After an exceptional success last year with the project Mobile Visitor Center, The Tourist Board of the Municipality of Rogoznica has successfully implemented another significant and innovative project.Along its over 50 km long coast, it has set up eight smart benches, one in each settlement, and thus became the first municipality in Croatia to bring this new combination of modern technology and practicality to all its categorized tourist resorts. “Every year we strive to realize something new and innovative that will improve the living conditions of guests throughout our municipality. With this project, we want to get even closer to our dear tourists and fellow citizens and provide them with free internet and carefree use of mobile devices while relaxing by the sea, swimming on the beach or sitting and enjoying the beautiful view. We are extremely pleased that we managed to install smart benches in all our coastal tourist resorts, and make a significant step towards a smart destination. ” said Marijo Mladinić, director of the Tourist Office, and added that HRK 150.000 had been set aside from the budget of the Rogoznica Tourist Board for this project, and the investment was realized with the company Include from Solin in partnership with Hrvatski Telekom.The installed Steora smart benches are completely energy independent, powered by solar panels, enable charging of all types of mobile devices via USB ports, wireless charging, equipped with advanced 4G internet, and in the evening they are adorned with ice ambient light.Related news:TZ ROGOZNICA – BLUE COW OF OUR TOURISM
Email LinkedIn Share Share on Twitter Pinterest Children who get a taste of their parents’ wine now and then may be more likely than their peers to start drinking by high school, according to a new report in the Journal of Studies on Alcohol and Drugs.Researchers found that, of 561 students in a long-term study, those who’d “sipped” alcohol by sixth grade were five times more likely than their peers to down a full drink by the time they were in high school. And they were four times more likely to have binged or been drunk.The findings do not prove that early sips of alcohol are to blame, said lead researcher Kristina Jackson, Ph.D., of the Center for Alcohol and Addiction Studies at Brown University in Providence, R.I. Share on Facebook “We’re not trying to say whether it’s ‘OK’ or ‘not OK’ for parents to allow this,” Jackson said.Still, she noted, some parents do believe in the “European model”–the idea that introducing kids to alcohol early, at home, will teach them about responsible drinking and lessen the “taboo” appeal of alcohol.“Our study provides evidence to the contrary,” Jackson said.The findings are based on 561 Rhode Island middle school students who were surveyed periodically over three years. At the beginning of sixth grade (around age 11), almost 30 percent of students said they’d ever sipped alcohol. In most cases, their parents provided it–often at a party or other special occasion.By ninth grade, 26 percent of those early “sippers” said they’d ever had a full alcoholic drink, versus less than 6 percent of their peers. What’s more, 9 percent had either gotten drunk or binged–compared with just under 2 percent of “nonsippers.”Of course, there are many factors that influence underage drinking, Jackson noted. Her team tried to account for as many of those factors as they could–including parents’ drinking habits and any history of alcoholism, as well as kids’ disposition (such as whether they tended to be impulsive and risk taking in general).Even then, Jackson said, there was still a connection between early sipping and risky drinking by high school.According to Jackson, it’s possible that those little tastes of alcohol send young kids a “mixed message.”“At that age, some kids may have difficulty understanding the difference between a sip of wine and having a full beer,” she explained.That said, she stressed that parents shouldn’t be alarmed if they’ve already let their child have a taste of wine.“We’re not saying your child is doomed,” Jackson said.But, she added, the findings do highlight the importance of giving kids “clear, consistent messages” about drinking and making sure they can’t get a hold of any alcohol kept in the house.
