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Did You Know..?, Brain Health, Health

Phantom Pain: The Feeling Is As Real As It Can Get!

Valerie Sidelkivska

Phantom pain is a sensation that various individuals perceive towards a part of the body or an internal organ that doesn’t exist. This phantom pain occurs usually when people undergo an amputation surgery. In other cases, it can also happen from birth, in those who are born with a birth defect or a congenital disorder. Sometimes, phantom pains can appear as a result of an injury to the spinal cord or avulsion. Avulsion means that a structure of the body becomes disconnected from the body. This can happen due to a surgical procedure or because of trauma when body parts like ears become removed from the body.

Some people may experience phantom pain for just a short amount of time. The pain will leave by itself eventually. On the other hand, other people might suffer for a long time. The pain is intense and extreme and they keep on suffering. If you or anybody you know might be experiencing phantom pain, do let your doctor know. A physician will be able to reduce the symptoms and provide treatment. And the sooner you get treatment for phantom pain, the better.

Phantom Pain

What is Phantom Pain?

What science knows of so far is that the majority of the people who lose a limb as a result of an accident, surgery etc. will experience a phantom limb.

This very realistic perception that the limb is still there happens quite often, apart from that it can still cause pain to those who experience it.

However, what is interesting about the phantom limb pain, is that one doesn’t necessarily need to have had a surgery to experience the effects. Maybe not the full effects and the full experience of what a real phantom pain feels like, but it can definitely come close enough. In order to understand the following example and the phantom pain, we need to say a few words about body proprioception and body ownership.

Phantom pain: Proprioception and body ownership

Body proprioception is the way we perceive each and every single one of our body parts. We know where our body parts are located to a relative degree. We are also able to subconsciously understand how strong we are which helps us with motor skills and movement. Concepts like muscle memory, hand-eye coordination are quite common in the everyday language. Both of them come from this sense of ownership of what each and every single one of us is.

Some scientists even call proprioception as the sixth sense. The other five senses that we know of – touch, hearing, sight, smell, and taste – provide us with the information from the outside world. Because of the five senses, we are able to perceive the world around us as a unified concept. In an everyday life we don’t just experience one thing at a time, however a multi-sensory integration of all. Proprioception, however, comes from the inside. Scientists call it the sixth sense because people are able to sense what is going on inside our bodies. We know the stimuli that start within our bodies, we understand our relative position in space, our range of motion and our equilibrium. We are aware of our limbs and body parts.

When we pass through a crowded area, we turn at the right moment and attempt to make ourselves smaller. We do that due to the fact that we subconsciously know how much space we occupy. We know that if we go straight on we will hit that nice lady on the left. If we move a little bit to the right, however, we will push the man in the hat who is reading his newspaper. We understand all of this because of proprioception.

Now that we understand a little bit more about body ownership and how we perceive ourselves, it’s time to go back to the example.

Phantom pain: Rubber Hand Illusion

As we have established, phantom pain involves vivid sensations in a lost limb. The general public, however, is able to experience similar sensations without losing a limb. Rubber hand illusion has a lot to do with that concept of proprioception and body ownership and you will see the link with the phantom pain in just a bit.

Ehrsson colleagues in their 2004 study explored the ownership that we as people have of our hands. We know that the hands we are looking at are ours. We can move them in every way possible, we can control the fingers, move each hand individually or clap them together. It is fully ours. Could we trick the brain into thinking another hand could be ours too? That’s the basic concept of the rubber hand illusion.

Phantom pain: Body ownership?

The illusion itself is quite ingenious. The participant will have to place both of their hands on the table, one on each side of a screen. The screen blocks the participant from seeing the left hand outside of the screen. A realistic looking rubber hand goes inside the screen. When the participant looks at the table, he or she will see their real right hand on the table and beside it the left rubber hand because their real left hand is on the outside of the screen, invisible to them. After this, the real experiment begins. The researcher will start by slowly stroking the rubber hand and the hidden left hand with a small brush. He does so in similar strokes on both hands, on the same finger and at the same pace.

The subject will see the scientists stroking the rubber hand but also feel the same stroke on their hidden left hand. After this goes on for a few minutes, the subject will start feeling like the rubber hand is part of their own body and he or she feels the strokes on the rubber hand. The scientist usually ends the illusion by hitting the rubber hand with the small hammer. Interestingly enough, the participant will usually flinch or let out a shock sound due to the fact that they truly felt like the rubber hand was their own.

This rubber hand illusion is a very common one among scientists and brings a lot of insight into our own view of body ownership. Do we really know that much about ourselves? How do we create our self-image? And what does it say about people who experience phantom pain?

