly, keep this new environment and action consistent – don’t start reaching for a banana every time you get home if you have been reaching for an apple when you walk into the kitchen. In order to form a habit it is critical to repeat a certain behavior in the same context. 

Now, we can now create good habits and break the old bad ones! With this information, make this the year that you actually follow through on your new year’s resolutions! Don’t let this month stop you. You have the knowledge and resources, get to it! New year, new you! Good luck! If you have any questions, feel free to comment below!

New Years Resolution

Cocaine’s Abuse on the Body: How Far Does it Go?

Cocaine powder on black table | 🇩🇪Professional Photographe… | FlickrCocaine pictured above

When it comes to cocaine, there is a long list of the drastic. negative effects it has on the human body–not only physically, but mentally as well. When we see major celebrities such as Mac Miller, Don Rogers, and Whitney Houston pass from a cocaine overdose, what do you think plays a part in it?

What is cocaine?

Cocaine is a powerful and highly addictive stimulant drug, which first arose in the US in the late 1800s. It can be snorted, injected, rubbed in one’s mouth, and smoked. It is made from the coca plant of South America. It raises our dopamine levels which cause us to feel joy and relief, however, it damages the natural communication cycle in our brain, leading people to take highter and more frequent doses in an attempt to achieve the same high as when they first began using.

Effect of cocaine on our bodies

Short-term health effects of cocaine include, but are not limited to:

  • extreme happiness and energy
  • mental alertness
  • hypersensitivity to sight, sound, and touch irritability
  • paranoia—extreme and unreasonable distrust of others

Some long-term effects of cocaine abuse include, but are not limited to:

  • headaches
  • extreme weight loss
  • cardiac complications such as irregular heartbeat, cardiomyopathy, and acute myocardial infarction (heart attack)
  • loss of smell/olfactory function
  • mood swings
  • movement disorders, including Parkinson’s disease
  • paranoia
  • auditory hallucinations
  • irregular heartbeat
  • death by overdose
On a cellular level…

Once in our system, cocaine rapidly crosses the blood-brain barrier and binds to various plasma membrane transporters on neurons. Neurons are the main focus here, as our brains are comprised of 3 to 6 layers. What are they? They are “the fundamental units of the brain and nervous system, the cells responsible for receiving sensory input from the external world, for sending motor commands to our muscles, and for transforming and relaying the electrical signals at every step in-between” (Queensland Brain Institute). Neurons contain cytoplasm, mitochondria and other organelles. Neurons carry out basic cellular processes such as protein synthesis and energy production. Regarding basic cell types and structure, neurons have a cell body comprised of a nucleus and cytoplasm, and also have a mitochondria. The nucleus produces ribosomes which are involved in protein production. The cytoplasm acts as a suspension medium for organelles, and the mitochondria is involved in complex processes of neurotransmission. Overall, this cell body is essential to the neuron’s function as it carries genetic information, maintains the neuron’s structure, and provides energy to drive important cellular activities.

File:Blausen 0657 MultipolarNeuron.png - Wikimedia CommonsNeuron structure pictured

Or, to put it very simply, cocaine alters our brains and DNA in a complex manner, relating to several neurotransmitter systems, leading to seizures and neurological disorders such as Parkinson’s disease, as well as the more mild symptoms listed above.

Crack and cocaine users: are they bad?

Yes, crack and cocaine use is objectively terrible. They can alter our behavior, emotions, physical abilities, and our future children in drastic ways. However, it is important not to villainize those suffering from substance abuse. Rather, we should focus on what causes these people to turn to drugs. Systemic racism plays a large role in who uses and is distributed crack/cocaine. Lack of access to mental healthcare is yet another factor. As a society, we need to do better and be aware of all these things. If you or someone you know may be susceptible or vulnerable to drug abuse, please contact the Substance Abuse National Helpline at 1-800-662-4357.

 

 

 

How Did Our Baby Learn That Word?!?!

Jason Sudeikis’ character is hosting a nice dinner party with his wife played by Jennifer Aniston, and all seems to be going great. Then, all of a sudden, their 12- month-old baby blurts out a curse word! “How could our baby learn such a thing?” In a flashback 8 months earlier, we see the less-experienced parenting pair blurt out some pretty R-rated things in a fit of frustration on the road with their baby in the backseat. And so the punch line sinks in.

In modern day parenting comedies, scenes like this fabricated one are a dime a dozen. But these humorous takes on life always get at least one thing right: babies are sponges. Let’s take a look at why on a cellular level.

image source: https://commons.wikimedia.org/wiki/File%3AComplete_neuron_cell_diagram_en.svg

Prior to birth, most neurons migrate to the frontal lobe of the brain where, during postnatal development, they link together and forge connections, allowing a baby to learn proper responses to stimuli. The “circuits” formed by the neural connections are incredibly flexible during the early months of development (roughly the first 6 months) and can quickly be formed or severed, resulting in a remarkable neonatal human ability to rapidly pick up new knowledge about our surroundings. But how are they so malleable?!

