from the world's big
The multifaceted cerebellum is large — it's just tightly folded.
- A powerful MRI combined with modeling software results in a totally new view of the human cerebellum.
- The so-called 'little brain' is nearly 80% the size of the cerebral cortex when it's unfolded.
- This part of the brain is associated with a lot of things, and a new virtual map is suitably chaotic and complex.
Just under our brain's cortex and close to our brain stem sits the cerebellum, also known as the "little brain." It's an organ many animals have, and we're still learning what it does in humans. It's long been thought to be involved in sensory input and motor control, but recent studies suggests it also plays a role in a lot of other things, including emotion, thought, and pain. After all, about half of the brain's neurons reside there. But it's so small. Except it's not, according to a new study from San Diego State University (SDSU) published in PNAS (Proceedings of the National Academy of Sciences).
A neural crêpe
A new imaging study led by psychology professor and cognitive neuroscientist Martin Sereno of the SDSU MRI Imaging Center reveals that the cerebellum is actually an intricately folded organ that has a surface area equal in size to 78 percent of the cerebral cortex. Sereno, a pioneer in MRI brain imaging, collaborated with other experts from the U.K., Canada, and the Netherlands.
So what does it look like? Unfolded, the cerebellum is reminiscent of a crêpe, according to Sereno, about four inches wide and three feet long.
The team didn't physically unfold a cerebellum in their research. Instead, they worked with brain scans from a 9.4 Tesla MRI machine, and virtually unfolded and mapped the organ. Custom software was developed for the project, based on the open-source FreeSurfer app developed by Sereno and others. Their model allowed the scientists to unpack the virtual cerebellum down to each individual fold, or "folia."
Study's cross-sections of a folded cerebellum
Image source: Sereno, et al.
A complicated map
Sereno tells SDSU NewsCenter that "Until now we only had crude models of what it looked like. We now have a complete map or surface representation of the cerebellum, much like cities, counties, and states."
That map is a bit surprising, too, in that regions associated with different functions are scattered across the organ in peculiar ways, unlike the cortex where it's all pretty orderly. "You get a little chunk of the lip, next to a chunk of the shoulder or face, like jumbled puzzle pieces," says Sereno. This may have to do with the fact that when the cerebellum is folded, its elements line up differently than they do when the organ is unfolded.
It seems the folded structure of the cerebellum is a configuration that facilitates access to information coming from places all over the body. Sereno says, "Now that we have the first high resolution base map of the human cerebellum, there are many possibilities for researchers to start filling in what is certain to be a complex quilt of inputs, from many different parts of the cerebral cortex in more detail than ever before."
This makes sense if the cerebellum is involved in highly complex, advanced cognitive functions, such as handling language or performing abstract reasoning as scientists suspect. "When you think of the cognition required to write a scientific paper or explain a concept," says Sereno, "you have to pull in information from many different sources. And that's just how the cerebellum is set up."
Bigger and bigger
The study also suggests that the large size of their virtual human cerebellum is likely to be related to the sheer number of tasks with which the organ is involved in the complex human brain. The macaque cerebellum that the team analyzed, for example, amounts to just 30 percent the size of the animal's cortex.
"The fact that [the cerebellum] has such a large surface area speaks to the evolution of distinctively human behaviors and cognition," says Sereno. "It has expanded so much that the folding patterns are very complex."
As the study says, "Rather than coordinating sensory signals to execute expert physical movements, parts of the cerebellum may have been extended in humans to help coordinate fictive 'conceptual movements,' such as rapidly mentally rearranging a movement plan — or, in the fullness of time, perhaps even a mathematical equation."
Sereno concludes, "The 'little brain' is quite the jack of all trades. Mapping the cerebellum will be an interesting new frontier for the next decade."
You may be surprised at how your body and brain react to this type of pleasure.
- An orgasm is described as a feeling of intense pleasure that happens during sexual activity.
- By studying the brain activity of people experiencing orgasms, researchers have been able to pinpoint some of the key changes that occur.
