Posts tagged brain structure
Articles and news from the latest research reports.
Changes in Brain Structure Found After Childhood Abuse
Different forms of childhood abuse increase the risk for mental illness as well as sexual dysfunction in adulthood, but little has been known about how that happens. An international team of researchers, including the Miller School’s Charles B. Nemeroff, M.D., Ph.D., Leonard M. Miller Professor and Chair of Psychiatry and Behavioral Sciences, has discovered a neural basis for this association. The study, published in the June 1 issue of the American Journal of Psychiatry, shows that sexually abused and emotionally mistreated children exhibit specific and differential changes in the architecture of their brain that reflect the nature of the mistreatment.
Researchers have known that victims of childhood abuse often suffer from psychiatric disorders later in life, including sexual dysfunction following sexual abuse. The underlying mechanisms mediating this association have been poorly understood. Nemeroff and a group of scientists led by Christine Heim, Ph.D., Director of the Institute of Medical Psychology at Charité University of Medicine Berlin, and Jens Pruessner, Ph.D., Director of the McGill Center for Studies in Aging at McGill University in Montreal, hypothesized that cortical changes during segments of mistreatment played a role. To study these potential changes, the researchers used magnetic resonance imaging (MRI) to examine the brains of 51 adult women who were exposed to various forms of childhood abuse.
The results showed a correlation between specific forms of maltreatment and thinning of the cortex in precisely the regions of the brain that are involved in the perception or processing of the type of abuse. Specifically, the somatosensory cortex in the area in which the female genitals are represented was significantly thinner in women who were victims of sexual abuse in their childhood. Similarly, victims of emotional mistreatment were found to have a reduction of the thickness of the cerebral cortex in specific areas associated with self-awareness, self-evaluation and emotional regulation.
“This is one of the first studies documenting long-term alterations in specific brain areas as a consequence of child abuse and neglect,” said Nemeroff, who is also Director of the Center on Aging. “The finding that specific types of early life trauma have discrete, long lasting effects on the brain that underlie symptoms in adults is an important step in developing novel therapies to intervene to reduce the often lifelong psychiatric/psychological burden of such trauma.”
“Our data point to a precise association between experience-dependent neural plasticity and later health problems,” said Heim. Pruessner agreed that the “large effect and the regional specificity in the brain that corresponds to the type of abuse is remarkable.”
The scientists speculate that a regional thinning of the cortex may serve as a protective mechanism, immediately shielding the child from the experience of the abuse by gating or blocking the sensory experience. However, that thinning of the cortical sections may lay the groundwork for the development of behavioral problems in adulthood. The results of this study extend the literature on neural plasticity and show that cortical representation fields can be smaller when certain sensory experiences are damaging or developmentally inappropriate.
Experience leads to the growth of new brain cells
A new study examines how individuality develops
The DFG-Center for Regenerative Therapies Dresden - Cluster of Excellence at the TU Dresden (CRTD), the Dresden site of the German Center for Neurodegenerative Diseases (DZNE), and the Max Planck Institute for Human Development in Berlin played a pivotal role in the study.
The adult brain continues to grow with the challenges that it faces; its changes are linked to the development of personality and behavior. But what is the link between individual experience and brain structure? Why do identical twins not resemble each other perfectly even when they grew up together? To shed light on these questions, the scientists observed forty genetically identical mice that were kept in an enclosure offering a large variety of activity and exploration options.
"The animals were not only genetically identical, they were also living in the same environment," explains principal investigator Gerd Kempermann, Professor for Genomics of Regeneration, CRTD, and Site Speaker of the DZNE in Dresden. "However, this environment was so rich that each mouse gathered its own individual experiences in it. Over time, the animals therefore increasingly differed in their realm of experience and behavior."
New neurons for individualized brains
Each of the mice was equipped with a special micro-chip emitting electromagnetic signals. This allowed the scientists to construct the mice’s movement profiles and to quantify their exploratory behavior. The result: Despite a common environment and identical genes the mice showed highly individualized behavioral patterns. They reacted to their environment differently. In the course of the three-month experiment these differences increased in size.
"Though the animals shared the same life space, they increasingly differed in their activity levels. These differences were associated with differences in the generation of new neurons in the hippocampus, a region of the brain that supports learning and memory," says Kempermann. "Animals that explored the environment to a greater degree also grew more new neurons than animals that were more passive."