What happens in the moments just before death is widely believed to be a slowdown of the body’s systems as the heart stops beating and blood flow ends.But a new laboratory study by the University of Michigan Medical School reveals a storm of brain activity that erupts as the heart deteriorates and plays a surprising destabilizing role in heart function.This near-death brain signaling may be targeted to help cardiac arrest patients survive. Most of the more than 400,000 Americans who experience cardiac arrest at home, at work or in public die without immediate help. Email Pinterest Share LinkedIn Share on Facebook Share on Twitter “Despite the loss of consciousness and absence of signs of life, internally the brain exhibits sustained, organized activity and increased communication with the heart, which one may guess is an effort to save the heart,” says senior study author Jimo Borjigin, Ph.D., associate professor of neurology and associate professor of molecular and integrative physiology.However the brain signaling at near-death may, in fact, accelerate cardiac demise, according to the study published in this week’s PNAS Early Edition.Researchers with backgrounds in engineering, neuroscience, physiology, cardiology, chemistry, and pharmacology looked at the mechanism by which the heart of a healthy person ceases to function within just a few minutes without oxygen.While the animal study examined asphyxia-induced cardiac arrest, sudden cardiac death can also follow fatal cardiac arrhythmias, ischemic stroke, traumatic brain injury, brain hemorrhage and epilepsy.For the study, performed in rats, researchers simultaneously examined the heart and brain during experimental asphyxiation and documented an immediate release of more than a dozen neurochemicals, along with an activation of brain-heart connectivity.Following a steep fall of the heart rate, brain signals strongly synchronized with the heart rhythm, as visualized beat-by-beat using a new technology developed in the Borjigin laboratory called electrocardiomatrix.According to the study, blocking the brain’s outflow significantly delayed ventricular fibrillation, in which the lower chambers of the heart quiver and the heart cannot pump any blood. It’s the most serious cardiac rhythm disturbance.“The study suggests that a pharmacological blockade of the brain’s electrical connections to the heart during cardiac arrest may improve the chances of survival in cardiac arrest patients,” Borjigin says.In previous work, Borjigin and her colleagues demonstrated significant organized activation of the brain in animals undergoing cardiac arrest. This new study provides a neurochemical foundation for the surge in brain activity and a brain-heart connectivity that may be targeted to lengthen detectable brain activity.
Email Share on Facebook Pinterest Share LinkedIn Though it might be great for fitness and self-defense, research suggests you should be skeptical of claims that martial arts provides measurable and consistent mental health benefits for kids.Marketing materials for martial arts studios often mention mental health benefits, and past research has found that Taekwondo can improve children’s prosocial behavior, classroom behavior, and mental math abilities. Another study found that participation in martial arts led to greater behavioral improvements for children.But a very large study on martial arts and mental health casts doubts on those claims. Share on Twitter In an article published October 2009 in Child and Adolescent Psychiatry and Mental Health, researchers explored the potential mental health benefits that martial arts provides children. The researchers used information collected by the Early Childhood Longitudinal Study. The publicly-available study followed 21,260 children, beginning when they were in kindergarten (1998), and continuing every year throughout childhood.In their martial arts study, the researchers compared teachers’ reports of the children’s classroom behavior in kindergarten, third grade, and fifth grade. The teacher questionnaires asked about children’s self-control, approaches to learning, interpersonal skills, externalizing problem behaviors (e.g. arguing, fighting, getting angry, and acting impulsively), internalizing problem behaviors (e.g. anxiety, loneliness, low self-esteem, sadness).Overall, 3.3% of kindergarteners, 7.5% of third graders, and 7.1% of fifth graders in the sample were participating in martial arts. To determine whether participation in martial arts has any benefits, the researchers compared children who were enrolled in martial arts to children who were not enrolled in martial arts from first through third grade, then again from third through fifth grade. The researchers did not observe any associations between participation in martial arts and teachers’ reports of children’s behavior (self-control, approaches to learning, interpersonal skills, externalizing problem behaviors, internalizing problem behaviors).“Changing students’ behavior outside the classroom in a way that generalizes to the classroom is, we suspect, in general not an easy task. This study fails to find evidence that martial arts training achieves this goal,” the researchers write.While these results cast doubt on the idea that martial arts provides mental health benefits, the researchers point out that this is still a possibility. The authors note that it is possible that the way each martial arts class is instructed plays a role, and because this study used a variety of martial arts studios and instructors, some may have been more effective than others.“It’s important to remind ourselves that educational interventions such as martial arts are not homogeneous. Martial arts as taught by one practitioner may be totally different from that taught by another. One practitioner may emphasize self-control and emotional regulation, whereas another might emphasize self-defense or preparation for competition, and a third might actually promote aggression,” the researchers explain.“Thus our results do not rule out the possibility that some studios regularly achieve positive effects, and others achieve negative ones. It could also be that even within individual studios, there are net positive effects on some children from encouraging self-discipline and respect, which are cancelled by net negative effects on others from practice of physical aggression.”This was the first time researchers explored martial arts’ mental health outcomes in such a large number and diverse group of children. Although the study did not find any mental health benefits, martial arts still continues to benefit children in other ways, potentially increasing children’s self-defense abilities and overall physical fitness.