Researchers at the University of California, San Francisco may have the answer! In a study coauthored by neuropathologist Eric Huang, they found neurons forming a chain moving towards the frontal lobe from the sub ventricular zone, a layer inside the brain where nerve cells are formed, in infants up to 7 months old!

This research seems to point to the idea that these new brain cells form connections with the pre-existing neurons in the frontal lobe later in the infant’s development, resulting in more cognitive flexibility for a longer period of time.

To quote the original article by Laurel Hamers, what the new neurons are doing is analogous to “replenishing the frontal lobe’s supply of building blocks midway through construction”.

Huang’s team observed postmortem infant brain tissue under an electron microscope and discovered a group of neurons synthesizing migration proteins, but the real major discovery came with the observation of rare tissue acquired moments after death. The team injected viruses tagged with glowing proteins into the neurons (thus making the nerve cells glow) in the sample and tracked their movement. While infants up to 7 months old were observed with migrating neurons, the researchers recorded the number of migrating cells at its highest at 1.5 months old and saw it diminish thereafter. The migrating neurons usually become inhibitory interneurons which, to quote the original article, are “like stoplights for other neurons, keeping signaling in check”.

So there you have it! To make sure your baby doesn’t learn that bad word, just suck up all the migrating neurons from its brain!

All jokes aside, this research presents an amazing window into the brain development of the most intelligent species on earth! It’s fascinating how it breaks down psychological mysteries using cellular evidence. And it raises new questions about these mobile neurons: When are they created and how long does it take them to move to the frontal lobe?

How do you think this new research will influence our understanding of the creation of social biases? Do you think this will lead to breakthroughs in research on the foundation of Autism spectrum disorders?  Do you have any funny baby stories? Let me know in the comments.

Editing the Brain Using Epigenetic Tools

Epigenetics is a huge part of our life and influences us in ways we may not be aware of. Did you know that it is impossible to create and save new memories without epigenetic tags? The brain is heavily reliant on Epigenetics to do its functions, and this makes it a huge topic of research to figure out the ways in which the epigenetics of the brain could affect certain diseases or memory. Recently special epigenetic molecular tools have been created that can erase specific epigenetic markers throughout the genome. The possible effects these tools could have on the curing of diseases of the brain or psychological ailments are tremendous.

These “epigenetic editing” procedure use either CRISPR (clustered, regularly interspaced, short, palindromic repeats) or TALE (Transcription activator-like effector) systems of modification. These systems can carry an Epigenome modifying enzyme and deliver it a specific site they are programmed to go to. This allows researchers to target very specific epigenetic changes and either shut them down or turn them on and possibly determine their correlation with certain ailments of the brain. “We’re going from simply being able to observe changes to being able to manipulate and recapitulate those changes in a controlled way,” Day said. This quote from Day, one of the researchers of this project, shows that we advance from only being able to observe epigenetic influences on the brain, to being able to manipulate and control them to potential aid us in combating diseases.

Researchers can catalog all of the epigenetic changes involved in forming and preserving a new memory. If we are able to track these epigenetic changes, then could we implant memories in to a person’s mind, by copying similar epigenetic changes? These researchers where also able to trigger not only the place where epigenetic change happens, but also the exact time using optogenetics. This form of using light to control neurons allows researchers to use the TALE system and a light switch apply epigenetic change to very specific brain regions or cell types.

One of the final goals of this research is to eventually be able to use epigenetic as a form of therapy to benefit PTSD, depression, schizophrenia, and cognitive function using the ability to alter epigenetic marks. This can also be used in a similar way to silence mutated genes that are damaging the cells or the body as whole. This form of using TALE and CRISPR to alter epigenetic tags creates a lot of hope for PTSD, depression, schizophrenia, Alzheimer’s, Parkinson’s, Huntington’s and other similar disease treatment options.

Sensing neuronal activity with light

neurons

Researches have recently developed a tool that may help in mapping the neural networks of living organisms using light. Observing these electrical signals of neurons can lead to numerous advancements in our understanding of neural circuitry.

In a collaborative study between Viviana Gradinaru, Frances Arnold and Barbara Dickinson, they developed a method to sense neuronal activity with light. These researchers used a protein named Archaerhodopsin (Arch) and exploited its light responsive qualities. They were able to optimize Arch through a process known as directed evolution. Using this method they created a variant of the Arch protein, called archer1 that acted as a voltage sensor under a red light and an inhibitor under a green light, while generating a light intensive enough to detect. When this protein acts as a voltage sensor it can show which neurons are active and synaptically connected and which aren’t under certain stimuli.