- These changes include heightened sensitivity to areas of the brain that control how we feel pain, making us less sensitive to it.
What really happens in the brain during orgasm?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzUzMjAzOS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNzk0MTg3N30.XMncIeu8myjL-bgF936p4NYAmXpCbI7dQl1AXuXBZc0/img.jpg?width=1245&coordinates=0%2C93%2C0%2C94&height=700" id="aab53" class="rm-shortcode" data-rm-shortcode-id="309e980e413d58c454f6fed13596917f" data-rm-shortcode-name="rebelmouse-image" alt="3D rendering of hypothalamus lighting up" />
The hypothalamus, which plays a key role in releasing hormones like dopamine and oxytocin, is one of the regions of the brain that lights up during orgasm.
Image by SciePro on Shutterstock<p><strong>Does the "logical" part of your brain shut down? That's hotly debated.</strong></p><p><strong></strong>There may be a reason why you feel bold and uninhibited during your climax.<br></p><p>"The lateral orbitofrontal cortex becomes less active during sex. This is the part of the brain that is responsible for reason, decision making, and value judgments. The deactivation of this part of the brain is also associated with decreases in fear and anxiety," explains clinical psychologist <a href="https://www.betweenusclinic.com/about-us/" target="_blank">Daniel Sher</a>. </p><p>However, not all experts in the field agree with this widely publicized study's findings. Recent (2017) research suggests otherwise, with results that show that these areas of the brain <a href="https://pubmed.ncbi.nlm.nih.gov/28986148/" target="_blank">did not deactivate within the 10 female participants of this study</a>.</p><p><strong>Parts of your brain associated with memories, touch, and movement may light up. </strong></p><p>Research has found that the hypothalamus, thalamus, and substantia nigra may light up during orgasm. "Dirty Minds: How Our Brains Influence Love, Sex and Relationships" author <a href="http://kaytsukel.com/" target="_blank">Kayt Sukel</a> <a href="https://www.theguardian.com/science/blog/2011/nov/16/orgasm-mri-scanner" target="_blank">was interviewed</a> for her work alongside researchers who studied the effect of an orgasm on the brain while she was in an MRI machine.</p><p>The thalamus helps integrate information about touch, movement, and sexual memories/fantasies. This could explain how you call upon sexual memories and fantasies (or why your imagination is able to be more active) during sexual arousal and peak. </p><p><strong>Oxytocin builds up and is released.</strong></p><p>Oxytocin is defined as a "bonding" hormone. The forming of oxytocin during sex happens in the pituitary glands and it is then released in the hypothalamus. The <a href="https://www.healthline.com/human-body-maps/hypothalamus" target="_blank">hypothalamus</a> plays a key role in many important functions including the releasing of other hormones (like dopamine), regulation of body temperature, controlling of appetite, and of course, the management of sexual behaviors.</p><p><strong>A surge of dopamine is released. </strong></p><p>During orgasm, your brain works hard to produce various hormones, like the aforementioned oxytocin. In that cocktail of hormones is dopamine, which is released at the moment of orgasm. Dopamine is responsible for feelings of pleasure and desire and therefore acts as a motivation to keep experiencing those feelings of pleasure and desire. </p><p>Dopamine is formed <a href="https://thebrain.mcgill.ca/flash/d/d_03/d_03_cr/d_03_cr_que/d_03_cr_que.html" target="_blank">in the part of the brain</a> that receives information from several other areas in order to define if your needs (specifically your human needs) are being satisfied. </p><p><strong>The release of endorphins, oxytocin, and vasopressin make you less sensitive to pain during sex. </strong></p><p>For many, pain and sex go hand in hand. Many people enjoy a little bit of pain during sex, and there is actually a very good