BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: oxytocin

Tickle, Tickle! : Great Apes Demonstrate Playful Teasing

Marco the chimpanzee at the Center for Great Apes

Researchers from the University of California Los Angeles (UCLA), the Max Planck Institute of Animal Behavior (MPI-AB), Indiana University (IU), and the University of California San Diego (UCSD) have identified playful teasing behavior in four species of great apes. This behavior shares similarities with joking in humans, characterized by its provocative, persistent nature, and inclusion of play elements. The presence of playful teasing across all four great ape species suggests its evolutionary roots in the human lineage at least 13 million years ago.

Playful teasing, similar to joking, emerges in humans as early as eight months of age. Infants engage in repetitive provocations, such as offering and withdrawing objects as well as disrupting activities. In a study published in the Proceedings of the Royal Society B, researchers examined spontaneous social interactions among orangutans, chimpanzees, bonobos, and gorillas to identify teasing behaviors.

The study involved analyzing teasing actions, bodily movements, facial expressions, and responses from the targets of teasing. Teasers exhibited intentional provocative behaviors, often accompanied by playful characteristics. The researchers identified 18 distinct teasing behaviors, such as waving or swinging objects in the target’s field of vision, poking or hitting, and disrupting movements.

Although playful teasing shares similarities with play, it differs in several aspects. Teasing tends to be one-sided, initiated primarily by the teaser and rarely reciprocated. Additionally, apes almost never use play signals like the primate ‘playface’ or ‘hold’ gestures. Teasing occurs in relaxed contexts and involves repetition and elements of surprise, similar to teasing in human children.

To offer an explanation for this teasing behavior among animals, oxytocin (love hormone) may play a role in doing so as well as promoting positive social interactions. Oxytocin goes into effects by binding to specific oxytocin receptors in the brain such as G protein-coupled receptors (as learned in AP Biology). Oxytocin receptors then activates the primary signaling pathways, involving the phosphoinositide 3-kinase (PI3K) pathway. Activation of PI3K leads to the production of second messengers, which regulate various cellular processes that contributes to the warm and fuzzy feeling we get due to oxytocin.

The presence of playful teasing in great apes, resembling behaviors in human infants, suggests its existence in our common ancestor over 13 million years ago. This study sheds light on the importance of understanding the evolutionary origins of behavior and the need for conservation efforts to protect these endangered animals.

Personally, I can definitely attest to the evolutionary pass-down of these playful teasings as I still find myself engaging in the same behaviors, oftentimes scorned and unreciprocated.

What are your thoughts on these findings?

Are Fish Mind Readers?

Several inherited behavioral mechanisms in humans and animals are deeply rooted in prehistoric animals. Some of these mechanisms, for example, fear, as well as the ability to fall in or out of love, humans have possessed for thousands of years and are found in our ancient genetic pathways. Although scientists are hesitant to attribute human-like feelings to animals, it has been proven that many animals, including fish, have moods. A recent study published in the journal; Science, demonstrated that fish can identify fear in other fish. This ability is regulated by the hormone oxytocin. This is the same “brain chemical” that controls the feeling of empathy in humans. The researchers discovered that fish could detect fear in other fish by deleting genes linked to producing and absorbing oxytocin. These fish became fearful as well.

Zebrafisch

Deleting genes involves various techniques, which is specific to the organism and the purpose for the deletion. Generally, there are two main approaches for deleting genes: Targeted Deletion and Random Deletion. In Targeted Deletion, very specific regions of the DNA sequence are removed or replaced to eliminate the gene of interest. Random Deletion occurs when large sections of the DNA sequence are randomly deleted in the hope of removing the gene of interest. The research focused on zebrafish brains; a small tropical fish often used for such research. The fish used in this experiment became practically antisocial and failed to change their behavior and could no longer detect when other fish were anxious. Scientists then injected oxytocin into some of the altered fish, and the fish’s ability to sense and react to the feelings of other fish was re-established. Fish behave just like humans in that they respond to other individuals being frightened. During this experiment, fish were seen paying considerably more attention to previously stressed or frightened fish.

Oxytocin is a hormone that plays a key role in social bonding and emotional communication in mammals, including humans. It is produced in the hypothalamus and released into the bloodstream by the pituitary gland. One of the primary functions of oxytocin is to produce social bonding between individuals. It has been shown to increase trust and cooperation between people, and it is often referred to as the love hormone because of its role in promoting feelings of love and intimacy.

Oxytocin with labels

Hans Hofmann, an evolutionary neuroscientist at the University of Texas at Austin, said that it’s less of a “love hormone” and more of a “scale” that helps fish recognize the most noticeable social situation. This recognition activates neural circuits that may make one run from danger or engage in behavior that results in mating. This ability is essential to certain species of fish survival.

Is there scientific reasoning for women to be stay at home moms?