Share Share on Twitter Share on Facebook Pinterest LinkedIn As everyone who has gotten up in the middle of the night to go to the bathroom knows, the brain maintains a sense of place and a basic ability to navigate that is independent of external clues from the eyes, ears and other senses.A series of immersive virtual reality experiments has now confirmed that the human brain’s internal navigation system works in the same fashion as the grid cell system, a specialized neural network discovered in rats only 10 years ago, which has since been identified in a number of other mammals, including mice, bats and monkeys.The experiments were performed by a research team headed by Timothy McNamara, professor of psychology at Vanderbilt University, and described in the June 29 issue of the journal Current Biology. Email Questions about the brain’s ability to navigate have engaged philosophers and scientists for a long time. For example, the 18th century philosopher Immanuel Kant argued that perception of place was an innate ability independent of experience. In 1948 American experimental psychologist Edward Tolman proposed that the brain must maintain a map-like representation of its surroundings.But it wasn’t until the 1970s that an English scientist, John O’Keefe, found where this map-like representation was hidden in the brain when he discovered the existence of ‘place cells’ in the hippocampus. Place cells are specialized neurons that become active whenever a free roaming rat reaches a specific location in its environment. Because different place cells become active when the animal is in different places, large numbers of these cells could provide the basis of the spatial representation Tolman had proposed.In 2005, a team of Norwegian scientists headed by Edvard and May-Britt Moser discovered that place cells were only one part of a more sophisticated system that not only serves as the basis for spatial memory but also gives individuals their basic navigational sense. It is called the grid cell system and it is located in a narrow strip of tissue on the bottom of the brain called the entorhinal cortex. The EC acts as the main interface between the hippocampus and the neocortex.By tracing connections from the place cells in the hippocampus to the EC and by moving their rats from small cages to larger enclosures, the Mosers discovered a set of neurons with an astonishing firing pattern. Instead of becoming active at the single location like place cells, they became active at several locations. When rats were allowed to explore these large enclosures for extended periods of time, it became apparent that the locations at which a particular grid cell was active formed a remarkably regular grid-like pattern, similar to honeycomb. As a result, they were named grid cells.In 2014, O’Keefe and the Mosers received the Nobel Prize in Physiology or Medicine for their discoveries.Since grid cells were identified in animals, researchers have found circumstantial evidence that humans have a similar navigation system. For example, direct recordings of nerve activity in the brains of patients with epilepsy during pre-surgical investigations have found evidence for place-like cells in the hippocampus and grid-like cells in the EC. However, other experiments, which found that individuals with damage to their hippocampus and EC can maintain their sense of direction while blindfolded, have raised questions about the extent to which humans depend on this part of the brain to navigate.McNamara and his collaborators — Vanderbilt doctoral students Xiaoli Chen and Qiliang He, Jonathan Kelly from Iowa State University and Ila Fiete from the University of Texas, Austin — became interested in a series of experiments where the researchers had recorded how the rat’s grid cell system responds when the size of the its enclosure is altered. The researchers who performed the experiments found that the grid spacing increased when the enclosure was enlarged and decreased when the enclosure shrunk.The activity of individual grid cells does not identify specific locations by themselves. But seven years ago Fiete showed mathematically that the activity patterns of collections of grid cells could be translated into unique spatial positions.McNamara realized that they could perform some similar experiments for human participants using immersive virtual reality and apply Fiete’s model to see if the human navigation system operates in the same fashion as a grid-cell system.Specifically, the researchers created virtual enclosures of different sizes, had participants walk to a series of way markers (colored columns of light that appear one at a time and disappear when a participant reaches them), blanked out their view, asked them to find their way directly back to the first marker and recorded how close they came to its position. The first few trials were conducted in an enclosure that remained the same size. For the final trial, however, they changed one of the dimensions by as much as 40 percent.‘In most cases, the participants don’t even notice that the size of the enclosure has changed,’ said McNamara. ‘But, when it does change, the positions where they stop are significantly farther from the target than they are when the enclosure remains the same. When the enclosure increases in size they tend to undershoot and when it decreases they tend to overshoot.’The amounts that the participants undershot and overshot were remarkably consistent with what the studies with rats and Fiete’s model predicted if the individuals were being guided by a grid-cell system that had been fixed by the dimensions of the original enclosure.‘We still can’t say for certain that people use a grid-cell system to navigate,’ said McNamara. ‘But we can say that, if people use a different system, it seems to behave in exactly the same way.’