reason for this: you're less susceptible to pain during sex. The pituitary gland is activated during sex, which then frees your brain up to release all kinds of endorphins that are able to promote pain reduction. </p><p>An interesting thing to note is that some of the same areas of the brain that are active during sex are also active when you experience pain. <a href="https://pubmed.ncbi.nlm.nih.gov/4000685/" target="_blank">A very interesting 1985 study</a> looked at the correlation between vaginal stimulation and the elevation of pain. </p><p><strong>In people who are unable to feel genital stimulation, the brain may actually be able to "remap" itself. </strong></p><p>People who have suffered lower-body paralysis can still achieve orgasm through stimulation of other body parts such as the nipples. In this case, the brain actually creates new pathways to pleasure that doesn't involve our genitalia. <a href="https://www.seattletimes.com/seattle-news/health/paralyzed-women-rediscover-orgasms/" target="_blank">This Seattle Times article</a> details paralyzed women who were able to rediscover their ability to orgasm through various other sensations.<br></p><p><strong>Having orgasms can keep your brain healthy. </strong></p><p>Because there is a significant increase in blood flow across multiple areas of the brain so dramatically when we achieve orgasm, it's entirely likely that orgasms may have developed in part to keep our brains healthy.</p>
What really happens in the body when you orgasm?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzUzMjAzOC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYwOTYyMzA2Nn0.-etGxz-ejxnP2n4CJ4OVoQy5KrrLL2uTxet7i-nBFZk/img.jpg?width=1245&coordinates=0%2C52%2C0%2C52&height=700" id="4b6fe" class="rm-shortcode" data-rm-shortcode-id="648070a56f9fea934d8780dba38bfb1f" data-rm-shortcode-name="rebelmouse-image" alt="woman holding blanket in her hand" />
What really happens in the body when we orgasm?
Photo by NATNN on Shutterstock<p><strong>Your body swells and becomes more sensitive.</strong></p><p>While men experience the obvious swelling in the genitals due to increased blood flow, women can experience some forms of swelling during sex as well. From your breasts to your vulva, many women experience swelling during sexual arousal and release. </p><p><strong>Your heart rate quickens, which leads to euphoria. </strong></p><p>Of course, your heart rate elevates when you're experiencing orgasm, but along with that, you also experience a blood pressure rise and your breathing rate also increases. Both of these things are considered mild aerobic activity responses and could factor into the kind of euphoria you feel during sexual experiences - similar to a "runners high."</p><p><strong>Muscles in the vagina, anus, and uterus contract and release - like a workout.</strong></p><p>Not only is your pulse racing, but you may also be working out some of the muscles in your body (aside from the ones you're using to physically have sex). </p><p>According to <a href="https://www.bustle.com/p/9-things-that-happen-to-your-body-when-you-have-orgasm-that-you-never-realized-8487239" target="_blank">Bustle</a>, "Increased blood flow to the genitals during orgasm also maintains the integrity of the smooth muscle that lines the vagina, rectum and connective tissue between the penile shaft and scrotum."</p><p><strong>Orgasms may improve allergy symptoms or clear blocked nasal passages.</strong></p><p>"Orgasms can be effective at opening blocked nasal passages and can alleviate some allergy and congestion symptoms," according to sexologist and clinical professional counselor Dr. Laura Deitsch.</p>
A new study on brain differences between sexes sparks a persistent question.
- A new study found brain volume differences between men and women.
- The research focuses on regional grey matter volume, a contentious measurement in neuroscience.
- Without environmental conditions being considered, how trustworthy is our emphasis on biology?