These researchers were able to test Archer1 in the worm C. elegans, which was chosen for its near transparent tissue that made it ideal for observing the luminescent protein. This was the first place they were able to observe the circuits of the neurons light up if they were expressed and dim down if they were repressed. For future studies they hope to make Archer1 bright enough to be detected through opaque tissue and accurate enough to detect voltage changed in more complex, behaving mammals. This study can prove to help us in our understanding of neural networks.

Original papers:

http://www.pnas.org/content/111/36/13034

http://www.nature.com/ncomms/2014/140915/ncomms5894/full/ncomms5894.html  (You can only read abstracts; you have to pay to read the full text)

The “Sleep Switch” Has Been Discovered

Screen Shot 2014-02-25 at 12.07.37 AM

http://www.flickr.com/photos/fourtwenty/2922398332/in/photostream/

If you’re like me, and most of you are since you’re all human, you’ve probably had a night or two where you just couldn’t fall asleep and figured that you had too much going on in your brain.  Maybe, if you’ve taken a biology course at some point or another, you’ve thought that your brain just has too much activity going on and you wished it would all just come to a nice rest.  In reality, if you’re experiencing that little bit of restlessness, your brain isn’t doing enough!  Scientists at Oxford University’s Centre for Neural Circuits and Behavior recently carried out a study on fruit flies in which they determined the “sleep switch” is really just a regulation of certain neurons in the brain which become more active when the body needs sleep.  Although the study was done on an entirely different species, these scientists still believe that the mechanism is comparable in humans due to the presence of similar neurons in the human brain.  The study showed that when sleep is needed by the body, the “electrical excitability” of the neurons increases, leading to the conclusion that their activity is related to how sleep is triggered.

While this recent discovery has already been inspiring new ideas on how to combat sleep disorders, it is really a step towards the much more basic question, “Why do we (animals) need to sleep?”  The next step towards answering this questions, explains Dr. Diogo Pimentel of Oxford University, is to identify “what happens in the brain during waking that requires sleep to reset.”

This “sleep switch” mechanism is one of two that are theorized to be used in the process of sleep.  The other being the body’s internal clock, which adjusts an animal to certain cycles based on the 24 hour day.  At the point of sleepiness, “The body clock says it’s the right time, and the sleep switch has built up pressure during a long waking day,” explains Professor Miesenböck, in whose laboratory the study was conducted.

Original Article: http://www.biologynews.net/archives/2014/02/19/scientists_identify_the_switch_that_says_its_time_to_sleep.html

Can Scientists Create a Brain?

 

attributed to hawkexpress

attributed to hawkexpress

The brain is one of the few things that scientists struggle to understand. For now, the only brain models you could find is one made of plastic or rubber. In a recent study, Viennese scientists Madeline Lancaster and Jürgen Knoblich have created “cerebral organoids”. These “cerebral organoids” are neural balls, about the size of a BB pellet. It is the most complex brain structure that has been created in a lab.

The scientists that created this placed cells in a nutrient broth for two months. After this time, the cells specialized into neurons that can be found in distinct parts of a developing brain such as  hippocampus, retina and choroid plexus, which produces cerebrospinal fluid in the brain. Although they look like clumps of tissue, the “cerebral organoids” had “discrete parts of the cerebral cortex, the outer sheet of the human brain that’s responsible for advanced thought processes.” The organoids also sent electrical messages and some groups of young neutrons moved from one place to another, an activity necessary to populate a brain with neurons. Also found abundantly in this tissue was a stem cell called radial glial stem cells, which is important to keep the number of neurons growing.

In order to create the organoids, the scientist must take human stem cells either from an embryo or from adult skin samples altered to an embryo-like state. The cells grow for a few days in a dish and medium and then moved to a nutrient broth to grow neuroectoderm tissue, the tissue that makes the beginnings of a brain. Then, the researchers inject the cells into a gel that gives a strict,”scaffold” to grow on. The final and most important step was to place the gel droplets into spinning flasks with nutrients. This was important because the “spinning motion distributed oxygen and nutrients to all of the cells in the organoid”  After two months, the cells stopped growing. Although they are still alive, they stop dividing and reach maximum size.

This research gives a very important window into the study of the brain, especially the study of brain development.  Although this information is groundbreaking, the organoids lack many important systems that the brain has.

Helpful links

http://www.ninds.nih.gov/disorders/brain_basics/ninds_neuron.htm

http://www.ncbi.nlm.nih.gov/pubmed/23995685

http://www.sciencenews.org/view/generic/id/352830/description/Tiny_human_almost-brains_made_in_lab

 

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