Adult neurogenesis, that is, the generation of new neurons in the hippocampus, allows the brain to react to new information flexibly. With this study, the authors show for the first time that personal experiences and ensuing behavior contribute to the „individualization of the brain.” The individualization they observed cannot be reduced to differences in environment or genetic makeup.
"Adult neurogenesis also occurs in the hippocampus of humans," says Kempermann. "Hence we assume that we have tracked down a neurobiological foundation for individuality that also applies to humans."
Impulses for discussion across disciplines
"The finding that behavior and experience contribute to differences between individuals has implications for debates in psychology, education science, biology, and medicine," states Prof. Ulman Lindenberger, Director of the Center for Lifespan Psychology at the Max Planck Institute for Human Development (MPIB) in Berlin. "Our findings show that development itself contributes to differences in adult behavior. This is what many have assumed, but now there is direct neurobiological evidence in support of this claim. Our results suggest that experience influences the aging of the human mind."
In the study, a control group of animals housed in a relatively unattractive enclosure was also examined; on average, neurogenesis in these animals was lower than in the experimental mice. „When viewed from educational and psychological perspectives, the results of our experiment suggest that an enriched environment fosters the development of individuality,” comments Lindenberger.
Interdisciplinary teamwork
The study is also an example of multidisciplinary cooperation — it was made possible because neuroscientists, ethologists, computer scientists, and developmental psychologists collaborated closely in designing the experimental set-up and applying new data analysis methods. Biologist Julia Freund from the CRTD Dresden and computer scientist Dr. Andreas Brandmaier from the MPIB in Berlin share first authorship on the article. In addition to the DZNE, CRTD, and the MPIB, the German Research Center for Artificial Intelligence in Saarbrücken and the Institute for Geoinformatics and the Department of Behavioural Biology at the University of Münster were also involved in this project.
Original publication
"Emergence of Individuality in Genetically Identical Mice", Julia Freund, Andreas M. Brandmaier, Lars Lewejohann, Imke Kirste, Mareike Kritzler, Antonio Krüger, Norbert Sachser, Ulman Lindenberger, Gerd Kempermann, Science
(Image: Dr Jonathan Clarke, Wellcome Images)
Brain Anatomy of Dyslexia Is Not the Same in Men and Women, Boys and Girls
Using MRI, neuroscientists at Georgetown University Medical Center found significant differences in brain anatomy when comparing men and women with dyslexia to their non-dyslexic control groups, suggesting that the disorder may have a different brain-based manifestation based on sex.
Their study, investigating dyslexia in both males and females,is the first to directly compare brain anatomy of females with and without dyslexia (in children and adults). Their findings were published online in the journal Brain Structure and Function.
Because dyslexia is two to three times more prevalent in males compared with females, “females have been overlooked,” says senior author Guinevere Eden, PhD, director for the Center for the Study of Learning and past-president of the International Dyslexia Association.
“It has been assumed that results of studies conducted in men are generalizable to both sexes. But our research suggests that researchers need to tackle dyslexia in each sex separately to address questions about its origin and potentially, treatment,” Eden says.
Previous work outside of dyslexia demonstrates that male and female brains are different in general, adds the study’s lead author, Tanya Evans, PhD.
“There is sex-specific variance in brain anatomy and females tend to use both hemispheres for language tasks, while males just the left,” Evans says. “It is also known that sex hormones are related to brain anatomy and that female sex hormones such as estrogen can be protective after brain injury, suggesting another avenue that might lead to the sex-specific findings reported in this study.”
The study of 118 participants compared the brain structure of people with dyslexia to those without and was conducted separately in men, women, boys and girls. In the males, less gray matter volume is found in dyslexics in areas of the brain used to process language, consistent with previous work. In the females, less gray matter volume is found in dyslexics in areas involved in sensory and motor processing.
The results have important implications for understanding the origin of dyslexia and the relationship between language and sensory processing, says Evans.
Study shows different brains have similar responses to music
Do the brains of different people listening to the same piece of music actually respond in the same way? An imaging study by Stanford University School of Medicine scientists says the answer is yes, which may in part explain why music plays such a big role in our social existence.
(Image: Anthony Ellis)
The investigators used functional magnetic resonance imaging to identify a distributed network of several brain structures whose activity levels waxed and waned in a strikingly similar pattern among study participants as they listened to classical music they’d never heard before. The results will be published online April 11 in the European Journal of Neuroscience.