Men vs. women: Why we’re imagining equality all wrong | Heather Heying | Big Think<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="dd7ac9538bd187ab6f36bec7877b849f"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/nzqxjx5pgJI?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>This new research not only found sex differences in terms of regional grey matter volume (GMV), but also tied those differences to sex chromosomes. Specifically, after discovering neuroanatomical sex differences, the team found "that sex differences in regional GMV are aligned with functional systems for face processing."</p><p>This sparked the question of the validity of using grey matter to measure social and physical functioning, as this <a href="https://www.wired.com/story/a-study-finds-sex-differences-in-the-brain-does-it-matter/" target="_blank">deep dive</a> in Wired details. Raznahan's research found larger volumes of grey matter in men than women, though previous research has found women are better than men at facial recognition. </p><p>Grey matter is often used as evidence of stronger neurological connections. The default example is the famous <a href="https://www.pnas.org/content/97/8/4398" target="_blank">London taxi driver study</a>, which found that drivers, who have to memorize the entirety of the city to pass a rigorous test, have larger GMV in the brain's posterior hippocampi (spatial memory and navigation) than non-taxi drivers. This line of argument has also been <a href="https://psychcentral.com/news/2015/01/24/meditation-shown-to-alter-gray-matter-in-brain/80342.html#:~:text=Meditating%20for%20just%20eight%20weeks,Massachusetts%20General%20Hospital%20(MGH)." target="_blank">used by meditation researchers</a>, who have extrapolated from GMV volume to argue that meditation helps increase memory and empathy while decreasing stress. </p><p>Back to correlation and causation. Taxi drivers must study street maps for years; mediation is a specific discipline that has measurable effects on the nervous system (beyond grey matter). In both cases, the subjects have changed their relationship to their environment, thus hinting at correlation. If anything, you can argue environmental changes <em>cause</em> changes in GMV. </p><p>Raznahan's study is looking at genetic differences, yet environment still plays a role. The data was pulled from the U.S. and UK, predominantly white, wealthy countries. Comparing that data to other sets in African or Asian countries, for example, could result in a Bell Curve-type controversy—gender studies are already controversial enough. How then do you study biology when everything is polarized? </p>
Dozens of women and men attend a rally and march in Washington Square Park for International Women's Day on March 8, 2018 in New York City.
Photo by Spencer Platt/Getty Images<p>One political party in America grows angry any time a connection between income disparity and ethnicity is made. We seem unable to move beyond this political wedge, especially since it fires up the base, yet it holds the key to freeing scientists to take a holistic approach. You can't <em>only</em> look at changes in brain function when contemplating social differences. But you can investigate such differences if you're trying to understand brain disorders—the focus of Raznahan's work.</p><p>The gender question might always be with us. In 2014, Fallon Fox, a transgender MMA fighter, <a href="https://www.bjjee.com/articles/transgender-mma-fighter-who-broke-female-opponents-skull-are-we-getting-too-politically-correct-with-reality/" target="_blank">broke Tamikka Brents's skull</a> during a match. Brents later said she had "never felt the strength that I felt in a fight as I did that night." There are real biological differences between men and women. Arguing against that is antithetical to good science. </p><p>Neuroscience will remain a sticky topic for some time, however. The methods for measuring blood flow and brain volume are, as Davis suggests above, more art than science. Until better measuring sticks are developed for understanding brain functionality, the field will be more speculative than declarative. That's okay: scientists need to fail in order to grow. In a time when even minor failures result in ostracism, however, that's a tough line to walk. </p><p>Environment always matters. Humans are the products of the spaces they inhabit. Genetic disorders aside, our chemistry is linked to our environment. When neuroscience is able to utilize brain scans in conjunction with sociology, real progress will be possible. Until then, controversies will abound, even where they should be none. </p><p>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a>, <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a> and <a href="https://derekberes.substack.com/" target="_blank">Substack</a>. His next book is</em> "<em>Hero's Dose: The Case For Psychedelics in Ritual and Therapy."</em></p>
While this has been a popular debate, the evidence suggests there isn't a strong link between pornography use and erectile dysfunction (ED).
- According to UW Health, around 5 percent of men that are 40 years old have complete erectile dysfunction. That number increases to about 15 percent by age 70.
- While there are many things that can cause or contribute to ED (such as high blood pressure, smoking, the use of drugs or alcohol, depression, and anxiety), there has been wide debate over the impacts of pornography use.
- Several studies outlined in this article look at the supposed link between ED and pornography use.