Phantom pain: a little background

According to the analysis by Weinstein SM, the first mention of the phantom limb pain occurred in the 16th century, by Ambrose Pare who happened to be a military surgeon.

Elan D. Louis and George K. York in mentioned that the term ‘phantom limb pain’ was coined by Weir Mitchell, who also happened to be a surgeon but at a different timeline. In the 19th century, he practiced during a Civil War and managed to give a description of phantom pain in detail.

Phantom Pain types

Phantom pain can appear in a variety of different ways and it’s important to recognize and understand the differences between them. Identifying what it is will surely help with faster diagnosis and an easier and faster approach to treatment. The differences might come from the variation in sensations that a person might feel.

  • Movement perception where the limb used to be
  • Noticing the weight of the phantom limb
  • Feeling the length of the phantom limb.
  • Feeling different senses where the phantom limb is situated – itchiness, touch, pressure.

As you can see, there are no clear cut differences between types of phantom limbs. Those who suffer from it may experience a variety of things. Sensations help us differentiate between the different types of phantom pain.

Phantom pain: Signs and Symptoms

Phantom Pain

There is a variety of symptoms that can pop up as a result of phantom pain. As mentioned before, the majority of the people will experience some symptoms if they have an amputation surgery. The sensations that can occur during the phantom limb experience include but are not limited to:

  • Warmth
  • Coldness
  • Tingling
  • Itchiness

These sensations are phantom limb sensations and are quite common after an operation. Phantom pain is a bit more severe. Just feeling pain from where the amputation occurred is not a symptom of phantom pain.

When the pain feels like it comes from a part of the body that doesn’t exist anymore, that’s what we call phantom pain. Few things can signify the appearance of phantom pain:

  • It can be prolonged or it can show up and leave at any moment.
  • It happens very shortly after the amputation occurs.
  • People describe the pain as pulsating and vibrating and burning.
  • People feel the phantom limb being put at an angle that bothers them and a position that brings discomfort.
  • The phantom pain usually happens in the part of the body that seems to be the most remote one from the body. Common examples include a leg or a foot
  • The phantom pain can be the cause of stress
  • The phantom pain can start as a result of pressure upon the limb that is left-over after the surgery.

Phantom pain: Causes and Risk Factors

As we mentioned before, the main risk factor for phantom pain still is surgery that results in amputation. The origin of the sensation of phantom pain, however, still remains a mystery. We do not know where it comes from, however, scientists speculate the involvement of certain brain regions and the spinal cord specifically.

Phantom pain: Causes

Different studies have used a variety of neuroimaging methods in order to see the activity that happens during a phantom pain sensation. They were able to discover certain brain areas of interest. A bit of a disturbance between brain connections in the brain might be the reason for the origin of a phantom brain. The signals can become mixed up together due to a sudden loss of a body part and the loss of input from that area. A lot of scientists put it down toward neuroplasticity that has gone wrong. Due to the fact that the brain and the spinal cord stop receiving input from a certain area, the brain tries to compensate and realize what happens and triggers a pain sensation in the lost limb.

Of course, we cannot forget about certain physiological factors like scar tissue, memory of the pain before the amputation and the damage done to nerve endings in the affected area.

Phantom pain: Risk factors

Apart from the obvious amputation surgery, there are a few other risk factors that can play a role in developing phantom pain. Doctors during the surgery should be aware of these risk factors and attempt to minimize the potential for developing phantom pain.

  • Stump pain: a lot of stump pain can contribute to the development of phantom pain due to the damage to the nerve endings.
  • Bad prosthetics: your doctor needs to show you the correct way to utilize the prosthetics. He needs to make sure it fits you and you know all the little details about it.
  • Painful sensations before the surgery: people are more likely to develop phantom pain if they experience pain in the limb beforehand; remembering that pain can contribute significantly to it.

Phantom pain and the Nervous system

In order to understand phantom pain, understanding of the nervous system is important. Many scientists believe that neuroplasticity plays a big role in the development of phantom pain.

Neuroplasticity is quite a famous concept nowadays and a lot of research goes into it. It talks about how the brain is able to form new connections between neurons over the course of a lifetime. Neuroplasticity seems to be responsible for the compensatory effect of diseases and injuries. It allows the brain to re-adjust the functions and certain stimuli responses that come from the outside. Wall and his colleagues explored the notion of neuroplasticity in their 1977 study. They found that the receptive field of certain neurons changes after partial cut off from the nerve supply. Many other studies show the reorganization of the somatosensory cortex following denervation or some sort of damage. That’s why many scientists believe in neuroplasticity as one of the major contributors to the formation of phantom pain.