Is there scientific evidence to prove that women are more maternal than man? According to recent discoveries by researchers at the LSU Department of Biological Sciences, that may be correct.
In a recent study about mice, Ryoichi Teruya, an associate professor at LSU, and his students found that oxytocin activates a specific group of cells in the female mouse brains which is not present in the male mouse brains. Student co-author Ryan LeBlanc used a red pen to meticulously locate each and every oxytocin receptor cell. This research aided greatly in their new discoveries. Oxytocin is seen as a hormone that induces maternal behavior or “love”. This new discovery seems to emphasize that these certain oxytocin receptor cells are only present when estrogen is present. Thus, only women have this maternal instinct. Teruya explains the importance of his study as “[m]any researchers have attempted to investigate the difference between the oxytocin system in females versus males, but no one has successfully found conclusvie evidence until now. Our discovery was a big surprise.” Apparently, the idea that women have an inherent maternal instinct is not just a joke anymore.
This discovery has actually opened the door for many new possible inventions and findings. Mothers with post-partum depression can now potentially have treatments to induce their oxytocin receptor cells in order to help them parent their children better. This would be an extreme breakthrough as children growing up with depressed mothers have many negative effects on their growth development.
As a feminist, I can’t help but wonder if this discovery will only further perpetuate the notion of seperate spheres between men and women where women should stay at home and become a caregiver as their main job. While the idea behind the results of these findings troubles me, I am hopeful about the possible new treatments for post-partum depression as about 10 to 20 percent of women experience this after giving birth. It is interesting to think about husbands who are more maternal than their wives and how that contradicts these findings.

 

 

 

Can Science Explain Love?

Sometimes it’s the greatest feeling in the world. Sometimes it hurts. Although we may never derive a fundamental recipe for it, much of love can be explained by chemistry and biology.

The brain (not the heart!) is responsible for romantic love, which, according to Dr. Helen Fisher at Rutgers University and Katherine Wu at Harvard University, can be broken down into three categories: lust, attraction, and attachment.

Credit: “Hearts” by eflon on Flickr.

Lust is our yearning for “sexual gratification.” This facet of love is grounded in our evolutionary, inherent need to reproduce. Lust is stimulated when the hypothalamus releases “sex hormones (testosterone and estrogen) from the testes and ovaries.”

Whereas lust concerns merely “sexual gratification,” another aspect of love, attraction, encompasses a variety of emotions with regard to a specific person. Attraction leads to the release of the chemicals dopamine and norepinephrine. As anyone whose ever been attracted knows, these chemicals make us “giddy, energetic, and euphoric.” Attraction also stimulates the brain’s reward center, which fires “like crazy when people are shown a photo of someone they are intensely attracted to.” Another hormone, serotonin, is found in low levels in both people with obsessive-compulsive disorder and people those who are experiencing attraction. As a result, scientists have theorized that attraction, and the ensuing low level of serotonin, is responsible for the obsessive infatuation so common in love.

The third aspect of love, attachment, is responsible for intimacy, is a key factor in long-term relationships, and is, of course, mediated by hormones.  The two hormones responsible for attachment, oxytocin and vasopressin, “are found in large quantities during sex, breastfeeding and childbirth,” all activities that are “precursors to bonding.” From this, it is easier to understand the concept of three different aspects of love: the “love” parents feel towards their children is merely the attachment aspect of it, but neither the lust nor the attraction aspect.

Although science can give us a biological basis for it, love, and all of its intricacies, can never be fully explained.

Smile, it makes your dog happy!

Looking at your dog can bring a smile to your face, and looking at you can actually make your dog smile too!  A new study shows that dogs have an emotional response to our facial expressions; dogs like smiling faces, and don’t like angry faces. This is linked to the hormone oxytocin, which influences what and how a dog emotionally experiences what it sees. Oxytocin is a neurotransmitter, dubbed the “love hormone,” so an increase in oxytocin yields a positive reaction.

University of Helsinki researchers studied 43 domestic dogs. The dogs were presented with pictures of unfamiliar faces with happy or angry expressions. Each dog was tested twice; once under the influence of oxytocin, and once without oxytocin. The dogs reactions were determined by their gaze and pupil size, because emotions and attentiveness regulate these reactions (for more information on the relationship between pupil size and emotions, click here). According to the authors, “dogs typically focus on the most remarkable aspect of each situation, such as threatening stimuli in a frightening situation.” Therefore in the trial, dogs will focus on the most remarkable face, either the happy or angry one.

The dogs under the influence of oxytocin were more interested in the smiling faces, and the oxytocin influenced their emotional state, as indicated by their pupil size. They had a larger emotional response to smiling faces under oxytocin, because their pupils were wider. When the dogs weren’t under the influence of oxytocin, their pupils were wider when looking at angry faces, so they were more focused on and had a larger emotional response to the angry faces. The researchers concluded that oxytocin made the angry faces seem less threatening, and the happy faces seem more appealing. This is why the dogs focused on happy faces with oxytocin, and angry faces without oxytocin.