Can pornography really cause erectile dysfunction?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzUyMjIxMS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyODc3NDE0MH0.YIoVjpvc1V2X6viFQ0q62Bfr37dzWZGDb_JdfzpOlv8/img.jpg?width=1245&coordinates=0%2C0%2C0%2C104&height=700" id="aeea4" class="rm-shortcode" data-rm-shortcode-id="cbb4798850bfefec88f62c3538741ba0" data-rm-shortcode-name="rebelmouse-image" alt="naked man hiding behind a pillow" />
Is there really any evidence proving porn causes ED?
Photo by PrinceOfLove on Shutterstock<p>Over the years, there have been multiple studies with conflicting results when it comes to this controversial question.</p><p><strong>A 2012 study links porn and erectile dysfunction in men ages 20-40 but says it is only "one piece of the puzzle."</strong></p><p>According to a <a href="https://www.webmd.com/sex/news/20170512/study-sees-link-between-porn-and-sexual-dysfunction#1" target="_blank">HealthDay News study</a>, porn-addicted men are more likely to suffer from erectile dysfunction and are less likely to be satisfied with sexual intercourse. This was determined based on a survey of 312 men between the ages of 20-40. Of men surveyed, 3.4 percent said they preferred masturbating to pornography over sexual intercourse, but the researchers found a statistical relationship between porn addiction and sexual dysfunction.</p><p>According to lead researcher Dr. Matthew Christman (staff urologist with the Naval Medical Center in San Diego), the rates of organic causes of ED in this age cohort are extremely low, so the increase in erectile dysfunction needs to be explained. "We believe that pornography may be one piece to that puzzle. Our data does not suggest it is the only explanation, however."</p><p><strong>A 2016 study has also been cited as proof that pornography use causes ED, however the study itself explains that more research is needed to prove this theory.</strong> </p><p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5039517/#B9-behavsci-06-00017" target="_blank">According to this study</a>, 1 in 4 participants who sought help for new-onset ED were younger than 40, which was highly unusual. The conclusion of this study was that traditional factors that once explained sexual difficulties in men appear insufficient to account for the sharp rise in sexual dysfunctions and low sexual desire in these men."Both the literature and our clinical reports underscore the need for extensive investigation of Internet pornography's potential effects on users, ideally by having subjects remove the variable of internet pornography in order to demonstrate potential effects of behavioral modification," the authors wrote.</p><p><strong>An Italian study suggests men could suffer from "sexual anorexia" after pornography use. </strong></p><p>A survey of 28,000 users suggests many Italian males started an "excessive consumption" of porn sites as early as 14 years of age. The study uses the term "sexual anorexia," which is referred to in this case as a pathological loss of appetite for romantic-sexual interactions. </p><p>This particular study has been cited in multiple articles that claim ED is directly linked to pornography use. However, the study, listed in ANSA, outlines "daily use" for people in their early-mid 20s, and how individuals <em>may </em>become "inured to even the most violent images" in porn. </p><p>"It starts with lower reactions to porn sites, then there is a general drop in libido and in the end it becomes impossible to get an erection," <a href="https://www.ansa.it/web/notizie/rubriche/english/2011/02/24/visualizza_new.html_1583160579.html" target="_blank">explains Carlo Foresta</a>, head of the Italian Society of Andrology and Sexual Medicine (SIAMS). </p><p><strong>A 2019 study that analyzed porn watching and ED risk suggested there isn't likely to be a link. </strong></p><p><a href="https://www.seksuologen-vlaanderen.be/wp-content/uploads/2019/06/Grubbs-Gola-2019-J-SEX-MED-no-causal-link-pornography-and-ED-2.pdf" target="_blank">According to this study</a>, which sampled 877 American men between the ages of 18-60, porn-watching and ED were not likely to be linked. While it was true that some porn-watching men in the study did report ED, researchers found "very little evidence that mere pornography use is associated with changes in erection function."</p><p><strong>While porn may have some impact on ED, that impact isn't always negative.</strong></p><p>"ED is a biopsychosocial phenomenon, meaning there are many factors that can contribute to it," Christene Lorenzo, a therapist specializing in sexual health and relationships, <a href="https://www.healthline.com/health-news/experts-debunk-new-survey-claiming-watching-adult-videos-causes-ed#What-sexual-health-experts-think" target="_blank">explains to HealthLine</a>. </p><p>There are many possible physiological, psychological, and relationship factors that impact ED that most surveys arguing the impacts of pornography of erectile function don't take into account. <span></span></p><p>Additionally, while porn-induced erectile dysfunction is possible, porn may also actually help with ED in some cases. Erectile dysfunction is a complex health issue that has both physical and mental health components, according to <a href="https://www.medicalnewstoday.com/articles/317117" target="_blank">Medical News Today</a>. </p><p>"A <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/sm2.58" target="_blank" style="">2015 study</a> found that men who reported more time spent viewing pornography had greater sexual responsiveness to a partner in a laboratory setting. This suggests that pornography might help prime the brain or body for sex, potentially improving intercourse with a partner." </p>
Nutrisystem is a smarter weight-loss program that users enjoy.