Neuroplasticity is supposed to lead to benefits and good reorganization in the brain. Many scientists believe that in phantom pain specifically neuroplasticity becomes maladaptive.

Other scientists disagree with the neuroplasticity view. Makin and colleagues in their 2013 study say that plasticity as a result of phantom pain and not the other way around. They looked at different individuals with amputations who have phantom pain. They found that these people actually have very strong cortical representations of the lost limb. Furthermore, they could not find re-organization of cortical representations. In fact, they found that the differences between the brains of amputees and those of non-amputees do not differ and showed similar brain activity. Of course, the sensorimotor cortex played a big role and Makin and colleagues mention it. They say that certain disconnection showed up between the parts responsible for touch and movement processing and some sensorimotor cortex parts and it linked to phantom pain.

Phantom pain: Peripheral Nervous System

Various studies mention the role of the peripheral nervous system in the formation of phantom pain. The nerve endings are disconnected during an amputation surgery. Because of this, neurons become injured and the input to the spinal cord doesn’t work properly anymore. Certain changes happen in the spinal cord. The disconnected nerves cause certain hyper-excitability and this could potentially cause phantom pain.

Phantom pain treatment

There is a variety of different therapeutic techniques that can decrease the symptoms of phantom pain and help cure it. Certain pharmacotherapy approaches should be looked at.

First of all, analgesia and anesthetics should be used before the surgery.  This could prevent the phantom pain from appearing in the first place. It could also decrease the symptoms due to the patient remembering the pain.

Here are some of the most common drugs used for the treatment of phantom pain. Make sure to consult with your physician before taking any medication!

  • Anti-inflammatory drugs: some of the most common medications for phantom pain. These drugs are involved in various brain pathways (e.g. serotonin)
  • Opioids: these drugs are able to bind with central and peripheral postsynaptic opioid receptors and they are able to provide pain relief. Can also help with the side effects of neuroplasticity that are believed to play a role in phantom pain.
  • Tricyclic antidepressants: these drugs can cause pain relief due to the fact that they affect hormones that send out pain signals.
  • Anticonvulsants: these drugs are used for seizures but they can help with nerve damage and pain.

Non-pharmacologically, patients may undergo mirror therapy proposed by Ramachandran and Rogers-Ramachandran in their 1996 study. In this technique patients will attempt to restore the proper visual and proprioceptive disengagement that happens in the brain. Surgical intervention may be needed if all other therapeutic strategies fail.

Phantom Pain: Life style and caring

It can be quite difficult living with constant pain in the lost limb. There are certain steps you can take if you or a loved one are experiencing the symptoms. These steps might be able to reduce the symptoms or at least distract you enough until you get proper treatment.

  • Support: it is very crucial to provide support for somebody who is experiencing phantom pain. Treat as if it’s real pain because to them it is very real.
  • Relax: engage in activities that can help you beat the stress and reduce muscle tension. Activities that make you happy.
  • Don’t be afraid to ask for help. Other people might be a valuable asset in distracting you from problems.
  • Do not forget your medication
  • Exercise: engage in physical activities like walking, cycling, dancing, swimming – whatever you enjoy.
  • Distract yourself: yet again, engage in activities that you love and that make you happy
  • Take care of the stump: follow your doctor’s instructions in order to let the stump properly heal.

Hope you enjoyed this article, please feel free to leave a comment below!

Did You Know..?, Brain Health, Health

Synesthesia: Can You Hear Colors?

Valerie Sidelkivska

What is it like to hear colors and see sounds – people who have synesthesia might be able to give a little insight into that. Imagine the world full of new possibilities, sounds, images, and tastes. The way you are able to perceive and sense nature is so different from everybody else. You can say that the sky tastes like plums. When you hear Vivaldi’s four seasons on the piano, vibrant colors appear from every possible direction, representing spring, summer, fall, and winter. You are able to differentiate months of the year by colors and different smells by taste. Some of these are just examples. If you are able to relate to any of them, you might have synesthesia.

What is synesthesia?

Synesthesia

Scientists consider synesthesia to be a neurological and perceptual condition. It comes from Greek words that represent ‘togetherness and sensation’.  It is quite extraordinary and brings a whole different understanding to what surrounds us. In fact, people who have synesthesia most often than not, embrace it. They do not want to ‘cure’ the condition, per say. To them, the world is full of tastes and colors and sounds, depending on their particular type of synesthesia, of course. That’s how they’ve always experienced the world. They understand that Monday to have a green color, but Saturday more of a purple one and it makes sense to them.