"We spend a lot of time listening to music — often in groups, and often in conjunction with synchronized movement and dance," said Vinod Menon, PhD, a professor of psychiatry and behavioral sciences and the study’s senior author. "Here, we’ve shown for the first time that despite our individual differences in musical experiences and preferences, classical music elicits a highly consistent pattern of activity across individuals in several brain structures including those involved in movement planning, memory and attention."
The notion that healthy subjects respond to complex sounds in the same way, Menon said, could provide novel insights into how individuals with language and speech disorders might listen to and track information differently from the rest of us.
The new study is one in a series of collaborations between Menon and co-author Daniel Levitin, PhD, a psychology professor at McGill University in Montreal, dating back to when Levitin was a visiting scholar at Stanford several years ago.
To make sure it was music, not language, that study participants’ brains would be processing, Menon’s group used music that had no lyrics. Also excluded was anything participants had heard before, in order to eliminate the confounding effects of having some participants who had heard the musical selection before while others were hearing it for the first time. Using obscure pieces of music also avoided tripping off memories such as where participants were the first time they heard the selection.
The researchers settled on complete classical symphonic musical pieces by 18th-century English composer William Boyce, known to musical cognoscenti as “the English Bach” because his late-baroque compositions in some respects resembled those of the famed German composer. Boyce’s works fit well into the canon of Western music but are little known to modern Americans.
Next, Menon’s group recruited 17 right-handed participants (nine men and eight women) between the ages of 19 and 27 with little or no musical training and no previous knowledge of Boyce’s works. (Conventional maps of brain anatomy are based on studies of right-handed people. Left-handed people’s brains tend to deviate from that map.)
While participants listened to Boyce’s music through headphones with their heads maintained in a fixed position inside an fMRI chamber, their brains were imaged for more than nine minutes. During this imaging session, participants also heard two types of “pseudo-musical” stimuli containing one or another attribute of music but lacking in others. In one case, all of the timing information in the music was obliterated, including the rhythm, with an effect akin to a harmonized hissing sound. The other pseudo-musical input involved maintaining the same rhythmic structure as in the Boyce piece but with each tone transformed by a mathematical algorithm to another tone so that the melodic and harmonic aspects were drastically altered.
The team identified a hierarchal network stretching from low-level auditory relay stations in the midbrain to high-level cortical brain structures related to working memory and attention, and beyond that to movement-planning areas in the cortex. These regions track structural elements of a musical stimulus over time periods lasting up to several seconds, with each region processing information according to its own time scale.
Activity levels in several different places in the brain responded similarly from one individual to the next to music, but less so or not at all to pseudo-music. While these brain structures have been implicated individually in musical processing, their identifications had been obtained by probing with artificial laboratory stimuli, not real music. Nor had their coordination with one another been previously observed.
Notably, subcortical auditory structures in the midbrain and thalamus showed significantly greater synchronization in response to musical stimuli. These structures have been thought to passively relay auditory information to higher brain centers, Menon said. “But if they were just passive relay stations, their responses to both types of pseudo-music would have been just as closely synchronized between individuals as to real music.” The study demonstrated, for the first time, that those structures’ activity levels respond preferentially to music rather than to pseudo-music, suggesting that higher-level centers in the cortex direct these relay stations to closely heed sounds that are specifically musical in nature.
The fronto-parietal cortex, which anchors high-level cognitive functions including attention and working memory, also manifested intersubject synchronization — but only in response to music and only in the right hemisphere.
Interestingly, the structures involved included the right-brain counterparts of two important structures in the brain’s left hemisphere, Broca’s and Geschwind’s areas, known to be crucial for speech and language interpretation.
"These right-hemisphere brain areas track non-linguistic stimuli such as music in the same way that the left hemisphere tracks linguistic sequences," said Menon.
In any single individual listening to music, each cluster of music-responsive areas appeared to be tracking music on its own time scale. For example, midbrain auditory processing centers worked more or less in real time, while the right-brain analogs of the Broca’s and Geschwind’s areas appeared to chew on longer stretches of music. These structures may be necessary for holding musical phrases and passages in mind as part of making sense of a piece of music’s long-term structure.