- The societal and economic consequences of obesity cannot be ignored.
- The economic impact is up to $190 billion every year in America.
- Americans spend up to $2.5 billion each year on popular weight-loss programs.
Credit: Nutrisystem<h3>The economics of obesity</h3><p>The obesity crisis in America has profoundly changed the health of our nation. Two-thirds of American adults are now <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4770258/" target="_blank">overweight or obese</a>. Excess body weight creates numerous health problems, <a href="https://www.niddk.nih.gov/health-information/weight-management/health-risks-overweight" target="_blank">such as</a> increased risk for heart disease, hypertension, cancer, sleep apnea, stroke, and type 2 diabetes. Tragically, the steep rise in obesity rates can, in large part, be traced back to the surge in processed foods made with filler ingredients, questionable preservatives, and excessive sugars. </p><p>That's part of what makes losing weight so difficult. Supermarket shelves are stocked with processed foods. A whopping 74 percent of packaged foods contain <a href="https://sugarscience.ucsf.edu/hidden-in-plain-sight/#.Xx3ly_hKhTY" target="_blank">added sugars</a>, which are conveniently disguised under 61 different names, including dextrose, maltose, and treacle. You shouldn't have to play detective every time you go to the grocery store. </p><p>Obesity has real-world consequences. Every year, up to <a href="https://www.cdc.gov/obesity/adult/causes.html" target="_blank">$6.38 billion is lost</a> in productivity costs due to obesity-related absenteeism. That number only accounts for people taking off of work. Overall, obesity-related costs in America are estimated to be <a href="https://academic.oup.com/ajcn/article/91/5/1520S/4597467" target="_blank">$147 billion</a> every year. One <a href="https://www.hsph.harvard.edu/obesity-prevention-source/obesity-consequences/economic/" target="_blank">study</a> shows that cost was $190 billion in 2005. </p><p>Overweight citizens are also <a href="https://www.psychiatryadvisor.com/home/conference-highlights/aaic-2015-coverage/mental-illness-and-obesity/" target="_blank">more likely</a> to suffer from poor mental health. The combination of poor self-image, social stigma, lack of exercise, and biological issues due to obesity increase the likelihood that someone will be anxious or depressed. This creates a crippling feedback loop: diets high in sugars and carbohydrates, which are fueling the rise in obesity, are <a href="https://bigthink.com/21st-century-spirituality/your-diet-might-be-causing-anxiety-and-depression" target="_self">also linked</a> to poor mental health. </p><p>Many people want a solution that works. In 2014, Americans spent <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4446719/" target="_blank">roughly $2.5 billion</a> on commercial or proprietary weight loss programs. As a society, we pay the price of obesity in the form of work absenteeism, inflated health care costs, and mental health issues, and we pay trying to solve it. Finding a solution to this problem is of utmost importance. </p>