Imagine looking at the sun each and every day and seeing that it’s yellow and one day wakes up and realize it’s a bland gray. That’s what it would be like for a synesthetic to lose their sense and understanding of the world. They would not only be very confused for a long period of time. No, despite that, they’d probably also feel sadness and grief for the loss of all of the beautiful imagery, sounds smell and touch that they will never experience again.

It’s quite difficult to understand synesthesia without experiencing it. A sky that tastes like blueberries or colors appearing when you hear music? That sounds crazy to anybody who has not experienced it themselves. Synesthesia, however, is not limited to just these people though. A lot of researchers looked into synesthetic occurrences in the regular population. These studies found that many are actually able to experience synesthesia. Sometimes they don’t even realize they are doing it.

Perhaps, in order to understand it better, you should experience a little touch of what synesthesia can be. This is what scientists call the McGurk effect

The McGurk effect

For a very long time, researchers understood speech as an auditory perception only. Now know the McGurk effect where there is an interplay between auditory and visual stimuli in the perception of speech. It is somewhat an illusion. Scientists, Harry McGurk and John Macdonald coined the effect in their 1976 study. It seems to be that when speech is paired with visual stimuli, a very extraordinary multi-sensory illusion happens.

They achieved this surprising effect by making a recording of a person voicing a consonant. After that they put the recording with a face, however, that face was expressing a different consonant. When the voice recording was heard by itself, the participants recognized it for what it was. However, when McGurk and Macdonald paired the voice recording along with a face expressing an incongruent sound – the participants heard a different sound. That sound ended up being the combination of the voice recording and the visual face articulation. The McGurk effect shows an absolutely astounding example of multisensory integration and how both, visual and auditory information can integrate and result in a unified experience.

If you can imagine, a lot of researchers found the illusion quite interesting and attempted to replicate it with different populations and conditions. What they found was quite astounding. Summerfield & McGrath found in their 1984 study that the effect happens with the use of vowels and not just consonants. The McGurk effect is present in pre linguistic infants according to the 1997 study by Rosenblum, Schmuckler & Johnson. Astonishingly enough, the effect even worked across a variety of languages which Massaro, Cohen, Gesi and Heredia showed in their 1992 study.

Synesthesia and the McGurk effect

It seems that even people who do not have the condition fall for the McGurk effect. The effect is very strong. Even when you know what to expect from it, you still cannot change it. When you think about it, it makes sense. The world we live in is full of senses and a variety of experiences. We do not just perceive sound by itself, or cannot look at something in a complete silence. There is always an ongoing integration of senses that happens all around us. It is no wonder that sometimes in our lives we are able to experience a synesthetic episode.

Types of Synesthesia

Synesthesia can appear in a variety of forms and types. In fact, researchers have been able to find over seventy types of synesthesia. We characterize the different varieties by what type of sensation they are able to cause and where that sensation came from. Here are some of the more common ones:

  • Number-Form Synesthesia: those who have this type of synesthesia are able to perceive numbers as mental maps. That means that these people will put the numbers in certain positions in space that will form a mental map. Whenever a person thinks of a number, a mental map will appear in their mind. Francis Galton introduced this type in his ‘The visions of sane persons’ work.
  • Lexical-Gustatory Synesthesia: people with this type will experience different tastes that correspond to specific words or phonemes. Badminton could taste like mashed potatoes but suitcase will taste like a chocolate cake. Quite a fun type, this one!
  • Grapheme Synesthesia: this one emerges with perceiving numbers and letters as different colors. This is one of the most common types of synesthesia. Interestingly enough, different people experience different colors in association with numbers and letters. Some commonalities occur. Letter ‘A’ often appears red for some reason.
  • Personification: A variety of ordered sequences will show up as different personalities. For example, Friday can be a happy go-lucky girl who enjoys dancing while Monday is an angry and bitter old man. Do you see any connection with real life?
  • Chromesthesia: people perceive sounds as a variety of colors. There is a variety of different experiences within this type with some people only perceiving colors during spoken speech and others seeing them during musical pieces. This type is quite common among musicians.
  • Misophonia: this one is not a particularly nice type of synesthesia. People who have this type experience very negative emotions when it comes to sounds. Examples of experienced emotions can be anger, disgust, sadness etc. Fortunately, this is one of the rarer types and it happens due to a disturbance between the limbic system and the auditory cortex.
  • Mirror-touch-pain Synesthesia: these people will experience a sensation of touch when they see somebody else being touched. The pain type can experience pain in a similar way when they see somebody else in pain. Researchers have linked this particular type of synesthesia with mirror neurons and regions responsible for empathy in the brain.