"A novelty of our work is that we identified brain structures that track the temporal evolution of the music over extended periods of time, similar to our everyday experience of music listening," said postdoctoral scholar Daniel Abrams, PhD, the study’s first author.
The preferential activation of motor-planning centers in response to music, compared with pseudo-music, suggests that our brains respond naturally to musical stimulation by foreshadowing movements that typically accompany music listening: clapping, dancing, marching, singing or head-bobbing. The apparently similar activation patterns among normal individuals make it more likely our movements will be socially coordinated.
"Our method can be extended to a number of research domains that involve interpersonal communication. We are particularly interested in language and social communication in autism," Menon said. "Do children with autism listen to speech the same way as typically developing children? If not, how are they processing information differently? Which brain regions are out of sync?"
(Source: eurekalert.org)
Neanderthal brains focussed on vision and movement
Neanderthal brains were adapted to allow them to see better and maintain larger bodies, according to new research by the University of Oxford and the Natural History Museum, London.
Although Neanderthals’ brains were similar in size to their contemporary modern human counterparts, fresh analysis of fossil data suggests that their brain structure was rather different. Results imply that larger areas of the Neanderthal brain, compared to the modern human brain, were given over to vision and movement and this left less room for the higher level thinking required to form large social groups.
The analysis was conducted by Eiluned Pearce and Professor Robin Dunbar at the University of Oxford and Professor Chris Stringer at the Natural History Museum, London, and is published in the online version of the journal, Proceedings of the Royal Society B.
Looking at data from 27,000–75,000-year-old fossils, mostly from Europe and the Near East, they compared the skulls of 32 anatomically modern humans and 13 Neanderthals to examine brain size and organisation. In a subset of these fossils, they found that Neanderthals had significantly larger eye sockets, and therefore eyes, than modern humans.
The researchers calculated the standard size of fossil brains for body mass and visual processing requirements. Once the differences in body and visual system size are taken into account, the researchers were able to compare how much of the brain was left over for other cognitive functions.
Previous research by the Oxford scientists shows that modern humans living at higher latitudes evolved bigger vision areas in the brain to cope with the low light levels. This latest study builds on that research, suggesting that Neanderthals probably had larger eyes than contemporary humans because they evolved in Europe, whereas contemporary humans had only recently emerged from lower latitude Africa.
'Since Neanderthals evolved at higher latitudes and also have bigger bodies than modern humans, more of the Neanderthal brain would have been dedicated to vision and body control, leaving less brain to deal with other functions like social networking,' explains lead author Eiluned Pearce from the Institute of Cognitive and Evolutionary Anthropology at the University of Oxford.
‘Smaller social groups might have made Neanderthals less able to cope with the difficulties of their harsh Eurasian environments because they would have had fewer friends to help them out in times of need. Overall, differences in brain organisation and social cognition may go a long way towards explaining why Neanderthals went extinct whereas modern humans survived.’
'The large brains of Neanderthals have been a source of debate from the time of the first fossil discoveries of this group, but getting any real idea of the “quality” of their brains has been very problematic,' says Professor Chris Stringer, Research Leader in Human Origins at the Natural History Museum and co-author on the paper. 'Hence discussion has centred on their material culture and supposed way of life as indirect signs of the level of complexity of their brains in comparison with ours.
'Our study provides a more direct approach by estimating how much of their brain was allocated to cognitive functions, including the regulation of social group size; a smaller size for the latter would have had implications for their level of social complexity and their ability to create, conserve and build on innovations.'
Professor Robin Dunbar observes: ‘Having less brain available to manage the social world has profound implications for the Neanderthals’ ability to maintain extended trading networks, and are likely also to have resulted in less well developed material culture – which, between them, may have left them more exposed than modern humans when facing the ecological challenges of the Ice Ages.’
The relationship between absolute brain size and higher cognitive abilities has long been controversial, and this new study could explain why Neanderthal culture appears less developed than that of early modern humans, for example in relation to symbolism, ornamentation and art.
Has evolution given humans unique brain structures?
Humans have at least two functional networks in their cerebral cortex not found in rhesus monkeys. This means that new brain networks were likely added in the course of evolution from primate ancestor to human. These findings, based on an analysis of functional brain scans, were published in a study by neurophysiologist Wim Vanduffel (KU Leuven and Harvard Medical School) in collaboration with a team of Italian and American researchers.