Share on Facebook Pinterest An emerging consensus among neuroscientists is that cognitive operations are performed not by individual brain regions working in isolation, but by networks consisting of several discrete brain regions — anatomically connected either directly via white-matter tracts or indirectly through intermediary nodes — that share ‘functional connectivity,’ meaning that activity in these regions is tightly coupled.Any given functional network is normally most active during the performance of the task associated with that network, as in the case of autobiographical memory (‘What did I eat for dinner last night?’). But the synchronous activity of component regions persists when networks are idling. Well over a dozen functional networks have been identified via a technique called resting-state functional magnetic resonance imaging, said Greicius, who is the medical director of the Stanford Center for Memory Disorders.In resting-state fMRI scans, the individual is asked to simply lie still and relax for several minutes. The results of these scans indicate that even at rest, the brain’s functional networks continue to hum along at their own distinguishable frequencies and phases, like different radio stations playing simultaneously, but quietly, on the same radio.Digging into fMRI imagesHowever, whether resting-state fMRI-derived images, which measure local blood flows in different places throughout the brain, actually reflect neuronal activity has been controversial.‘There’s been some skepticism regarding the validity of resting-state network activity,’ said Greicius. ‘We wanted to dig deeper and get to the molecular underpinnings of these imaging results, which indicated that the brain maintains its exquisite functional-network architecture even at rest.’To start, Greicius and his colleagues computationally blended resting-state fMRI data they’d obtained from eight-minute scans of 15 healthy adults whose sole instructions were to lie still and relax. This enabled them to pinpoint numerous well-delineated functional networks.Hoping to find genes that might promote or at least be involved in functional connectivity, the investigators next sought gene-expression profiles — measurements of activity levels of each of the human genome’s approximately 20,000 known genes — of regions within corresponding functional networks.There’s no noninvasive way to obtain gene-profile expressions of brain tissue in living humans. But Jonas Richiardi, Ph.D., a postdoctoral scholar in Greicius’ lab now at the University of Geneva in Switzerland, made use of massive amounts of carefully annotated and meticulously archived data derived from the Allen Institute’s collection of six post-mortem human brain samples. The institute’s scientists have obtained gene-expression profiles of several hundred tissue samples excised from specific locations throughout the brain. Richiardi shares lead authorship of the study with neurology instructor Andre Altmann, Ph.D., who was also a postdoctoral scholar during the study’s duration.Greicius and his colleagues narrowed their focus to cortical areas associated with four functional networks that are all well characterized in the imaging literature, consist of discrete, noncontiguous regions in both hemispheres, and are well represented in the Allen Institute’s human-brain database. Along with the default-mode network associated with autobiographical memory, they looked at gene-expression profiles in component regions of the brain’s sensorimotor, visuospatial and salience (emotion) networks.Zeroing in on gene activityThe researchers were hunting specifically for a set of genes whose expression rose or fell in a more synchronized fashion from region to region within a given network than between networks or outside any network. Using sophisticated statistical methods, they identified a set of 136 genes that showed a correlated pattern of gene expression in regions within each network.These 136 genes weren’t specific to any single network, Greicius noted. Rather, ‘any one of these genes that was being expressed at a high, intermediate or low level in one region of any network, regardless of which network you’d picked, was also being expressed at corresponding levels in the other regions of that network,’ he said.Importantly, a number of these genes encode proteins that aid in nerve cells’ signature activity: propagating electrical impulses. Some are ion channels, which maintain and modulate voltage differences across nerve cells’ outer membranes. Others are found at the junctions where one nerve cell in a circuit contacts another.The Stanford team validated their findings by turning to another database. The IMAGEN Consortium has conducted widespread imaging, cognitive and genetic tests on 14-year-olds in an effort to predict who’s at high risk of encountering problems such as substance abuse by age 16. Among other things, the IMAGEN database contains detailed information on tiny variations from the norm in subjects’ genomic sequences. Altmann spearheaded an analysis of the variants present in the 136 genes of interest in 259 healthy adolescents. These subjects’ network-connectivity strength was determined, in part, by the genetic-variant profiles of these 136 genes.Additional experiments using tissue samples obtained from two additional data sets, the Allen Institute’s mouse-brain and mouse-connectivity atlases, confirmed and amplified the findings from research on human brains. The reliance on large, shared data sets was another important feature of the study and, Altmann said, ‘highlights the value of making scientific data freely available. We had an idea and found collaborators willing to share their painstakingly collected data.’The identification of functional-connectivity-associated genes sets the stage for targeted clinical applications, such as finding out how neurodegeneration propagates within a network.