There are many other types of synesthesia. If you think you might be experiencing synesthesia but did not find your specific type above, you can type in your symptoms into google search, and sure enough, there will be somebody else with similar symptoms.

Synesthesia: Diagnostic Criteria

Synesthesia

Up to this date, there is no clear cut method for diagnosing synesthesia. Certain criteria exist that specialists adopt in order to help with the diagnosis. Keep in mind, however, that some of the leading scientists and researchers do not follow these criteria. Despite that, it gives at least a little bit of guidance in diagnosing synesthesia.

Symptoms

  • Projection: people will see the sensations outside of their body (hearing sounds outside during a musical piece)
  • Memory: associations that the synesthetic has will stick with him and will often overpower new associations that he or she might experience in the course of a lifetime.
  • Involuntary: sensations happen without the control of these people
  • Emotion: sensations can be perceived either positively or negatively.
  • Duration: the perceptions have to be stable and unchangeable.

Synesthesia and the Brain

Synesthesia

The original cause for synesthesia is still unknown. Due to such a variation in types of synesthesia, it is quite difficult to generalize brain studies to all of the different types. The brain uses different parts of the brain for the processing of different senses, therefore, with such a large variety of synesthesia types, an involvement of different brain parts happens. Researchers have to study each type separately and see whether there are some similarities between them. Some studies reported the activity in the superior posterior parietal cortex in relation with the grapheme-color synesthesia. Both visual cortex and the auditory cortex are activated during the McGurk effect because we are both listening and seeing at the same time.

The consensus among scientists is that depending on the type of synesthesia, the brain regions responsible for that sense will activate. What we speculate is that the uniqueness of synesthesia comes from a different way of network connections within the brain. Baron-Cohen and colleagues mention the excessive quantity of neuronal connections in the brain of synesthetics. According to him, during normal perceptual experiences, we have different brain areas for different senses and a different perception. The connection between those areas is present but is restricted. However, when you have synesthesia, your brain develops more connections between different neurons. This makes the restrictions between the areas to disappear and leads to synesthesia.

Peter Grossenbacher, on the other hand, says that the feedback communications are not subdued in a way that it happens in normal perception. The information that is processed from areas responsible for high-level of processing is not able to come back to each signified area. Instead of different senses going back to areas responsible for single senses, they mix together, allowing synesthesia.

Ramachandran and Hubbard support the increase in neural connection theory, but they also add that it happens due to the fact that the pruning between different sensory modalities is decreased.

Pruning is the removal process of the synaptic connections and more neurons in order to enhance the work of already existing neural transmissions.

Synesthesia and Genetics

Some studies have found a genetic link with the development of synesthesia. Asher and colleagues claim there is a link between auditory-visual synesthesia and certain chromosomes. Due to previous research suggesting a familial trend and a genetic factor helping in the development of synesthesia, they decided to look at 43 different families who had it. They found four different types of loci that could cause the variation in brain development in the brain of those who have the condition. What is interesting is that one of the genes that they identified, might be important for pruning.

Thomsen and colleagues focused on different genetic components. This leads to a variety of scientists to believe that synesthesia occurs due to a combination of a variety of genes.

Famous people throughout history with Synesthesia

Synesthesia is more common than some people believe. In fact, a variety of famous people are believed to have had this condition.

  • Vincent Van Gogh: chromesthesia
  • Lorde: music –> color
  • Vladimir Nabokov: grapheme -> color
  • Pharrell Williams: chromesthesia
  • Stevie Wonder: chromesthesia
  • Billy Joel: chromesthesia, grapheme-> color
  • Duke Ellington: chromesthesia

Prevalence

As mentioned before, diagnosis synesthesia is quite difficult so knowing its prevalence can bring some challenges as well. Before people used to think that the condition is quite rare, however, nowadays we know that it is a lot more common. Simner and colleagues in their 2006 study investigated the overall population. They found that around 1% of the population have the grapheme-color type. Around 5% have some sort of type of synesthesia. Due to the difficulty of diagnosis, this could be a very low account of the overall numbers, however.

Synesthesia is very common and a lot of people might have it. Family members, friends, co-workers, and classmates. Even you might have some sort of type of synesthesia and not know about it!

Did You Know..?, Health

Human Pheromones: Our Customized Perfume

Clara Morris

Human Pheromones have been a long-debated topic in science. New perfumes come out every year claiming to have human pheromones that will make you more attractive to the opposite sex. The research doesn’t yet know if we can really sniff out human pheromones or if it’s just a smelly coincidence. Studies suggest that there are ways we make inferences on pheromone related smells, though and maybe someday it can become a form communication. To learn more, read ahead to learn more about human pheromones, our evolutionary perfume!