Our ancestors evolutionarily split from those of rhesus monkeys about 25 million years ago. Since then, brain areas have been added, have disappeared or have changed in function. This raises the question, ‘Has evolution given humans unique brain structures?’. Scientists have entertained the idea before but conclusive evidence was lacking. By combining different research methods, we now have a first piece of evidence that could prove that humans have unique cortical brain networks.
Professor Vanduffel explains: “We did functional brain scans in humans and rhesus monkeys at rest and while watching a movie to compare both the place and the function of cortical brain networks. Even at rest, the brain is very active. Different brain areas that are active simultaneously during rest form so-called ‘resting state’ networks. For the most part, these resting state networks in humans and monkeys are surprisingly similar, but we found two networks unique to humans and one unique network in the monkey.”
“When watching a movie, the cortex processes an enormous amount of visual and auditory information. The human-specific resting state networks react to this stimulation in a totally different way than any part of the monkey brain. This means that they also have a different function than any of the resting state networks found in the monkey. In other words, brain structures that are unique in humans are anatomically absent in the monkey and there no other brain structures in the monkey that have an analogous function. Our unique brain areas are primarily located high at the back and at the front of the cortex and are probably related to specific human cognitive abilities, such as human-specific intelligence.”
The study used fMRI (functional Magnetic Resonance Imaging) scans to visualise brain activity. fMRI scans map functional activity in the brain by detecting changes in blood flow. The oxygen content and the amount of blood in a given brain area vary according to a particular task, thus allowing activity to be tracked.
Excessive Alcohol Use When You’re Young Could Have Lasting Impacts on Your Brain
Excessive alcohol use accounts for 4% of the global burden of disease, and binge drinking particularly is becoming an increasing health issue. A new review article published in Cortex highlights the significant changes in brain function and structure that can be caused by alcohol misuse in young people.
Functional signs of brain damage from alcohol misuse in young people mainly include deficits in visual learning and memory as well as executive functions. These functions are controlled by the hippocampus and frontal structures of the brain, which are not fully mature until around 25 years of age. Structural signs of alcohol misuse in young people include shrinking of the brain and significant changes to white matter tracts.
Age of first use may be considered to trigger alcohol misuse. According to the researchers however, changing the legal drinking age is not the answer. In Australia the legal drinking age is 18, three years earlier than in the US. Despite the difference in legal drinking age, the age of first use (and associated problems) is the same between the two countries.
Instead, the authors stressed the need for early intervention, by identifying markers and thresholds of risky drinking behaviour at an early stage, while individuals are in vulnerable stages of brain development.
(Source: alphagalileo.org)
Stem Cell Research Helps to Identify Origins of Schizophrenia
New University at Buffalo research demonstrates how defects in an important neurological pathway in early development may be responsible for the onset of schizophrenia later in life.
The UB findings, published in Schizophrenia Research, test the hypothesis in a new mouse model of schizophrenia that demonstrates how gestational brain changes cause behavioral problems later in life – just like the human disease.
Partial funding for the research came from New York Stem Cell Science (NYSTEM).
The genomic pathway, called the Integrative Nuclear FGFR 1 Signaling (INFS), is a central intersection point for multiple pathways of as many as 160 different genes believed to be involved in the disorder.
“We believe this is the first model that explains schizophrenia from genes to development to brain structure and finally to behavior,” says lead author Michal Stachowiak, PhD, professor in the Department of Pathology and Anatomical Sciences in the UB School of Medicine and Biomedical Sciences. He also is director of the Stem Cell Engraftment & In Vivo Analysis Facility at the Western New York Stem Cell Culture and Analysis Center at UB.
A key challenge with the disease is that patients with schizophrenia exhibit mutations in different genes, he says.
“How is it possible to have 100 patients with schizophrenia and each one has a different genetic mutation that causes the disorder?” asks Stachowiak. “It’s possible because INFS integrates diverse neurological signals that control the development of embryonic stem cell and neural progenitor cells, and links pathways involving schizophrenia-linked genes.
“INFS functions like the conductor of an orchestra,” explains Stachowiak. “It doesn’t matter which musician is playing the wrong note, it brings down the conductor and the whole orchestra. With INFS, we propose that when there is an alteration or mutation in a single schizophrenia-linked gene, the INFS system that controls development of the whole brain becomes untuned. That’s how schizophrenia develops.”