‘Our work holds potential implications for a number of neuropsychiatric disorders,’ said Richiardi.Evidence suggests, for instance, that Alzheimer’s disease spreads from one brain region to the next within the brain’s so-called default-mode network, which is activated when a person is recalling recent autobiographical events. Resting-state imaging holds exceptional potential in cases where task-based fMRI isn’t applicable. Alzheimer’s patients, for example, have difficulty focusing on memory-based tasks. Future work will focus on genes whose expression is correlated within one network, but not in other networks. Focusing on default-mode network-specific genes, for example, may lend novel insights into Alzheimer’s disease. Email Share LinkedIn A new study by researchers at the Stanford University School of Medicine found that synchronized physiological interactions between remote brain regions have genetic underpinnings.The research was performed at Stanford but was made possible by collaborations with the Seattle-based Allen Institute for Brain Science and the IMAGEN Consortium, a multicenter European project, said the study’s senior author, Michael Greicius, M.D., an associate professor of neurology and neurological sciences.The study will be published June 11 in Science. Share on Twitter
A hidden camera and correct answers to the question, which was based on the name of a fictitious cartoon character, enabled the researchers to identify who had peeked, despite denials.Further questioning, including about the colour of the answer on the cards, allowed researchers to identify who was a good liar, by lying to both entrapment questions; or a bad liar, by lying about one or none of the entrapment questions.During the experiment, researchers from the Universities of Sheffield and North Florida then measured two elements: verbal and visuo-spatial working memory in the children.Verbal working memory is the number of words a person can remember all at the same time. Visuo-spatial working memory is the number of images a person can remember all at the same time.Results showed that the good liars performed better in the verbal working memory test in both processing and recall, compared to the bad liars.The link between lying and verbal memory is thought to stem from the fact that covering lies involves keeping track of lots of verbal information. As a result, kids who possessed better memories and could keep track of lots of information were able to successfully make and maintain a cover story for their lie.In contrast, there was no difference in visuo-spatial working scores between good and bad liars. The researchers suspect this is because lying usually doesn’t involve keeping track of images, so visuo-spatial information is less important.The results have been published today in the Journal of Experimental Child Psychology and are the first time it has been shown that verbal working memory in particular has strong links to lying, not just any working memory.Dr Elena Hoicka, from the University of Sheffield’s Department of Psychology, said: “While parents are usually not too proud when their kids lie, they can at least be pleased to discover that when their children are lying well, it means their children are becoming better at thinking and have good memory skills.“We already know that adults lie in approximately a fifth of their social exchanges lasting 10 or more minutes, so it’s interesting to know why some children are able to tell more porkies than others. We’ll now be looking to move the research forward to discover more about how children first learn to lie.”Dr Tracy Alloway, project lead from the University of North Florida, said: “This research shows that thought processes, specifically verbal working memory, are important to complex social interactions like lying because the children needed to juggle multiple pieces of information while keeping the researcher’s perspective in mind.” Children who benefit from a good memory are much better at covering up lies, researchers from the University of Sheffield have discovered.Experts found a link between verbal memory and covering up lies following a study which investigated the role of working memory in verbal deception amongst children.The study saw six to seven year old children presented with the opportunity to do something they were instructed not to -peek at the final answers on the back of a card during a trivia game. Share Share on Twitter LinkedIn Email Share on Facebook Pinterest
A brain-chemistry deficit in children with autism may help to explain their social difficulties, according to new findings from the Stanford University School of Medicine.The research team found a correlation between low levels of vasopressin, a hormone involved in social behavior, and the inability of autistic children to understand that other people’s thoughts and motivations can differ from their own.The research will be published July 22 in PLOS ONE. Share on Twitter LinkedIn Share Email Pinterest Share on Facebook “Autistic children who had the lowest vasopressin levels in their blood also had the greatest social impairment,” said the study’s senior author, Karen Parker, PhD, associate professor of psychiatry and behavioral sciences.The findings raise the possibility that treatment with vasopressin might reduce social problems for autistic children who have low vasopressin levels, a hypothesis that Parker and her team are now