Human Pheromones: Our Customized Perfume

Animal vs. Human Pheromones

Our knowledge of human pheromones is based on evidence of pheromones in animals. Years of research has shown that there is an evolutionary purpose for pheromones’ existence. The pheromones that exist in animals help to chemically communicate, rely and detect the health status or fertility of other animals of the same species. These tiny sets of compounds transmit information as either “signalers”, that tell of a social status or health, or they have an instant behavioral response. Experiments with mice, dogs, and monkeys illustrate pheromones that exist within proteins and those molecules that elicit a response, making it easier for research to be done. A sense of smell, the olfactory system, in pheromones acts as the sensory system responsible for detecting changes in the environment and if compatibility remains in the other being.

When it comes to human pheromones, the research is divided. Studies have observed that ovulation in women and oil or sweat excretions may influence testosterone levels in men. Though, there is currently no sound evidence yet that an observable and behavioral based response is produced and cue by human pheromones. This being said, a working theory currently supports the idea that certain human pheromones can be sensed at birth and regress as newborns develop. Newborn babies have been shown to differentiate among matters like their mother’s smell and the milk of their mother that contains pheromone like substances from secretions of the areola gland.

Science suggests that humans may not contain the high olfactory senses that animals like moths or spiders have, or if we do they are regressed in infancy. Instead, the smells and senses we infer work as scent recognition and detection. Humans use scent recognition as a mechanism of interpreting others’ imprints of behaviors, hygiene, food intake, environment, and even sexual compatibility that may influence socio-sexual contexts, but may not be pheromone based.

Animal vs. Human Pheromones

Seduction and Pheromone Perfume

 Human pheromones related to seduction and sexuality is still an area of little research. One study found that ovulating women may increase testosterone levels in men and another study pointed to oil and sweat secretion that could be responsible for inferences peoples’ attractiveness in the opposite sex. Human pheromones working as a “perfume” for seduction might give insight to certain chemical compounds, or smells, we sense that elicit responses in us.

The luxurious perfumes that do claim to have pheromones that make you sexier and more attractive to the opposite sex more than likely contain pig pheromones that do not have nearly any influence on humans’ anatomical structure or olfactory senses. Recently, studies and research are investigating three classes of putative human pheromones of male and female pheromones: axillary steroids, vaginal aliphatic acids, and Vomeronasal organ stimulators. These three classes of human pheromone classes could provide data to suggest they could be smelly enough for the nose to pick up.

Pheromones in Men

Axillary Steroids exist in both men and women. Axillary steroids as pheromones in men are secreted by the adrenal glands, apocrine glands, and testes and are not usually observed until biological puberty occurs.

  • Androstenone is held as an attractant and positive mood effector and pheromone for women. Ovulating women seem to be the targeted population in regards to androstenone, as studies have shown that exposure of androstenone induces a skin conductance mechanism and mood enhancement to women during ovulation.
  • Androstadienone is the other prominent male pheromone found in male semen and sweat and has effects on the limbic system and mood improvement for women. Researchers have found that exposure to androstadienone in women resulted in higher attentiveness to emotional words and facial expressions. These findings attribute that emotional arousal modulates how women process information that can potentially enhance focus.

Pheromones in Women

Axillary Steroids in women as pheromones are secreted by the ovaries, the adrenal glands, and apocrine glands and are like men are not observable until biological puberty occurs.

  • Androstenol is the infamous female pheromone that put “menstrual syncing” into popular culture. Androstenol was used in a study that predicted unconscious odor cues by menstruating women could influence the menstrual cycles of other women. This has been debunked by recent studies that show there is too little evidence for the claim to be reliable. Now, this pheromone is regarded as a mood enhancer when study results show that women exposed to androstenol when asked to rate the attractiveness of objects and people stated the objects as “friendlier” and enhanced their behavioral and social responses.
  • Estratetraenol is another highly regarded pheromone that is found in the urine of pregnant women. This pheromone is an endogenous steroid that is synthesized in the ovaries by aromatase found in androstadienone. This pheromone is related to estrogen sex hormones but has yet to show effects of estrogen. Estratetraenol pheromones exist on the market for women as attractant perfumes, yet consensus remains that it works as a human seduction pheromone.

Vaginal aliphatic acids are the other group of pheromones in women to differentiate from as they are different from the group of axillary steroids and are present in women’s vaginal fluids. Aliphatic acids are a kind of fatty acid that produces copulins and may attribute to human pheromone communication.