Using embryonic stem cells, Stachowiak and colleagues at UB and other institutions found that some of the genes implicated in schizophrenia bind the FGFR1 (fibroblast growth factor receptor) protein, which in turn, has a cascading effect on the entire INFS.
People who take cocaine over many years without becoming addicted have a brain structure which is significantly different from those individuals who developed cocaine-dependence, researchers have discovered. New research from the University of Cambridge has found that recreational drug users who have not developed a dependence have an abnormally large frontal lobe, the section of the brain implicated in self-control. Their research was published in the journal Biological Psychiatry.
For the study, led by Dr Karen Ersche, individuals who use cocaine on a regular basis underwent a brain scan and completed a series of personality tests. The majority of the cocaine users were addicted to the drug but some were not (despite having used it for several years).
The scientists discovered that a region in the frontal lobes of the brain, known to be critically implicated in decision-making and self-control, was abnormally bigger in the recreational cocaine users. The Cambridge researchers suggest that this abnormal increase in grey matter volume, which they believe predates drug use, might reflect resilience to the effects of cocaine, and even possibly helps these recreational cocaine users to exert self-control and to make advantageous decisions which minimize the risk of them becoming addicted.
They found that this same region in the frontal lobes of the brain was significantly reduced in size in people with cocaine dependence, confirming earlier research that had found similar results. They believe that at least some of these changes are the result of drug use, which causes drug users to lose grey matter.
They also found that people who use illicit drugs like cocaine exhibit high levels of sensation-seeking personality traits, but only those developing dependence show personality traits of impulsivity and compulsivity.
Dr Ersche, of the Behavioural and Clinical Neuroscience Institute (BCNI) at the University of Cambridge, said: “These findings are important because they show that the use of cocaine does not inevitably lead to addiction in people with good self-control and no familial risk.
“Our findings indicate that preventative strategies might be more effective if they were tailored more closely to those individuals at risk according to their personality profile and brain structure.”
The researchers will next explore the basis of the recreational users’ apparent resilience to drug dependence. Dr Ersche added: “Their high level of education, less troubled family background or the beginning of drug-taking only after puberty may all play a role.”
Pannexins are abundant in the central nervous system of vertebrates
Pannexins traverse the cell membrane of vertebrate animals and form large pored channels. They are permeable for certain signalling molecules, such as the energy storage molecule ATP (adenosine triphosphate). The best known representative is Pannexin1, which occurs in abundance in the brain and spinal cord and among others in the hippocampus - a brain structure that is critical for long-term memory. Malfunctions of the pannexins play a role in the development of epilepsy and strokes.
No more scope in long-term potentiation
The research team studied mice in which the gene for Pannexin1 was lacking. Using cell recordings carried out on isolated brain sections, they analysed the long-term potentiation in the hippocampus. Long-term potentiation usually occurs when new memory content is built - the contacts between nerve cells are strengthened; they communicate more effectively with each other. In mice without Pannexin1, the long-term potentiation occurred earlier and was more prolonged than in mice with Pannexin1. “It looks at first glance like a gain in long-term memory”, says Nora Prochnow. “But precise analysis shows that there was no more scope for upward development.” Due to the lack of Pannexin1, the cell communication in general was increased to such an extent that a further increase through the learning of new knowledge was no longer possible. The synaptic plasticity was thus extremely restricted. “The plasticity is essential for learning processes in the brain”, Nora Prochnow explains. “It helps you to organise, keep or even to forget contents in a positive sense, to gain room for new inputs.”
Autistic-like behaviour without Pannexin1
The absence of Pannexin1 also had an impact on behaviour: when solving simple problems, the animals were quickly overwhelmed in terms of content. Their spatial orientation was limited, their attention impaired and an increased probability for seizure generation occurred. “The behavioural patterns are reminiscent of autism. We should therefore consider the Pannexin1 channel more closely with regard to the treatment of such diseases”, says the neurobiologist from Bochum.
Theory: feedback regulation gets out of hand without Pannexin1
According to the scientists’ theory, nerve cells lack a feedback mechanism without Pannexin1. Normally the channel protein releases ATP, which binds to specific receptors and thus reduces the release of the neurotransmitter glutamate. Without Pannexin1 more glutamate is released, which leads to increased long-term potentiation. This causes the cell to lose its dynamic equilibrium, which is needed for an efficient learning process.