testing in a clinical trial.However, the new research also showed that children without autism can have low vasopressin levels without displaying social impairment, Parker noted; in other words, autism is not explained by a vasopressin deficit alone.Investigating vasopressinAutism is a developmental disorder that affects 1 out of every 68 children in the United States. It is characterized by social and communication deficits and repetitive behaviors. The new study examined a social trait that psychologists call “theory of mind”: the ability to understand that others have different perspectives. Poor “theory of mind” makes it harder for people with autism to empathize and form relationships with others.Vasopressin is a small-protein hormone that is structurally similar to oxytocin. Like oxytocin, it has roles in social behavior. Vasopressin also helps regulate blood pressure.In the new study, the researchers first verified that vasopressin levels in the blood accurately reflected vasopressin levels in the brain by measuring the hormone’s levels simultaneously in the blood and cerebrospinal fluid of 28 people who were having the fluid collected for medical reasons.They then recruited 159 children ages 3-12 for behavioral testing. Of these children, 57 had autism, 47 did not have autism but had a sibling who did, and 55 were typically developing children with no autistic siblings. All of the children completed standard psychiatric assessments of their neurocognitive abilities, social responsiveness, theory of mind, and ability to recognize others’ emotions, which is known as affect recognition. All children gave blood samples that were measured for vasopressin.In all three groups, children had a wide range of vasopressin levels, with some children in each group having low, medium and high levels. Children without autism had similar scores on theory of mind tests regardless of their blood vasopressin level, but in children with autism, low blood vasopressin was a marker of low theory of mind ability.
Pinterest Share on Facebook Share on Twitter Share LinkedIn Email “Approximately 70% of individuals who use marijuana also use tobacco,” explained Francesca Filbey, Ph.D., the study’s principal investigator and Director of Cognitive Neuroscience of Addictive Behaviors at the Center for BrainHealth. “Our findings exemplify why the effects of marijuana on the brain may not generalize to the vast majority of the marijuana using population, because most studies do not account for tobacco use. This study is one of the first to tease apart the unique effects of each substance on the brain as well as their combined effects.”Dr. Filbey’s research team used magnetic resonance imaging (MRI) to examine the hippocampus; an area of the brain that is know to have altered size and shape in association with chronic marijuana use. Participants completed a substance use history assessment and neuropsychological tests three days prior to an MRI head scan. The team compared four groups: nonusers (individuals who have not had any marijuana or tobacco in the past three months), chronic marijuana users (individuals who use marijuana at least four times per week), frequent nicotine users (10 or more times daily) and chronic marijuana plus frequent nicotine users (at least four marijuana uses per week and 10 or more nicotine uses per day).“We have always known that each substance is associated with effects on the brain and hypothesized that their interaction may not simply be a linear relationship. Our findings confirm that the interaction between marijuana and nicotine is indeed much more complicated due to the different mechanisms at play,” said Filbey. “Future studies need to address these compounding effects of substances.”She continued, “The combined use of marijuana and tobacco is highly prevalent. For instance, a ‘blunt’ is wrapped in tobacco leaf. A ‘spliff’ is a joint rolled with tobacco. We really need to understand how the combined use changes the brain to really understand its effects on memory function and behavior.” How scientists study the effects of marijuana on the brain is changing. Until recently marijuana research largely excluded tobacco users from its participant pool, but scientists at the Center for BrainHealth at The University of Texas at Dallas have found reason to abandon this practice, uncovering significant differences in the brains of individuals who use both tobacco and marijuana and the brains of those who only use marijuana.In a study that appears online in the journal Behavioural Brain Research, scientists report an association between smaller hippocampal brain volume and marijuana use. Although the size of the hippocampus, an area of the brain associated with memory and learning, is significantly smaller in both the marijuana group and marijuana plus tobacco group compared to non-using controls and individuals who use tobacco exclusively, the relationship to memory performance is unique.Hippocampal size of nonusers reflects a direct relationship to memory function; the smaller the hippocampus, the poorer the memory function. Individuals who use marijuana and tobacco show an inverse relationship, i.e., the smaller the hippocampus size, the greater memory the function. Furthermore the number of nicotine cigarettes smoked per day in the marijuana and nicotine using group appears to be related to the severity of hippocampal shrinkage. The greater the number of cigarettes smoked per day, the smaller the hippocampal volume and the greater the memory performance. There were no significant associations between hippocampal size and memory performance in individuals who only use tobacco or only use marijuana.