  • Copulins are a class of aliphatic acids that secrete six different types of vaginal fluids. Copulins in pheromones are produced before ovulation to signal the ovulation process. Sexual communication is suggested as one of the evolutionary mechanisms of Copulins, though the research still varies if copulins are responsible or a different vaginal fluid can illicit human pheromone communication.

Vomeronasal Organ

Potential human pheromone action in the vomeronasal organ is theorized to be conducted by the stimulators within it. The olfactory sensory structure lies in the nasal bones and are found in multiple animals. In humans, the vomeronasal organ contains a potential chemical sensory organ called epithelial, though the sensory neurons in the structure are present in the fetus but regress and disappear with age. Pheromone receptor genes found here show a response in “sex-specific manners”. No studies have been done to know if human pheromone communication exists in these receptors. Receptor sub-classes in the olfactory epithelium of mice have pheromone responses that scientists suggest could be a key mechanism in human pheromone research. The orthologous receptors that exist in human pheromone communication illustrate that research of trace proteins in mice pheromones could provide evidence to support human pheromone communication.

A Smelly Debate

Human pheromone in research explains a multitude of aspects we didn’t know before. For example, though we are not as equipped as animals in sniffing out compatible partners, it does tell us that human evolution has come this far that we use our smell recognition as a higher social mechanism. Seduction and human pheromones as a perfume of our biological data is still a wide concept that tells us little. The question remains if our human pheromones can give us animal instincts, but for now, we’ll let the scientists do the sniffing.

Watch a video of Tristram Wyatt, zoologist, explaining the fundamental flaws in current pheromone research and how for him there is no conclusive research regarding this matter.

Brain Health, Did You Know..?, Health, Seniors

Hippocampus: the orchestra director in the deepest part of our brain

Alejandra Salazar

Hippocampus. Have you ever gone blank and forgotten what you were going to say? Our brain is full of important data and information that we have stored over the years. Sometimes we have so much information that we force our brain to get rid and ignore some data. The part of the brain in charge of such important functions as memory and learning is the hippocampus. Without this brain structure, we would lose the ability to remember and feel the emotions associated with memories. You want to know more? Keep reading!

Hippocampus

What is the Hippocampus?

The hippocampus is named after the anatomist Giulio Cesare Aranzio who in the 16th century observed that this brain structure bears a great resemblance to a seahorse.

The word hippocampus comes from the Greek Hippos (horse) and Kampe (crooked). In his discovery, this part of the brain was related to the sense of smell and he advocated the explanation that the hippocampus’ main function was to process the olfactory stimuli.

This explanation was defended until in 1890 when Vladimir Béjterev demonstrated the actual function of the hippocampus in relation to memory and cognitive processes. It is one of the most important parts of the human brain because it is closely related to memory functioning and emotions. It is a small organ located within the temporal lobe (approximately behind each temple), which communicates with different areas of the cerebral cortex in what is known as the “hippocampus system.” It is a small organ with an elongated and curved shape. Inside our brain, we have two hippocampi, one in each hemisphere (left and right).

The hippocampus is known as the main structure in memory processing.

Where is the Hippocampus?

It is very well located, connected to different regions of the brain. It is located in the middle temporal lobe.

The hippocampus along with other brain structures such as the amygdala and hypothalamus form the limbic system and are responsible for managing the most primitive physiological responses. They belong to the most “ancient, deep and primitive” part of the brain, in a part of the brain known as “archicortex” (the oldest region of the human brain) that appeared millions of years ago in our ancestors to meet their most basic needs.

The blue part is the hippocampus

What does the Hippocampus do?

Among its main functions are the mental processes related to memory consolidation and the learning process. As well as, processes associated with the regulation and production of emotional states and spatial perception. How does the brain learn?

Some research has also linked it to behavioral inhibition, but this information is still in the research phase as it is fairly recent.

Hippocampus and Memory

The hippocampus is primarily related to emotional memory and declarative memory. It allows us to identify faces, to describe different things and to associate the positive or negative feelings that we feel with the memories of the lived events.

It intervenes in forming both episodic and autobiographical memories from the experiences we are living. The brain needs to “make room” to be able to store all the information over the years and for this, it transfers the temporal memories to other areas of the brain where memory storage takes place in the long term.

In this way, older memories take longer to disappear. If the hippocampus were damaged, we would lose the ability to learn and the ability to retain information in memory. In addition to allowing the information to pass into long-term memory, it links the contents of the memory with positive or negative emotions that correspond depending on whether the memories are associated with good or bad experiences.