This photo is credited to Max Pixel.

To further the studies, the scientists said that more studies are needed to determine wether the results are only for domestic dogs or if the same reaction occurs with other animals. More studies should also be conducted on dogs with familiar faces, to see if familiarity would change the results of oxytocin on emotional face processing. They also added that in future studies, account of the dog breed, sex, and personality traits should be taken into account because oxytocin does not have uniform effects.

For more information, click here. For the research, click here.

Love Hormone: From Maternal Love to Romantic Attachment to Basic Survival Need

Photo Credit: Roberto Pagani

Introduction

The hormone oxytocin, known as the Love Hormone and sometimes the Cuddle Hormone, is responsible for a plethora of emotional and nervous responses in our bodies. It is a hormone exclusively found in mammals. It causes maternal bonds to form between mothers and their children along with romantic bonds to form between monogamous pairs. Oxytocin controls many social responses that aid bonding and even cause us to feel sympathy. Oxytocin is also known for its ability to cause subjects to feel content, reduce anxiety, and feel calm and secure around one’s mate. The presence of oxytocin is a basic survival adaptation for mammals because it causes them to trust members outside the family unit and therefore permits mating to occur among unrelated members of the same species, thus creating a healthier, more diverse gene pool.

Maternal Love

It’s not surprising that oxytocin is only present in mammals. After all, it controls the release of milk to the nipples during lactation, helps dilate the cervix and trigger labor, and aids formation of bonds between members of species that are vital to the survival of many mammals. One particular bond that oxytocin helps initially form is that between mother

Under Creative Commons Licensing

and offspring. However, one study found that oxytocin levels are higher when first creating a maternal bond than once the bond has been made, therefore oxytocin begins the maternal behavior in the mother, but does not solely maintain it. Researchers have also found that the higher level of oxytocin in mothers during pregnancy, the stronger the bond between mother and child will be once the baby is born and the more maternal the mother will act towards the baby.

Romantic Attachment

Oxytocin is also responsible for causing romantic attachment to form between a monogamous pair. Oxytocin is the cause of the anxiety a person feels when they have been separated from the one they love or, more specifically, have been monogamously paired with. When a monogamous pair is with each other, oxytocin is released. This release causes them to feel content, happier, relaxed, and trusting: basic components of “feeling in love”. However, when the pair is separated for a prolonged period of time, separation anxiety kicks in because the oxytocin which was keeping stress levels low before is no longer being release. Large amounts of oxytocin are released during sexual intercourse and orgasm, hence its name “the love hormone”. Therefore, habitual sexual intercourse between a monogamous pair works to strengthen the romantic bond and causes heightened separation anxiety.

Mammalian Evolutionary Benefits of Oxytocin

The presence of oxytocin is a basic survival adaptation for mammals because it causes stress levels to fall and trust levels to rise, thus it creates the proper conditions for bonding between non-family members or in other words, strangers who they’re instinctually wired to avoid. The social bonding between non-family members aided and maintained by oxytocin is the psychological strategy which enables humans to override our neophobia and to mate with and create a strong, life-long bond with a complete stranger. Mating with non-family members is fundamental to a species survival because it creates a healthier, more diverse gene pool. On top of social bonding that leads to mating, the maternal instincts and maternal bonds are increased by higher levels of oxytocin. The presence of oxytocin in mother is vital for mammalian survival because they have evolved to care for our young and provide them with milk and protection until they are old enough to fend for themselves. Without the oxytocin present during labor, mammals wouldn’t have maternal instincts when offspring is born, the dilation of the cervix would become impaired, milk would not be let down to the nipples during lactation (so there would be no lactation), and mothers wouldn’t have the strong bonds or urges to care for their young.

 

My Opinion and Conclusion

We know that oxytocin causes romantic bonds to form between monogamous humans and causes us to feel sympathy, but what about animals? The “Love Hormone” is known to form maternal bonds between rat mothers and their young and even helps rats form life long monogamous mating bonds. Is it possible that if oxytocin forms bonds and causes sympathy in humans and also causes pair bonding between animals that it could also cause animals such as rats to feel sympathy? Evidence of this would be groundbreaking because it would prove that animals are capable of feeling emotions previously thought to be solely possessed by humans.

 

For More:

http://www.biomedcentral.com/1745-0179/content/2/1/28#B14

http://jn.physiology.org/content/94/1/327.long

http://www.springerlink.com/content/m761t10000r382q5/

http://www.annualreviews.org/doi/abs/10.1146/annurev.neuro.27.070203.144148?url_ver=Z39.88-2003&rfr_dat=cr_pub%3Dpubmed&rfr_id=ori%3Arid%3Acrossref.org&journalCode=neuro

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2953948/?tool=pmcentrez

 

 

 

 

 

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