There are many types of memory: semantic memory, visual memory, working memory, implicit memory, etc. In the case of the hippocampus, it intervenes specifically in declarative memory (it covers our personal experiences and the knowledge we have about the world), managing the contents that can be expressed verbally. The different types of memory are not governed solely by the hippocampus but are formed by other brain regions. It does not take care of all the processes related to memory loss but it covers a good part of them.

Hippocampus and Learning

It allows learning and retention of information since it is one of the few areas of the brain that have neurogenesis throughout life.

That is, it has the ability to generate new neurons and new connections between neurons throughout the life cycle. Learning is acquired gradually after many efforts and this is directly related to it. For new information to be consolidated in our brains, it is vitally important that new connections are formed between neurons. That is why the hippocampus has a fundamental role in learning.

Curiosity: Is it true that the hippocampus of London taxi drivers is bigger or more developed? Why? London taxi drivers must pass a hard memory test where they must memorize a myriad of streets and places to get the license. In the year 2000, Maguire studied London taxi drivers and observed that the posterior hippocampus was greater. He also noted that the size was directly proportional to the time the taxi drivers were working. This is because of the effect of training, learning and experience changes and shapes the brain.

Spatial perception and its relationship with the hippocampus

Another important function in which the hippocampus stands out is the spatial orientation, where it plays a very important role.

Spatial perception helps us to keep our mind and body in a three-dimensional space. It allows us to move and helps us interact with the world around us.

There have been different studies with mice where it is stated that it is an area of vital importance for orientation capacity and spatial memory.

Thanks to its correct functioning, we are capable of performing acts such as guiding us through cities we do not know, etc. However, the data concerning people are much more limited and more research is needed.

What happens when the hippocampus is disturbed?

An injury to the hippocampus can mean problems generating new memories. An brain injury can cause anterograde amnesia, affecting specific memories but leaving intact learning skills or abilities.

Lesions can cause anterograde or retrograde amnesia. Non-declarative memory would remain intact and uninjured. For example, a person with a hippocampal injury may learn to ride a bicycle after the injury, but he would not remember ever seeing a bicycle. That is, a person with the damaged hippocampus can continue to learn skills but not remember the process.

Anterograde amnesia is memory loss that affects events occurring after the injury. Retrograde amnesia, on the other hand, affects the forgetfulness generated before the injury.

At this point, you will wonder why the hippocampus is damaged when there are cases of amnesia. It is simple, this part of the brain acts as a gateway to brain patterns that sporadically retain events until they pass to the frontal lobe. One could say that the hippocampus is key to memory consolidation, transforming short-term memory into long-term memory. If this access door is damaged and you can’t save the information, it won’t be possible to produce longer-term memories. In addition to losing the ability to remember, when injuries or damage to the hippocampus occurs, you may lose the ability to feel the emotions associated with such memories, since you would not be able to relate the memories to the emotions that evoke it.

Why can the Hippocampus be damaged?

Most of the alterations that may occur in the hippocampus are produced as a result of aging and neurodegenerative diseases, stress, stroke, epilepsy, aneurysms, encephalitis, schizophrenia.

Aging and dementias

In aging in general and dementias such as Alzheimer’s disease in particular, the hippocampus is one of the areas that has previously been damaged, impairing the ability to form new memories or the ability to recall more or less recent autobiographical information. Memory problems, in this case, are associated with the death of hippocampal neurons.

Most of us know of someone who has suffered or suffers from some kind of dementia and has experienced memory loss. It is curious how the memories that remain are childhood memories or the oldest memories. You may wonder why this happens if the hippocampus is supposed to be damaged.

Well, although it is severely damaged (whether by dementia or any other type of illness), the most common memories are the oldest and they are also the most relevant to the life of the person. This is because over time these memories have been “becoming independent” of the hippocampus to be part of other structures related to long-term memory.

Hippocampus and stress

This region of the brain is very vulnerable to periods of stress because it inhibits and atrophies the neurons of this structure.

Have you noticed that when we are very stressed and we have a billion things to do sometimes we feel forgetful?

Stress and specifically cortisol (a type of hormone that is released in response to stressful moments) damage our brain structures sometimes causing neuronal death. That is why it is fundamental that we learn to remain calm and manage our emotions to get our hippocampus to remain strong and continue to exercise their functions optimally.

To know more watch the following video.

If you like this super interesting subject about memory, I recommend you watch the movie “Memento”. I’ll leave the trailer here so you can see what it’s about.

If you liked this post, leave your comment below. I will be happy to read it and answer your questions :).

This article is originally in Spanish written by Mairena Vázquez, translated by Alejandra Salazar.